Advanced materials and systems for electrochemical energy storage

Resume : Sodium ion batteries (SIBs) have been considered as an alternative to lithium ion batteries due to the abundance on the earth’s crust and low cost of sodium. However, a larger cation radius of Na ion raised critical problems in Na ion kinetics and sodium storage properties. Even though various cathode and anode materials have been explored, there is a significant demand for the development of promising active materials. Here, we report a synthesis of copper sulfide (CuxSy) mircospheres with controllable porosity and their electrochemical performance as a new anode material for SIBs. Porous CuxSy microsphere has been synthesized by a solvothermal method and porosity was controlled by post-calcination and thermal phase transitions. CuxSy microspheres have a uniform particle size of about 5 μm. After calcinations, the phase of CuxSy microspheres was transformed from CuS to Cu2S with a formation of pores in the range of 10 – 100 nm. The electrode prepared with CuxSy microspheres shows a high reversible discharge capacity of ~350 mAh/g at 0.1C, stable cycle performance and capacity retention of ~ 300 mAh/g even at 2C.

Resume : Graphene has been considered as a promising anode material for Li-ion batteries (LIBs), thanks to its large surface area and high electrical conductivity.[1] Graphene nanoflakes with multi- and single-layer graphene prepared by liquid phase exfoliation (LPE) of pristine graphite have drawn growing attention on the application of LIBs,[2] because of its high purity and quality and salability.[3] However, the Li storage mechanisms, e.g., the link between the morphological properties of the flakes, including lateral size, thickness and edges, and their electrochemical performances, have not been established yet, neither for RGO, nor with the less investigated un-functionalized graphene flakes. Our work[4] unravels the role of flake-dimensionality on electrochemical performance of binder-free anodes[5] based on LPE graphene flakes with different lateral sizes and thicknesses sorted by sedimentation-based separation. The electrochemical results show that both initial specific capacity and irreversible capacity are increasing with the decrease in lateral size and thickness of flakes. As for the anode based on small lateral flakes (<100 nm), we discover a detrimental effect on the average de-lithiation voltage, resulting on low voltage efficiency due to the preferential Li ions storage by adsorption rather than intercalation. Our study provides the guidelines for the practical exploitation of graphene-based electrodes. [1] R. Raccichini, et al. Sci. Rep., 6 (2016) 23585 [2] J. Hassoun, et al. Nano let., 14 (2014) 4901 [3] F. Bonaccorso, et al. Mater. Today, 15 (2012) 564 [4] H. Sun, et al. Solid State Commun, 251 (2017) 88 [5] H. Sun, et al. J. Mater. Chem. A, 4 (2016) 6886

Resume : Despite the unique combination of exceptional energy and power density, making lithium-ion batteries the state-of-the-art electrochemical energy storage technology for small- and large-scale applications [1], further improvement is needed for realizing lightweight and small-sized batteries to achieve, for instance, in case of electric vehicles extended driving ranges without requiring tremendous additional load. For this reason, alternatives to the classic intercalation chemistry are attracting great attention. With respect to the anode, these are so far mainly alloying [2] and conversion materials [3]. Both, however, suffer from intrinsic issues, including extensive volume variations and large voltage hystereses, as in particular in case of the former and the latter, respectively [2,3]. Recently, an additional class of anode materials has gained steadily increasing attention, combining these two lithium storage mechanisms in a single compound: conversion/alloying materials (CAMs) [4]. Herein, a comprehensive overview on this new material class will be provided, starting from a brief summary of the major strengths and issues related to pure alloying and conversion electrodes, subsequently introducing the two approaches to realize CAMs while highlighting some recent results, before finally summarizing their potential advantages and the remaining challenges. [1] B. Scrosati, J. Garche, J. Power Sources. 195 (2010) 2419. [2] M. Obrovac, V. Chevrier, Chem. Rev. 114 (2014) 11444. [3] J. Cabana et al., Adv. Mater. 22 (2010) E170. [4] D. Bresser et al., Energy Environ. Sci. DOI:10.1039/c6ee02346k (2016).

Resume : Recently, the nanostructured Si/Ti4Ni4Si7 (STN) system[1] has been fabricated by low-cost melt-spinning, which can be used as anode for Li-ion batteries. However, the lithiation mechanism remains poorly understood for either pure silicon or silicon alloys. We consider Atom Probe Tomography (APT) as a powerful tool to understand the lithium insertion and interaction mechanisms in active battery materials. APT has been so far used for lithium transition metal oxide cathode materials[2,3]. Aided by focused ion beam (FIB) preparation of a sample tip, APT can address elemental distribution for light elements as well as heavy elements at near-atomic resolution. In this study, the STN alloy has been investigated under different state of charge (SOC)[4]. After five full cycles, we revealed a Li-rich area around pure silicon precipitate. On the other hand, we obtained a detailed understanding of SEI formation on STN alloy anodes by HAXPES measurements. The results reveal that the main components of SEI are similar to pure Si, except for some additional partial formation of oxides at the interface. We believe that this study will be beneficial not only for silicon alloys, but also for understanding pure silicon lithiation mechanisms. 1. Son S-B, et al. Adv Energy Mater. 2012;2(10):1226. 2. Devaraj A, et al. Nat Commun. 2015;6:8014. 3. Diercks DR, et al. Microsc Microanal. 2015;21(S3):523. 4. Zheng Y, Marshal A, Pradeep KG, Moeremans B, Renner FU. 2017. to be published

Resume : During the last years, the interest for alternative sources dedicated to energy generation and storage has significantly increased. While Li-ion batteries technology is quite mature, there remain questions regarding Li-ion battery safety, life time, poor-low temperature performances and cost. Meanwhile, Na-ion batteries gain a lot of attention because of the sodium environmental friendly nature and its high natural abundance compared to lithium. The aim of this work is to obtain new carbon/metal hybrid materials which can be successfully used as anodes for Na-ion batteries. Their properties were improved compared to conventional batteries by using hard carbon/metallic nanoparticles hybrid materials as negative electrode. In order to get higher capacity, carbon materials with added electrochemically active phases having higher theoretical capacity than carbon, were investigated. Antimony is considered one of the most promising candidate material for the negative electrode for Na-ion batteries. By using C/Sb materials, we succeded to increase the reversible capacity and cycling life, and in the same time, to overcome the inconvenients which limit the performances of the batteries: the irreversible capacity during the first charge-discharge cycle due to the reactions of the electrolyte with the high surface area of the porous carbon, and the volume expansion of the particles during cycling which determines the formation of the bulks and the loss of performances. In this work, we have synthesized different C/Sb anodes materials in order to study the influence of two parameters: the influence of the carbon type and the influence of the Sb loading on the electrochemical performances of the Na-ion batteries. For the first study, two different hard carbon supports were used: a mesoporous carbon and a densecarbon. The mesoporous carbon allows the confinement of the Sb small particles in the pores which limit the expansion volume during sodiation processes, in the same time the agglomeration of the particles is prevented and the diffusion of the electrolyte favorized. The second type is a hard carbon which presents a smaller surface area compared to the mesoporous one, and so, the irreversible capacity is reduced. The weight loading of Sb was variated between 40 and 80 wt.% (theoretical values). The XRD patterns prove the formation of the Sb metallic phase. The TG analysis show that our synthesis route allows the obtaining of materials with high loading of Sb, and in the same time, the dependence between the theoretical values of Sb and the real ones. The STEM images present small (5 nm) and very well distribution of the metallic particles in the carbon matrix. The N2 and CO2 adsorption measurements show different textural characteristicsofthe two types of carbon, and in the same time, confirm the increase of the Sb particles confinement in the mesoporous carbon’s pores, by increasing the initial loading.

Resume : Society will need energy storage that exceeds the limits of Li-ion batteries. Such a need drives investigation of alternative technology such as aprotic Li/Na/Mg-air because of their high theoretical specific energy.[1-5] The challenges associated with obtaining efficient, reversible charge and discharge in aprotic metal-air batteries are well-documented in the field.[6-11] Here we focus on the processes at the positive electrode. Lithium-air is the most well-known aprotic metal-air battery and has been the focus of intense research over the past decade. The overall reaction is: O2 + 2e- + 2Li+ = Li2O2 However, this simple reaction belies several complex problems that have been revealed as our understanding unfolds. For example, the product on discharge is an insulating solid, Li2O2, which if it grows on the electrode surface passivates it, leading to low rates and low capacities. Oxidation of Li2O2 on the carbon cathode generates Li2CO3 that passivates the electrode on charge, resulting in large voltage polarization. Li2O2 has a high specific capacity of 1200 mAh g-1, making it a good medium for charge storage, but its insulating nature makes it a challenging electrochemical material. Using molecular mediators that transfer electrons between the electrode surface and the Li2O2 on discharge and charge, it is possible to form and decompose Li2O2 from solution rather than on the electrode surface. The mediator on discharge raises the discharge potential, suppressing the direct surface reduction of O2 to Li2O2, it also catalyzes the reaction in solution, Fig. 1. The Na-air battery recently emerged as an alternative to the Li-air battery and offers some distinct advantages. Namely, discharge is predominantly via formation of a partially soluble NaO2, avoiding electrode passivate and increasing capacity. However, arresting the reaction after the first electron transfer has negative implications for the final energy density of the battery. Challenges surrounding the Na-air battery will be discussed. REFERENCES [1]. Bruce, P. G.; Freunberger, S. A.; Hardwick, L. J.; Tarascon, J.-M. Nature Materials 2012, 11, 19. [2]. Lu, Y. C.; Gallant, B. M.; Kwabi, D. G.; Harding, J. R.; Mitchell, R. R.; Whittingham, M. S.; Shao-Horn, Y. Energy & Environmental Science 2013, 6, 750. [3]. Black, R.; Adams, B.; Nazar, L. F. Advanced Energy Materials 2012, 2, 801. [4]. Girishkumar, G.; McCloskey, B.; Luntz, A. C.; Swanson, S.; Wilcke, W. The Journal of Physical Chemistry Letters 2010, 1, 2193. [5]. Li, F.; Zhang, T.; Zhou, H. Energy & Environmental Science 2013, 6, 1125. [6]. Horstmann, B.; Gallant, B.; Mitchell, R.; Bessler, W. G.; Shao-Horn, Y.; Bazant, M. Z. The Journal of Physical Chemistry Letters 2013, 4, 4217. [7]. Hummelshoj, J. S.; Luntz, A. C.; Norskov, J. K. The Journal of Chemical Physics 2013, 138, 034703. [8]. McCloskey, B. D.; Scheffler, R.; Speidel, A.; Girishkumar, G.; Luntz, A. C. The Journal of Physical Chemistry C 2012, 116, 23897. [9]. Trahan, M. J.; Mukerjee, S.; Plichta, E. J.; Hendrickson, M. A.; Abraham, K. M. Journal of The Electrochemical Society 2013, 160, A259. [10]. Sharon, D.; Etacheri, V.; Garsuch, A.; Afri, M.; Frimer, A. A.; Aurbach, D. The Journal of Physical Chemistry Letters 2012, 4, 127. [11]. Jung, H. G.; Kim, H. S.; Park, J. B.; Oh, I. H.; Hassoun, J.; Yoon, C. S.; Scrosati, B.; Sun, Y. K. Nano Letters 2012, 12, 4333.

Resume : Operation of the rechargeable Li-O2 battery depends crucially on the reversible formation/decomposition of Li2O2 at the cathode on discharge/charge. If this cannot be achieved, then the Li-O2 battery will never succeed. The greatest challenge facing progress of the Li-O2 battery arises from severe parasitic reactions that decompose the electrolyte as well as the porous electrode. These processes have serious consequences, resulting in poor rechargeability, low efficiency, and early cell death within a few cycles. So far these parasitic reactions have been ascribed to the reactivity of Li2O2 and superoxide intermediates, which form during discharge and charge. Yet, their reactivity cannot consistently explain the observed irreversible processes. Unsurprisingly, strategies to mitigate the irreversibilities using materials with higher stability against superoxide and peroxide proved only partially successful. Therefore, only better knowledge of parasitic reactions may allow them to be inhibited so that progress towards fully reversible cell operation can continue. Here we discuss our recent insights into irreversible parasitic reactions during cycling of a Li-O2 battery, that have so far been overlooked and that account for the majority of the parasitic products on discharge and nearly all on charge. We discuss their detection via newly developed methods and strategies to suppress them effectively. Awareness of these reactions in non-aqueous Li-O2 batteries gives a rationale for future research towards achieving highly reversible cell operation.

Resume : Recently, downsizing the metal nanoparticulate forms into an atomic level and stabilizing onto certain supports has been attracted more attentions because of its high potential in new energy applications. Such efforts can exhibit a maximum efficiency of single metal atoms (SMAs) and distinct chemoselectivity for special catalysis compared to traditional catalysts. Strategies for enhancing interactions between SMAs and supports to avoid aggregations have been proposed, including engineering vacancy defects or modifying special chemical ligands on supports, which is based on constructing anchor sites to coordinate with SMAs. What’s more, the electronic properties of SMAs can be automatically tuned with different supports because of strong interaction between them. It is perspective to generate an attractively catalytic activity and selectivity in contrast to bulk materials. In this presentation, we will propose a new strategy to synthesize a high density loading of SMAs supported on various nanocarbon structures via pyrolysis and other techniques, which will form a Metal-Nx structure and embedded metal atoms in nanocarbon’s matrix. It has been considered as a promising alternative instead of precious metal catalysts in most catalytic reaction. Taking iron (Fe) SMAs catalyst as example, it shows a high activity and stability for the oxygen reduction reaction (ORR) in alkaline medium, as well as an excellent performance and stability in zinc-air batteries with ultralow catalyst loading. Therefore, we believe this may be of the broad general interest in the material sciences, chemistry and energy related community. 1) Q. Liu, X. Li, Z. Xiao, Y. Zhou, H. Chen, A. Khail, T. Xiang, J. Xu, W. Chu, X. Wu, J. Yang, C. Wang, Y. Xiong, C. Jin, P. Ajayan and L. Song, Adv. Mater., 27 (2015) P4837-P4844. 2) S. Chen, Q. Yang, H. wang, S. Zhang, J. Li, Y. Wang, W. Chu, Q. Ye and L. Song, Nano Lett., 15 (2015) P5961-P5968. 3) D. Liu, W. Xu, Q. Liu, Q. He, Y. Haleem, C. Wang, T. Xiang, C. Zou, W. Chu, J. Zhong, Z. Niu and L. Song, Nano Research, 9 (2016) P2079-P2087. 4) C. Wang, D. Liu, S. Chen, Y. Sang, Y. Haleem, C. Wu, W. Xu, Q. Fang, M. Habib, J. Cao, Z. Niu, P. Ajayan and L. Song, Small, (2016) DOI: 10.1002/smll.201601738. 5) Q. Liu, Q. Shang, A. Khail, Q. Fang, S. Chen, Q. He, T. Xiang, D. Liu, Q. Zhang, Y. Luo and L. Song, ChemCatChem, 8 (2016) P2614-P2619.

Resume : Manganese oxide was deposited from a non-aqueous solution, dimethylsulfoxide (DMSO), via the reduction of dissolved oxygen. The formed superoxide radical ion (O2.-) reacts rapidly with the manganese ions forming a smooth and thin film (80 nm) of manganese oxide. The fast precipitation was proven by using a thin gap rotating ring-disk electrode, which also illustrated the self-limiting property of the electro-precipitation reaction. This self-limiting behavior is a key property to obtain a closed thin film, thanks to the poor conductivity of the deposited oxide, oxygen reduces preferentially where the deposited film is the thinnest. This leads to the electrodeposition of a very smooth thin film shown on nanoSEM-FIB images. Although ex situ XRD pattern shows no characteristic MnO2 peak for the as deposited layer, post treatments can be used to obtain a specific MnO2 crystal structure depending on the application. Electrochemical quartz crystal microbalance (EQCM) was used as an in situ technique to study the deposition mechanism, which led to the conclusion that a two electron reduction resulted in the formation of a MnO2 layer at a growth rate of 0.077 nm s-1 for a 80 nm thin layer. Due to the self-liming behavior of the deposition technique, MnO2 can be deposited on high aspect ratio structures for 3D all-solid state lithium-ion batteries or supercapacitors.

Resume : The growing global energy demand, coupled with the depletion of fossil fuels and the related environmental problems, is promoting intensive research into the probing and utilization of various types of renewable energy conversion and storage technologies with high efficiency, low cost, and environmental friendliness. Water splitting into hydrogen and oxygen using electrocatalysts was widely regarded as an effective pathway to obtain renewable energy. Designing highly efficient electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) plays a key role in the development of various renewable energy storage and conversion devices. To date, some noble metals and their oxides, such as Pt-based and Ir/Ru-based compounds are recognized to be the best OER electrocatalysts in aqueous acidic and alkaline solutions since their versatile advantages. Nevertheless, the high cost and low abundance hinder the widespread use. In the previous reports, significant efforts and progress have been made towards efficient HER and OER catalysts with earth-abundant materials such as cobalt phosphate, perovskite oxides and transition metal oxides or hydroxides for OER and transition metal sulfides and nickel molybdenum alloy for HER. However, it is difficult to coordinate the electrode reactions in the integrated electrolyser for practical use due to the mismatch of pH ranges in which these catalysts are stable and remain the most active. Sequentially, various electrocatalysts have been assessed as a bifunctional electrocatalyst for overall water splitting, HER and OER, such as MoO2, CoP, NiP, CoOx, FeP, whereas for transition metal oxides including iron, nickel, and cobalt or their extension mixed oxides nanocomposites show good catalytic and stable activities. However, most of them are either semiconducting or insulating, which greatly hampers the electrons transporting from the electrocatalyst to the substrates, thereby giving rise to the efficiency of the overall water splitting becoming worse. Compared to the oxides or hydroxides, metal nitrides display superior metallic performance owing to their distinct electronic structure with special properties such as low electrical resistance and good corrosion resistance. It has been confirmed that the introduction of N atoms strongly affects the electronic structure of the nanocomposites by charge-transfer processes or concomitant structural modification. Herein, we fabricate NiCo-nitrides via in situ nitrogenation for NiCo2O4 on the graphite fibers, constructed by 3D nanostructures consisiting of nanosheets decorated by nanoparticles as a bifunctional electrocatalyst towards HER and OER, which achieved an extremely small overpotential of 183 mV and 71mV at a current density of 10 mA cm-2 for OER and HER, respectively.

Resume : Smart micro-/nano-devices or stimuli-responsive devices, which can be engineered to respond to a variety of inputs, such as pH, ions, heat, light, magnetic field, etc., have attracted substantial attention due to a wide range of needs for smart modern electronics. However, it is still a great challenge to integrate various kinds of stimuli into modern functional devices without affecting the device performance, most probably due to the poor compatibility between stimuli, active materials and processing technologies. On-chip micro-supercapacitors (MSCs) are one kind of new-generation micro-sized power sources and have attracted considerable attention due to their small size, controllable patterning, in-plane feature and outstanding electrochemical performance. Unfortunately, stimulus-responsive micro-supercapacitors have not been reported to date. We demonstrate the fabrication of the first stimulus-responsive and flexible MSC (SR-MSC) with a reversible electrochromic window. Taking advantage of the synergistic effect of one-dimensional (1D) V2O5 nanoribbons and two-dimensional (2D) exfoliated graphene (EG) nanosheets, EG/V2O5 hybrid nanopaper was prepared as electrode for MSCs, which delivered a high volumetric capacitance of 130.7 F cm-3 at 10 mV s-1 and high volumetric energy density of 20 mWh cm-3 at 0.75 W cm-3 with a polyvinyl alcohol (PVA)/LiCl gel electrolyte. These results are superior to most of graphene-based MSCs. Notably, as-prepared flexible SR-MSCs possess remarkable ultrafast response time down to 10 seconds, which provides a direct visual observation of the working state of MSCs. The progress for MSCs not only offering direct visualization of the energy storage state without the aid of extra techniques, but also making it possible for enhanced human-device interaction experience in the future. Beside this electrochromic MSCs, a few other stimuli-responsive MSCs developed by our group will be introduced.

Resume : During the last few years, the synthesis of inorganic two dimensional (2D) materials tremendously increased, due to their promising surface area(1,2). However, the synthesis of these 2D materials can significantly influence our environment, by the use of harmful chemicals and severe reaction conditions(3,4). Herein, we report on a simple and green strategy for fabricating hydrated vanadium pentoxide (V2O5.nH2O) nanosheets from commercially available vanadium oxides precursors via water based exfoliation technique. Operando and ex situ X-ray diffraction (XRD) studies were conducted to track the structural changes during the exfoliation process. The vanadium oxidation states and the water content of the material were determined by X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), respectively. Electron microscopy and atomic force microscopy (AFM) showed that the V2O5.nH2O is composed of a few nanometer thick nanosheets. A composite material of the V2O5∙nH2O nanosheets and multi-walled carbon nanotube (MW-CNT) were fabricated and then tested as a free standing electrodes (FSE) and conventionally casted electrodes (CCE) for lithium battery. Both electrodes showed promising capacities and rate capabilities for lithium-ion intercalation. References: (1) Nicolosi, V.; Chhowalla, M.; Kanatzidis, M. G.; Strano, M. S.; Coleman, J. N. Liquid Exfoliation of Layered Materials. Science (80-. ). 2013, 340 (6139), 1226419. (2) Etman, A. S.; Asfaw, H. D.; Yuan, N.; Li, J.; Zhou, Z.; Peng, F.; Persson, I.; Zou, X.; Gustafsson, T.; Edström, K.; Sun, J. A One-Step Water Based Strategy for Synthesizing Hydrated Vanadium Pentoxide Nanosheets from VO2 (B) as Free-Standing Electrodes for Lithium Battery Applications. J. Mater. Chem. A 2016, 4 (46), 17988–18001. (3) Wei, Q.; Liu, J.; Feng, W.; Sheng, J.; Tian, X.; He, L.; An, Q.; Mai, L. Hydrated Vanadium Pentoxide with Superior Sodium Storage Capacity. J. Mater. Chem. A 2015, 3, 8070–8075. (4) Zhou, K.-G.; Mao, N.-N.; Wang, H.-X.; Peng, Y.; Zhang, H.-L. A Mixed-Solvent Strategy for Efficient Exfoliation of Inorganic Graphene Analogues. Angew. Chem. Int. Ed. Engl. 2011, 50 (46), 10839–10842.

Resume : An original synthesis way of high purity nanosized V2O5 by a facile fluorination reaction in aqueous solution followed by a heat-treatment at low temperature (230°C) has been developped. The obtained nanosized V2O5 is made of highly porous calisson-like particles with crystallite sizes in the 13-30 nm range, i.e. about one order of magnitude lower than in micro-V2O5. The electrochemical lithium insertion/extraction process in the 4 V/2 V region is precisely studied and discussed at the light of structural data of nano-LixV2O5 determined over the large Li composition range 0 ≤ x < 2 using XRD and Raman microspectrometry. While never described in the literature, upsetting structural changes have been highlighted in nanosized V2O5. Indeed lithiation produces a single phase behavior of the ε’-type whose interlayer distance and unit cell volume linearly increase with x which strongly contrasts with the successive wide biphasic regions for the micro-LixV2O5 system. This outstanding structural behaviour combined with shorter Li diffusion pathways allow to get a high specific capacity of 260 mAh g-1 , a higher rate capability than micro-V2O5 with a capacity of still 150 mAh g-1 at 2 C and an excellent cycle life with a stable capacity of 200 mAh g-1 at C rate after 50 cycles. These findings well explain the typical voltage profile of nanosized V2O5 and give a unique insight into the impact of nanostructures in terms of electrochemistry and solid state chemistry.

Resume : High power and extended cycle life at high energy density are key benefits for energy storage, which can be achieved through synthesis of materials in specific 3-D electrode and battery configurations. Thin film process technologies are primary enablers of this design and fabrication flexibility. Guidelines for effective designs include thin ion storage layers available over large accessible electrode surface area, integrated current collectors, robust structure to withstand volume changes during charge/discharge, and dense packing of such structures. We have created and evaluated a variety of advanced 3-D structures, from nanowire-based electrodes and a nanopore battery using organic electrolyte, to 3-D solid state batteries employing interdigitated electrode arrangements. These results exploit atomic layer deposition (ALD) to achieve challenging geometries of current collector, storage electrode, and solid electrolyte materials. We have also developed ALD processes for solid electrolytes, which deliver value in the forms of (1) thin protection/passivation layers on Li and Na metal anodes and conversion material electrodes, and (2) versatile thin film electrolytes in 3-D-structured battery configurations (e.g., interdigitated anode/cathode assemblies). Finally, we examine how thin film technologies may play important roles in future battery manufacturing, either as single processes (e.g., ALD) inserted into conventional battery fabrication, or as a completely new manufacturing paradigm.

Resume : From a fundamental point of view, the interface between the cathode and the solid electrolyte is a complex multilayer system and a extensive playground for electronic and ionic phenomena, which need to be understood and controlled in order to progress to competitive solid state battery concepts. The state-of-the-art archetype of a lithium based thin film battery features a lithium cobalt oxide (LCO) cathode, and a solid electrolyte, e.g. amorphous LiPON glass. Both materials can be easily processed by thin film technology. Our experimental surface science approach is based on a contamination free preparation of thin film model systems under UHV conditions paired with in situ photoelectron spectroscopy. For electrochemical characterization we build functional thin film batteries. Here, we present recent results with regard to the chemical stability and interface resistance of the LCO-LiPON interface, and their improvement. By using a co-sputter process, the lithium content of the cathode can be controlled, simulating different charging states of a battery system. Processes at the LCO /LiPON interface can then be discussed as a function of lithiation state and temperature, acquired experimentally by post-annealing of the respective samples . A more sophisticated picture of the interface in terms of ion migration results in insights on the chemical stability of electrode solid electrolyte interfaces and related improvement strategies, such as passivating interlayers.

Resume : Emerging applications such as the Internet of Things (IoT) and Body Area Networks (BAN) typically require thin-film energy storage devices that possess a high energy and power output per unit of area. All-solid-state 3D Li-ion batteries have the potential of meeting these requirements. In this paper, we present a functional cell in which the battery materials (i.e. two Li-ion electrodes and a solid-state electrolyte) are coated as thin-films conformally over a microstructured high-aspect ratio (HAR) current collector pillar array. The HAR current collector can take a variety of forms, where we currently have done our developments on 50 μm high pillars with a 2 μm interpillar spacing. By scaling towards higher aspect ratios of these pillars, the energy and power output per unit area of the cell can be increased. Indeed, by increasing the height of the pillars, more active material per unit area can be deposited, resulting in a higher capacity. Simultaneously, the power output of the battery improves due to the increased internal surface of the 3D battery. Notice that a similar approach is not possible with conventional thin-film batteries. Increasing the active film thickness in these batteries results in more capacity, but this goes at the cost of power output due to the increased resistance of the thicker active layers. Because these solid-state 3D batteries do not contain any flammable and corrosive liquid electrolytes, they are considered as intrinsically safe.

Resume : An important feature of redox flow batteries (RFB) is that the power is independent of the energy density, because of the separation of the cell/stack (where the electrochemical reactions take place) from the energy storage tanks. This causes the power to depend on the characteristics of the cell/stack, whereas the energy is determined by the concentration and volume of the redox solutions. The most commonly used electrodes in RFB are based on carbon foams or carbon paper and new electrode concepts are required to overcome the limitations that these electrodes show, such as high-pressure drop, electrochemical activity in the potential window of interest, contact resistance with current collectors depending on the clamping force and non-uniform potential and current distributions that restrict the performance of the RFB. Three-dimensional (3D) textile electrodes fabricated by technical embroidery are a new electrode concept that can overcome the mentioned problems. The high degree of freedom in fabrication of these 3D porous structures allows the control over morphological characteristics and spatial distribution of properties, such as porosity, interspaces, surface areas and variations in surface characteristics. In this work, we present the use of textile electrodes made of stainless steel yarn fabricated by technical embroidery for the characterization of an all-iron aqueous RFB. The proposed all-iron aqueous system is based on high-concentrated solutions Fe(III)/Fe(II)-triethanolamine(TEA) as negative and ferro/ferricyanide [Fe(CN)6]4-/3- as positive half-cell electrolyte, showing good stability and electrochemical activity for the negative system. The electrochemical behaviour of the redox couples is evaluated with cyclic voltammetry using standard working electrodes and the textile electrodes. A calibration method for monitoring the real state-of-charge (SOC) for the negative electrolyte is presented, independent of the cell geometry and electrodes used. Finally, two different textile electrode configurations are evaluated using electrochemical impedance spectroscopy (EIS) measurements, charge and discharge cycles under no flow and discharge polarization curves, in order to investigate the electrochemical behaviour of the proposed all-iron aqueous system in RFB.

Resume : Supercapacitors are regarded as promising energy storage technologies due to their characteristic advantages of high power density and stable cycling performance. Much progress has been made to overcome the major disadvantage to demanded high-energy-density supercapacitors by using pseudocapacitive materials such as metal oxides or conductive polymers. Meanwhile, integrated smart functions for supercapacitors have attracted considerable attention[1-5]. With regard to the multifunction of materials, metal oxides, especially semiconductors, have great advantages. In this talk, we present a typical semiconductive metal oxide, WO3 as the electrode material for supercapacitors, which shows high capacitance, as well as the intrinsic smart functions. First, we successfully fabricate the hexagonal phase WO3 (h-WO3) by adapting a capping agent (NaCl). The prepared h-WO3 show very high capacitance: almost highest among WO3 based supercapacitors. After thorough investigation of the mechanism behind the high capacitance, we reveal that large hexagonal tunnels in h-WO3 efficiently facilitate the insertion of protons, which greatly enhance the energy storage ability[3]. Furthermore, the capacitance of h-WO3 shows apparent response to the solar light. This is because the h-WO3, due to its semiconductive nature, will generate excited electrons under bias potential and illumination of the solar light. Subsequently, the excited electrons effectively facilitate the insertion of protons into large hexagonal tunnels so that the capacitance is enhanced. In turn, this light dependent capacitance served as the solar light indicator that is intrinsically integrated to the WO3 based supercapacitors[4]. In addition to the function of the light indicator, the WO3 self can effectively indicate its energy storage status as it is a well-known electrochromic material. One step further to the qualitatively indication from the color change of WO3 during the charging/discharging process, we successfully quantify the relationship between the energy storage status and the color change of WO3 by relating it with the characteristic optical transmission of WO3. WO3 is further incorporated into supercapacitors based on other high-performance materials to indicate the energy storage status, which shows the immense potential in application of all kinds of supercapacitors[5]. References: [1] Huang, Y.; Zhu, M.; Huang, Y.; Pei, Z.; Li, H.; Wang, Z.; Xue, Q.; Zhi, C.; Adv. Mater. 2016, 38, 8344. [2] Zhu, M.; Huang, Y.; Deng, Q.; Zhou, J.; Pei, Z.; Xue, Q.; Huang, Y.; Wang, Z.; Li, H.; Huang, Q.; Zhi, C.; Adv. Energy. Mater. 2016, 21, 1600969. [3] Zhu, M.; Meng, W.; Huang, Y.; Huang, Y.; Zhi, C.; ACS Appl. Mater. Interfaces. 2014, 6, 18901. [4] Zhu, M.; Huang, Y.; Huang, Y.; Pei, Z.; Xue, Q.; Li, H.; Geng, H.; Zhi, C.; Adv. Funct. Mater. 2016, 25, 4481. [5] Zhu, M.; Huang, Y.; Huang, Y.; Meng, W.; Gong, Q.; Li, G.; Zhi, C.; J. Mater. Chem. A. 2015, 3, 21321.

Resume : It is critically important to develop miniature energy harvesting and storage devices in modern electronics, e.g., for portable and foldable electronic facilities. Here novel miniature fiber-shaped energy conversion and storage devices as well as their integrated devices are carefully discussed with unique and promising advantages such as lightweight and weaveable compared with the conventional planar architecture.1-5 For the fiber-shaped energy conversion devices, dye-sensitized solar cells, perovskite solar cells and polymer solar cells are covered. For the fiber-shaped energy storage devices, electrochemical capacitors, lithium ion batteries, lithium sulfur batteries, lithium air batteries and zinc air batteries are carefully investigated. The main efforts will be made to highlight the recent advancement in the electrode material, device structure and property extension. REFERENCES (1) Chen, T.; Qiu, L.; Yang, Z.; Peng, H. Chem. Soc. Rev. 2013, 42, 5031-5041. (2) Pan, S.; Yang, Z.; Li, H.; Qiu, L.; Sun, H.; Peng, H. J. Am. Chem. Soc. 2013, 135, 10622?10625. (3) Yang, Z.; Sun, H.; Chen, T.; Qiu, L.; Luo, Y.; Peng, H. Angew. Chem. Int. Ed. 2013, 52, 7545-7548. (4) Ren, J.; Li, L.; Chen, C.; Chen, X.; Cai, Z.; Qiu, L.; Wang, Y.; Peng, H. Adv. Mater. 2013, 25, 1155-1159. (5) Chen, T.; Qiu, L.; Yang, Z.; Cai, Z.; Ren, J.; Li, H.; Lin, H.; Sun, X.; Peng, H. Angew. Chem. Int. Ed. 2012, 51, 11977-11980.

Resume : MXenes are a new family of two-dimensional (2D) layered transition metal carbides and nitrides, comprised of conductive carbon core with outer transition metal oxide-like terminations, have shown promise as a potential pseudocapacitive electrode for electrochemical energy storage. For instance, Ti3C2 is the most studied member of the MXene family because of its well-known etching conditions and detailed theoretical and experimental studies on its physical and electrochemical properties. Metallic conductivity (up to 6500 S/cm), surface hydrophilicity and excellent ion intercalation behavior, made clay-like Ti3C2 MXene exhibit specific volumetric capacitances as high as 900 F/cm3, but reports on MXene based supercapacitor devices are scarce. We report a simple and scalable direct laser machining process to fabricate MXene-on-paper co-planar microsupercapacitors. Commercially available printing paper is employed as a platform in order to coat either HF-etched or clay-like 2-dimensional Ti3C2 MXene sheets, followed by laser machining to fabricate practically thick MXene co-planar electrodes over a large area. The size, morphology and conductivity of the two-dimensional MXene sheets are found to strongly affect the electrochemical performance due to the efficiency of the ion-electron kinetics within the layered MXene sheets. The areal performance metrics of Ti3C2 MXene-on-paper microsupercapacitors show very competitive power-energy densities as that of the reported state-of-the-art paper based microsupercapacitors. Various device architectures were fabricated using the MXene-on-paper electrodes, and successfully demonstrated as a micropower source for light emitting diodes (LEDs). This study opens up new avenues towards developing flexible on-paper energy storage devices based on 2D materials. Reference: N. Kurra, B. Ahmed, Y. Gogotsi, H. N. Alshareef, MXene-on-Paper Coplanar Microsupercapacitors, Advanced Energy Materials, 6, 1601372 (2016).

Resume : Although manganese oxide- and graphene-based supercapacitors have been widely studied, their charge storage mechanisms are not yet fully investigated. In this work, we have studied the charge storage mechanisms of K-birnassite MnO2 nanosheets and N-doped reduced graphene oxide aerogel (N-rGOae) using an in situ X-ray absorption spectroscopy (XAS) and an electrochemical quart crystal microbalance (EQCM). The oxidation number of Mn at the MnO2 electrode is +3.01 at 0 V vs. SCE for the charging process and gets oxidized to +3.12 at +0.8 V vs. SCE and then reduced back to +3.01 at 0 V vs. SCE for the discharging process. The mass change of solvated ions, inserted to the layers of MnO2 during the charging process is 7.4 ?g cm-2. Whilst, the mass change of the solvated ions at the N-rGOae electrode is 8.4 ?g cm-2. It is also found in this work that [H+] plays a significant role in the charge storage capacity at pH of the electrolyte, 0.5 M Na2SO4(aq) < 2.03. At pH 2.03-4.02, the solvated Na+ plays a major role to the charge storage capacity of the MnO2. At pH >5.36, the specific capacitance of the device is significantly reduced since the birnassite MnO2 layers having negative charge do not like to adsorb/absorb solvated anions i.e., OH-. An asymmetric supercapacitor of MnO2//N-rGOae (CR2016) provides a maximum specific capacitance of ca. 467 F g-1 at 1 A g-1, a maximum specific power of 39 kW kg-1 and a specific energy of 40 Wh kg-1 with a wide working potential of 1.6 V and 93.2% capacity retention after 7,500 cycles. The MnO2//N-rGOae supercapacitor may be practically used in high power and energy applications.

Resume : Flexible, portable and wearable electronic devices such as smart clothes are emerging in the mainstream and represent promising directions for future lifestyles. The rapid development strongly demands indispensable power systems that can be miniaturized, flexible, and adaptable. Lithium ion batteries have been used as one of the most ubiquitous types of power supplies. However, conventional lithium ion batteries, including both rigid bulk and flexible film, cannot satisfy the above requirements. These batteries have limited flexibility and cannot effectively adhere to soft substrates such as our bodies under deformation. Besides, they are not breathable, which is also a major consideration for wearable electronics. A revolution in lithium ion battery structure is necessary to ultimately solve these problems. Herein, we have developed a new family of fiber-shaped lithium ion batteries and lithium air batteries with high performance based on carbon nanotube hybrid fiber electrodes. The unique fiber architecture allows batteries to be deformable in all dimensions and bear various deformations such as bending, tying and twisting and stretching. They are scaled up and further woven into breathable, light-weight, flexible, stretchable and shape-memory textiles to effectively meet the requirements of the modern electronics such as wearable products. The obtained flexible energy textiles with an area of 0.1 m2 can power an iPhone for 10 hours. REFERENCES (1) Zhang Y.；Peng H.* “ Flexble and stretchable lithium-ion batteries and supercapacitors based on electrically conducting carbon nanotube fiber springs”， Angew. Chem. Int. Ed. 2014, 53, 14564. (2) Zhang, Y.; Peng, H.* “Realizing both high energy and power densities by twisting three carbon nanotube-based hybrid fibers”, Angew. Chem. Int. Ed. 2015, 54, 11177. (3) Zhang, Y.; Peng, H.* “Advances in wearable fiber-shaped lithium-ion batteries”, Adv. Mater. 2016, 28, 4524

Resume : Electrochemical capacitors are considered to be promising charge storage devices due to their long life cycle, high power and energy density characteristics. Here, some recent results on the preparation and supercapacitive performance of potentiostatically electrodeposited nanostructured manganese dioxide films have been reported. Manganese dioxide films were electrodeposited potentiostatically by applying a potential of 0.1 V, 0.2 V, and 0.3 V (vs. a saturated Ag/AgCl electrode) in a solution bath of 0.1 M potassium permanganate for 2000 s at room temperature. XRD analyses reveal that the deposited films possess the hexagonal phase of epsilon manganese dioxide. Raman scattering spectroscopy studies also confirm the manganese dioxide phase of the deposited films. Cyclic voltametry studies show the maximum specific capacitance to be 259.4 F/g at the scan rate of 5 mV/s for the film deposited at the potential of 0.2 V, while the chrono charge-discharge measurements exhibit the maximum specific capacitance to be 325.6 F/g at the current density of 1 mA/cm2. It has been observed that the specific capacitance deceases as the current density increases. The specific energy has been found to be maximum for the film deposited at the potential of 0.2 V.

Resume : Nickel (Ni)-foam-based symmetric/asymmetric electrochemical supercapacitor studies have recently gained considerable attention due to their 3D structure geometry and potential market perspective where measurement of electrochemical performance of active electrode material mass is an important and critical issue. Here we report, for the first time, annealing environment reliant structure, morphology and electrochemical properties of Ni-foam, after air-annealing at 400 and 800 ? and also in nitrogen and argon environment annealing at 800?, due to formation of NiO, a secondary phase, on Ni-foam so called NiO@Ni are considerably changed. We demonstrate that due to the oxidation of nickel by transfer of electrons through the interface to form a monolayer of adsorbed oxygen ions at the surface together with the diffusion of oxygen anions into the nickel metal causes for crystalline NiO as byproduct on Ni-foam due to which electrochemical properties of NiO@Ni are significantly changed which have not been previously considered in Ni-based electrochemical supercapacitor studies, particularly, for air-annealed cases. Through various measurements it has been corroborated that obtained electrochemical measurement results are due a combination of Ni-foam and NiO instead of only Ni-foam which can also be valid in studies where different metal-foams are used.

Resume : Recently, the study of Ni-rich cathode materials is focusing to newly-commercialized layer-structured LiNi0.8Co0.1Mn0.1 (NCM811), because of its potential opportunity to provide higher-energy-density lithium-ion battery applicable to electric vehicles having higher cruising range. Once basic characterization of its storage properties such as capacity and energy density was established with conventional carbonate-based electrolyte solution (e.g., initial discharge capacity of about 210 mAh g-1 at 0.1C-rate), optimization of electrolyte additives is also necessary to enhance further the other charge-discharge characteristics such as cycle performance, rate capability, and their temperature-dependency. In this study, two additives (vinylene carbonate (VC) and 1.3-propane sultone (PS)) were selected to add to the base electrolyte solution (GEN) as a conventional carbonate mixture, and to yield the resultant electrolyte solution (GEN0) containing both additives. After characterizing the 4 electrolyte samples (GEN, GEN+VC, GEN+PS, GEN0) in terms of ionic conductivity, electrochemical stability, and redox behaviors, the electrochemical performance of the NCM811/Li half-cell was investigated as well as the interfacial properties of solid electrolyte interphase (SEI) in the cathode side using morphology observation by SEM and surface group analysis by XPS. The cycle performance is greatly improved by an addition of VC that an abrupt decreases in discharge capacity are eventually appeared by dendrite formation and its growth. Results mechanism will be discussed more precisely using some additional analysis data in the presentation.

Resume : Electrochemical capacitors (ECs), also termed as supercapacitors, are regarded as the most promising energy storage devices due to their high power density, fast charge/discharge time, excellent cycling stability, and superior safety. In the past decades, nickel-based materials have attracted much attention in serving as electrode materials for ECs owing to low-cost, earth-abundant, and environmentally friendly nature. Among these nickel compounds, nickel phosphide (Ni2P) with metallic properties and excellent electric conductivity could benefit for electrons transport between electroactive sites and current collector, leading to its outstanding electrochemical performance. In this work, we successfully synthesize Ni2P via a simple annealing treatment at 300 ℃ for 2 h, in which nickel chloride and sodium hypophosphite were mixed uniformly and placed in a crucible. The cyclic voltammetry curves tested in 6 M KOH aqueous electrolyte at different scan rates from 1 to 50 mV/s exhibit a pair of redox reaction peaks, which indicates the electrode is highly reversible with excellent electrochemical capability and redox processes. The specific capacitances calculated from galvanostatic discharge curves possess values of 1095, 995, 910, 753, 722, 711 F/g at current densities of 1, 2, 5, 10, 15, 20 A/g. Therefore, the nickel phosphide electrode can be served as an outstanding candidate for electrochemical capacitors.

Resume : Perovskite-type Li3xLa(2/3)−x□(1/3)-2xTiO3 (LLTO) is regarded as a promising inorganic solid electrolyte for use in all solid-state batteries. However, the practical use of LLTO is limited by its large domain boundary resistance, leading to the low total conductivity. In order to reduce the large domain boundary resistance, a correlation between the microstructures and Li+ conducting properties of LLTO is thoroughly investigated. In practice, we found that the sintering temperature and Li concentration are predominant factors for determining the microstructures of LLTO and affecting the domain boundary resistance. By controlling the synthesis parameters, LLTO shows a total Li+ conductivity as high as 4.8 × 10–4 S cm–1 at room temperature. It would be helpful to understand Li+ conducting behaviors of LLTO and make a further progress in this research field.

Resume : Featuring high conductivities and attractive mechanical properties, metal foams are intensively studied as 3-D bulk mass-support for various applications. However, the relatively low surface area of conventional metal foams largely limits their performance (e.g., in charge storage devices). Here, taking Cu foams as an example, we present a convenient electrochemical method for addressing this problem. High surface area Cu foams are fabricated in a one-pot one-step manner by repetitive electrodeposition and dealloy treatments. The thus obtained Cu foams enable greatly improved performance for different applications, e.g., as Surface Enhanced Raman Spectroscopy (SERS) substrates and 3-D bulk supercapacitor electrodes.

Resume : Double-layered nanoporous silver is fabricated by dealloying an electrodeposited AgCu double-layer with different composition in each layer. The pore/ligament size and porosity of each layer can be conveniently tailored by controlling the electrodeposition voltage profile used for fabricating the AgCu double-layer precursors. Therefore, nanoporous Ag double-layers with tailor-made porous profile along the film thickness can be easily fabricated. The Ag structures thus obtained prove to be particularly attractive for surface enhanced Raman spectroscopy (SERS) applications by serving as novel multi-functional SERS substrates. When a higher porosity is created in the top layer, the double layer can trap more light due to the anti-reflection effect, enabling stronger SERS enhancement. On the other hand, with smaller pores formed in the top layer, the double layer readily works as a size-screening SERS substrate that can help distinguish SERS signals from a mixture of reagents of different sizes. Theoretical simulation has been carried out showing good agreement with the experimental observations.

Resume : The hierarchical porous structure has garnered considerable attention as a multiscale engineering strategy to bring unforeseen synergistic effects in a vast variety of functional materials. Here, we demonstrate a “microporous covalent organic framework (COF) net on mesoporous carbon nanotube (CNT) net” hybrid architecture as a new class of molecularly designed, hierarchical porous chemical trap for lithium polysulfides (Li2Sx) in Li-S batteries. As a proof of concept for the hybrid architecture, self-standing COF-net on CNT-net interlayers (called “NN interlayers”) were fabricated through CNT-templated in situ COF synthesis. Two COFs with different micropore sizes (COF-1 (0.7 nm) and COF-5 (2.7 nm)) were chosen as model systems. The effects of the pore size and (boron-mediated) chemical affinity of microporous COF nets on Li2Sx adsorption phenomena were theoretically investigated through density functional theory (DFT) calculations. Benefiting from the chemical/structural uniqueness, the NN interlayers effectively capture Li2Sx without impairing their ion/electron conduction. Notably, the COF-1 NN interlayer, driven by the well-designed microporous structure, allowed for the selective deposition/dissolution (i.e., facile solid–liquid conversion) of electrically inert Li2S. As a consequence, the COF-1 NN interlayer provided a significant improvement in the electrochemical performance of Li-S cells that lies far beyond those accessible with conventional Li-S technologies.

Resume : Regarding their energy density, commercial Li-on battery cathodes are lagging behind the anode materials. By allowing easy manipulation on compound structure and functionality, and thus tuning of the resulting electrode properties, organic redox materials have the potential to reduce this gap. One illustration of these novel possible electrode materials is the poly(2,5-dihydroxyaniline) (PDHA), a hybrid molecular configuration with redox active sites and electrical charge conduction along the polymer chain. The active sites consist in the carbonyl groups of quinone monomers, which – in theory – can reversibly exchange two electrons. These characteristics allow for a high theoretical capacity of 443 mAh g-1, alongside an intrinsic electrical conductivity as high as 1 S cm-1. This polyquinone was prepared following two distinct approaches: chemical and electrochemical synthesis routes. The results will be discussed from two perspectives: the synthesis of the active electrode materials and the electrochemical behavior in non-aqueous cells. The electrode formulation of the material, first reported by Vlad et al. [1], was the object of an optimization procedure, leading to current improved cycling performances. [2] These results confirm the interesting potential of such quinone-type compounds, calling for their continued investigation as modern battery electrode materials, with aim at further improvements in terms of energy density and capacity retention. [1] A. Vlad et al., J. Mater. Chem. A 3, 11189 (2015). [2] L. Sieuw et al., submitted to Sci. Rep.

Resume : In recent years, nanostructured SiO2 has attracted much attention as anode for lithium-ion batteries because of its superior theoretical capacity and low lithiation potential, but its large volume variation during lithiation/delithiation cycling results in poor cyclic stability. Meanwhile, its low electronic conductivity induces bad rate capability. Herein, CNTs/SiO2/C and hollow-sphere SiO2@C nanocomposites both were prepared by hydrolysis of tetraethyl orthosilicate to form SiO2 nanoparticles on templates (CNTs and polyacrylic acid, respectively) followed by subsequent carbonization of sucrose on the SiO2 surface. The morphology and microstructure were studied and the electrochemical performance was evaluated. The hollow space efficiently accommodates the volume change and the carbon coating effectively improves the electronic conductivity. The reversible capacity of as-prepared CNTs/SiO2/C nanocomposite can reach 537 mAh g−1 after 100 cycles at current density of 0.1 mA cm−2 and the capacity recovery ability is 94% after discharge/charge cycling at high current density (1.5 mA cm−2). Low solid electrolyte interphase (SEI) resistance and charge transfer resistance can be achieved after 30 cycles. Interestingly, the as-prepared SiO2@C nanocomposite exhibits an increase in reversible capacity from initial 154 mAh g−1 to 650 mAh g−1 over 160 cycles at current density of 0.1 mA cm−2. Furthermore, it has relatively low SEI resistance and charge transfer resistance. The carbon-coated silica nanocomposites with hollow structure are promising anode candidates for high energy-density lithium-ion batteries.

Resume : With excellent electrochemical properties, transition metal oxides have been extensively investigated to replace noble metals. Compared with noble metals, transition metal oxides not only provide relatively high capacity, but low price, environment friendliness and natural abundance. It should be noted that the nanostructure of electrode materials can largely influence the electrochemical performance of batteries. As templates, MOFs exhibit enhanced electrochemical performance as anode materials for LIBs. Here we report the preparation of a hybrid nanostructure constructed with MnO2 nanowires self-inserted hollow Co3O4 nanocages by using MnO2-penetrated ZIF-67 as precursors. This novel structure can integrate advantages of one dimensional nanowires and three dimensional hollow nanocages. In order to increase its electrochemical performance, it is further hybridized with reduced graphene oxide (RGO) nanosheets. As a lithium-ion anode, the as-obtained MnO2–Co3O4–RGO composite exhibits remarkable enhanced performance compared with the MnO2–RGO and Co3O4–RGO samples. The MnO2–Co3O4–RGO electrode delivers a reversible capacity of up to 577.4 mAhg-1 after 400 cycles at 500 mAg-1 and the coulombic efficiency of MnO2–Co3O4–RGO is about 96 %.[1] [1] Q. Zhu et al. Chem. Eur. J. 2016, 22, 6876.

Resume : Spinel phase Li4Ti5O12 (s-LTO) with an average crystallite size at around 150 nm was prepared via a solid state route by calcining a highly reactive precursor at 600 °C. The precursor was prepared from a stoichiometric mixture of TiO2 nanoparticles and an ethanolic solution of Li acetate and activated by ball-milling. Effects of the calcination temperature and atmosphere are examined in relation to the coexistence of impurity phases by X-ray diffraction and 6Li MAS NMR. 6Li MAS NMR indicates LTO with a Li site occupation which is near to that expected for Li4Ti5O12 with ideal stoichiometry. The charge capacity of s-LTO determined from cyclic voltammogram at a scan rate of 0.1 mV/s was 142 mAh/g, which is about 80% of theoretical capacity and is superior to commercially available (a-LTO) fine powders, despite having a smaller specific surface area of 1.4 m2/g. Superior electrochemical performance by s- LTO over a-LTO was also observed by galvanostatic charge/discharge. From these observations, we conclude that the presented low-temperature solid state synthesis of LTO provides highly active LTO material for applications in Li-ion batteries. Acknowledgment: This work was supported by the Grant Agency of the Czech Republic (15-06511S).

Resume : The electrochemical double layer plays a fundamental role in energy storage applications. Control of the distribution of ions in the double layer at the atomistic scale offers routes to enhanced material functionality and device performance. Here we demonstrate how the addition of an element from the third row of the periodic table, phosphorus, to graphene oxide (GO) increases the capacitance and present density functional theory (DFT) calculations that relate the enhanced charge storage to structural changes of the electrochemical double layer. Our results point to how rational design of materials at the atomistic scale can lead to improvements in their performance for energy storage. Highly phosphorus doped graphene oxide (PGO) was prepared by the thermal decomposition of P containing surfactants and the specific capacitance of the as-prepared samples increased with the amount of P incorporated in the GO layers. PGO with P at.% of 7.77% displayed 95.6 F g-1 and 72.4 F g-1 at 2 A g-1 and 10 A g-1, and maintained 70.4 F g-1 after 5000 cycles at 15 A g-1. DFT calculations show that phosphorus atoms prefer to adsorb to defects in the GO sheet rather than substitute for carbon atoms in the basal plane of GO. The doping of P atoms can improve the charge storage capability by increasing interlayer separation of GO and the strong polarity of P-O groups leading to specific adsorption of ions at the surface.

Resume : With the significant development of portable electronics, lithium ion batteries as an energy storage device should be required to have a higher energy density for long-term operation, which can be achieved by increasing mass loading and density of active materials. However, this causes a severe decrease of electrode porosity and electrolyte permeation into the electrode. A development of new binder systems could be an effective way to overcome those obstacles. In this study, we report the effect of cross-linked poly (acrylic acid) - carboxymethyl cellulose hydrogels and styrene-butadiene rubber as an effective binder system for a thick and dense graphite anode. The graphite anode prepared with PAA-CMC and SBR shows improved electrolyte permeability and adhesion strength compared to those of an electrode without PAA. Electrochemical performances show the graphite anode with PAA has better cycle retention and rate capability. Especially, capacity retention at 1 C is significantly improved from 81 % to 91 %. Our strategy opens a new avenue to a potential use of the new binder system for the higher energy density anode of Li-ion batteries.

Resume : With an increasing demand for a high energy density of LIBs, graphite based anodes became thicker and denser along with transition metal oxide cathodes to generate a large current density. However, this may cause a critical problem in Li+ diffusivity due to a decreased electrode porosity and long tortuosity which result in a degradation of overall electrochemical performances. In this work, we report PVDF-HFP treated graphite anode by using a simple solution coating method for the high energy density LIBs. PVDF-HFP has a high dielectric constant (ɛ = 8.4) and good affinity with liquid electrolytes. As a result, the electrode treated with PVDF-HFP promotes the electrolyte permeability into the high energy density graphite electrode with a high mass loading of 13.8 mg cm-2, which contributes to an improvement of the electrochemical performance including charge/discharge capacities, cycle retention, and rate capability compared to those of the pristine graphite electrode. Specifically the cycle retention was increased from 70 to 95 %. This results are owing to not only an improvement of Li+ ion kinetic but also a formation of stable solid electrolyte interphase (SEI) layer for the thick and dense graphite anode.

Resume : In order to keep pace with the development of consumer electronics, an increase in an energy density of lithium ion batteries became a key issue for a long-term operation. To achieve this, many studies have carried out on anode materials with high capacities over 500 mAh g-1 such as Si, SiOx, Sn and so on. But those materials have not been successfully commercialized due to their large volume changes. On the other hand, a trend of an electrode design is toward a high mass loading and density of active materials in the cell. However, it causes a critical problem with Li+ ion diffusivity owing to reduced electrode porosity. Here we report a porous graphite/SiOx electrode via a sulfur sublimation method for the high energy density anode of LIBs. To increase the energy density, not only 9.8 % SiOx with a practical capacity of 1500 mAh g-1 was added in the graphite electrode which leads to a target capacity of 500 mAh g-1 but also porosity in the electrode was formed in the range of 10-30μm for a release of the electrode stress. Particularly, electrolyte permeability of the electrode was enhanced 2 times higher than that of a reference without porosity, and stress was reduced during cycling confirmed by Raman mapping, which leads to enhanced electrochemical performance.

Resume : Lithium ion batteries (LIBs) would be one of the most promising energy conversion/storage systems for large-scale devices. To warrant their future applications, the thermal properties of current carbonate electrolytes should be improved because the combustible carbonate electrolytes can seriously participate in a battery explosion as a fuel. In this regards, ionic liquids (ILs), composed of cations and anions, have been considered to be an alternative electrolyte due to their thermal stability. However, IL-only electrolyte could not offer favorable kinetics during electrochemical process because of their high viscosity. Therefore, the balance between current carbonates and ILs would be useful to achieve more effective electrolytes. In this paper, some non-flammable organic electrolytes composed of pyrrolinium-based ILs and carbonates are suggested to provide synergistic effects between non-flammable ILs and carbonates with low viscosity (ACS Sustainable Chem. Eng. 2016, 4, 497.). Especially, the mixed electrolyte with 40 wt% of IL (E40) shows high ionic conductivity (10.8 mS/cm), and the mixed electrolyte with 60 wt% of IL (E60) exhibits outstanding the self-extinguish time (5 s/g). In addition, the pyrrolinium cation would be helpful to reduce viscosity of the electrolytes, resulting in some positive effect on the electrochemical properties. We will present the physicochemical and electrochemical properties as well as the improved thermal stability of the mixed electrolytes.

Resume : Supercapacitors (SCs) exhibit high power density, long cycle lifetime, and excellent safety in extreme conditions, which makes them very useful in various applications such as backup power suppliers, hybrid buses, and heavy hybrid trucks.[1] Recently, the research on SCs has been focused on improving the energy storage ability of conventional carbon-based SCs (< 10 Wh kg-1) for broader applications.[2] Other materials like metal oxides including RuO2 and MnO2 which show significantly higher capacitance than that of carbon-based materials thanks to the pseudocapacitive behaviour involving fast surface faradaic redox reaction. However, the scarcity and high cost of RuO2 and poor stability of MnO2 may hamper their production in large scale in the practice. Layered double hydroxide (LDH) is a type of material which is considered to be desirable for supercapacitors due to its high surface area and feasibility for fast intercalation/de-intercalation of charged ions.[3] The properties of flexible anionic exchange, laminar structure, and hydrophilic nature of LDH result in an efficient electron and ion transport even under a large charge current density in the application of SCs. Specifically, Ni and Co based LDH (NiCo-LDH) materials have attracted lots of attention due to their high activity. As a battery-type material, the whole crystalline structure of NiCo-LDH is involved in the faradaic charge storage process through intercalation/de-intercalation of electrolyte ions [4], resulting in an extraordinary charge storage capacity. However, these candidates normally suffer from low conductivity and fragile crystalline structure, leading to a limited capacitance, poor rate and cycling stabilities. In this work, we fabricate NiCo-LDH directly on a carbon fiber cloth (CFC) as binder-free SC electrodes. Through a facile one-step solvothermal method, ultra-thin NiCo-LDH nanosheets are intimately grafted on the surface of the CFC forming a 3D porous hierarchical nanostructure. This unique nanostructure enables high exposure of the active sites of the material for efficient charge transfer during the operation of SCs. The absence of binder material in our NiCo-LDH/CFC electrode ensures good electrical properties of the material and efficient kinetics in the charging/discharging process of the device. Owing to these merits, as-prepared NiCo-LDH/CFC electrode exhibits a considerable high capacitance, outstanding cycling stability (61% at 60 A g-1), and long-term cycling duration. The energy density and power density of the material were assessed by assembling a hybrid SC, which achieves a high energy density (59.2 Wh kg-1 at a power density of 850 W kg-1) and a large power density (34 kW kg-1 at 13.4 Wh kg-1). This highlights the advantage of the new method for the synthesis of high electrochemical performance electrode materials for supercapacitors. References [1] T. Brousse, D. Bélanger, K. Chiba, M. Egashira, F. Favier, J. Long, J. R. Miller, M. Morita, K. Naoi, P. Simon and W. Sugimoto, in Springer Handbook of Electrochemical Energy, eds. C. Breitkopf and K. Swider-Lyons, Springer Berlin Heidelberg, Berlin, Heidelberg, 2017, 495-561. [2] P. Simon and Y. Gogotsi, Nat. Mater., 2008, 7, 845-854. [3] V. Augustyn, P. Simon and B. Dunn, Energy Environ. Sci., 2014, 7, 1597-1614. [4] Y. Wang, Y. Song, Y. Xia, Chem. Soc. Rev., 45 (2016) 5925-5950.

Resume : With the rapid increase in energy demand and the dwindling of lithium resources worldwide, sodium-ion batteries emerged as an alternative to Li-ion battery,.[1] However, it is very essential to further push the energy and power densities, along with improved cycle life, in-order to meet the growing energy needs. Hybrid capacitors that combine the advantages of both intercalation (faradaic) and adsorption (double layer) processes, provide high energy and power density, respectively.[2,3] Herein, electrochemical performance of layered sodium titanium oxide hydroxide [Na2Ti2O4(OH)2] nanomaterial is studied as anode for Na-ion hybrid capacitor. Na2Ti2O4(OH)2 exhibits pseudocapacitive nature with a specific capacity of 150 mAhg-1 at 100 mAg-1 with good electrochemical kinetics showing a capacitive behaviour of 57.2% at 1.0 mV s-1. A full cell Na-ion hybrid capacitor is assembled with Na2Ti2O4(OH)2 as anode and activated carbon as cathode, in 1 M NaPF6 in Propylene Carbonate electrolyte, and the device exhibits improved electrochemical performance with a remarkable energy density of ~65 Wh kg-1 with ~ 93% capacitive retention after 3000 cycles. 1. M. D. Slater et al., Adv. Funct. Mater. 23, (2013), 947–958. 2. K.Naoi et al., Energy Environ.Sci. 5, (2012), 9363-9373. 3. B. Babu et al., Electrochim. Acta 211, (2016), 289-296.

Resume : Non-aqueous redox flow battery (RFB) has received attention as a way to generate large-scale energy storage system. RFB is operated by the reduction and oxidation of the redox-active species in the organic electrolyte solution. The requirements of the membrane which separate the half-cell of the RFB are high anion conductivity and low permeability of the active species, but there is no commercial anion exchange membrane developed for the non-aqueous RFB. One of the main reason is the low chemical stability of the commercial membrane. Therefore we developed a new interpenetrated polymer network (IPN) anion exchange membrane using urushiol and diallyl ammonium chloride (DADMAC) as precursors for a chemically stable matrix and anion exchange sites, respectively. The ion conductivity increased with the amount of DADMAC while the vanadium acetylacetonate permeability decreased which is explained from the decreasing interchain distance determined by wade angle x-ray spectroscopy. In order to improve the ion conductivity, urushiol/DADMAC solution was coated on the surface of the cellulose membrane and crosslinked at 100℃ for 24h. The ion conductivity, vanadium acetylacetonate, porosity of the cellulose membrane coated with urushi/polyDADMAC IPN were investigated and the performance of a non-aqueous RFB based on vanadium acetylacetonate using cellulose membranes with urushi/polyDADMAC IPN coating was evaluated and compared to that with commercial Neosepta AHA membranes.

Resume : Wind power, and solar energy, etc. are promising energy sources to replace fossil fuels, but the electric generations from the renewable energy are unpredictable and intermittent. Therefore, researches on energy storage devices such as aqueous vanadium redox flow battery (VRFB) for the smart grid system have been actively conducted. Proton exchange membrane such as Nafion is important components of VRFB to determine the battery performance. Nafion based membrane is chemically stable and has a high ionic conductivity, but it has a drawback to permeate the active species through the swollen ion channels in aqueous electrolyte solution. Therefore, we modified the Nafion membrane by blocking the ion channels using chemically stable urushi material in order to reduce the permeability of the active vanadium ions. Urushol was penetrated inside of the ion channel of the Nafion 212 by the immersion of the Nafion into the urushiol/ dimethylformamide solution for 6hrs. Then the membrane was put in the 100°C oven for 6 hours in order to complete crosslinking reaction of urushiol to form urushi. The ionic conductivity and the vanadium permeability of the modified Nafion membranes containing 2.1 wt% of urushi decreased to be 0.6 S/cm and 7.36E+07 cm2/min, respectively, which are lower than those of Nafion. The coulombic efficiency (CE) and energy efficiency (EE) values for VRFB increased with an increasing amount of urushi in the Nafion membrane, and achieved 95.0 % and 91.0 %, respectively, with a 3.2 wt% of urushi, which were higher than those using in Nafion membranes. This result implies that a modified Nafion membrane with an urushi blocking material is a promising membrane for VRFB applications.

Resume : Sodium-ion batteries (SIBs), considered to be a promising low-cost alternative to common lithium-ion batteries (LIBs), undoubtedly offer a competitive solution for scalable energy storage such as large-scale stationery storage devices and electric vehicles. Among the many anode materials studied for SIBs, one of the most appealing ones is TiO2 having the merits of low cost, environmental friendliness, intrinsic safety and negligible volume expansion. In particular, downsizing TiO2 to the nanoscale level together with the employment of a surface modification strategy has shown to be very effective to improve its electrochemical performance. Herein, we have chosen Al2O3 to modify nanostructured anatase TiO2 by a facile two-step approach and we investigate the effect of Al2O3 surface modification on the SIB performance with various Al:Ti molar ratio. Benefiting from the more feasible Na insertion/extraction kinetics and better reversibility derived from the Al2O3 surface layer, the modified TiO2 exhibits improved performance compared to the pristine one. The effect of different electrolytes on cycling performance for the optimized sample (with Al:Ti molar ratio of 1%) was further studied. Especially, under the best configuration our SIB could deliver a high reversible capacity of 188.1 mAh g-1 at 0.1C after 50 cycles, good rate capability, and remarkable long-term cycling stability at the rate of 1C for 650 cycles.

Resume : In this work, we present the novel electrochemical platform, which consists of crumpled chemically modified graphene (CMG) as electric collector and catalytic nanoparticles with uniform distribution fabricated from block copolymer (BCP) lithography. BCP lithography can provide dense periodic functional nanopattern via well-established self-assembly, but it has generally been restricted in 2D patterning technology. To extend its applications to electrochemistry, the advantages of BCP should be utilized in the 3D direction for high areal density. Here, it is demonstrated that this 2D BCP nanopattern could be converted to 3D complex nanopattern via mechanical instability which is explained by stress relaxation process in compressing bilayer system. This simple process enabled the areal density multiplication of highly dense BCP nanopattern by shrinkage ratio. Also, under controlled substrate shrinkage process, diverse 3D complex nano-morphologies were obtained. And, this platform of highly dense 3D catalytic nanoparticles was applied to the hydrogen evolution reaction (HER) which is one of representative electrochemical reactions. We found that our 3D complex nanostructure was advantageous to immediately remove the as-formed hydrogen gas, which helps to maximize the active catalytic region. Via this process, our novel electrochemical platform showed the superior performance compared to Pt/C catalyst.

Resume : All-solid-state lithium battery with a solid electrolyte has been regarded as alternative technology for lithium-ion batteries (LIBs) because of its superior safety. However, for the practical application of the solid electrolyte to the all solid-state lithium battery, it is critical to develop highly reliable solid-state inorganic electrolytes with high ionic conductivities and acceptable processability. Li1+xAlxTi2-x(PO4)3 (LATP) with a NASICON-like structure is regarded as a potential solid electrolyte, owing to its high bulk conductivity and excellent chemical stability. However, the solid LATP electrolyte still suffers from a low total conductivity, mainly due to the blocking effect of grain boundaries to Li+ conduction; it hence requires a high-temperature sintering process to reduce grain boundary resistances. In this work, we reported the LATP(Li1.4Al0.4Ti1.6(PO4)3)–Bi2O3 composite as a solid electrolyte for all-solid-state battery. Bi2O3 was introduced as a microstructural modifier to reduce the fabrication temperature of the solid electrolyte and to enhance its ionic conductivity. The nano-sized LATP powder was first synthesized via the Pechini route to achieve improvements in densification and the LATP–Bi2O3 solid electrolytes with various Bi2O3 contents were fabricated via sintering process. Based on the analyses of structural and electrochemical properties for LATP–Bi2O3 composite electrolytes, the effects of Bi2O3 addition on the microstructure and the behavior of lithium ion conduction in LATP solid electrolyte were examined.

Resume : In recent years, significant attention has been paid to the development of micro-devices as innovative energy storage solutions. For instance micro-sensor networks such as sensor actuators or implantable medical devices require power densities and cyclability that are several orders of magnitude higher than those of conventional Lithium-Ion batteries. For such applications, Microsupercapacitors (MSCs), a developing novel class of micro/nanoscale power source are rising alternatives, and their integration ?on-chip? could allow significant innovations to emerge.[1] Therefore, a great deal of attention has been focused on MSCs, for which large series of nanostructured active materials have been developed. Following this trend, our work focuses on MSCs made of silicon nanotrees[2],[3] functionalized by high-k dielectrics and transition metal oxides as new nanostructured materials to improve their performances. Here we deposit NiCo2O4[4] oxides particles synthetized by various facile and scale up inorganic processes such as oxalate route and electrodeposition. Oxides based on Ni and Co have been chosen for their promising performances, as NiCoO4 nanowires electrodes were shown to exhibit a specific capacitance of 743 F.g-1 at 1 A.g-1 with excellent rate cycling stability (6.2% loss after 3000 cycles)[5]. We have also investigated the impact of the addition of a high-k dielectric layer, such as Al2O3 and HfO2 as protective films on silicon nanotrees exhibiting outstanding cycling performances with more than 4 billion cycle stability within a stability window of 4V. [1] Beidaghi, M. Gogotsi, Y. Energy & Environ. Sci. 2014, 7 (3), 867-884 [2] Thissandier, F. Gentile, P. Sadki, S., 2014, Journal of Power Sources 269, 740-746 [3] Gaboriau, D. Aradilla, D. Gentile, P. Sadki, S., RSC Advances, 2016, 6, 81017-81027 [4] Puang H, Deng J., RSC Advances, 2012, 2, 5930-5934 [5] Jiang H., Ma J., Li C.,ChemComm, 2012, 48, 4465-446

Resume : A major issue towards the practical development of Mg batteries is the lack of high voltage cathode materials exhibiting fast and reversible Mg2+ mobility, mainly hampered by the high polarizing character of the hard Mg2+ ion in solid hosts. Within this challenging research context, a layered, ternary MgMoN2 is herein originally studied as a potential high voltage cathode material for Mg batteries. This study discloses an optimized synthetic route for high purity, layered MgMoN2, with a detailed characterization of its structure, morphology and physical properties by several techniques. The electroactivity of the synthesized phase is investigated both chemically and electrochemically. The obtained experimental results are rationalized through a detailed Density Functional Theory (DFT) study of the MgMoN2 (de)-intercalation process and physical properties. The combined experimental and theoretical study here presented may contribute to the fundamental understanding of the Mg2+ mobility issue and to outline the missing steps towards the development of high voltage cathode materials for Mg batteries.

Resume : Paper is a cheap, lightweight and renewable material with increasing applicative interest as a substrate for disposable and flexible electronics. The fabrication of paper-based energy storage devices is a necessary step for the development of smart and autonomous flexible microelectronic platforms (e.g. sensors and biomedical devices) and requires the development of high throughput coating techniques enabling the integration of porous thin films into fragile materials, such as paper. Supersonic Cluster Beam Deposition (SCBD) is an additive technology based on the production of intense and highly collimated nanoparticle beams that enables the large-scale and high throughput integration of nanostructured materials on a wide variety of substrates and microfabricated platforms [1-2]. The room temperature assembling of carbon nanoparticles via SCBD is an effective approach for the production of porous carbon thin films with promising electrochemical properties. Recently, the use of SCBD for the fabrication of flexible binder-free microsupercapacitors on conventional substrates has been reported [3-4]. Here we report the one-step, room temperature, fabrication of planar microsupercapacitors where nanostructured current collectors and carbon electrodes are deposited by SCBD on plain paper sheets and ionic liquids are used as electrolyte. SCBD-made microsupercapacitors exhibit energy storage performances that are consistent with the typical low-power requirements of paper-based electronic systems. The possibility to encapsulate the SCBD-made microsupercapacitors by means of a polydimethylsiloxane (PDMS) layer and their usability in driving a temperature sensor are also presented. [1] K. Wegner, P. Piseri, H. Vahedi Tafreshi, P. Milani, J. Phys. D: Appl. Phys., 2006, 39, R439 [2] G. Bongiorno, A. Podestà, L. Ravagnan, P. Piseri, P. Milani, C. Lenardi, S. Miglio, M. Bruzzi, C. Ducati, J Mater Sci: Mater Electron, 2006, 17: 427 [3] L.G. Bettini, P. Piseri, F. De Giorgio, C. Arbizzani, P. Milani, F. Soavi, Electrochim. Acta, 2015, 170, 57 [4] F. Soavi, L.G. Bettini, P. Piseri, P. Milani, C. Santoro, P. Atanassov, C. Arbizzani, J. Power Sources, 2016, 326, 717

Resume : Nanostructured silicon electrodes have attracted attention as a potential candidate for high capacity anode in lithium-ion batteries, thanks to their high specific capacity (3580 mAh g-1 at RT) and their ability to accommodate silicon volume changes upon cycling. However, the silicon amount deposited on these nanostructured electrodes is generally low (below 0.3 mg cm-2) and leads to low surface capacities. To increase the areal density of silicon on the electrode, a new original structure is proposed: interconnected SiNWs are synthesized on a stainless steel current collector thanks to a two-step CVD process. The second growth leads to a “nano-tree” structure with surface capacities between 1.8 and 7.1 mAh.cm-2. These highly loaded silicon electrodes led to very high surfacic capacities at C/50, up to 7.1 mAh.cm-2. They maintain very good rate capabilities and a rather stable cycling is observed for the intermediate loadings, with a capacity maintained above 2.5 mAh.cm-2 after 100 cycles at C/5. Besides, these high loaded nano-tree electrodes can still deliver 38 % of the lithiated capacity and 88 % of the delithiated capacity at 1C which is a very promising performance.

Resume : In 2015, we introduced an aqueous zinc-ion battery based on copper hexacyanoferrate nanoparticles (CuHCF) for grid-scale energy storage devices with high reversible specific charge. This battery provides good cycle stability, with a specific charge retention of 96.3% after 100 cycles in 20mM ZnSO4. Moreover, an operational discharge voltage of 1.73 V is achieved in this system.[1] Recently, we show that the current rate and the electrolyte (nature and concentration) is greatly affects the performance and aging of the CuHCF. In particular, the aging of the active material in the cathode active material occurred at a shorter number of cycles when the concentration of the electrolyte is higher and when the current rate is lower.[2] In addition, it has been observed that during cycling of CuHCF in presence of Zn salts, two separated phases are formed in the cathode.[2] This result is completely different from previous studies.[3] We proposed a mechanism for this phase transformation, in which insertion of zinc ions in interstitials positions of CuHCF upon intercalation could lead to a distortion of the lattice. It is assumed that some vacancies in the lattice exist, which are incorporating zinc ions into the lattice. After reaching a certain amount of zinc substitution, ZnHCF nucleates from CuHCF. Besides, a partial incorporation of Cu in ZnHCF and a partial incorporation of Zn in CuHCF could occur.[2] Since the aging of the CuHCF is caused by the phase transformation, we have focused on the modification of the active material structure in order to stabilize the system and reach a longer cycle life. Therefore, several materials in which Cu was substituted by Zn were synthesized, namely with Cu:Zn ratios equal to 85:15, 90:10, 93:7, 95:5, and 98:2. Among them, the mixture with the Cu to Zn ratio of 93:7 has shown the best performance with the capacity fading of 98.1% and 85.5% in 20 mM ZnSO4 after 500 and 1000 cycles, respectively. However, pure CuHCF had a capacity fading of 93.92% and 74.35% in the same solution after 500 and 1000 cycles, respectively. Furthermore, there is no evidence of the phase transformation upon cycling the mixture of KCu0.93Zn0.07HCF even after 1000 cycles in 20 mM ZnSO4. Therefore, it can conclude that the presence of zinc as a co-ion in the structure not only prevents the appearance of the second phase but also prolongs the cycle life of the battery. In the other word, in this battery the aging phenomenon is postponed. References: [1] R. Trócoli, F. La, An Aqueous Zinc-Ion Battery Based on Copper Hexacyanoferrate, ChemSusChem. 8 (2015) 481?485. doi:10.1002/cssc.201403143. [2] G. Kasiri, R. Trócoli, A.B. Hashemi, F. La Mantia, An electrochemical investigation of the aging of copper hexacyanoferrate during the operation in zinc-ion batteries, Electrochim. Acta. (2016). doi:10.1016/j.electacta.2016.10.155. [3] A. Widmann, H. Kahlert, H. Wulff, F. Scholz, Electrochemical and mechanochemical formation of solid solutions of potassium copper ( II )/ zinc ( II ) hexacyanocobaltate ( III )/ hexacyanoferrate ( III ) KCu x Zn 1-x [ hcc ] x [ hcf ] 1-x, J Solid State Electrochem. 9 (2005) 380?389. doi:10.1007/s10008-004-0635-5.

Resume : Conducting polymers are very interesting for their application as pseudocapacitor. We present the electrochemical application of Mn3O4-polypyrrole composite in achieving supercapacitors with specific capacitance as high as ~ 602 F g-1 at a current density 1 A g-1 in the voltage window from -0.5 to 0.5 V in 1 M Na2SO4 electrolyte in three electrode measurement. One major limitations of such materials have been their rapid decay as a function of cycling. Therefore, we propose to coat the composite using graphene. This can bring advantages of : (a) enhancing conductivity, (b) improved redox site and (c) tunable surface area. The scanning and transmission electron microscopic data show a uniform coating of graphene over the Mn3O4-polypyrrole composite. The electrochemical response is much higher than graphene. We also propose the promising model to explain the increase in the cycling stability. The use of these composite materials in actual two-electrode supercapacitor, will also be presented.

Resume : This work is about developing hydrocarbon based membranes with reinforcements which can perform on par with Nafion. In this study, we have synthesized crosslinked Polyvinyl Alcohol- Sulfosuccinic Acid- Sulfonated CNT membranes (PVA-SSA-SCNT) where sulfonated CNTs were added in different weight percentages (0.05%, 0.1%, 0.5% & 1%). Sulfonated CNTs were used to increase the mechanical strength and proton conductivity of the membrane. PVA-SSA-SCNT membranes were synthesized via solution casting method. These cast membranes were characterized for water uptake capacity, ion exchange capacity, and durability studies, using Fenton?s reagent. The proton conductivity studies were performed using electrochemical impedance spectroscopy (EIS). To get an idea on the inherent functioning of such a membrane, different membrane electrode assemblies (MEA) were synthesized by varying the PVA-SSA-SCNT and conventional Nafion® ionomers in catalyst layers. Properties of synthesized MEAs were characterized using scanning electron microscopy, electrochemical impedance spectroscopy and contact angle measurement. I-V characteristics of each cell incorporated with above MEAs were carried out at different operating conditions. The performance of PVA-SSA-SCNT membranes are compared over Nafion membranes and the results are discussed.

Resume : Secondary lithium ion batteries (LIB) have gained much attention as a mobile power source of small electronics, electric vehicles (EVs) and energy storage system (ESS). However, serious safety concerns in LIB have been unavoidable since the flammable organic liquid electrolytes are used as lithium ion medium, which in turn, resulted in explosion or flammability. To address these issues, solid electrolytes have been developed intensively due to their improved safety including non-flammability, reliability and leakage-free property when used as an electrolyte in LIB. Moreover, along with the improved safety, the battery system exploiting solid electrolyte could provide cell design flexibility as well as high energy density through exploiting the Li metal electrode. Among arising solid electrolytes, oxide ceramics are considered to be promising candidates, showing better stability and easier handling characteristics in comparison to polymer or non-oxide materials. A representative oxide solid electrolyte with a composition of Li-La-M-O(M=Ta, Nb, Zr) have been widely studied as a fast lithium ion conductors over the last decade. Murugan and coworkers have successfully synthesized garnet-type Li7La3Zr2O12 providing high lithium ion conductivity (3ⅹ10-4 S cm-1), chemical stability against lithium metal and wide electrochemical window [1]. However, solid state method requires several steps of thermal treatment and grinding as well as relatively high temperature and long sintering time. In our work, we demonstrate a doping induced synthetic route to prepare Li7La3Zr2O12 (LLZO) with cubic garnet-like structure. We have investigated how the doping element affected the site preference of Li atom and synergistically determined ionic conductivity of LLZO. Furthermore, the optimal Li content in LLZO for acquiring the facile Li diffusion path has been explained.

Resume : When looking for post-lithium battery systems multi valent ions such as aluminum offers advantages in terms of a high theoretical capacity as well as recyclability and good resource abundancy. In the present work we investigated the usability of different oxide and graphite materials as cathode for aluminum batteries. Different manganese oxides were analyzed because of their promising 3d channel crystal structure. However, the test cells with synthesized Li1-xMn2O4 and AlNiMn2O4 spinels as intercalation cathodes showed lacking electrochemical reversibility over multiple CV curves. Therefore, a carbon based cathode was studied whose advantage is a fast and reversible kinetics according to literature. On the downside graphitic based cathodes show typically lower capacities due to aluminum salt intercalation. In our experiments we achieved an electrochemical activity of 40 mAh/g for up to 50 cycles by using graphite sheets with an aluminum anode electrode within a voltage range of 1.5 V. The capacity and cycle stability has to be further improved. By using an ionic liquid electrolyte it was possible to increase the voltage window. In further tests with a carbon aerogel a clear capacitor like behavior with a capacity of about 3400 mF/g could be achieved. This is a first step for developing an aluminum-ion battery-capacitor.

Resume : Efficient and sustainable batteries are a key challenge to pave the way for the availability of energy from renewable sources. Despite the fact that Li-based systems provide a good energy density, they still suffer from some disadvantages concerning cost and safety issues. To overcome these drawbacks alternative systems are under intensive research. Currently sulfur is one of the most promising cathode materials due to its high energy density of 1672 mAh g−1, its low cost and environmental friendliness. Magnesium features significant advantages as it is abundant and shows no dendrite formation during cycling, which ensures superior safety. Above all magnesium offers a high theoretical volumetric and gravimetric capacity of 3832 mAh cm−3 and 2230 mAh g−1 respectively. Thus the combination of a negative magnesium electrode and a positive sulfur electrode (Mg-S) represents a promising cell technology. Until now Mg-S cells suffer from fast capacity decay in the first few cycles and poor cycle stability. To understand the underlying processes and to identify the origin of the rapid degradation, different approaches regarding the synthesis and characterization of S-C electrodes in Mg2+-based electrolyte systems are investigated. The cathodes prepared are characterized with cell cycling experiments and optimized regarding their electrochemical performance. Electrochemical impedance spectroscopy and X-ray diffraction are applied to examine internal processes and to identify phases.

Resume : Single wall carbon nanohorns (SWCNHs) are porous carbon materials with unique horn-shaped tubes aggregate to form dahlia-like structures. This material with high surface area and good conductivity can be used as ‘conductive host’ for various insulative materials like Lithium sulfide (Li2S) making it attractive as cathode host material for Lithium sulfur batteries. Moreover, the use of Li2S, instead of sulfur, allows the use of Tin (Sn), Silicon (Si) and Germanium (Ge) as anode material for a safer energy storage device. Therefore, it is presented for the first time, a full battery made of Li2S-nitrogen doped SWCNHs composites (Li2S@N-SWCNHs) as cathode material and Sn-nitrogen doped SWCNHs composites (Sn@N-SWCNHs) as an anode material, using an industrially scalable method. Each composite material (Li2S@ N-SWCNHs and Sn@N-SWCNHs) were separately tested in a half cell configuration which were later combined to verify their performance as a full cell using 1M lithium bis-(trifluoromethyl-sulfonyl)-imide (LiTFSI) in 1,2-dimethoxy ethane (DME) and 1,3-dioxolane (DOL).

Resume : Graphene is regarded as a potential material for many application fields due to its unique electrical, mechanical, and thermal properties. Since its first isolation in 2004, the interest has grown in the development of facile and scalable synthesis routes. So far, the commercial application of graphene is hindered by expensive and time-consuming synthesis techniques, e.g., growth on sacrificial substrates by epitaxy and chemical vapor deposition (CVD). In this paper, we present a facile synthesis method for preparing free-standing few-layer-graphene (FLG) by gas-phase reaction, which is carried out in a plasma reactor using ethanol as precursor. This scalable synthesis route can produce highly pure FLG with production rates up to 1 g/h. The prepared FLG has been characterized by X-ray diffraction, FTIR, Raman, and impedance spectroscopy, XPS, and TEM in combination with EELS. The results indicate that the gas-phase generated samples show similar materials properties as known from well-established synthesis techniques like the modified Hummers’ method. Gas-phase synthesis produces graphene with highly pure surfaces. This makes the material very attractive for electrochemical applications, e.g., for composites used in lithium-ion batteries, electrocatalysis, or superconductors.

Resume : Silicon is regarded as a high-capacity anode material for advanced lithium-ion batteries (LIBs). So far, its commercial application is hindered by its poor electric conductivity and large volume change during charging and discharging. This work reports on silicon/graphene nanocomposites with outstanding electrochemical performance that have been synthesized using self-assembly between Si and graphene which both were produced by gas-phase synthesis. The materials aim at enhanced cycling capability of silicon anodes while allowing for scalable production. Si nanoparticles (NPs) were produced in a pilot-plant-scale hot-wall reactor using monosilane as precursor. This process enables the formation of high-purity Si NPs with tunable crystal size and crystallinity at production rates of 0.5–1.0 kg/h. Graphene was synthesized in a plasma reactor using ethanol as a precursor. Even on lab scale we were able to increase the production rate from mg to g/h. The characterization of graphene with X-ray diffraction, FTIR, Raman, and impedance spectroscopy, XPS, and TEM in combination with EELS indicated the formation of high-purity few layer graphene (FLG). Our experiments indicated that about 25 wt% of FLG is sufficient to significantly stabilize the electrochemical properties of the composite with an initial specific discharge capacity of approximately 2200 mAh/g and stable cycling performance over 300 cycles with a small capacity decay of 0.02% per cycle.

Resume : Transition metal sulfides (TMS) like ZnS, SnS2, Fe3S4, FeS and CoS2 have gained much attention as promising candidates for anode materials of lithium ion batteries due to their high specific capacity, low redox potential and good reversibility, resulting from the conversion and alloying type mechanism. Previous reports on the preparation of TMS mainly focused on the solid state or hydrothermal reaction with sulfur or thio-compounds as the sulfur source, respectively, which have the drawbacks of high temperatures, long reaction times and limited control over particle size and morphology. Herein we report a facile solvothermal synthesis as a general method to obtain TMS nanoparticles under mild reaction conditions by using 4-methoxybenzyl mercaptan as sulfur source and microwaves as a heating method. We obtained ultrafine polyhedron ZnS particles with sizes ranging from 4-6 nm, flower-like particles assembled from SnS2 nanosheets, hollow CoS2 nanotubes and Fe3S4 nanoplatelets, which all showed electrochemical activity. Annealing of the Fe3S4 platelets with glucose yielded carbon-coated FeS, which delivered about 280 mAh/g reversible capacity after 600 cycles at a current rate of 1 A/g.

Resume : With the aim of finding an interpretation for the isomerization reaction of icosadeca-ene by quantum methods, we have studied a series of three molecules giving the following results:  The studied segments (C20H20, C20H10F10, C20H10Cl8, C20H10Br8 and C20H10I8) are very stable. This stability is justified by the HOMO-LUMO found energy gap. However, examination of the stability of several conformations shows that the trans conformer is more stable than the cis conformer in the general assembly.  According to the study of different reaction profiles, we noticed that the size and nature of the dopant plays a very important role on the evolution of the activation energy.  From the obtained values of the activation energy, we find that the speed constants of the isomerization reaction are in the order: kC20H22 >> k C20H10F10 >> k C20H10Cl10 >> k C20H10Br10 >> k C20H10I10  The search for intermediate products during the transition Cis-Trans shows that the geometric parameters (angles and dihedral angles) are the most varied settings, this remark has been observed in the case of substituted and non-substituted icosadeca-ene.  The methods of calculations performed in this work are the Ab-initio and DFT methods, with the bases (6-31G, 3-21G **). All these calculations are performed with the Hyperchem software, where parameters obtained are in a closer order to those obtained with the Gaussian 03W software  Examination of different molecules obtained during the Cis-Trans isomerization reaction shows that the total energy of the resulting intermediate product is of the order of -10487.05 eV, corresponding to a 0.87eV activation energy (23.67 kcal / mol).  With the same HF method (6-31G and 3-21 G**), a close geometry was obtained for the intermediate product in the isomerization reaction with a total energy of 0.93 eV (25.30 kcal/mole), which shows that the different values of the activation energy obtained by the HF and DFT methods at the 6-31G level can be compared to those obtained by Ito, Montaner and Bernier. Keywords: Ab-initio; DFT; kinetics; isomerisation; substituted icosadeca-ene

Resume : The rapid technological advances in portable electronic products (mobile-phone, computers, e-labels, e-packaging and disposable medical testers, among others) lead to the need of increasing battery autonomy and performance [1]. The most widely used battery types are lithium-ion batteries, with a market share of 75% [2]. The key components of a battery are the anode, cathode and separator/electrolyte where the cathode (positive electrode) is responsible for the cell capacity and cycle life and the anode (negative electrode) should have a low potential in order to provide a high cell voltage with the cathode [3]. The performance of a battery is typically optimized for either power or energy density through the improvement of electrodes and separator materials. For conventional lithium ion batteries, typical volumetric energy and power densities are around 10–60 μWh cm-2 μm-1 and 1–100 μWh cm-2 μm-1, respectively. It has been nevertheless evaluated that it is possible to achieve higher power density up to 1000 μW h cm-2 μm-1 [4]. A possible way for developing high-power and high-energy density batteries is by using interdigitated structures. In the present work, battery performance has been evaluated for different geometries taking into account their suitability for different applications. These different geometries include conventional and interdigitated batteries as well as unconventional geometries such as horseshoe, spiral, ring, antenna and gear batteries. The geometry optimization was performed by the finite element method, applying the Doyle/Fuller/Newman model. At 330C, the capacity values for conventional, ring, spiral, horseshoe, gear and interdigitated geometries are 0,58 Ahm-2, 149 Ahm-2, 182 Ahm-2, 216 Ahm-2, 289 Ahm-2 and 318 Ahm-2, respectively. The delivered capacity depends on geometrical parameters such as maximum distance for the ions to move to the current collector, d_max, distance between of current collectors, d_cc, as well as the thickness of separator and electrodes, allowing to tailor battery performance and geometry for specific applications. Acknowledgments Portuguese Foundation for Science and Technology (FCT) - UID/FIS/04650/2013, PTDC/CTM-ENE/5387/2014 and SFRH/BPD/112547/2015 (C.M.C); Basque Government Industry Department under the ELKARTEK Program. References [1] M. Wakihara, O. Yamamoto, Lithium ion batteries: fundamentals and performance, Kodansha, 1998 [2] J.B. Goodenough, K.-S. Park, Journal of the American Chemical Society, 135 (2013) 1167-1176. [3] M. Park, X. Zhang, M. Chung, G.B. Less, A.M. Sastry, Journal of Power Sources, 195 (2010) 7904-7929. [4] J. H. Pikul, et all, Nature Communications, 4:1732 (2013) 1-5.

Resume : Recently, transition metal phosphides(TMPs) have received much attention as anode material for lithium ion batteries due to high reversible capacity at relatively low potential. [1] However, most metal phosphides suffers from a relatively large irreversible capacity due to the decomposition of LixM, LixP, and metal during cycling. In addition to the decomposition, volume expansion of metal phosphides leads to the degradation of electrochemical properties during cycling. In order to solve these problems, numerous material concepts have been suggested and some of them prove to be effective in improving the cycle performance. One of the effective ways to enhance the cycle performance is the use of active/inactive composite material [2] and nano-crystallization of active materials. [3] Inactive compound material acts as buffer layer to suppress the volume expansion in active/inactive composite. In this work, we developed a new MoP/MP composite alloy to improve the structural stability and electrochemical properties with introducing the MoP in the pristine MP. We investigated the differences in physical and electrochemical properties between MoP and MoP/MP composite, examined using powder X-ray diffraction, SEM, and TEM, and galvanostatic charge-discharge test. We also investigated the volume expansion of MP and MoP/MP composite during cycling, considering the influence of introducing MoP layers in MoP/MP composte. References 1. D. C. S. Souza, V. Pralong, A. J. Jacobson, L. F. Nazar, Science 296, 2012 (2002). 2. G. Park, C. Lee, J. Lee, J. Choi, Y. Lee, S. Lee, J. Alloys compd. 585, 534 (2014). 3. P. G. Bruce, B. Scrosati, J.-M. Tarascon, Angew. Chem. Int. Ed. 47,2930 (2008)

Resume : Si thin film is considered as a very promising anode for future development of lithium-ion batteries. In spite of its well-known advantages, silicon thin film anode still has problems of rapid capacity fading due to the electrical contact loss during lithium ions insertion and extraction processes. On the other hand, thin film mass loading is not enough to design a battery with good performance. Herein, we report on employing 3D structured Ni foam with graphene coating (grown by CVD) as a substrate for Si thin film sputtered on its surface by magnetron. The porous graphene coated foam can overcome the problems with capacity fade and low mass loading owing to its high specific area of the porous current collectors, which is capable of keeping a good electrical contact between the graphene coating and the Si film during the electrochemical tests. In addition, the voids in the porous structure will help the active silicon to accommodate the volume change without pulverizing. The Si thin film on pristine and chemically pre-treated Ni foam were tested for the comparison. The results on material preparation, characterization and electrochemical test will be discussed at the conference. Acknowledgements This research was funded under the target program №0115РК03029 "NU-Berkeley strategic initiative in warm-dense matter, advanced materials and energy sources for 2014-2018" from the Ministry of Education and Science of the Republic of Kazakhstan.

Resume : Silicon is an attractive material for use as anode in Li-ion batteries with a theoretical capacity of 3,579mAh/g, ten times that of graphite, as well as being the second-most abundant element in the earth’s crust, and therefore both cheap and eco-friendly. Its main challenges are structural degradation due to a large volume change (∼300%) associated with the high lithium uptake during lithiation, high occurrence of side reactions with the electrolyte and the low electrical conductivity of silicon. In this study we have produced silicon nanoparticles in a free space reactor, subsequently coated with a sacrificial layer of silicon dioxide based on a modification of the Stöber process using TEOS-molecules, before being treated with a carbon shell and final removal of the silicon dioxide. This provides a means of tackling all three problems, as the silicon particles can expand and contract within a confined carbon shell with high electric conductivity, and reduce the risk of de-activation of the resultant yolk-shell nanoparticles, due to large amounts of solid-electrolyte-interphase layer. The controlled oxide and carbon coating has been investigated for particles with a size distribution between 100nm and 500nm, where it is difficult to achieve homogeneous coating. Methods of carbon coating based on corn starch and a resorcinol-formaldehyde resin have been tested for assessing ease of fabrication and product quality.

Resume : Since the development of lithium-ion batteries in 1990, lithium-ion batteries have received much attention from researchers. The researchers have carried out many studies to improve the performance of lithium ion batteries. By adopting the results of the research, the lithium ion battery has been continuously improved in performance. Lithium iron phosphate is one of the important cathode materials. Lithium iron phosphate is used in lithium-ion batteries for electric buses because of its high safety in China. One of the disadvantages of lithium iron phosphate is low discharge voltage. Therefore, the performance of lithium ion battery can improve by development of a lithium transition metal phosphate with high discharge voltage. In this study, lithium vanadate phosphate was chosen as the experimental material. It is assumed that when lithium ions move freely in the crystal by the crystal lattice grown. Therefore, in this study, we have chosen a method to increase the crystal lattice of lithium vanadium phosphate by doping with sodium ions. One of the disadvantages of lithium vanadium phosphate is its low electronic conductivity in the particles. So we chose to improve the conductivity of lithium vanadium phosphate by coating of conductive material on the particle surface. Carbon black was chosen as the conductive material. In previous studies, the organic material was coated on the surface of lithium vanadium phosphate and then heated to carbonize the organic material. In this process, one of the disadvantages is that the uncarbonized material remains after heating process. In this study, I chose to add carbon black itself into the sol of lithium vanadium phosphate to overcome this disadvantage. The structure and shape of the lithium vanadium phosphate cathode materials were analyzed by SEM and XRD. Experimental electrodes were made by mixing with lithium vanadium phosphate cathode material, binder and conductive agent in proportions. Electrochemical tests were carried out after assembling the half-cells with the test electrodes. The capacity of the sodium ion doped lithium vanadium phosphate was slightly lower than that of the undoped lithium vanadium phosphate, but the C-rate performances were improved. The capacity of the carbon coated cathode material was higher than that of the cathode material without the carbon coating. At the conference I will present the physical and electrochemical properties of lithium vanadium phosphate cathode materials with both carbon coating and sodium ion doping.

Resume : Uniform Cu2O nanospheres with tailored hollow structure are successfully synthesized by employing the Ostwald ripening approach, and used as anodes in Li-ion battery. The synthesis involved a facile room temperature chemical reaction of cupric nitrate with hydrazine. Hydrazine served as an alkali and reducing agent, converting Cu2+ to Cu2O nanoparticles, which self-assembled due to their large interfacial energy and formed 100–400 nm nanospheres. The Cu2O nanospheres were characterized by SEM, TEM, XRD, UV-vis spectroscopy and BET techniques. These Cu2O nanospheres were comprised of a mesoporous shell (20–50 nm) and a hollow interior part (50–100 nm). Galvanostatic charge–discharge measurements at different current densities, slow scan cyclic voltammetry (CV) and impedance measurements were used to analyze the electrochemical performance of the Cu2O nanospheres. The hollow Cu2O nanospheres exhibited a capacity of
650 mA h g1 at 100 mA g1 current density, showing greater than 80% capacity retention after 100 cycles. The enhanced electrode performance is attributed to the mesoporous hollow nanostructure that ensured an increased number of electrochemical sites, shorter Li ion diffusion lengths facilitating fast electrochemical kinetics, and sufficient void spaces to buffer the volume expansion.

Resume : We report a novel method to preparing one-dimensional carbon nanorods by morphology-preserved thermal transformation of zeolite imidazolate framework-8 (ZIF-8) nanorods. The morphology of ZIF-8 crystals can be tuned from rhombic dodecahedron nanoparticles to nanorods with the assistance of triblock co-polymer Pluronic F127 at precisely controlled concentrations. The nanorods are composed of assembly of F127-presented ZIF-8 nanoparticles, which could provide mesopores and micropores after calcination. The electrochemical performance of derived carbon nanorods demonstrates this synthetic approach can produce multi-pores carbon with high specific capacitance up to 281 F g-1 at a sweep rate of 10 mV s-1.

Resume : Silicon has been presented as an appealing anode material for boosting the Li-ion battery technology. Nonetheless, associated with its large Li-ion hosting capacity is the large volume expansion that leads to electrode damage and thus to poor cycling ability of the battery. To address these challenges, surface coatings are proposed with a favorable influence on Si-based anodes. These surface coatings can enhance the current collection efficiency, promote the formation of a stable solid-electrolyte-interface and can act as a mechanical constraining layer. Despite the benefits, little knowledge is available on the impact of such coatings on the electrochemical and mechanical stability. Here we detail on the effect of conformal metallic Ni coatings on the lithiation behavior of crystalline Si nanopillars. The evaluated composites have different morphological parameters: Ni shell thicknesses of 40 nm, 80 nm and 120 nm with a Si core diameter of 170 nm, 330 nm and 480 nm. Different swelling behavior and corresponding fracture regimes are identified based on the ratio of coating thicknesses to the Si nanopillars radius, h/A. For thin coatings (h/A<1/6), fractures are found along <110> family of directions which corresponds to regions of high plastic strain accumulation while for thick coatings (h/A<1/6), a random fracture pattern is observed. One remarkable effect of the coating is to reduce the overall anisotropy to an extent which scales with the coating thickness. These observations are sustained by a combined thermodynamic-mechanical framework. The proposed models can be extended to other types of coatings or nanostructures and provide guidelines for tailoring high-performance Si-based electrode materials (1). (1) G. Sandu et al., ACS Nano 2014, 8, 9427.

Resume : The improvement of the life cycle for a zinc-air system is a point of origin in literature. [1,2] To prevent Zn-corrosion, that dramatically reduces the battery’s shelf life the influence of electrolyte additives was investigated. Several organic and inorganic additives, e.g. Triton 100, Tetrabutylammonium bromide, Kalium citrate or Polyethylenglycol 600, were tested in the present work. [3] Galvanostatic charge- discharge experiments clearly show the improvement regarding battery performance (e.g. battery’s theoretical capacity) using different addivites. Additionally the images from computer tomography and scanning electronic microscope analysis document the morphological changes taking place at the electrode surface and in the electrode-core upon cycling. Literature: [1] F.Mansfeld, S. Gilman, J. Electrochem. Soc. 117, 1970, 1328-1333. [2] J. W. Diglle, A. Damjanovic, J. Electrochem. Soc. 119, 1972, 1649-1658. [3] J. Dobryszycki, S. Biallor, Corros. Sci. 43, 2001, 1309-1319.

Resume : Electrochemical energy storage using lignin as renewable electrode material is a cheap and sustainable approach for future batteries and supercapacitors. Previous reports mainly focus on lignosulfonates (LS) or composites with conductive polymer additives. Disadvantages are declining LS supply or additional polymerization steps of often expensive monomers. More available Kraft lignin in combination with conductive carbon may be a promising alternative, and understanding the electrochemical behavior is crucial for future applications. We evaluate charge storage in this system in terms of electrochemical double layer storage and redox reactions, aiming at a better understanding of desired lignin properties for capacitive energy storage. Resulting electrodes are cheap, reliable, stable for at least 500 charge-discharge cycles, and represent a step towards more sustainable energy storage.

Resume : In Lithium-ion batteries, polymer electrolytes are preferred in order to meet all-solid-state requirements such as flexibility, leak-proof packing, processing feasibility etc. In this study, a polymer blend of 25 mol% poly(acrylic acid) (PAA) and 75 mol% poly(vinyl alcohol) (PVA) was optimized based on its thermal, mechanical and structural properties. The ionic liquid electrolyte, 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYRTFSI) with 0.2m lithiumbis(trifluoromethansulfonyl)imide (LiTFSI) was added to the polymer blend in different molar ratios. A maximum ionic conductivity of 1 mScm–1 is observed at 90 °C for the membrane with 70 mol-% IL. Cyclic voltammetry of the polymer electrolytes shows peaks corresponding to lithium stripping (+0.25V vs Li+/Li) and deposition (-0.3V vs Li+/Li) process indicating the occurrence of highly reversible redox process. Linear sweep voltammetry of the polymer electrolyte reveals that they are stable up to 5 V, making these electrolytes suitable for high voltage cathode materials. A lithium transference number (tLi+) of 0.4 was determined for the polymer electrolytes by using chronoamperometry and impedance measurements. Galvanostatic charge-discharge studies of the polymer electrolytes in a lithium half-cell were tested with LiCoO2 (LCO) as cathode, shows a capacity of about 100 mAh/g at 60 °C. The coin-type half-cell with 70 mol-% IL doped polymer electrolyte and LiFePO4 (LFP) as cathode delivers a capacity of 172 mAh/g. The composite – polymer electrolyte added LiFePO4 electrode (LFP-C) – shows better electrochemical performances than pure cathode such as high capacity of 215 mAh/g cycled at 60°C.

Resume : This work presents the successful synthesis and characterization of a new hybrid material based on poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (PTMA) for lithium battery applications. Our strategy relies on the anchoring of nitroxide-embedding polymer chains onto multi-walled carbon nanotubes (MWCNTs). Moreover this strategy takes benefits of the synthesis of the PTMA-b-PAzPMA functional polymer via a controlled polymerization process. This polymer contains redox active nitroxide as well as azide functionalities, the latter being involved in the tethering of the chains to the MWCNT surface. The physicochemical characterization of the hybrid materials is consistent with their core-shell structures. Electrochemical characterizations of MWCNT-g-PTMA were carried out in half cell configuration vs. Li/Li+. The measurements indicate an excellent extraction of the theoretical capacity along with a good cycling stability. Variable-rate measurements demonstrate the ability of the material to sustain high charge/discharge current rates. Eventually this approach is not only affording a mean to suppress the solubilization of the active material but also permits high power performances thanks to the intimate contact of PTMA with the MWCNT conductive network. Bibliography: O. Bertrand, B. Ernould, F. Boujioui, A. Vlad and J.-F. Gohy, Polym. Chem., 2015, 6, 6067-6072. B. Ernould, O. Bertrand, A. Minoia, R. Lazzaroni, A. Vlad and J.-F. Gohy, submitted for publication, 2016.

Resume : Since 2015 is widely considered a milestone year for energy storage, batteries are expected to continue to gain momentum as technology prices continue to fall. Romania committed to play a role in the development of energy storage through the new Romanian Energy Storage Technologies (ROM-EST) laboratory (ICIT Ramnicu Valcea), whose aim is to integrate a complete solution for Lithium battery production and testing. Based on this new approach, various studies focused on battery manufacturing are currently under development. The results obtained so far consist of preliminary experimental work involving the ROM-EST infrastructure. This involves some standard electrode preparation routes in order to understand the relation between the electrode morphology and energy storage capacity of our Li-ion batteries. The first set of 18650-LiMn2O4 batteries has been obtained at ROM-EST ICSI Rm. Valcea. The overall performance of the 18650- LiMn2O4 batteries is good in terms of specific capacity (i.e., 86 mAh/g), whose value is only with ~30% lower than that of commercially available LiMn2O4 batteries (i.e., 120 mAh/g). The lifetime assessment indicate that our LiMn2O4 batteries exhibit excellent coulombic efficiency (i.e., >99.8%) and thermal stability (i.e., <15%, between -20°C and +65°C), although the specific capacity retention decreases gradually to nearly 73 mAh/g during the 100 cycle charge/discharge test at 0.3C rate capacity.

Resume : We developed a novel fabrication method LaCoO3-SSZ composite cathode for solid oxide fuel cells via electrochemically assisted deposition of LaCoO3 into a porous SSZ scaffold. To do so, a highly porous SSZ scaffold was fabricated by screen printing SSZ ink containing 30 wt % PMMA pore-former onto a dense SSZ electrolyte layer of a NiO–SSZ|SSZ half-cell. The porous SSZ scaffold was made electrically conductive for the electrodeposition process by carbon deposition in a flowing N2/acetylene environment at 800 °C. Subsequently, lanthanum and cobalt were simultaneously deposited into the porous carbon coated SSZ scaffold by electrochemically assisted deposition involving the nitrate reduction and the hydroxide precipitation processes. The perovskite LaCoO3 phase was formed after a heat treatment in air at 800 °C for 5 h. The LaCoO3–SSZ composite cathode functional layer was characterized by the SEM, EDS and XRD analysis. The results indicated a formation of LaCoO3 into the porous SSZ scaffold in the form of dendrites initially and as the deposition time was increased the LaCoO3 dendrites were thickened and finally formed a dense layer on the top of SSZ scaffold. The deposition was found to be uniform inside the SSZ scaffold up till the dense electrolyte layer. The electrochemical testing of button cells showed a high performance, which indicated that the developed technique is promising and it should be further explored to fabricate high performance SOFCs.

Resume : Alloy-type anode materials are of great potential in replacing current generation of graphite anode owing to its high theoretical capacity (e.g. Si = 4200, Ge = 1600, GeO2 =1126 mAh g-1). However, large volume changes during lithiation/delithiation plagues these materials, resulting in poor cycling stability. On the other hand, alloying reaction in GeO2 has been shown to be more stable due to the presence of Li2O matrix that is able to buffer the volume changes during Ge alloying reaction.[1] Li2O is formed during the initial conversion of GeO2 to Ge as shown in equation 1. And equation 2 describes the reversible alloying of Ge and Li in subsequent charge-discharge cycles. GeO2 + 4 Li+ --> Ge+ 2 Li2 O (1) Ge+4.4 Li+ + 4.4 e- <--> Li4.4 Ge (2) Unfortunately, the conversion reaction (equation 1) is usually irreversible and the formation of Li2O results in low initial Coulombic efficiency (ICE). Early attempts by Kim et. al. to utilize transition metals as a catalyst to promote the reversible decomposition of Li2O in MGeO3 (M = Cu, Fe, and Co) saw a significant increase of ICE from 42.9 to 71.3 %.[2] Following this success, Seng and Hwang synthesized GeO2 with Ge embedded composites and demonstrated not only improved ICE but also significantly increased capacity as high as 1860 mAh/g at 2.1 A/g current density.[3, 4] Hence, by tapping on the reversible conversion reaction of Ge and decomposition of Li2O, the effective capacity of GeO2 can be increased to 2152 mAh/g (8.4 Li+) from 1126 mAh/g (4.4 Li+). However, despite the high capacities, the composites were unable to sustain over 100 charge-discharge cycles. This leads us to design and synthesize a nanocomposite that taps on catalyst mediated conversion reaction and an effective volume change buffer to fully realize the high potential of GeO2 as a suitable anode for Lithium-ion batteries. The nanocomposite consists of a Prussian Blue (PB) derived Fe2O3 core and GeO2 inner-shell and carbon coating as an outer shell. As a catalyst, HCl etching will be utilized to control the Fe composition in the composite. Porous carbon coating on the Ge2O3/Fe2O3 can be easily achieved through PB growth layer followed by annealing in N2. In this manner, the rational designed Ge2O3/Fe2O3/C structure is expected to deliver high energy density, good rate capability and able to sustain long cycles. References [1] M. N. Obrovac, V. L. Chevrier, Chem. Rev. 2014, 114, 11444. [2] C. H. Kim, Y. S. Jung, K. T. Lee, J. H. Ku, S. M. Oh, Electrochim. Acta 2009, 54, 4371. [3] K. H. Seng, M. H. Park, Z. P. Guo, H. K. Liu, J. Cho, Nano Lett. 2013, 13, 1230. [4] J. Hwang, C. Jo, M. G. Kim, J. Chun, E. Lim, S. Kim, S. Jeong, Y. Kim, J. Lee, ACS Nano 2015, 9, 5299.

Resume : The present work investigates the electrochemical performance of Fe/Fe2O3 incorporated porous electrospun carbon nanofibers (PCNFs) towards ultra-high charge-discharge aqueous supercapacitors. We will demonstrate our cost effective thermal treatment, where in-situ pores and FeOx nanostructures attributes both EDLC and Faradaic behavior, which results in a two-fold increase of charge storage. The HRTEM phase filtered composition shows the presence of a cubic Fe yolk surrounded by cubic Fe2O3 shell. The formation of these yolk-shell nanostructures will be explained by differences in the diffusion velocities between Fe3 and O2-, which is known as reductive transformation [1]. In our initial results, the cyclic voltammograms show quasi-EDLC behavior at 8 V/s and capacitance retention of about 97 % over 10,000 cycles at a scan rate of 1V/s. Additionally, we noticed the best ultra low time constant of 106 ms [2], remarkably, comparable to microsupercapacitor technology [3]. Under similar conditions, we also compare these results with CNFs and highly porous CNFs in various aqueous electrolytes. The fabrication of these yolk-shell nanostructures on CNFs matrix using one-step thermal treatment can provide cost effective high power supercapacitors to the energy storage community. References [1] B.D.A. and J.B. Tracy, Nanoparticle conversion chemistry: Kirkendall effect, galvanic exchange, and anion exchange, Nanoscale. 6 (2014) 12195–12216. doi:10.1039/C4NR02025A. [2] L. Wang, T. Wei, L. Sheng, L. Jiang, X. Wu, Q. Zhou, B. Yuan, J. Yue, Z. Liu, Z. Fan, “Brick-and-mortar” sandwiched porous carbon building constructed by metal-organic framework and graphene: Ultrafast charge/discharge rate up to 2Vs−1 for supercapacitors, Nano Energy. 30 (2016) 84–92. doi:10.1016/j.nanoen.2016.09.042. [3] D. Pech, M. Brunet, H. Durou, P. Huang, V. Mochalin, Y. Gogotsi, P.-L. Taberna, P. Simon, Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon, Nat. Nanotechnol. 5 (2010) 651–654. doi:10.1038/nnano.2010.162.

Resume : The performance of a lithium ion battery depends to a great extent on the properties of the electrolyte solution. Electrolytes used in commercial lithium-ion batteries are mainly formulated by the dissolution of lithium hexafluorophosphate (LiPF6) in mixtures of cyclic and linear carbonates. However, it is well known that LiPF6 is thermally unstable and decomposes in LiF and PF5, as well as, that PF5 can be hydrolysed in presence of residual water to form HF and PF3O [1]. Thereby, in depth studies have been conducted to select another safer lithium salts, including perfluoro anions, such as bis(trifluoromethylsulfonyl)imide (LiTFSI) and tris(pentafluoroethane)trifluorophosphate (LiFAP), as candidates for a more stable electrolyte [2]. In addition, the development of carbonate-based electrolytes is intimately linked to the desire to apply very high and very low voltage materials such as the LiNi1/3Mn1/3Co1/3O2 (NMC) and the graphite. Other systems such as the LiFePO4/Li4Ti5O12 (LFP/LTO) cells present a restricted voltage limits (3.4 and 1.5 V vs. Li+/Li for LFP and LTO, respectively) which permits the use of other solvents. Therefore, we present here a study on electrolytes composed of Li-salts (LiPF6 and LiTFSI) dissolved in acetonitrile at and above (i.e. superconcentrated) usual concentrations. The electrolytes were characterized of in terms of transport properties, such as the conductivity, viscosity and self-diffusion coefficients. Cyclic voltammetry, galvanostatic charge-discharge, and electrochemical were performed in order to study the performances of the LFP/LTO batteries in the acetonitrile based electrolytes. Results clearly indicate the reversible lithium intercalation into the LFP/LTO batteries. Acetonitrile-based superconcentrated electrolyte showed good cyclability (140 mAh.g-1 after 500 cycles) and coulombic efficiency (99%). [1]Z.chen,W,Q.Lu, J.Liu, K. Amine, LiPF6/LiBOB blend salt electrolyte for high power lithium-ion batteries, Electrochim. Acta 51 (2006) 3322-3326. [2] S.J. Gnanaraj, D.M. Levi, Y. Gofer, D.Aurbach, M Schmidt , A Salt for Rechargeable lithium Ion batteries. J.electrochem.Soc. (2003), 150, 445-454

Resume : Fe, Mo co-substituted BaTiO3 perovskite ceramics with compositional formula: BaTi0.5(Fe0.33Mo0.17)O3, which were synthesized by the standard solid-state reaction method and studied by X-ray diffraction, scanning electron microscopy (SEM) and a dielectric study was also invested. The X-ray powder diffraction data for this compound were refined using the Rietveld method. It was identified as a h-BaTiO3-type hexagonal perovskite with the space group of P63/mmc. New dielectric properties have been observed in this compound. Indeed, dielectric measurements showed that prepared compositions exhibit an evolution from a relaxor ferroelectric to a classical ferroelectric by increasing the temperature. Three dielectric peaks have been observed, which are originated from phase transitions from a cubic paraelectric to a tetragonal ferroelectric at the Curie temperature (TC), and then to an orthorhombic ferroelectric (at TT-O), and finally to a rhombohedral ferroelectric (at TO-R) similar to those of pure BaTiO3. A typical ferroelectric relaxor behavior is observed in regions I (330–473 K) and II (473–550 K) with a maximum in the dielectric permittivity (ε’r~3518 at 443K at 1 KHz and ε’r~4335 at 502K at 1 KHz) that shifts to higher temperature with increasing frequency. In region III (T > 650K), a classical ferroelectric behavior is observed. What is important in our study is that the three phase transitions observed in BaTiO3 are kept despite the significant doping made in titanium site, unlike many other recent works. The electrical properties analysed by impedance and electrical modulus spectroscopies showed that the grains play a major role in electrical properties, compared with the grain boundaries. The co-existence of the overlapping and separation between the frequency dependence plots of the normalized imaginary part ofimpedance (Z/Zmax) and electric modulus (M/Mmax) peaks is observed.

Resume : Sn possesses three times higher capacity in comparison to graphite anode (372 mAhg-1) that makes it a promising candidate for enhanced performance Li ion batteries. Contrary to Si, Sn is compliant and ductile in nature and thus is expected to readily relax the Li diffusion-induced stresses. The low melting point of Sn additionally allows for stress relaxations from time-dependent or creep deformations even at room temperature. In this study, numerical modeling is used to reveal the significance of plasticity and creep-based stress relaxations in the Sn working electrode. The maximum elastic tensile hoop stresses for 1 μm micropillar size with 1C charging rate conditions reduces down from ∼1 GPa to ∼200 MPa when Sn is allowed to plastically deform at a yield strength of ∼150 MPa. After experimentally determining the creep response of Sn nanopillars, creep deformations are incorporated in numerical modeling to show that the maximum tensile hoop stress is further reduced to ~ 0.45 MPa under the same conditions. Moreover, the Li induced stresses are analyzed for different micropillar sizes to evaluate the critical size to prevent fracture, which is determined to be 5.3 μm for C/10 charging rate, which is significantly larger than that in Si. Experimental verification of fracture resistance of Sn will also be dicussed.

Resume : Polycrystalline Hematite thin films doped by Cr were successfully deposit on glass substrate coated with fluorine-doped tin oxide (FTO) by electrodeposition method. The electrodeposition bath consisted of an aqueous solution containing FeCl36H2O, KCl, and H2O2 and subsequently the as-deposited samples were annealed in air at 650 °C for 2 hours. Structure and Morphological characteristic of α-Fe2O3 thin films were charactrized by X-ray differection, scaning electron microscopy and UV- Vis spectroscopy. The effect of doped Cr were proven by defraction peaks (012) and (104) shifs to the lower angls. the photoelectrochemical performance of the thin films was eximined by chronoaperometry and linear sweep voltametry tecniques. Results of these studies showed that Cr doped films exibited higher photoelectrochemical activity over un-doped α-Fe2O3 thin films. The highst photocurrent density of 0.015 mA cm-2 was obtaind for 8% Cr doped films in 1 M NaOH electrolyte under standerd illumination conditions ( AM 1.5 G, 100 mW cm-2). This high photoactivity can be attributed to the high active surface area and increasd doner density caused by Cr doping in the α-Fe2O3 films.

Resume : Nowadays, one of the most interesting research in the renewable energy field is to design lignocelluosic biomass structure to produce higher valuable products. The valorization of waste is very attractive for both sustainable and material chemistries. Recently, waste-derived biomasses including glucose, cellulose, starch, lignin, or biochar has been used as a natural and abundant precursor to synthesize functional carbon nanomaterials. Among various biomass materials, the lignocellulosic biomass consisting of cellulose, hemicellulose and lignin is the most abundant renewable resource. In this study, we report a high-performance sodium ion energy storage and highly selective CO2 adsoprtion using novel phosphorous (P), sulfur (S) and nitrogen (N) doped nanoporous carbon via a one-step hydrothermal method. In addition, during hydrothermal process cellulose and lignin were simultaneously separated from lignocellulosic biomass without any pre-treatment. The doped nanoporous carbons have highly active sites and well-developed pores with the high surface area and pore volume of 1154 m2 g-1 and 2.47 cm3 g-1, respectively, 330 times greater than those of raw lignocellosic biomass. In particular, P doped porous carbons exhibited the high specific capacitance of 298.43 F g-1 at 10 m V-1 and cycle retention of 90.67% after 1000 cycles in 1M KOH. For the CO2 adsorption test, N doped porous carbon showed the highest CO2 adsorption capacity of 10.79 mmol g-1 among the doped porous carbons and excellent cycle retention of 88.90 % after 10 cycles. Consequently, this chemical synthesis can be an important opportunity for the transformation of raw biomass to valuable materials.

Resume : With the development of wearable devices, research on flexible energy storage devices has become necessary. To apply those to a wearable device, it is necessary to avoid harmful elements to the human body. The use of a gel electrolyte is essential for the energy storage device to be used for wearable devices, since there is a risk of spillage of liquid-type electrolyte. The choice of a flexible current collector is also important. Graphite felt and graphite foil are suitable as current collectors due to their high electrical conductivity, excellent mechanical properties and non-toxic properties. Supercapacitors have higher power density and better life stability than lithium-ion batteries. On the other hand, they have a lower energy density than lithium ion batteries. To improve the energy density of supercapacitor, a battery-type electrode and an EDLC-type electrode are configurated as a hybrid system. The hybrid configuration extends the operating voltage over 1V and combines the high capacity of battery-type electrode and the high power of EDLC-type electrode. In this study, the intense pulsed white light (IPWL) technique is used to fabricate the battery-type electrode. Using this technique, metal oxides can be synthesized simply and quickly on various type of current collectors. EDLC-type electrode is fabricated by casting the slurry of the active material. It is important to control the charge balance in a hybrid configuration. The optimal charge balance condition is found by controlling the mass ratio and the working potential of the cathode and anode.

Resume : Carbon materials in duo with metal/metal oxide (M/MO) nanostructures are preferred candidates in Li-ion battery (LIBs) and Supercapacitors (SC) by virtue of their good electrical conductivity and excellent mechanical/electrochemical stability. However multistep synthesis methods hinder their practical applications. To address this issue we proposed the simple and scalable, deep eutectic solvent (DESs) assisted synthesis route for the preparation of M /MO –carbon nanocomposite (M/MO-C). In this work, a tin/tin oxide nanoparticles embedded in a carbon matrix with high surface area (~500 m2/g) are fabricated by one-pot pyrolysis of DESs in the inert ambient. The DESs in this work collectively acts as a solvent-precursor-reactant system and thus offers an interesting alternative for the conventional multistep synthesis route. Also, the selection of less toxic component is possible by virtue of compositional versatility of DESs. Furthermore, electrochemical measurements of synthesized carbonaceous composite for LIBs and SCs reveal its high capacity value and superior cycling performance compared to those of literature by the virtue of their high electrochemically active surface area, good conductivity, and firm structure framework. The present biocompatible synthesis route can open the new era for design and development of other M/MO-C composite with a high electrochemical performance for energy storage devices.

Resume : Recently photoelectrochemical (PEC) water splitting has considered as one of the most promising method for clean and renewable energy. In an effort to find proper materials for water splitting, many metal oxides and semiconductors were studied in recent years. Among various materials, copper oxide (CuO) have attracted a lot of interest due to non-toxicity, abundance, facile, low cost, and scalable production. In particular, CuO could absorb a wide range of the solar light including near IR region due to its narrow band gap (Eg = 1.2 eV). However, its short diffusion length and low conductivity cause the recombination of photo-generated carriers. As a result, it could lead to decrease of PEC performance immediately. To prevent this problems in water splitting, several approaches have been developed including a three-dimensional (3D) branched nanowires (b-NWs) design or 3D networks structure design or TiO2 coating on the NWs surfaces, or a TMD materials used as co-catalyst. In this work, we report the fabrication of 3D CuO b-NWs for efficient water splitting. Highly dense 3D b-NWs were grown on copper substrates, on which MoS2 nanosheets were coated. Using the 3D CuO b-NWs, we demonstrated an improved PEC performance compared to the CuO NWs. To improve the PEC performances, three-dimensional (3D) CuO branched nanowires (b-NWs) were fabricated by combining several solution-based process. The copper mesh was used as the starting substrate. The growth process of Cu(OH)2 NWs by wet chemical oxidation method, Cu(OH)2 NWs turned into CuO NWs by annealing process in the furnace, Cu thin film as a seed layer by E-beam evaporation, and CuO nanorod as branches by chemical precipitation methods performed. Then, highly dense 3D CuO b-NWs were grown on copper mesh substrates and it used as photocathodes directly. Diameters ranging from 50 to 500 nm and over 10 µm in lengths CuO NWs were observed. In particular, bending of CuO NWs were observed due to H2O molecule released during annealing process. The transformation of Cu(OH)2 NWs to CuO NWs as follows: Cu(OH)2 → CuO + H2O. The scanning electron microscopy showed the three-dimensional (3D) CuO branched nanowires (b-NWs). Highly dense branches were attached to CuO NWs backbone. Branches ranging from 100 to 500 nm in length and ranging from 10 to 200 nm in diameter 3D CuO b-NWs were observed. PEC measurement showed dark current and photo current simultaneously. The 3D b-NWs provide a higher photocathodic current density compared to conventional CuO NWs due to effective charge transport and increased surface area. In particular, maximum current density 1.37 mA/cm2 was observed at ~0.05 V under 100 mW/cm2 (1 sun) illumination when 3D CuO b-NWs grown on copper gauze substrates. In case of conventional CuO NWs on copper gauze substrates, maximum current density 0.77 mA/cm2 was observed at ~0.05 V under 100 mW/cm2 (1 sun) illumination. When MoS2 nanosheets were coated on the b-NWs, the current density enhanced by three times. This provides evidence that the MoS2 played a critical role in producing H2 generation during the electrochemical reaction. From these, the mechanism for the H2 production at the surface of MoS2 will be discussed.

Resume : Recently, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) has attracted intensive attention for energy storage applications.[1] Organic radical batteries built with this polymer display high power performance. However, the solubility of PTMA in commercial electrolytes shortens the lifespan and the overall performance of the battery. To circumvent this issue, we propose to immobilize PTMA in a threedimensional network. Indeed, an electrolyte swollen network (gel) enables a good ionic diffusion and brings good mechanical properties to the cathodic material. Here we report on the synthesis of PTMA gels by a combination of Cu(0)-mediated reversible-deactivation radical polymerization and coppercatalyzed azide–alkyne cycloaddition (CuAAC).[2] The structure of the accordingly obtained gels is characterized by NMR, SEC and FTIR and the mechanical properties of these materials are studied by rheology. Finally, their electrochemical performances are studied in the context of organic radical batteries. [1] A. Vlad, N. Singh, J. Rolland, S. Melinte, P. Ajayan, J.-F. Gohy, Scientific Reports, 2014, 4. [2] F. Boujioui, O. Bertrand, B. Ernould, J. Brassinne, T. Janoschka, U. S. Schubert, A. Vlad and J.-F. Gohy, Polym. Chem., 2017, 8, 441-450.

Resume : The project aims at developing in-operando experimental methods to study the process of heterogeneous catalysis in PEM fuel cells under realistic conditions. This will enable a deeper insight into catalytic mechanisms and will help designing more efficient fuel cells. PEM fuel cells optimized for in-operando characterization will be realized at Charles University of Prague by the group of Prof. Vladimír Matolín, and the in-operando analysis will be carried out at Elettra synchrotron at Trieste, by the groups of Heinz Amenitsch (SAXS) and Giuliana Aquilanti (XAS). Operando SAXS and XAS spectroscopy will be used to investigate the catalytic activity in PEM fuel cell on both chemical and structural level and will be focused onto degradation phenomena such as coalescence, dealloying and dissolution. Further information will be obtained via accelerated durability tests.

Resume : Immobilization driven materials design has alleviated the poor capacity retention of organic electrode materials to a great extent in recent years.[1] However, organic materials have an inherent drawback of low reduction potential and consequent low discharge potential, which remains as a catastrophic block for its applications at the cathode side. 3,4,9,10-perylenetetracarboxylic anhidride (PTCDA), with a low lying LUMO and eight free bay and ortho positions for substitutions, is an ideal system to tailor a molecule with higher reduction potentials.[2] Firstly, a polyimide (PI) was synthesized through polymerization of PTCDA with hydrazine linker to yield a low molecular weight polymer which offers high reversible capacities above 120 mAhg-1 at 0.25 C with a good cyclic stability upon gavalnostatic cycling against Li and Na.[3-4] Subsequently, an all-organic sodium ion full cell is fabricated for the first time, with PI as cathode and disodium terephthalate as anode, offering an energy density of 100 Whkg-1.[4] Further, we demonstrate a simple and efficient approach to tune the redox properties of perylene poly/diimides by various aromatic electrophilic substitution reactions as high voltage cathodes for organic-based SIBs.[5] [1] Y. Liang, Z. Tao, J. Chen, Adv. Energy Mater. 2012, 2, 742 [2] C. Huang, S. Barlow, S. R. Marder, J. Org. Chem. 2011, 76, 2386 [3] P. Sharma, D. Damien, K. Nagarajan, M. M. Shaijumon, M. Hariharan, J. Phys. Chem. Lett. 2013, 4, 3192 [4] H. Banda, D. Damien, K. Nagarajan, M. Hariharan, M. M. Shaijumon, J. Mater. Chem. A 2015, 3, 10453 [5] H. Banda, D. Damien, K. Nagarajan, M. Hariharan, M. M. Shaijumon, Chem. Mater. 2017 (Under revision)

Resume : The vat dyes are one of the cheapest commercial dyes that are widely applied to the textile industry using their reversible redox-reactions. Among others, 9,10-anthraquinone (AQ), which is the smallest vat dye, have been successfully employed as cathode material for secondary batteries, so far. However, it suffers from fast capacity fading due to high solubility in organic electrolytes and poor rate performance arising from low electrical conductivity. To solve these issues, many strategies have been proposed including polymerization and physical/chemical immobilization of the molecules on the surface of carbon nanomaterials. But, from a practical point of view, these methods raise new difficulties such as additional cost for preparing the polymers and/or the carbon nanomaterials, and low active content in the electrode. Here, we present a series of commercial vat dyes including indanthrone, flavanthrone, and violanthrone, which are derivatives of AQ, for use in secondary batteries as cathode materials. It is found that the three vat dyes have higher redox potential than that of AQ attributed to the enlarged π-conjugation and/or electron withdrawing effect of the heteroatoms. Most importantly, in coin cells, electrodes containing the dyes show much improved cyclability and rate performance compared to AQ without any additional treatments due to their complete insolubility in organic solvents and high charge transport ability due to strong π-π intermolecular interaction.

Resume : Among the various electrochemical storage systems, lithium-ion batteries (LIBs) appear as a flagship technology able to power an increasing range of applications because of their high energy density values. Consequently, the world production of LIBs is expected to keep on growing. However, faced with a production of several million units a year, one has also to consider their own environmental burden. In this context, finding alternative and ?greener? electrochemical storage systems appears also quite important. A possible parallel research consists in developing organic electrode materials. Basically, organic materials are composed of quite naturally abundant chemical elements (C, H, N, O, in particular) giving them the true possibility of being potentially prepared from renewable resources and eco-friendly processes. In addition, this multiplicity of chemical combinations at the molecular level also gives rise to an incomparable tool for tuning the redox potential of promising organic structures. Finally, two types of electrochemical insertion mechanisms can be used in practice with either reversible uptake/release of cations or anions. In this communication, we will present recent advances for developing high potential organic electrode materials. In particular, we will report on several types of terephthalate derivatives able to reversibly host cations or anions by electrochemical reactions.

Resume : Aqueous electrolyte ion-batteries constitute a new promising technology in the context of low cost energy storage systems, which reduces the cost, risk and environmental impact compared to other battery technologies. However, among the enormous range of active materials available from the field of non-aqueous batteries, only few of them offer the combination of appropriate potential as well as high chemical and electrochemical stability in aqueous media. One of the main goal being the use of cheap, abundant, recyclable and non-toxic organic active materials, appears as a logical step towards the improvement of environmental and economic aspects[1]. This talk will present the electrochemical and physical behaviors of n and p type derivatives in several neutral aqueous electrolytes showing outstanding cyclability and coulombic efficiency can be achieved. [1] Nishida, S., Yamamoto, Y., Takui, T., & Morita, Y. (2013). ChemSusChem, 6(5), 794-797

Resume : Binders are key materials in Lithium-Ion Batteries (LIB), especially with regard to the electrode manufacturing processes. In fact, the binder provides the adhesion between the particles and to the current collector and affects the slurry rheology. The possibility of using water-based processes, which grant substantial cost and environmental impact reduction with respect to those based on organic solvents, is determined by the binder nature [1]. Therefore, we investigated an appealing biopolymer, Guar gum, and two of its derivatives. These polymers are electrochemically stable within the operating voltage of LIBs (0.01 – 5 V) and do not show evidences of thermal decomposition up to 200° C. The electrochemical performance of several electrode materials, e.g., lithium nickel manganese cobalt oxide (NMC), graphite and lithium titanate (LTO), prepared using guar gum binders was investigated. The results are compared with those obtained using sodium carboxymethyl cellulose (Na-CMC) binder. While at low currents (0.1C) guar gum-based electrodes deliver only slightly higher capacities than those based on Na-CMC, at higher currents the improvement in performance is outstanding. For instance, a NMC cathode at 5C delivered around 100 mAh g-1 and 88 mAh g-1 using guar gum and Na-CMC, respectively. We attribute this behaviour to a better affinity of the guar gum biopolymer chain to organic electrolytes [2,3]. Furthermore, the use of guar gum permits to increase the NMC loading (from 88 wt.% to 90 wt.%), thus, allowing for further enhanced energy densities. 1. Loeffler, N.; Von Zamory, J.; Laszczynski, N.; Doberdo, I.; Kim, G. T.; Passerini, S. Performance of LiNi1/3Mn1/3Co1/3O 2/graphite batteries based on aqueous binder. J. Power Sources 2014, 248, 915–922. 2. Lee, B.-R.; Kim, S. -j.; Oh, E.-S. Bio-Derivative Galactomannan Gum Binders for Li4Ti5O12 Negative Electrodes in Lithium-Ion Batteries. J. Electrochem. Soc. 2014, 161, A2128–A2132. 3. Carvalho, D. V.; Loeffler, N.; Kim, G. T.; Passerini, S. High temperature stable separator for lithium batteries based on SiO2 and hydroxypropyl guar gum. Membranes. 2015, 5, 632–645.

Resume : One of the main limitations in today?s lithium (Li) ion batteries lies in the flammability of the conventional liquid electrolyte. A solution is to replace it by an inherently safe solid polymer electrolyte. For this purpose, a new generation of nanostructured single-ion blockcopolymer electrolytes (BCE), comprising poly(ethylene oxide) (PEO) as conducting block and a polyanionic poly(styrene sulfonyl(trifluoromethanesulfonyl) imide of lithium) (PSTFSI) as structural block, has successfully been developed . To evaluate the influence of the structural block on the electrolyte performance, we compare here the physico-chemical and electrochemical properties of several families of single-ion BCE with different structural blocks like acrylate, methacrylate and styrene with grafted STFSI. Small-angle X-ray scattering revealed that at temperatures lower than the PEO block melting temperature, the morphology of all SIELs is lamellar whereas at higher temperatures the electrolytes are in a disordered state. All the block copolymer electrolytes reported here behave as single-ion conductor, independently of the nature of the structural block. Moreover, at high salt concentration, the ionic conductivity of the ATFSI-based electrolytes is larger than that of the PSTFSI-based electrolytes by at least a factor of two. Based on detailed transport analysis by impedance spectroscopy and PFG-NMR, we argue this results from an improved compatibility between the acrylate and PEO blocks. Our study underlines the need of carefully selecting the nature of the structural block to optimize the performance of single-ion BCE. At last, for a complete analysis, the results obtained with several prototypes of batteries will be presented.

Resume : Polycarbonates have been proposed as alternative materials to poly(ethylene oxide) as the polymeric matrix for solid polymer electrolytes (SPEs). Aliphatic polycarbonates SPEs have shown excellent ionic conductivity values even at room temperature, good electrochemical stability and high lithium transference number. In these works, the aliphatic carbonates have been synthesized using two main routes, ring-opening polymerization of cyclic carbonates[1] and copolymerization between CO2 and epoxides[2]. Although these synthetic routes are successful, they show some limitations and synthetic difficulties for the chemical modification of the polymer backbone. Alternatively in this oral presentation, we present conventional polycondensation as a route to innovative polycarbonates for SPEs[3]. The synthetic reaction involves the melt condensation of dimethylcarbonate with different diols at high temperatures and high vacuum conditions in the presence of an organocatalyst[4]. In this oral presentation the influence of electrochemical properties, such as ionic conductivity, electrochemical window and lithium transfer number will be studied based on the chemical structure of the polycarbonate, the type of the salt utilized on the SPE and salt concentration. References [1] J. Mindemark, B. Sun, E. Törmä, D. Brandell, High-performance solid polymer electrolytes for lithium batteries operational at ambient temperature, Journal of Power Sources, 298 (2015) 166-170. [2] Y. Tominaga, T. Shimomura, M. Nakamura, Alternating copolymers of carbon dioxide with glycidyl ethers for novel ion-conductive polymer electrolytes, Polymer, 51 (2010) 4295-4298. [3] J. Sun, D. Kuckling, Synthesis of high-molecular-weight aliphatic polycarbonates by organo-catalysis, Polymer Chemistry, 7 (2016) 1642-1649. [4] L. Meabe, N. Lago, L. Rubatat, C. Li, L. M. Rodríguez-Martinez, H. Sardon, M. Armand, D. Mecerreyes, Polycondensation as a Versatile Synthetic Route to Aliphatic Polycarbonates fof Solid Polymer Electrolytes, Electrochimica Acta, (2016) (submitted).

Resume : Lithium-ion batteries are the most appropriate technologies for electric and hybrid vehicles. More than energy density, cost, lifetime or recyclability, safety issue has to be considered. Separator impacts all these properties and it is important to evaluate its evolution in time because, although it is frequently considered as electrochemically inert, it can age and take part in the degradation of a battery. The aim of this study is to determine the evolution of its morphological and mechanical properties under various ageing conditions by evaluating its porosity (Helium pycnometer), its mechanical properties (tensile test). Surface chemical composition is also investigated by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, and surface state by scanning electronic microscopy (SEM) and by atomic-force microscopy (AFM). Moreover, consequences of these evolutions in term of electrochemical performances are analyzed by impedance spectroscopy and C-rate test. The separators, which are studied herein, are in polyethylene with PVdF-HFP coating and have been took from NMC/G batteries systems which aged in calendar at two different temperatures and at 100% of their state of charge. We will show that some conditions of aging have produce degradation on the separator. A mechanistic model of aging will be proposed.

Resume : A high cross-over of vanadium ions through the separator located between the porous electrodes in the VRB results in capacity and efficiency losses and limits its use as energy storage device. For the use in VRBs we, therefore, designed ion-exchange membranes (IEMs) with reduced vanadium permeability and ohmic resistance lower or comparable to that of Nafion® 117. ETFE-g-poly(S-co-AN) and ETFE-g-poly(VP) membranes were obtained by radiation-induced grafting of styrene (S), acrylonitrile (AN) and vinylpyridine (VP) monomers onto ethylene tetrafluoroethylene (ETFE) films followed by functionalization to introduce cation exchange sites and vanadium barrier motifs. Thus, the key properties of the membranes, such as vanadium ion permeability and ohmic resistance, could be readily tuned and improved. The modification of membranes with functionalities such as positively charged vinylpyridinium units or amidoxime groups, which can prevent vanadium ions from entering the membrane, resulted in significant suppression of their vanadium permeability. The presence of protogenic groups in the membranes, such as sulfonic acid groups, furthermore allowed the reduction of their ohmic resistance. As a result of their improved properties, cells with radiation grafted membranes carrying distinct functionalities showed higher efficiency and a less pronounced capacity fading compared to the cells with Nafion® 117.

Resume : Recently, solid polymer electrolytes are largely considered as possible advanced materials for the development of flexible and safer solid-state supercapacitors. Here, we report the study of supercapacitor cells constructed with carbon xerogel electrodes and with solid polymer electrolyte based on sulfonated polyether ether ketone (SPEEK). The carbon xerogel is a pre-commercial carbon kindly furnished from CSIC-INCAR of Oviedo (Spain); whereas the sulfonated PEEK was synthesized in our lab by a well-experienced process based on the heterogeneous sulfonation of the bare PEEK polymer with sulfuric acid. Various types of solid-state supercapacitor cells were realized by contacting face-to-face the SPEEK electrolyte membrane and the two 2 cm2 electrodes. The electrochemical characteristics of supercapacitors were investigated in a specific designed titanium cell provided of a reference electrode. A KI solution was used as an additive of electrolyte and impregnate in the positive electrode while the Na2SO4 was used to realize a cation exchange SPEEK membrane and to impregnate the negative electrode. The SPEEK membrane in the supercapacitors acted as an ion conductor and electronic insulator between the two carbon composite electrodes. Whereas, the KI salt added to the positive side of supercapacitor had the task of providing additional capacity through the I?/I3? redox reaction, to which a possible hydrogen electro-sorption reaction occurred to the negative electrode of the carbon?carbon capacitor. These supercapacitors were electrochemical investigated by cyclic voltammetry (CV), DC galvanostatic charge/discharge and AC electrochemical impedance spectroscopy (EIS). As results, it were found that the solid-state supercapacitor based on Na-SPEEK membrane and with iodide species in the positive electrode exhibited higher specific capacitance (180 Fg?1) compared to these with the porous separator impregnated with 1M Na2SO4 (93 Fg?1), while the specific capacitance obtained with Na-SPEEK electrolyte membrane (83 Fg?1). The EIS analysis highlighted that the solid-state supercapacitor based on Na-SPEEK and KI showed very stable low resistance and full capacitance retention during a long stability test with 20000 cycles at 2 Ag?1 and more than 200 h in voltage holding condition at 1.6 Volt. The results of the remarkable electrochemical performance (200 Fg?1, 20 Wh kg?1) and excellent lifetime stability displayed from this configuration of supercapacitors is promising for the development of next-generation low cost, high-performance, solid-state and flexible energy storage devices.

Resume : With the advent of flexible and wearable electronics, there has been an escalating demand for efficient and safe energy storage technologies. Supercapacitors (SCs) constitute a sustainable solution due to their high power density, high charging rate and stability. Hybrid carbon–metal oxide nanomaterials are promising electrode materials for the production of high-performance SC devices on paper and textiles with improved flexibility and lightness. In this work, a novel hybrid carbon-based nanomaterial was produced through the grafting of cobalt(II) ferrite nanoparticles (CoFe2O4) onto N-doped carbon nanotubes (CNT-N) by an in situ eco-friendly one-pot coprecipitation route. The resulting hybrid contained ~30 wt% of CoFe2O4 at the CNT-N surface, with 5.4 nm average size. Both the hybrid and CNT-N were incorporated on paper substrates in order to produce symmetric and asymmetric solid-state paper-based SCs. The asymmetric hybrid SC presented the best performance, with an enhancement of the energy density (ES) and power density (PS) of ~12% and ~13%, respectively, relative to the CNT-N based SC counterpart, reaching ES = 3.1 Wh/kg and PS = 21.7 W/kg at 0.5 mV/s. The high conductivity and N-containing groups of CNT-N support combined with the redox properties of CoFe2O4 were responsible for this achievement. Acknowledgements: Work funded by FCT/MEC and FEDER under Program PT2020 (projects “UniRCell”, ref. POCI-01-0145-FEDER-016422 and UID/QUI/50006/2013-POCI/01/0145/FEDER/007265). CP thanks FCT for Investigator contract IF/01080/2015.

Resume : Lithium-ion and sodium-ion batteries have attracted increasing attention because of the critical demands from high-power portable electronics, electric vehicles, and large-scale storage devices for renewable energy. Although Lithium-ion batteries have gained applications in portable electronics, their current performance is unsatisfied for these new demands in terms of capacity and rate capability. Depending on the low cost and abundant source of sodium, sodium-ion batteries are of great importance, especially for larger-scale energy storage devices. However, the larger radius of Na+ leads to a worse kinetics and structural stability for electrode materials compared to lithium-ion batteries. In principle, nanoparticle-based electrode materials have huge potential to achieve excellent electrochemical performance because of potentially fast transport kinetics. Nonetheless, nanoparticle-based electrodes still give rise to a multitude of challenging kinetics and structure stability problems, such as the agglomeration of nanoparticles, increased contact electronic resistance between nanoparticles, volume change on cycling, and instability of solid electrolyte interphase (SEI). As a result, the performance of nanoparticles-based electrode materials is not as good as expected, and prevents their use in commercial batteries. To overcome the above persistent problems of nanoparticle-based electrodes, we have developed a series of electrode materials with multi-scale, multi-dimensional and hierarchically ordered nanostructures.1-3 In such hierarchical structures, the low-dimensional nanoparticles serve as active components to contribute capacities while the high-dimensional conductive carbon skeletons play an important role to favor the kinetics of electron/ions transport and to keep the electrode structure stable. For the high capacity nanoparticles based the conversion and alloy storage mechanisms, the appropriate void spaces around them are involved to address the large volume change issues on cycling. The electrode structure designs integrate the advantages of low-dimensional nanoparticles and high-dimensional electron conductive network, and construct highly efficient and stable electrochemical circuits involving the active nanoparticles. As a result, the obtained electrode materials show excellent lithium/sodium storage performances in terms of reversibility, cycle-stability and rate-capability. For instance, the graphene/NaTi2(PO4)3 electrodes show a high rate-capability for sodium storage (112 mAh g-1 at 1C, 105 mAh g-1 at 5C, 96 mAh g-1 at 10C, 67 mAh g-1 at 50C) and a long cycle-life (capacity retention of 80% after 1000 cycles at 10C).3 The graphene/Ni2P electrodes deliver an initial charge capacity of 461 mAh g-1 at 0.3 A g-1 for lithium storage, almost no capacity fades even after 500 cycles.1 Reference: 1. Wu, C.; Kopold, P.; van Aken, P. A.; Maier, J.; Yu, Y., Advanced Materials 2017, 29, 1604015. 2. Wu, C.; Maier, J.; Yu, Y., Advanced Functional Materials 2015, 25, 3488. 3. Wu, C.; Kopold, P.; Ding, Y. L.; van Aken, P. A.; Maier, J.; Yu, Y., ACS Nano 2015, 9, 6610.

Resume : Phosphorene, monolayer or few-layer black phosphorus (BP), has recently triggered strong scientifi c interest for lithium/sodium ion batteries (LIBs/ SIBs) applications. However, there are still challenges regarding large-scale fabrication, poor air stability. Herein, we report the high-yield synthesis of phosphorene with good crystallinity and tunable size distributions via liquidphase exfoliation of bulk BP in formamide. Afterwards, a densely packed phosphorene–graphene composite (PG-SPS, a packing density of 0.6 g cm −3 ) is prepared by a simple and easily up-scalable spark plasma sintering (SPS) process. When working as anode materials of LIBs, PG-SPS exhibit much improved fi rst-cycle Coloumbic effi ciency (60.2%) compared to phosphorene (11.5%) and loosely stacked phosphorene–graphene composite (34.3%), high specifi c capacity (1306.7 mAh g −1 ) and volumetric capacity (256.4 mAh cm −3 ), good rate capabilities (e.g., 415.0 mAh g −1 at 10 A g −1 ) as well as outstanding long-term cycling life (91.9% retention after 800 cycles at 10 A g −1 ). Importantly, excellent air stability of PG-SPS over the 60 days observation in maintaining its high Li storage properties can be achieved. On the contrary, 95.2% of BP in PG sample was oxidized after only 10 days exposure to ambience, leading to severe degradation of electrochemical properties.

Resume : The family of two-dimensional (2D) transition metal carbides, MXenes, has been expanding rapidly since the discovery of Ti3C2 in 2011 [1]. About 20 different MXenes have been synthesized, and the structure and properties of more than 30 other MXenes have been theoretically predicted. The availability of solid solutions on M and X sites, control of surface terminations, and a recent discovery of multi-element layered MXenes offer a potential for synthesis of dozens of new distinct structures rendering MXenes the largest known family of 2D materials. MXenes versatile chemistry renders their properties tunable for different applications, such as energy storage devices, reinforcement for composites, water purification, catalysts in the chemical industry, bio- and gas-sensors, lubrication, photocatalysts, etc. We will describe energy storage and related applications of MXenes ranging from Li- and Na-ion batteries and supercapacitors to Li-S batteries. At the end, a general summary and outlook for the future research on 2D transition metal carbides, carbonitrides and nitrides will also be presented. 1. B. Anasori, M. R. Lukatskaya, Y. Gogotsi, 2D metal carbides and nitrides (MXenes) for energy storage, Nature Reviews Materials, 2, 16098 (2017)

Resume : Recently, rapid developments of compact mobile and wearable electronics and micro-medical devices are accelerating an increasing demand for miniaturized energy storages such as micro-supercapacitors. Graphene, a representative two-dimensional carbon material, has attracted enormous interest due to its excellent electrical, mechanical, physical and chemical properties. In particular, many efforts have been made to fabricate graphene-based micro-supercapacitors due to its large specific surface area and superior electrical conductivity. However, many of the attempted fabrication processes have drawbacks, such as complicated multiple-step procedures to create micron-sized interdigitated electrodes and usage of harmful or toxic chemicals during the etching process. In addition, high-temperature treatment is demanded to obtain high-quality graphene materials which is suitable for high-performance graphene-based micro-supercapacitors. Therefore, simple, cost effective and energy efficient strategies are still required for the fabrication of graphene-based micro-supercapacitors. Here, we report a simple, agile and facile method for the fabrication of three-dimensionally printed micro-supercapacitors with high-aspect-ratio electrode micro-arrays using a pneumatic printing technique in conjunction with an intense pulsed white light (IPWL) technology. By using this combined method, micron-sized electrode patterns can be easily printed on diverse substrates, and graphene- or metal oxide-based three dimensional micro-patterns can be fabricated within milliseconds by irradiating the IPWL on graphene oxide or metal oxide precursor patterns, which is exceptionally faster and easier than other graphene reduction and metal oxide formation methods. The as-prepared micro-patterns are further utilized as micro-supercapacitor electrodes, and their electrochemical properties and supercapacitive performance are investigated by means of cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy.

Resume : KEYWORDS: Ti3C2Tx, Flexible films, Electrochemistry, Vanadium oxide hydrates, Super-capacitors ABSTRACT: 2D Ti3C2Tx MXene are considered to be promising candidates for the use in supercapacitors. It is worthy to effectively design hierarchical structures to expand the spaces between the Ti3C2Tx MXene layers. Herein, we describe a 2D freestanding Ti3C2Tx-V2O5•0.5H2O films for super-capacitors. The V2O5•0.5H2O nanowires were uniformly sandwiched between the MXene layers, which effectively enhances the spaces for charge storages. Until submit the abstract, roughly, our study show that the freestanding MXene paper electrodes exhibit a volumetric capacitance of 375 F cm-3 at 5 mV s-1 in neutral KCl electrolyte, which is higher than that of 269 F cm-3 in LiCl and 267 F cm-3 in NaCl electrolytes. The present study provides direct experimental evidence for the contribution of ultra-long V2O5•0.5H2O nanowires to expend layered MXene, which is also helpful for the development of metal oxides-MXene hybrids beyond energy storage devices.

Resume : Mixed transition metal oxides have recently attracted great attention due to improved electrochemical and electrical properties than simple oxides especially in energy storage applications. Herein, we report on facile synthesis of a novel 2D nanocomposite of porous nanosheets of NiCoMnO4 with reduced graphene oxide as high performance material for energy storage devices. Samples were characterized by XRD, Raman, TGA, TEM and N2 ad/desorption measurements. Their electrochemical behavior was investigated through cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The reaction conditions were systematically optimized to get the highest energy storage performance. Accordingly, 2D porous NiCoMnO4 nanosheets/graphene nanocomposite exhibited a high capacity of 115 mAh g-1. Furthermore, integration of this 2D porous nanocomposite electrode with reduced graphene oxide electrode resulted in an asymmetric aqueous device with capacity and specific energy as high as 36 mAh g-1 and 26 Wh kg-1, respectively, while keeping excellent cycling stability over 2000 cycles. This work not only reports for the first time the rational design and fabrication of a novel 2D porous NiCoMnO4/graphene nanocomposite as high performance electrode material for energy applications but also paves the path towards facile synthesis of 2D mixed metal oxides nanocomposites for different applications.

Resume : At the height of the technology-driven society era, technology relies upon development of advanced energy storage systems that can power a wide variety of portable gadgets and mobile or stationary applications, from handy electronics to renewable energy storage systems. Within the last three decades, scientific and engineering community focused efforts on the development of batteries and supercapacitors to satisfy requirements of such a widespread range of applications. Although supercapacitors present superior features than batteries in almost all aspects, it is their low energy density that has condemned them in most of the applications and boost batteries market entry. Nevertheless, in the race to fulfill the need of new fast growing and forthcoming applications, such as electric vehicle or aerospace, achieving a combination of high energy density and high power density is an essential requirement for success. Consequently, interest in supercapacitors has grown over the past years and they are now back in the playground, lately mostly in the form of hybrid supercapacitors. Recently, most promising results arise from the use of graphene. In this contest, we present a fully graphene based lithium ion capacitor with high energy and power densities in gravimetric terms with long cycle life. Anode is based on a self-standing, binder free 3D macroporous foam formed by reduced graphene oxide and decorated with submicron tin oxide-based nanoparticles while the cathode is based on a physically activated thermally expanded graphene oxide. Bringing them together, an all graphene based lithium ion capacitor capable to deliver 180Wh/kg at 150 W/kg and 10Wh/kg at 10KW/kg was fabricated.

Resume : Battery materials exhibit high energy density by utilizing reversible redox reactions, but their slow ion diffusion leads to long charging times. Electrochemical double layer capacitors (ELDCs) offer several advantages over batteries, including fast charging and long lifetimes. However, ELDCs do not involve redox reactions and exhibit lower energy densities compared to batteries. For this reason, there is widespread interest in pseudocapacitance, a faradaic process involving surface or near-surface redox reactions, that can lead to high energy density at high charge-discharge rates. This paper will review our work on identifying Li+ conducting materials which exhibit pseudocapacitive behavior. Our research on Li+ insertion in Nb2O5 has established certain criteria for pseudocapacitance as the rate of charge storage is determined by surface-like kinetics rather than semi-infinite diffusion as occurs with battery materials. Another factor is that the structure does not undergo a phase transformation upon Li+ insertion. In addition, when materials are reduced to nanoscale dimensions, they may begin to exhibit pseudocapacitive characteristics because of the large number of surface sites or because phase transitions are suppressed. The ensemble of these results suggests that over the next few years we can expect that there will be a growing number of materials whose energy density at high charge-discharge rates far exceeds that of typical battery materials.

Resume : The present work evaluates the electrochemical performance of metal oxide (MOx) incorporated porous electrospun carbon nano fibers (CNFs) towards ultra-high charge-discharge aqueous supercapacitors. The work will be conveyed in three major sections. Firstly, we will demonstrate our one-step thermal treatment in the numerous MOx systems (M= Mn, Fe and Co). In addition to CNFs carbon ladder and MOx formation, this thermal treatment provides distinctive diffusion velocities between M+ and O2- which enables in-situ pore formation on CNFs matrix [1]. These in-situ pores and MOx matrix attribute both EDLC and Faradaic behavior, bringing a two-fold increase of charge storage. We also show the influence of these in-situ pores and MOx matrix in kinetic dependent bulk and surface charges by means of linear capacitance-scan rate models [2]. Among numerous MOx system, the best performing MOx system triumphs to 200 times faster charge-discharge rates with outstanding capacity retention thanks to aforementioned in-situ pores and excellent conductivities. Secondly, we will show the ideal methods to enhance further the electrochemical performance of selected MOx-CNFs, i.e. through varying MOx: (i) precursor concentrations and (ii) precursor anion. These variations show a trend in MOx morphology, pore size distribution, surface area and electrical conductivities, which influences the electrochemical behavior such as capacitance and time constants. For example, HRTEM phase filtered composition shows varation of mixed MOx phases in dependence with the precursor anion type. Based on the observed trends, we design a model to achieve ultra high charge-discharge behavior, which will be expanded in detail. Using these models, in our initial results, the cyclic voltammograms show EDLC behavior at 8 V/s and quasi-EDLC even at 12.5 V/s. Additionally, we observe the best ultra-low time constant of 87 ms [3], which is comparable to microsupercapacitor technology [4]. Lastly, we will conclude by sharing our large area fabrication method of using 10 nozzles electrospinning and device design [5] to ease the cost of production (Area > 60 cm x 15 cm and loading > 5 mg/cm2). Acknowledgement: Authors thank Dr. Sònia Abelló (IREC, Tarragona) for N2 sorption measurments. References [1] B.D.A. and J.B. Tracy, Nanoscale. 6 (2014) 12195–12216. doi:10.1039/C4NR02025A. [2] L. Coustan, P. Lannelongue, P. Arcidiacono, F. Favier, Electrochim. Acta. 206 (2016) 479–489. doi:10.1016/j.electacta.2016.01.212. [3] L. Wang, T. Wei, L. Sheng, L. Jiang, X. Wu, Q. Zhou, B. Yuan, J. Yue, Z. Liu, Z. Fan, Nano Energy. 30 (2016) 84–92. doi:10.1016/j.nanoen.2016.09.042. [4] D. Pech, M. Brunet, H. Durou, P. Huang, V. Mochalin, Y. Gogotsi, P.-L. Taberna, P. Simon, Nat. Nanotechnol. 5 (2010) 651–654. doi:10.1038/nnano.2010.162. [5] Hemesh Avireddy, Joan Ramon Morante, Cristina Flox, Energy Harvesting and Systems (2016), Volume 3, Issue 4, Pages 287–296. https://doi.org/10.1515/ehs-2016-0015

Resume : Solid state ion conductors are significant class of materials for battery, fuel cell, electrocatalysis, and artificial ion channel, etc. Challenges are how to have fast ion conductivity with wide working temperature range, and how to handle the materials? mechanical properties and morphology for device integration. To approach these issues, we focus on coordination polymer (CP) or metal organic frameworks (MOF) consist of metal ions and bridging molecular ligands [1]. The structures have ordered arrangement of functional groups, and for example, the optimized hydrogen bond networks in the frameworks offer anhydrous H+ conductivity (10?2 S cm?1 at above 100 °C) which is a big demand for fuel cell-based vehicle technology. In addition to the beneficial designability of crystal structures for ion conductivity, we found some ion conductive CP/MOF crystals show melting behavior or transformation of glassy state (vitrification) by thermal/mechanical treatments. The phase transitions enable to fabricate variety of materials morphology such as film, fiber, and composites. The organic/inorganic hybrid nature of these material for solid state ionics will be discussed. [1] S. Horike, D. Umeyama, S. Kitagawa, Acc. Chem. Res. 2013, 46, 2376-2384.

Resume : The glass system Li2S-P2S5 has been extensively studied as electrolyte for application in all-solid-state Li-ion batteries [1,2]. The addition of lithium halides to glass electrolytes has been shown to improve the ionic conductivities and form favorable contacts at the electrode/electrolyte interface [3,4]. Recently, the LiBH4-Li2S-P2S5 system has attracted attention owing to its interesting ionic properties for solid state battery electrolytes [5,6]. LiBH4 is a good Li-ion conductor only above its solid state phase transition temperature (ortho  hexa, Ttr ~110°C). However, the high-T phase can be stabilized by partly substituting BH4- with halides, e.g. Li(BH4)0.75I0.25, thus preserving high ionic conductivity on cooling to room temperature. In addition, this phase has been reported to form a stable electrode/electrolyte interface in a Li half-cell [6,7]. The present work deals with the investigation of the ionic properties of the Li(BH4)0.75I0.25 (LI) phase embedded in a 0.75Li2S·0.25P2S5 (LPS) amorphous matrix. The mixed systems are first prepared by ball-milling and their ionic conductivities were studied in a wide composition range by varying the LI weight ratio between 0.2–0.8 in the system LI–LPS. Afterwards, heat treatment is applied to the mixed samples in a second stage. The temperature dependence of the ionic conductivities for the glass system 0.75Li2S-0.25P2S5 before and after addition of the Li(BH4)0.75I0.25 phase were analyzed by electrochemical impedance spectroscopy and compared to previous data for the single components [8]. Significant enhancements of the ionic conductivities are found when the LI phase is added to the LSP glass system. The study is supplemented by electrochemical stability (I-E) measurements and battery tests for some privileged compositions. Finally, vibrational spectroscopy investigation is also addressed for the understanding of the nature of the interaction between the two LI and LPS components. References [1] A. Hayashi, S. Hama, H. Morimoto, M. Tatsumisago, T. Minami, Preparation of Li2S–P2S5 Amorphous Solid Electrolytes by Mechanical Milling, J. Am. Ceram. Soc., 84 (2001) 477-479. [2] M. Tatsumisago, S. Hama, A. Hayashi, H. Morimoto, T. Minami, New lithium ion conducting glass-ceramics prepared from mechanochemical Li2S–P2S5 glasses, Solid State Ionics, 154–155 (2002) 635-640. [3] S. Ujiie, A. Hayashi, M. Tatsumisago, Structure, ionic conductivity and electrochemical stability of Li2S–P2S5–LiI glass and glass–ceramic electrolytes, Solid State Ionics, 211 (2012) 42-45. [4] R. Mercier, J.-P. Malugani, B. Fahys, G. Robert, Superionic conduction in Li2S - P2S5 - LiI - glasses, Solid State Ionics, 5 (1981) 663-666. [5] A. Yamauchi, A. Sakuda, A. Hayashi, M. Tatsumisago, Preparation and ionic conductivities of (100 − x)(0.75Li2S·0.25P2S5)·xLiBH4 glass electrolytes, J. Power Sources, 244 (2013) 707-710. [6] A. Unemoto, H. Wu, T.J. Udovic, M. Matsuo, T. Ikeshoji, S.-i. Orimo, Fast lithium-ionic conduction in a new complex hydride-sulphide crystalline phase, Chem. Commun., 52 (2016) 564-566. [7] A. Unemoto, K. Yoshida, T. Ikeshoji, S.-i. Orimo, Bulk-Type All-Solid-State Lithium Batteries Using Complex Hydrides Containing Cluster-Anions, MATERIALS TRANSACTIONS, advpub (2016). [8] R. Miyazaki, T. Karahashi, N. Kumatani, Y. Noda, M. Ando, H. Takamura, M. Matsuo, S. Orimo, H. Maekawa, Room temperature lithium fast-ion conduction and phase relationship of LiI stabilized LiBH4, Solid State Ionics, 192 (2011) 143-147.

Resume : Complex hydrides have recently shown large interest as fast Li+ and Na+ solid conductors for all-solid-state batteries.(1,2) The fast cation motion firstly discovered in LiBH4 was later studied in higher boranes systems showing low activation energy for diffusion process and ionic conductivity approaching the liquid electrolyte regime already at room temperature.(3,4) This class of compounds is represented by closo-boranes and carba-closo-boranes. Here we report the sodium ionic conductor Na3(CB11H12)(B12H12) exhibiting a high Na-conductivity of 1 mS cm-1 at 20°C. The conductivity increased to 10 mS cm-1 at 100 °C with an activation energy of 136 meV. Cyclic voltammetry measurements revealed electrochemical stability in the window voltage 0-5 V (vs Na/Na+). In-situ X-ray diffraction showed a thermal stability up to 300°C. Half and complete Na-cells were assembled using this new electrolyte. We present the electrochemical performance of several all solid state cells using sulphates and sulphides as positive materials and graphite as negative electrode. Ref: (1) Matsuo et al. Appl. Phys. Lett. 2007, 91 (2) Matsuo et al. Appl. Phys. Lett. 2012, 100 (3) Tang et al. Adv. Energy Mater. 2016, 6 (4) Tang et al. ACS Energy Letters 2016, 659

Resume : All solid-state batteries using a solid-state electrolyte (SSE) promise higher temperature stability, higher energy densities and higher operational safety than state-of-the-art batteries employing flammable liquid organic electrolytes. However, developing a solid-state electrolyte that combines high ionic conductivities with high electrochemical and thermal stability represents a major scientific challenge. Here we report the discovery of new borohydride and closo-borates based Li and Na SSE which combine room temperature conductivities above 1 mS/cm with thermal stabilities of up to 300 °C and electrochemical stability windows of up to 3 V. We also demonstrate reversible stripping/plating and stable cycling in half-cell configurations. We discuss the conduction mechanisms on the basis of thermally activated, anion assisted diffusion along continuous conduction paths within the crystal structure. Financial support by the Swiss National Science Foundation by the Sinergia project “Novel ionic conductors” under the contract number CRSII2_160749/1 is gratefully acknowledged

Resume : Mass storage is the key for energy storage technologies. Different from conventional materials which accommodate component M (=Li, Na, etc) in the bulk phase, the job-sharing composites allow the mass storage occurring in a heterogeneous way: M is able to be accommodated at the interfaces of two phases even though neither of the constituent phases can store M alone [1]. In this contribution, we will demonstrate that Li, H2, and Ag can be job-sharingly stored in the composite materials [2-4]. The non-stoichiometry is established not only for excess but also for deficiency. Such composites, as they behave like classic mixed conductors, can be treated as artificial mixed conductors. In particular, the rate of silver storage in the composite of superionic conductor RbAg4I5 and electronic conductor graphite is extremely fast, which corresponds to the ultrahigh solid-state chemical diffusivity that even exceeds the values for NaCl in water. The finding of the study can pave the way for artificial electrodes in batteries, supercapacitors, and permeation membranes. References: [1] J. Maier, Angewandte Chemie International Edition, 52, 4998-5026 (2013). [2] L. Fu, C.-C. Chen, D. Samuelis, J. Maier, Physical Review Letters, 112, 208301 (2014). [3] L. Fu et al., Nano Letters, 15, 4170-4175 (2015). [4] C.-C. Chen, L. Fu, J. Maier, Nature, 536, 159-164 (2016).

Resume : LiNi0.80Co0.15Al0.05O2 (NCA) can provide about 200 mAh/g[1] discharge capacity when working within the 3.0 to 4.2 V vs. Li+/Li potential window. The specific charge of this material and thus its overall energy density could be potentially increased by 10% of its value if this electrode is operated to higher upper cut off potentials (~4.6 V) or to lower cut off potentials (below 3.0 V) against Li metal. When the cathode material operates under abusive conditions, its degradation can be accelerated. Thus, the understanding of the mechanisms associated with the degradation of the material is essential to assess the cell performance and safety after long term cycling. We investigate here the decay of the cycle performance of the NCA cathode material under abusive conditions by careful examination of ex situ synchrotron X-ray powder diffraction data at different stages of charge and discharge. XRD results evidence the continuous buildup of strain in the oxide due to the presence of vacancies in the MO2 slabs and subsequent Li/Ni interlayer mixing at high state of charge. Careful examination of the crystal structures reveals that the microstrain does not completely recover to the pristine material value after full discharge (lithiation), and it increases in the following cycles. At overdischarge conditions, lithiation of LiNi0.8Co0.15Al0.05O2 at about 1.8 V is associated to a two-phase transition[3] process in which an additional lithium ion can be inserted into the Li1+xNi0.8Co0.15Al0.05O2. This process leads to a phase transition that, although it provides high specific charge values, has a detrimental effect on the stability of the NCA lattice. Overall, the microstrain created during the first and subsequent cycles under abusive conditions has a strong negative impact on the cycling performance of the NCA material, and thus on the cell cycle-life. [1] R. Robert, C. Villevieille, P. Novák, J. Mater. Chem. A 2014, 2, 8589. [2] R. Robert, C. Bünzli, E. J. Berg, P. Novák, Chem. Mater., 2015, 27, 526. [3] C. S. Johnson, J.-S. Kim, A. J. Kropf, A. J. Kahaian, J. T. Vaughey, L. M. L. Fransson, K. Edström, M. M. Thackeray, Chem. Mater. 2003, 15, 2313.

Resume : Next generation Li-ion battery requires continuous improvements to satisfy the demands of modern technology, spanning from portable internet of things applications to large batteries for electric vehicles. In the quest for high energy densities, power output and safety, all solid state 3D thin-film batteries are drawing the attention of the community. Many materials are screened to optimize each part of the battery. However, new metrology solutions are required to provide fundamental understanding at the relevant length scales and drive the materials’ selection. In this work we report on the characterization of thin film electrodes by combining electrical atomic force microscopy (AFM) and secondary ions mass spectroscopy (SIMS). We focus our study on two cathode materials LiMn2O4 and Li4Ti5O12, as they show a competitive capacity (296 and 175 mAh/g) combined with a spinel structure which is beneficial for 3D thin-film batteries. Different cycling and deposition conditions are investigated for which we show how the Li-ion mobility can vary due to local material properties. Using a nanosized conductive probe, we present a method to probe the local contribution of electronic and ionic current with nm-lateral precision. The latter is for the first time combined with SIMS in a single apparatus assessing the chemical composition of the material, providing a sub-µm resolved analysis-setup for the unique correlation of electrical, ionic and chemical properties of cathode materials.

Resume : Currently, lithium-ion batteries incorporated in electric vehicles do not allow to store enough energy to ensure sufficient autonomy. Therefore, it’s necessary to develop new generations of batteries with higher energy density. Among battery technologies, the lithium-sulfur system (Li-S) is considered to be one of the most promising solutions due to a theoretical energy density of 2500 Wh/kg. However, its lifetime remains limited due to the polysulfide shuttle effect, induced by the use of liquid electrolyte. Indeed, many polysulfides (noted Li2Sx 1 ≤ x ≤ 8), formed during the sulfur reduction to Li2S, dissolve in liquid electrolyte and diffuse between both electrodes, leading to a rapid decrease of electrochemical performances and the appearance of redox shuttle phenomena. In this presentation, we will describe several interesting ways of solving Li/S batteries issues such as using argyrodite ionic conductor in solid state batteries or using new solid and polymer separators presenting very good coulombic efficiency.

Resume : Nickel-rich lithium transition-metal oxides for Li-ion batteries have been interested under intense commercialization as high-energy cathode materials because of their high specific capacity and relatively low cost. However, it still demands the necessities of higher energy density and more improved thermal stability to compete with requirements of smart mobile applications and x-EVs (extended electric vehicles). Accordingly, further research to increase both Ni content over 60 mol% and the cut off voltage to more than 4.5 V are being carried out to increase the energy density of Li-ion cells. Two critical problems (structural instability both at >60 °C cycling and fast exothermic oxygen evolution at >200 °C) affecting such Ni contents should be solved. Here, we present electrochemical performance of a nickel-rich lithium transition-metal oxide (Ni content from 60 mol% to 91% mol %. Furthermore, by employing various surface chemistry on the cathode materials such as dry powder mixing, direct precipitation, colloidal deposition, Improvement of structural instability have been studied. The degradation of LiMO2 (M = Co, Ni, and Mn) cathode materials was strongly related to their surface chemistry. Among the proposed degradation mechanisms, the irreversible formation of inactive Ni species in the layer structure, the particularly those localized in surface regions, are the products of such reactions. In other words, when the cathode materials are charged above 4.3 V, the cathodes could be partially transformed into an electrochemically inactive NiO-like phase or spinel structure with volumetric changes due to the migration of the Ni cations from the original transition metal (TM) layers. Our surface treatment cathode materials suppressed formation of NiO-like phase or spinel structure over 5% compared with bare cathode materials. The experimental results suggest one of way for applications that require high energy, long maintain life and excellent safety .

Resume : Although the energy of Li-ion batteries has considerably increased over the last two decades, further improvements are expected for next generation of cells. The development of high capacity Li-alloy anode (e.g. Si) and that of high capacity and high potential cathodes materials (e.g. Ni-rich NMC, HV-LMNO) is indeed driving such improvement. We will present our latest results on the development of prototype pouch cells manufactured with Si-alloy (3M) based anodes and Ni-rich NMC (Umicore) cathodes. The anode was developed starting from aqueous slurry using poly acrylic acid (PAA) as the solely binder, which demonstrated excellent dispersant and binding properties. The NMC-based (532 or 622) cathodes were manufactured from NMP-based slurry using an advanced PVDF-based binder (ARKEMA). The electrodes electrical and electrochemical properties were evaluated with the aim of finding the best formulations, which was thereafter used to manufacture 1.2Ah pouch-cells. We here note that the electrodes reversible areal capacity was always well above 3.5 mAh/cm2. Finally, we will compare the specific energy (Wh/kg) and power (W/kg) of such cells with that of more state-of-the-art cells that used graphite anodes and NMC cathodes. Acknowledgment This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement n° 653531

Resume : Recently, a promising cathode material for Li-ion batteries, Li2FePO4F (L2FPF), was obtained from LiNaFePO4F by electrochemical ion-exchange. Upon charging, the Na was completely removed at 75oC. The resulted framework was used for the insertion of Li during discharge. In this work we studied the structure changes occurring during the ion-exchange process [1]. Electron diffraction tomography was used to obtain the crystal structure from a single ~200nm crystal. By this technique multiphased samples for which only a small amount of material is available can be analyzed. The structure refinement of L2FPF revealed that Fe-Li antisite disorder takes place and 30% of Li occupies Fe positions and vice versa. To find the reason, we studied L2FPF prepared at 25oC and LiFePO4 (LFP) cycled at 100oC. In the first case the antisite disorder was present, whereas in the last one it was not. This shows that the main factor is not elevated temperature but is specific features in L2FPF crystal structure. In L2FPF two oxygens are coordinated by one P and three Li atoms, two out of which are electrochemically active. In charged state these O atoms become underbonded which cannot be compensated by shrinking of the P-O bonds. Therefore, Fe3+ atoms partially migrate into the Li position to eliminate the misbalance. It does not occur in LFP, since there all O atoms are connected with electrochemically active Li and Fe. 1. O. M. Karakulina, et al., Chem. Mater., 2016, 28, 7578

Resume : Despite their increasing popularity as solid electrolytes, the structure/property relationship of Lithium Phosphorus Oxynitrides has not yet been clarified. Theoretical work offers an invaluable insight into the atomistic properties of solids, provided the availability of valid structural models. The simulation of glassy structures represents a main challenge from a computational point of view, and is further complicated by their non-trivial composition. In this contribution, a new approach to the ab-initio simulation of amorphous structures of virtually any desired composition is described. A realistic composition has been suggested by experiments recently conducted by academic partners. The defect thermodynamics of LiPON suggests its instability against metallic lithium. [1] The formation of a solid-electrolyte interphase (SEI) at this interface has been recently observed and quantified experimentally. Following up on this result, the interfacial structural and electronic properties have been investigated with a special focus on reactivity. This work does not only describe a novel approach to the simulation of a more realistic electrolyte, but also provides unprecedented insights, supported by experimental results, into its stability and reactivity under operational conditions. [1] S. Sicolo, K. Albe, J. Power Sources 331, 382-390 (2016).

Resume : Understanding the formation of the SEI layer is a key-point for improving the lifetime of Li-ion batteries. Inorganic compounds, such as Li2O, Li2CO3, and LiF, have been found in the SEI layer along with organic compounds. Here, we explain the formation of LiF and H2 evolution in the LP57 electrolyte on metal single crystals, during the first cycles of charging and discharging a Li-ion battery using density functional theory (DFT) and ab-initio molecular dynamics to interpret experimental cyclic-voltammetries at the atomic-scale level. The formation of LiF is related to the work function of the clean metal slab. In fact, the adsorption of a Li-ion is the first and necessary step to run the LiF formation reactions. We, thus, show that the trends behind the adsorption of ionic elements, like Li, are different from the ones of covalent species, and in particular are strongly depend on the electrostatic interaction between the ion and the surface, and scale with the work function of the metal slab, i.e. the larger the work function, the stronger the ionic bond between Li and the surface. The adsorption of Li is then required to dissociate HF. Once HF is dissociated, LiF and H2 are formed.

Resume : Understanding the microscopic mechanism of the de/lithiation processes during electrical cycling is crucial for improving the design of battery materials. Efforts to experimentally detect the lithium distribution in partially charged/discharged battery states at nanoscale resolution are therefore essential. Lithium iron phosphate (LiFePO4, LFP), which is an intercalation cathode material, has been extensively studied by numerous techniques for tracking its de/lithiation process. This work [1] revisited this issue for the case of LFP. TEM based automated crystal orientation mapping (ACOM) [2], originally designed for orientation analysis of nanocrystalline materials [3], relying on the crystallographic information recorded in diffraction patterns, was used to map the de/lithiated phases of half discharged LFP nanoparticles ex situ. In agreement with the Domino-Cascade model [2], the map indicates that large number of particles are either LFP or FePO4 (FP) under thermodynamically stable condition. However, interestingly, quite a number of particles are observed with a typically well-defined planar phase boundary between LFP and FP. According to the crystallographic information possessed in the ACOM phase map, we analyzed the properties of the LFP/FP interfaces. On average a 1.4 ° misorientation is observed at the interfaces. The interfaces have a preferred orientation with the normal close to the [101] crystallographic direction, instead of the widely speculated [100] (a-axis) [4] or [010] (b-axis) [5]. This experimentally confirms the theoretical predictions based on the interfacial strain energy [6,7]. The results offer a deeper understanding of the intercalation reaction from the crystallographic point of view. It indicates the existence of an energetically preferred two-phase reaction boundary. The aspect ratio of the material particles along the preferred crystallographic orientation of the reaction boundary could have an effect on the reaction. References: [1] X. Mu et al, Ultramicroscopy. 170 (2016), p.10. [2] G Brunetti et al, Chem Mater 23 (2011), p4515. [3] EF Rauch et al, Zeitschrift für Krist 225 (2010), p103. [4] L. Laffont et al, Chem. Mater. 152 (2006), p.5520. [5] Y. Zhu et al, Adv. Mater. 25 (2013), p.5461. [6] DA Cogswell, MZ Bazant, ACS Nano. 6 (2012), p2215. [7] M Welland et al, ACS Nano. 9 (2015), p.9757.

Resume : The increasing demand of higher energy density batteries is driving the research for performant electrode towards materials presenting either high redox voltage or high capacities. This second alternative has put into light sulfide structures. Among them, Bornite (Cu5FeS4) is a natural mineral, composed of abundant and cost-effective elements : iron and copper [1]. Bornite presents an antifluorine structure (figure 1), with two vacancies statistically put on the tetraedric sites (Cu5∎2FeS4) [1]. Cations and vacancies ordering creates temperature-dependant superstructures [2]. Moreover, these vacancies could allow ion diffusion and lithium insertion, which could then lead to interesting electrochemical properties. We report here a synthesis of bornite (Cu5FeS4) by ball-milling,[3] and its use as positive electrode in lithium-ion battery. This material presents a first capacity of 250 mAh/g at C/5 (0.2 Li/h). This capacity rapidly decreases with cycling, but two reversible plateaus are still observed at 2.2 V and 1.5 V vs. Li+/Li during the following cycles (80 mA/g after 10 cycles). The redox mechanisms have been studied by in situ characterizations, revealing strong changes during cycling, which will be presented. [1] Grguric, B. A., Putnis, A. & Harrison, R. J.. Am. Mineral. 83, 1231–1239 (1998). [2] Qiu, P. F., Zhang, T. S., Qiu, Y. T., Shi, X. & Chen, L. D. Energy Environ. Sci. 7, 4000–4006 (2014). [3] Guélou, G., Powell, A. V. & Vaqueiro, P. J. Mater. Chem. C 3, 10624–10629 (2015).

Resume : Solid electrolytes for lithium-ion batteries provide increased safety and wider operating temperature range than liquid electrolytes. Bulk all-solid-state batteries are thus a safer alternative to Li-ion battery and allow storing more energy than microbatteries, but need very good ionic conductors as solid electrolytes. Sulfide-based solid electrolytes show good ionic conductivities, but also reactivity issues towards active materials. Their reactivity versus metallic lithium has been extensively studied, however less studies have been focused on their reactivity with positive electrode materials. In this work we investigated argyrodite Li6PS5Cl, which possesses high ionic conductivity at room temperature, as solid electrolyte in all solid state batteries with different active materials in the positive composite electrode. The reactivity of Li6PS5Cl towards LiCoO2, LiNi1/3Co1/3Mn1/3O2 and LiMn2O4 was investigated using X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). We show that Li6PS5Cl is oxidized into elemental sulfur, lithium polysulfides, P2S5, phosphates and LiCl within the composite positive electrode during cycling. In spite of this interface reactivity, it is possible to cycle argyrodite-based batteries for over 300 cycles.

Resume : An in-depth understanding of (de)lithiation induced phase transition in electrode materials is crucial to grasp their structure-property relationships and provide guidance to the design of more desirable electrodes. By operando synchrotron XRD (SXRD) measurement and Density Functional Theory (DFT) based calculations, we discover a reversible first-order phase transition for the first time during (de)lithiation of CeO2 nanoparticles. The LixCeO2 compound phase is identified to possess the same fluorite crystal structure with FM3M space group as that of the pristine CeO2 nanoparticles. The SXRD determined lattice constant of the LixCeO2 compound phase is 0.551 nm, larger than that of 0.541 nm of the pristine CeO2 phase. The DFT calculations further reveal that the Li induced redistribution of electrons causes the increase in the Ce-O covalent bonding, the shuffling of Ce and O atoms, and the jump expansion of lattice constant, thereby resulting in the first-order phase transition. Discovering the new phase transition throws light upon the reaction between lithium and CeO2, and provides opportunities to the further investigation of properties and potential applications of LixCeO2.

Resume : Amongst the available energy storage technologies, lithium-ion batteries (LIBs) are to date the most suitable for electric vehicles (EVs), power tools and portable electronics as they operate with a high efficiency, easy to scale, possess high-energy density and allow reasonable power delivery. Despite, the power performances are still unsatisfactory given the sluggish kinetics of positive and negative electrodes [1]. Here, we propose a hybridization of LIB materials with a redox polymer (poly (2,2,6,6-tetramethyl-1-piperinidyloxy-4-yl methacrylate or PTMA) to improve power performances. By adequately selecting the hybrid redox materials, effective synergy in operation can be attained. This was recently demonstrated in a LiFePO4 - PTMA composite electrode where an original intra-electrode charge transfer process between the components was observed, enabling high power recharge capability [2]. Here, we present the electrochemical response of a PTMA - LiMn2O4 (LMO) hybrid electrode. Results prove the energy transfer between the constituent enabling high power delivery. Furthermore, at high discharge rate PTMA act as power buffer and improves the capacity-cycle retention of hybrid electrodes compared to pure LMO. Hybrid electrodes also deliver higher energy when subjected to power pulse tests further supporting the hybrid design working principle of PTMA power buffer and LMO (high) energy electrode. These results prove the potential of the hybrid energy-power electrodes in pulsed discharge applications. [1] M. S. Whittingham, Chem. Rev. 104 (2004) 4271-4301. [2] A. Vlad, N. Singh, J. Rolland, S. Melinte, P. M. Ajayan, and J.-F. Gohy, Sci. Rep. 4 (2014) 4315.

Resume : Robust porous SiO2/Si/graphene/C microspheres were prepared by a ultrasonic spraying method with partial magnesiothermic reduction to investigate the combination of Si and SiO2 for the first time. The microspheres are formed by accumulation of carbon coated Si/SiO2 nanoparticles, where graphene networks connect each nanoparticle, which reinforces the structure stability and improves electrical and ion conductivities. In addition, each Si/SiO2 nanoparticle is coated with a layer of pyrolytic carbon which isolates the active materials from the electrolyte and thus help forming stable SEI. More importantly, due to the accumulation of nanoparticles, numerous pores thereby form in the microspheres which not only provide large space voids for electrolyte reserve to reduce the ion transport path, but allow for the effortless expansion and contraction of Si nanoparticles. As a result, the obtained composite exhibits not only the characteristics of individual nanoparticles, but also new collective properties derived from the 3D mesoporous microspherical structure. When evaluated for their electrochemical properties in LIBs, although the microsphere does not show the highest capacity, it has perfect cycling stability. Another obvious advantage is the usage of commercial SiO2, and especially retaining the remaining SiO2 in the microspheres can reduce procedures and costs. The obtained SiO2/Si/graphene/C microspheres show an increasing capacity during cycling, with the 2nd discharge capacity of 1104.9 mAh/g and capacity retention of 103.3% after 200 cycles.

Resume : Here we report a simple, scalable and low-cost method to improve the electrochemical properties of the Mn oxide electrodes for high-efficient flexible symmetrical supercapacitors. The low-cost method involving printer printing, pencil-drawing and electrodeposition is established to fabricate Mn oxide/Ni nanotube/graphite/paper hybrid electrodes operating with a low-cost, novel PVA/urea-LiClO4 quasi-ionic liquid as electrolyte for flexible solid-state supercapacitor (FSSC) devices. The Mn oxide nanowire/Ni nanotube/graphite/paper (MNNGP) electrodes in PVA/urea-LiClO4 quasi-ionic liquid electrolyte show large specific capacitance (Csp) of 960 F/g in the voltage region of 0.8 V at a scan rate of 5 mV/s and exhibit excellent capacitance retention rates of more than 85% after cycling for 5000 cycles. Moreover, the electrochemical behavior of the MNNGP electrodes in PVA/urea-LiClO4 at various operating temperatures (27°C~110°C) is investigated and the results show that the MNNGP electrodes in PVA/urea-LiClO4 exhibits outstanding performance (1100 F/g) even at 90°C. The assembled FSSC devices based on the MNNGP electrodes in PVA/urea-LiClO4 exhibit great Csp (380 F/g in the voltage region of 2.0 V at 5 mV/s, and exhibiting a superior energy density, 211.1 W h kg-1) and great cycle stability (less 15% loss after 5000 cycles at a high scan rate of 25 mV/s). The mechanism of energy storage is also examined by in-situ X-ray absorption spectroscopy (XAS). The FSSC devices would open up new opportunities in developing novel portable, wearable and roll-up electric devices because of the low-cost, high-performance, wide operating temperature range and simple large-area fabrication procedures.

Resume : Concerns on Li supply have prompted the search for suitable alternatives to rechargeable Li-ion battery technology. Among these, batteries based on divalent charge carriers (Mg and Ca) exhibit advantages in terms of energy density, given the possibility to use metal anodes which do not seem to be plagued with dendritic growth. Moreover, for a certain amount of charge carriers reacting with an electrode material, the capacity is doubled when compared to monovalent carriers like Li or Na. Calcium appears as an attractive candidate due to its low cost, natural abundance and low reduction potential, only 170 mV above that of Li. The feasibility and reversibility of Ca plating in conventional alkyl carbonate electrolytes at moderate temperatures has been recently reported by Ponrouch et al. (Nat. Mater. (2015), 15, 169-172) which opens the way to the development of a new rechargeable battery technology using Ca metal anodes, provided appropriate cathode materials are developed. While progress in multivalent cathode research is typically hampered by slow ionic diffusion in the solid state, the lower polarizing effect (charge-to-radius ratio) for Ca when compared to Mg seems to a priori present some advantages with respect to reaction kinetics and resulting power performances. This contribution reviews trends and preliminary results on the exploration of electrode materials to achieve proof of concept of a full Ca based cell.

Resume : Energy storage has become a scientific and technological issue no less important than energy production. Supercapacitors (SCs) show great promise for high-performance energy storage. Efficient energy storage is particularly important in the context of flexible electronics-one important aspect of modern electronics. Printing methods have the potential to yield useful energy storage devices at low-cost and flexible. Flexible substrates, such as polyethylene terephthalate and paper, due to the low-cost nature and the excellent mechanical properties, has great potential as the substrate for flexible electronic devices.[1] We synthesized a class of highly porous materials, metal-organic frameworks (MOFs). An extremely simple in situ self-transformation methodology was developed to introduce pseudocapacitance into the MOF system resulting in a largely boosted electrochemical performance.[2] Inkjet printing was employed to print conductive materials on paper as a low-cost and large scale process to fabricate continuous patterns as current collectors and/or electrodes for SCs.[3] REFERENCES [1] Zhang, Y.-Z.; Wang, Y.; Cheng, T.; Lai, W.-Y.; Pang, H.; Huang, W. Chem. Soc. Rev. 2015, 44, 5181. [2] Zhang, Y.-Z.; Cheng, T.; Wang, Y.; Lai, W.-Y.; Pang, H.; Huang, W. Adv. Mater. 2016, 28, 5242. [3] Jenkins, G.; Wang, Y.; Xie, Y. L.; Wu, Q.; Huang, W.; Wang, L.; Yang, X. Microfluid. Nanofluid. 2015, 19, 251.

Resume : Conducting polymers (CPs) are a promising material for the electrochemical energy storage. Amongst, PEDOT: PSS as a p-type conductive polymer was intensely investigated in electrochemical supercapacitors. The pseudocapacitance of PEDOT: PSS can be significantly influenced by the redox reactions and ion diffusion at the interface between the active material and the electrolyte.1 Conducting polymer aerogels could be an efficient route to get highly porous electrodes with open pores and exposed high inner surface area.2 Here we report a simple method for the fabrication of PEDOT: PSS aerogel foam utilizing commercial PEDOT: PSS. The synthesis route for the PEDOT: PSS foam will be discussed in detail. SEM and BET analysis (as high as 467m3/g) reveal peculiar morphology and textural properties beneficial for the charge storage. The electrochemical properties are investigated in various electrolyte formulations. Different response and capacitance values are attained function of the electrolyte chemistry and electrode morphology with the highest attained of about 200 F/g. Electrochemical performance differences both in different electrolytes and with different fabricating parameters will be discussed. The electrodes also display good cyclic stability with 86.7 % capacitance retention after 1000 charge/discharge cycles. These performances demonstrate that this ingenious method is a promising approach on achieving CPs/composites aerogels for high performance energy storage devices.3 1. Z. Zhao, et al, Nanotechnology, 2016, 27, 042001. 2. A. C. Pierre, et al, Chem. Rev., 2002, 102, 4243–4266. 3. L. Cheng, et al, submitted.

Resume : Despite the importance of understanding the structural and bonding properties of solid-liquid interfaces for a wide range of (photo-)electrochemical applications, there are presently no experimental techniques available to directly probe the microscopic structure of solid-liquid interfaces. To develop robust strategies to interpret experiments and validate theory, we carried out attenuated total internal reflection (ATR-IR) spectroscopy measurements and ab initio molecular dynamics (AIMD) simulations of the vibrational properties of interfaces between liquid water and well-controlled prototypical semiconductor substrates. We show the Ge(100)/H2O interface to feature a reversible potential-dependent surface phase transition between Ge-H and Ge-OH termination. The Si(100)/H2O interface is proposed as a model system for corrosion and oxidation processes. We performed AIMD calculations under finite electric fields, revealing different pathways for initial oxidation. These pathways are predicted to exhibit unique spectral signatures. A significant increase in surface specificity can be achieved utilizing an angle dependent ATR-IR experiment, which allows to detect such signatures at the interfacial layer and consequently changes in the hydrogen bond network.

Resume : Nanoporous iridium electrodes are prepared and electrochemically investigated towards the water oxidation (oxygen evolution) reaction. Due to its good electric conductivity and high catalytic activity, iridium is used as active surface for the four-electron water oxidation to oxygen, which represents the kinetic bottleneck of water splitting. The preparation bases on ?anodic? aluminum oxide templates which provide straight, cylindrical nanopores. Their walls are coated by atomic layer deposition (ALD) using a newly developed reaction from (1,3 cyclohexadiene)(ethylencyclopentadienyl)iridum and ozone, which results in a metallic iridium layer. The ALD film growth is quantified by spectroscopic ellipsometry and X-ray reflectometry. The morphology and composition of the nanostructured electrodes is characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Their catalytic activity is quantified by cyclic voltammetry, steady-state electrolysis and electrochemical impedance spectroscopy for various pore geometries in different pH. This preparative method allows for a systematic tuning of the electrode?s geometric surface area by variation of the nanopores? diameter and length. The electrocatalytic current densities vary accordingly.

Resume : To achieve high performance on small electronic devices, the three-dimensional integration technology such as Through-Silicon Via (TSV) or microvia is essential. Cu electrodeposition has been widely used to fill the TSV and microvia, and the defect-free filling of Cu is an important issue for these technologies. For the defect-free filling, a leveler, one of the organic additives in the Cu electrodeposittion, is considered to be crucial because of its convection-dependent adsorption behavior. In our previous reports [Electrochim. Acta, 2015, 163, 174-181, J. Electrochem. Soc., 2015, 4, D31-D34.], a triethylene glycol (TEG)-based leveler containing two quaternary ammoniums at both ends has been synthesized and successfully applied for the defect-free filling performance of TSV. In this study, several derivatives of the TEG-based leveler have been synthesized to investigate their structure-property relationships on Cu electrodeposition. These derivatives were designed to have various length of an ethylene glycol unit, an aliphatic backbone, and/or different terminal functional groups. Linear sweep voltammetry showed that all the levelers had the convection-dependent adsorption characteristics. However, their suppression effects were varied with the functional groups of their backbone and terminal structures.

Resume : The ability to electrolyze water into its elements in benign conditions at low cost will imply the exclusive use of cheap, abundantly available materials, in-stead of most advanced catalysts. Here, we demonstrate that iron oxide, the most abundant and least expensive transition metal compound, can be used as a catalytically active surface for the four-electron water oxidation to O2 at neutral pH which represents the kinetic bottleneck of the overall reaction. Nanotubular iron(III) oxide electrodes are optimized for catalytic proficiency in the water oxidation reaction. Nanostructured electrodes are prepared from anodic alumina templates coated with Fe2O3 by atomic layer deposition. Scanning helium ion microscopy, X-ray diffraction and Raman spectroscopy characterize the morphology and phase of samples submitted to various treatments. These methods document the contrasting effects of thermal annealing, on the one hand, and of electrochemical treatment, on the other hand. The electrochemical performance of the corresponding electrodes is quantified by steady-state electrolyses and electrochemical impedance spectroscopy. A rough and amorphous Fe2O3 with phosphate incorporation proves to be optimal in the water oxidation reaction. The combination of electrochemical treatments with the ?anodic? pore geometry delivered an effective turnover increase by a factor of 540 with respect to a smooth, planar Fe2O3 surface.

Resume : This work focuses on the potentials of monolithic integrated lithium ion cell and thin-film silicon solar cell in a simple cell-to-cell integration without any control electronics as a compact power solution for self-sustained operation of sensors or other electronics with low power consumption. To demonstrate this we used a lithium ion battery cell with Lithium iron phosphate (LiFePO4, LFP) as cathode and Lithium titanate (Li4Ti5O12, LTO) as anode connected directly to triple-junction thin-film silicon solar cell based on a-Si:H and µc-Si:H absorber layers. The theoretical voltage of the battery is about 1.9 V. We use the solar cell to charge the battery and in turn discharge the battery through the solar cell. Our results show that with appropriate voltage matching the solar cell provides efficient charging for lab-scale lithium ion storage cell without using control electronics. We show that the discharge rate of the Li-ion cell through the non-illuminated solar cell can be much lower than the charging rate when the current voltage (IV) characteristics of the solar cell is matched properly to the charge-discharge characteristics of the battery. This indicates good sustainability of the ultimately simple integrated device. A simple method to find the optimal conditions for the integrated PV-battery device will be presented. Maximum power point and average solar energy-to-battery charging efficiencies of 8.5 and 8.0% were obtained respectively. The maximum power point efficiency is equal to the efficiency of the standalone solar cell which indicates loss-free energy transfer to the battery.

Resume : Electrochemical polymerization is normally performed on electrodes with electric wires connected to a direct current power source. It has been impossible to realize electrochemical polymerization reactions on the surfaces of individual nanoparticles in aqueous systems due to the difficulty of connecting all the nanoparticles to a power source with wires or with the aid of microfabrication. In this work, a micro pseudo-electrochemical polymerization reaction was proposed to in situ synthesize polyaniline (PANI) on the surface of ferroelectric nanocrystals to form core-shell nanocrystals, which is by using ferroelectric nanocrystals with spontaneous polarization as both electric potential origination and micro-electrode. Briefly, when the ferroelectric nanocrystals were dispersed in an aqueous electrochemical system, the adjacent ferroelectric nanocrystals might form the ?( z?-z)~( z?-z)? alignment, which could form an instantaneous micro-electric field between the nanocrystals. This instantaneous micro-electric field was expected to work as an instantaneous micro-electrochemical cell, which could be utilized in the in-situ electrochemical synthesis or polymerization. In the aqueous electrochemical system, a large number of pseudo-electrochemical cells form a special electrochemical system, which can realize various electrochemical reactions. However, unlike traditional electrochemical process, without continuous power supplement by external circuit, the surface charges of ferroelectric nanocrystals are static and limited. It could be saturation during the pseudo-electrochemical polymerization reaction. Fortunately, ultrasonic irradiation can be used to introduce periodical stress, which could induce periodical increase and decrease of spontaneous polarization potential, and renew the charge distribution on the surface of ferroelectric nanocrystals. Therefore, ultrasonic irradiation endows this micro pseudo-electrochemical polymerization reaction a good continuity. Moreover, the ultrasonic wave induced stress can enlarge the polarization electric field in the ferroelectric nanocrystals, and this enlarged potential can enhance the electrochemical polymerization reaction in the ferroelectric nanocrystals aligned micro pseudo-electrochemical cells. The spontaneous polarization of ferroelectric nanocrystals results in opposite induced charges on the surfaces of nanocrystals. This surface charge induced potentials have been well studied as piezoelectronic effect, which is a new approach to enhance the electronic process by inducing piezotronic effect[1-2]. Recent years, piezoelectrochemical catalysis was proposed and realized with stress-induced piezoelectric potential of nanomaterials. Direct water splitting[3] and azo dye decolorization in aqueous solution[4] through vibrating (i.e., ultrasonic vibration) piezoelectric ZnO microfibers or BaTiO3 microdendrites have been reported. While this work proposes a new application of piezotronic effect to electrochemical reaction, and will have great influences related to nanomaterials based electrochemical synthesis, electrochemical water splitting, electrophotocatalysis, and even ultrasonic therapy. Keywords: micro pseudo-electrochemical polymerization; ferroelectric nanocrystals; spontaneous polarization; ultrasonic irradiation References: [1] J. Yang, J. Chen, Y. Liu, W. Yang, Y. Su, Z. L. Wang, ACS Nano 2014, 8, 2649-2657. [2] Y. Liu, S. Niu, Q. Yang, B. D. B. Klein, Y. S. Zhou, Z. L. Wang, Advanced Materials 2014, 26, 7209-7216. [3] K.-S. Hong, H. Xu, H. Konishi, X. Li, The Journal of Physical Chemistry Letters 2010, 1, 997-1002. [4] K.-S. Hong, H. Xu, H. Konishi, X. Li, The Journal of Physical Chemistry C 2012, 116, 13045-13051.

Resume : Here, we demonstrate a scalable, eco-friendly and cost effective hydrothermal protocol to synthesize grass-like tangled cobalt vanadium oxide hydrate (CVO) nanocanes array. Finally, a very high performance robust mesoporous hybrid composite electrode has been fabricated by controlled wrapping-up of conducting globular polypyrrole (PPy) over CVO (CVO-PPy) nanocane surfaces through in-situ oxidative polymerization of pyrrole at a low temperature in presence of CVO. As a consequence of extensive mutual synergistic interactions between CVO and PPy, CVO-PPy hybrid electrode provides an ultrahigh specific capacitance (2215 F/g at 1 A/g) with excellent cyclic stability (96.5% specific capacitance retention after 3000 charge-discharge cycles at 1 A/g). Furthermore, an exclusive all-solid-state asymmetric supercapacitor (ASC) device with an outstanding energy density of 38.2 Wh/Kg (corresponding power density of 700 W/Kg at 1 A/g) with amazing cycling stability (95% capacitance retention after 5000 charge-discharge cycles) and durability has been fabricated by assembling CVO-PPy as positive and graphene nanoplatelets (GNP) as negative electrode operable within a wide potential window of 0-1.4 V in presence of PVA-KOH gel electrolyte membrane. The device can instantly power-up several electronic appliances. Such superior electrochemical performance reasonably indicates great prospective of the assembled ASC for high energy and power device application in modern electronic industries. KEYWORDS: Robust, cobalt vanadium oxide hydrate, polypyrrole, specific capacitance, energy density.

Resume : Hierarchical assemblies and supramolecular structures are increasingly becoming important for developing next generation energy devices such as supercapacitors, Na- or Li- ion batteries, gas sensors, catalytic reactors, etc. Few recent articles have suggested that stabilizing hollow nanostructures may lead to significant improvement in the performance of energy storage devices similar to what has been observed in applications such as gas sensing and catalysis. We present the successful and economical strategies to stabilize oxides of copper viz., CuO and Cu2O, with stable hollow morphologies. These materials show significant improvement in the electrochemical performance of the energy storage device such as supercapacitors. The enhancement in the performance of the electrode material is explained on the basis of a combined effect of increased: surface area, redox sites, potential and shorter diffusion length for ions transportation. For examples, the specific capacitance of a device based on Cu2O negative electrode was found to be 164 F/g at 10 mV/s in 2M KOH solution in comparison to 97 F/g obtained by using the solid particles having nearly spherical morphology of the same active electrode material. The devices fabricated using such hollow electrodes materials also retained 95% capacitance retention even after 3000 cycles. The industrial application of such devices would also be presented.

Resume : Increasing power and energy demands for next-generation portable and flexible electronics such as roll-up displays, photovoltaic cells, and wearable devices has inspired intensive efforts to explore flexible, lightweight, and environmentally friendly energy storage devices. Flexible solid-state supercapacitors (SCs) represent a new class of energy storage devices that can provide high specific/volumetric energy and power densities for flexible electronics. Electrode materials are the fundamental key components for energy storage devices that largely determine the electrochemical performance of energy storage devices. Various materials such as carbon materials, metal oxides and conducting polymers have been widely used as electrode materials for energy storage devices, and great achievements have been made. Recently, metal nitrides have attracted increasing interest as remarkable electrode materials for supercapacitors due to their outstanding electrochemical properties, high chemical stability, standard technological approach and extensive fundamental importance. In this work, we select the Self-supported transition metal nitride Nickel-Cobalt-Nitride nanomaterials as the electrode. We use a facile electrochemical deposition method for large-scale growth of ultrathin mesoporous nickel cobalt (NiCo2O4) nanosheets on flexible and conductive graphene fibers and nickel foam with robust adhesion as a the precursor, then annealed at 300? 400?, 500? for 1h, 2h and 3h in flowing NH3 gas and characterized by the X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HR-TEM) along with selective area electron diffraction (SAED) and X-ray photoelectric spectroscopy (XPS) techniques. The electrochemical responses of the transition metal nitrides were analyzed at the three electrode system by primarily cyclic voltammetry (CV) using 6M KOH electrolyte employing various scan rates (2mV/s to 100mV/s). High performance allsolid-state flexible SCs were constructed based on freestanding Graphite fibers or nickel foam/Nickel-Cobalt-Nitride hybrid electrodes with KOH /polyvinyl alcohol (PVA) gel as solid-state electrolyte and thinner separator. Accordingly, the performance of the materials as a supercapacitor varied with increasing annealing temperature and time, it showed that only the samples annealing at the NH3 atmosphere for 2h at 400 ? the Nickel-Cobalt-Nitrides have the best electro performance, which is due to the existence of little amount of oxygen and enhance the conductivity of the materials. The Graphite fibers and nickel foam supported Nickel-Cobalt-Nitride promise fast electron and ion transport, large electroactive surface area, and excellent structural stability. As a result, superior pseudocapacitive performance is achieved with an ultrahigh specific capacitance of 1568 F g-1and 1750 F g-1, even at a very high current density of 20 A g? 1, and excellent cycling performance at high rates, suggesting its promising application as an efficient electrode for electrochemical capacitors. The remarkable performance of these hybrid composite electrodes implies that supercapacitors based on them have potential for many practical applications.

Resume : Oxygen ion conductors, like yttrium stabilized zirconia (YSZ) or doped ceria, are currently the most suitable electrolytes for solid oxide fuel cells due to their mechanical and chemical stability and compatibility with the employed electrode materials [1]. Their electrical conductivity is strongly influenced by dopant concentration, temperature, atmosphere and microstructure of the material. While theory and experiments generally agree on the influence of the first three parameters, the influence of the microstructure remains a hot topic. Nanocrystalline samples could display superior conductivity through enhanced grain boundary diffusion or through the effects of space charge overlap. However, accepted theories all predict a lower conductivity for nanocrystalline materials [2], [3] ? a point of view that is backed up by many experimental studies [1] but opposed by some [4], [5]. Experimentally, it is possible to separate the bulk and grain boundary conductivities using Electrochemical Impedance Spectroscopy (EIS), but the interpretation of the obtained impedance spectra is not straightforward. The current approach is to interpret the measurement data using the dilute solution model with the Mott-Schottky approximation. However, we know from measurements and atomistic simulations that these assumptions are simply not accurate at realistic doping percentages [6]. This implies that currently, EIS can only provide a qualitative comparison of these materials but not a quantitative assessment of the underlying physical processes. Modelling can help us to gain insight in those underlying physics. Oxygen ion conductivity is a prime example of a material property that cannot be completely understood or studied on a single length scale. Fundamental parameters, like interaction energies or diffusion barriers, are determined on the atomic scale. Dopants and vacancies cluster together to influence the transport properties on the mesoscopic scale [7], [8]. And the influence of grain-size, grain boundaries and interfaces is best studied using a continuum model [2], [3], [9]. We propose a formal link between Metropolis Monte Carlo simulations to calculate the local crystal structure [8], and transport processes on a continuum scale, based on the Cahn-Hilliard description of solid electrolytes [9]. We use this multiscale model to calculate impedance spectra and ionic conductivities and we show how parameters such as interaction energies, diffusion barriers and grain boundary orientations influence these results. [1] X. Guo and R. Waser, ?Electrical properties of the grain boundaries of oxygen ion conductors: Acceptor-doped zirconia and ceria,? Progress in Materials Science, vol. 51, no. 2, pp. 151?210, 2006. [2] M. C. G?bel, G. Gregori, and J. Maier, ?Numerical calculations of space charge layer effects in nanocrystalline ceria. Part I: comparison with the analytical models and derivation of improved analytical solutions,? Physical Chemistry Chemical Physics, vol. 16, no. 21, pp. 10214?10231, 2014. [3] D. Van Laethem, J. Deconinck, D. Depla, and A. Hubin, ?Finite element modelling of the ionic conductivity of acceptor doped ceria,? Journal of the European Ceramic Society, vol. 36, no. 8, pp. 1983?1994, 2016. [4] I. Kosacki, T. Suzuki, V. Petrovsky, and H. U. Anderson, ?Electrical conductivity of nanocrystalline ceria and zirconia thin films,? Solid State Ionics, vol. 136, pp. 1225?1233, 2000. [5] T. Suzuki, I. Kosacki, and H. U. Anderson, ?Microstructure-electrical conductivity relationships in nanocrystalline ceria thin films,? Solid State Ionics, vol. 151, no. 1, pp. 111?121, 2002. [6] F. Giannici, G. Gregori, C. Aliotta, A. Longo, J. Maier, and A. Martorana, ?Structure and oxide ion conductivity: local order, defect interactions and grain boundary effects in acceptor-doped ceria,? Chemistry of Materials, vol. 26, no. 20, pp. 5994?6006, 2014. [7] M. Nakayama and M. Martin, ?First-principles study on defect chemistry and migration of oxide ions in ceria doped with rare-earth cations,? Physical Chemistry Chemical Physics, vol. 11, no. 17, pp. 3241?3249, 2009. [8] S. Grieshammer, B. O. Grope, J. Koettgen, and M. Martin, ?A combined DFT+ U and Monte Carlo study on rare earth doped ceria,? Physical Chemistry Chemical Physics, vol. 16, no. 21, pp. 9974?9986, 2014. [9] D. S. Mebane and R. A. De Souza, ?A generalised space-charge theory for extended defects in oxygen-ion conducting electrolytes: from dilute to concentrated solid solutions,? Energy \& Environmental Science, vol. 8, no. 10, pp. 2935?2940, 2015.

Resume : Silicon-based materials have attracted much interest as negative electrodes of Li-ion batteries due to the high theoretical capacity of Si (3600 mAh g-1), low working potential and environmental friendliness. However, silicon suffers from severe pulverization on cycling that induces rapid capacity fading. Embedding silicon in a nanostructured matrix able to buffer volume changes and to improve electronic conductivity is expected to overcome this hurdle. In this work, we explore the properties of two-phase Si/TiSi2 composites which crystallinity and topological distribution is tuned by mechanochemistry. Intimate phase mixtures at the nanoscale and crystallite sizes below 30 nm are achieved after 20 h of ball milling. Galvanostatic cycling experiments were conducted for this material in half-cell configuration at regime of C/5 within a potential window 0.07-2 V. The composites provide a very interesting initial capacity of 1400 mAh g-1, but a significant capacity loss of 50% over 70 cycles attributed to mechanical instability. To solve this issue, the Si/TiSi2 nanocomposite was further milled with 10 wt.% of graphite for 6 h. Under the same cycling conditions, this new Si/TiSi2/C nanocomposite delivers an initial capacity of 1000 mAh g-1 with a capacity loss reduced to 22.5 % over 200 cycles and an outstanding coulombic efficiency (99.5%).This study was undertaken in the framework of the project NEWMASTE of the French Research Agency ANR under the grant N°ANR-13-PRGE-0010.

Resume : One of the main technological challenges of present days is to increase the energy density of energy storage systems, which is related to technological advances in the portable electric devices market [1]. Lithium-ion batteries are the most used energy storage systems as they are lighter, cheaper, with higher energy density (210Wh kg-1), no memory effect, and higher number of charge/discharge cycles than any other battery type [2]. The separator membrane of lithium-ion batteries is typically fabricated through different polymers and poly(vinylidene fluoride), PVDF, and its copolymers have been intensively investigated for this application due to their high polarity, excellent thermal and mechanical properties, controllable porosity and wettability by organic solvents, and chemical inertness and stability in cathodic environment [3]. PVDF polymer is dissolved in aprotic polar solvents that are toxic, dangerous to use on large scale and hazardous. Considering the environmental issues, the focus of this work is to produce porous PVDF membranes replacing the conventionally used dangerous solvent by a ?green" solvent, N,N?-dimethylpropyleneurea (DMPU) for battery separator. Separators were thus prepared with a porous microstructure and ionic conductivity, tortuosity and MacMullin number values of 0.1 mS.cm-1, 4 and 82, respectively. Li/C?LiFePO4 half-cells with this separator and conventional electrolyte solution (1M LiPF6 in EC:DMC) showed good cyclability and rate capability, with a discharge value after 50 cycles of 56 mAh.g-1 at C, corresponding to 50% of the capacity retention. This PVDF separator soaked with ionic liquid ([C2mim][NTf2]) shows a discharge capacity of 45 mAhg-1 at C/5-rate and capacity retention of 60 %, respectively. Acknowledgments This work was supported by the Portuguese Foundation for Science and Technology (FCT) and FEDER funds through the COMPETE 2020 Programme, projects UID/FIS/04650/2013, PTDC/CTM-ENE/5387/2014, and grants SFRH/BD/90313/2012 (A.G.), and SFRH/BPD/112547/2015 (C.M.C.). SLM thanks financial support from the Basque Government Industry Department under the ELKARTEK Program. The authors thank Solvay, Timcal and Phostech for kindly supplying the high-quality materials. References [1] Tarascon, J. M.; Armand, M., Issues and Challenges Facing Rechargeable Lithium Batteries. Nature 2001, 414, 359-367. [2] M. Wakihara, O. Yamamoto, Lithium Ion Batteries: Fundamentals and Performance, John Wiley & Sons, 2008. [3] Costa, C. M.; Silva, M. M.; Lanceros-Mendez, S., Battery Separators Based on Vinylidene Fluoride (Vdf) Polymers and Copolymers for Lithium Ion Battery Applications. RSC Advances 2013, 3, 11404-11417.

Resume : The lithium sulphur battery (LSB) possesses high gravimetric and volumetric energy density and is, nowadays, the closest technology to fulfil energy requirements for the upcoming revolution on electric vehicles. Our work has been mainly focused on the positive electrode. We have prepared several carbon nanofibers (CNFs) by the electrospinning technique, a simple and cost-effective way to produce binder-free electrodes. The fibbers act as a conductive matrix for the insulating polysulfide phases formed during electrochemical reduction and minimize migration of these species to the lithium metal or negative electrode. The fibbers have 300-400 nm of diameter and show homogeneous distribution of sulphur which was incorporated into the matrix by the impregnation method. Electrochemical testing in half-cell (vs Li) show that sulfurized CNFs deliver high capacity with good retention i.e. ? 900 mAhg-1 at C/20 and 223 mAhg-1 at 1C. The morphology of the CNFs may be tuned by the use of different reagents during the electrospinning process, leading to a significant increase of material surface area for sulphur impregnation. This research is funded by the HELIS project (HORIZON 2020); 666221.

Resume : Over the past few years, polymer electrolyte fuel cells (PEFCs) have been deeply studied and are now considered as one of the most efficient and cleanest technologies for electricity generation. However, PEFCs technologies rely heavily on electrocatalysis for the Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER). These reactions are sluggish and thus require precious metals (e.g. Platinum) as catalysts. Some previous works have been done to replace platinum with non-precious metal phosphides, such as cobalt and nickel phosphide. Reported phosphide catalysts perform well in alkaline media but show poor performance in acidic media because of corrosion. In this work, chromium atoms are doped in cobalt and nickel phosphides to improve their corrosion resistance and their performances toward HER, HOR, ORR and OER would be investigated using the standard electrochemical method.

Resume : Light-Sensitive Solid State Supercapacitor: Direct Utilization of Illumination Signal for Storage Buddha Deka Boruah and Abha Misra Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, Karnataka, India 560012 Supercapacitor are considered as a promising energy storage device because of their additional unique features such as high power density, fast charge discharge rate, long cycling life, safe operation and low cost, etc.1,2 Therefore, the fabrication of highly efficient supercapacitor is considered as great research challenge. In this work, novel illumination signal sensitive solid state supercapacitor was fabricated based on decorating electroactive material, NiCo2O4 on optically sensitive, zinc oxide nanorods (ZnO NRs) as electrode directly grown on transparent indium tin oxide. Coating of NiCo2O4 on NRs surfaces introduces more electrochemically active surface area of electrode material due to the large surface to volume ratio of NRs. Morphology and crystal studies show that ZnO NRs are vertically aligned c-axis orientation having hexagonal wurtzite crystal structure whereas coating of NiCo2O4 on NRs is cubic spinel crystalline phase structure. The direct growth of electroactive material on the current collector reduces the junction resistance by providing the unique ion/charge conduction path and hence excellent ion-diffusion efficiency. It was noticed that the fabricated electrode NiCo2O4-ZnO NRs is highly sensitive towards the ultraviolet (UV) illumination signal. Therefore, the electrochemical performance of fabricated solid state supercapacitor, NiCo2O4-ZnO NRs//NiCo2O4-ZnO NRs was studied both in absence and presence of UV illumination. Interestingly, the capacitive response of the supercapacitor doubles in presence of UV illumination intensity of 3 mW/cm2 as compared to absence of UV. Under UV illumination, the photo generated charge carriers directly participate in the electrolyte ions driven process towards the respective electrode. Moreover, as-fabricated solid state supercapacitor demonstrated outstanding capacitance retention of 97% of its initial capacitance after 2000 charging discharging cycles under UV illumination. Furthermore, the power density and energy density of the supercapacitor enhance from 1199 to 1202 mW/kg and 0.74 to 1.35 mWh/kg during UV illumination at a constant current density of 3 mA/g. Thus, present work reveals direct utilization of illumination signal for storage in the form of electrochemical energy. References 1. P. Simon, Y. Gogotsi, Nat. Mater. 2008, 7, 845. 2. X. Peng, L. Peng, C. Wu and Y. Xie, Chem. Soc. Rev., 2014, 43, 3303.

Resume : Fresh water is swiftly becoming a restricted resource due to rising demand globally. Seawater desalination is a potential solution to this problem because seawater accounts for more than 97% of the world?s water supply. Currently, the primary limitation preventing the widespread use of seawater desalination as a fresh water supply is the immense amount of energy required to drive the process. A variety of desalination technologies have been developed over the years. Reverse osmosis requires a large electrical energy input, which accounts for 44% of its cost, and it is based on selective membranes, which are prone to fouling and require frequent replacement. Thermal energy based multistage flash distillation requires energy intensive heating to temperatures above 90 °C, accounts for 50 % of its cost. Forward osmosis is a promising new process that utilizes lower temperatures (60 °C) but still requires the use of membranes. In this work we are trying a new technique to desalinate water by combining CDI and battery system. which operates by performing cycles in reverse. This desalination system contain a rGO-SnO2 nano composite electrode for holding the Na ions and chloride ions held in electric double layers formed at the surface of Ag Electrode. In this work we fabricated the nano composite of rGO-SnO2 by Hydrothermal Process. The morphology, Crystal structure and elemental analysis were performed by using TEM (Transmission Electron Microscopy),EDS (Energy Dispersive Spectroscopy),XRD (X-ray Diffraction ), FTIR(Fourier Transform Infrared Spectroscopy),Raman Spectroscopy. The Electrochemical Properties were evaluated by a Cyclic Voltammetry (CV) test and desalination performance tested in a customized desalination cell. rGo-SnO2 composite showed high reversibility, excellent cycling and distinguished electro sorption capacity , which make this system of potential interest for addressing the issue of fresh water and feasible method for desalting the brackish water in capacitive techniques. Key Words: Desalination ; Capacitive Deionization ; rGO-SnO2 ; Electrosorption

Resume : Carbon dots (C-dots) have attracted great attention because of their unique optical and electronic properties. Current applications of C-dots are mainly focused on bioimaing and biosensing relying on their optical properties, and only a few papers have been reported on C-dots for energy-harvesting such as capacitors or solar cells. Here, we report the utilization of nano-sized C-dots for a new type of solid electrolyte by incorporating metal counter cations (M+). C-dots synthesized by the top-down method, have polyanionic forms of oxygen-bearing functional groups on their surface exhibiting strong electrostatic interaction with metal counter cations. Composites of C-dots and various metal counter cations ((C-dots)-Mx+) were applied as electrolytes in various solvent conditions, and showed excellent performance over conventional supporting electrolytes. The (C-dots)-Mx+ was then employed as liquid and gel electrolytes for electrochromic devices (ECDs), and the devices showed excellent electrochromism with fast response time, long lifetime, high coloration efficiency and low power consumption.

Resume : Si? with cubic crystal lattice (3C-SiC) is a promising candidate for anode material for Li-ion batteries due to its superior mechanical and electrochemical stability upon cycling with the theoretical capacity of 2638 mAh/g [1,2,3]. In the present work, we perform the study of the electrochemical performance of the novel 350 nm B-doped 3C-SiC thin film anode prepared by means of reduced pressure chemical vapor deposition (RPCVD) method. Microscopic investigation before and after 20 cycles showed no structural changes in the thickness of the film. The battery cell with B-doped 3C-SiC anode exhibited no capacity fading upon cycling within 0.01 ? 1.5 V for more than 200 cycles. The impedance measurement result reveals an improvement of the electrical conductivity with cycling number increase. The electrochemical results as well as synthesis route and characterization details will be detailed at the conference. Acknowledgements This research was funded under the target program ?0115??03029 "NU-Berkeley strategic initiative in warm-dense matter, advanced materials and energy sources for 2014-2018" from the Ministry of Education and Science of the Republic of Kazakhstan. References [1] H. Zhang and H. Xu, Sol. St. Ion. 263, 23?26 (2014) [2] T. Sri Devi Kumari et al., RSC Adv. 3, 15028?15034 (2013) [3] H. Li et al., Chem. Mater. 28, 1179?1186 (2016)

Resume : Silicon holds promise as a next-generation negative electrode for lithium-ion batteries and has already seen some utilization commercially. But its advantage over graphite in theoretical capacity is counter-weighted by its disadvantage in stability, as the silicon expands and contracts in volume during lithiation cycles. However, silicon in the form of nanoparticles provides an opportunity to improve cycle stability. At the Institute for Energy Technology (IFE), we use a free space reactor to create high purity silicon nanoparticles from the pyrolysis of silane gas. By controlling process parameters such as reactor temperature, quench rate, and dwell time, we exert control over the nanoparticle size and size distribution, as observed by scanning and transmission electron microscopy. Using our in situ method of extracting sample nanoparticles, we have identified a relationship between reactor temperature, optical spectrum, and particle size distribution using a reactor design with scalability to mass production. In addition, we harvested the silicon nanoparticles and implemented them into lithium-ion half cells for electrochemical testing. We compared the performance of free space reactor silicon nanoparticles with stock silicon nanoparticles of average particle sizes of less than 50 nm, 100 nm, and 1 to 5 microns.

Resume : Rapid decline of fossil fuels and increasing environmental pollution as well as increasing the amount of waste and lack of appropriate methods of collection and the elimination of waste and increasing co, co2 and sulfur in the air from the consequences of burning garbage and fossil fuels that increase the temperature of the atmosphere and many problems for society has created.This article tries to overcome these problems with thermal energy recycle waste using plasma arc methods have in some way to go high temperature bonds between the molecular material and power breakdown is not resistance The decomposition process must be very high temperatures (thermal plasma), and without the presence of oxygen (Pyrolisis) will be done. Move in this article how to break down without oxygen and process waste elimination system by the plasma arc, forming arc plasma reactor and gas-forming major components of the waste elimination system and economic and environmental results we have discussed that Saving fossil fuels and fuel conservation for future generations and environmental pollution to a considerable size and reduces the remains of recyclable materials can be used as raw materials in the industry that makes its economy Efficiency of industrial raw materials are. This way, as a significant waste volume reduction has found hazardous waste disposal will be followed. KEYWORDS : : Elimination waste, recycling thermal energy, reactor, plasma, Aspars.

Resume : Silicon has been in the spotlight of the next generation anode materials due to its distinctive Li-related features such as the ability to form Li rich compounds, corresponding to an exceptional capacity of 3579 mAh/g at low working voltages. In exchange, many engineering concerns are associated to the structural deformation during lithium alloying that can lead to material pulverization as well as limited cycling life. We detail on an anode configuration based on interconnected kinked Si nanowires (k-SiNWs) fabricated by metal assisted chemical etching. A chemical peeling step is introduced to facilitate the extraction of the etched k-SiNWs from their originating Si substrate. The three-dimensional (3D) interconnected k-SiNWs-based anode materials are assembled, using a vacuum filtration technique, with multi-walled carbon nanotubes. The k-SiNWs are expected to be more robust to lithiation-induced stresses as they typically behave like microsprings. In addition, the kinks provide interlocking joints resulting in a fairly resilient anode material. The evaluation of the mechanical properties of the anode assemblies revealed a foam-like architecture that benefits from high porosity. The electrochemical evaluation of these 3D Si-based assemblies showed valuable cycling life in ionic liquids compared to conventional electrolytes, retaining 70% of the initial capacity and displaying an average Coulombic efficiency of 97.5% after 50 cycles. Further performance improvements were obtained by coating the k-SiNWs with a 33 nm Ni coating. The exemplary mechanical behavior and electrochemical robustness were assigned to the kinked morphology of the SiNWs [Sandu G. et al. submitted].

Resume : Here, the electrochemical performance of a polyaniline based porous ternary composite (PNHFeG) electrode material is presented for a high performance supercapacitor. The PNHFeG ternary composite was prepared through in-situ oxidative polymerization of aniline in the presence of a binary composite NHFeG that involves combination of flower-like nanostructured Ni(OH)2 and iron oxides-doped reduced graphene oxide (Fe-RGO). The porous ternary PNHFeG composite with high surface area (239 m2 g-1) notably exhibits maximum specific capacitance (Csp) of 2714 F g-1 at 5 A g-1 current density, along with 98.5 % retention of its initial capacitance even after 2000 cycles. Moreover, even at a higher current density of 30 A g-1, the composite electrode material maintains a remarkable Csp value of 1223 F g-1. Finally, the PNHFeG electrode material reveals a power density of 1498 W kg-1, along with a maximum energy density of 135.7 Wh kg-1 at 5 A g-1, suggesting the current composite electrode material can be considered as a promising candidate for high-performance supercapacitor applications. Keywords: Supercapacitor, oxidative polymerization, specific capacitance, energy density.

Resume : Efficient high-energy Lithium-ion cathode materials with fast-charging ability are needed for the increasing demand of mobile devices as well as electric vehicles with longer operating distance. LiFePO4 is one of the most promising cathode materials for these applications. It is inexpensive, non-toxic and chemically as well as thermally stable with a reasonable specific capacity. However, its main drawbacks are low ionic and electronic conductivity. The key factor to enhance the electrochemical performance of LiFePO4 materials is the reduction of the lithium-ion diffusion length. LiFePO4 shows anisotropic lithium-ion diffusion, which takes place exclusively along its crystallographic b-axis. So far, only a few studies compared LiFePO4 materials with different particle morphologies. In these the LiFePO4 nanomaterials differ in morphology but also in particle size, so it is not surprising that the materials with the smallest dimension along the b-axis show the best electrochemical results. In our contribution, we present a study on the influence of particle morphology on the electrochemical performance of LiFePO4/C nanoparticle composites with similar dimensions along the b-axis. For this purpose we synthesized monodisperse LiFePO4 nanoparticles via a solvothermal approach with rod-, plate- and sphere-like shape.[1] A carbon shell smaller than 10 nm was produced around each LiFePO4 particle by a resorcinol-formaldehyde resin coating and subsequent calcination.[2] Electrochemical characterization focusing on fast-charging tests of all materials are carried out in commercial standardized electrochemical test cells (PAT-Cells, EL CELL) to reduce variation by cell test assembly to a minimum. References: [1] B. Guan, X. Wang, Y. Xiao, Y. Liu, Q. Huo, Nanoscale 2013, 5, 2469?75. [2] C. Nan, J. Lu, L. Li, L. Li, Q. Peng, Y. Li, Nano Res. 2013, 6, 469?477.

Resume : Solid lithium electrolytes with garnet structure have been widely studied for their potential use in new generation lithium batteries. These materials show high lithium conductivity of the order of 10-4 ? 10-3 S/cm at room temperature. However, in order to successfully use them in electrochemical cells one must decrease the overall resistance of the garnet solid electrolyte. The thickness of garnet layer should not exceed 10-100 µm to obtain the surface resistivity value below 10 ?×cm2. Therefore, it is important to develop methods suitable for preparing thin garnet layers, while preserving their remarkable conductivity. In this work we prepared thin garnet layers using two techniques: (i) sintering of a thin surface layer of a porous garnet pellet by high energy electron irradiation, (ii) hot pressing of two attrited porous garnet pellets with the formation of a dense layer in between them. The chemical composition, crystal structure, morphology, thickness and ionic conductivity of the layers have been investigated and the results will be discussed in the report.

Resume : Solid polymer electrolytes (SPEs) have been proposed as safe replacement for conventional liquid electrolytes in lithium-ion batteries, being PEO the most widely used due to its strong salt solvation power. Herein, the preparation of a new type of comb polymer material based on Jeffamine® sidechains and a poly(ethylene-alt-maleic anhydride) backbone is reported. Reaction proceeds by imide ring formation through the -NH2 moieties showing higher thermal stability than the conventional polymer matrices. Moreover, the high configurational freedom and flexibility of propylene oxide/ethylene oxide units in Jeffamine® provides good elastomeric properties. SPEs based on these polymer matrices and LiTFSI show low Tg (~ 40 ºC), high ionic conductivity and good electrochemical stability. The ionic conductivity is higher than that of the conventional SPEs comprising of LiTFSI and linear PEO (5.3 × 10?4 S cm?1 vs 4.5 × 10?5 S cm?1 at 70 ºC). This is attributed to the fully amorphous and flexible nature of the Jeffamine®-based polymer matrices that have a comb structure with a high concentration of free end groups compared to the semi-crystalline PEO. The electrochemical performance could be significantly improved by varying the salt compositions. The feasibility of these compounds in lithium metal batteries is further demonstrated by the implementation of these polymers as binders for cathode materials, and the stable cycling of Li|LiFePO4 and Li-S cells using Jeffamine®-based SPEs.

Resume : Vanadium Redox Flow Batteries (VRFBs) have emerged as promising energy storage systems contributing to the implementation of power generation from renewable energy sources in large-scale and remote applications. Although the energy is converted and stored in the electrolytes, the electrodes also have an important role in the battery performance as supports of the reactions involved in the charge/discharge of the device. Consequently, the development of more efficient electrode materials, far from the widely used graphite felts (GFs), is essential to obtain batteries with enhanced energy densities and to make them more competitive. In this context a graphene-modified graphite felt, obtained by electrophoretical deposition (EPD) from a raw GF and a graphene oxide (GO) water suspension, was proposed as a novel electrode material. The excellent morphological, chemical and physical properties of the resulting hybrid material explain its outstanding performance, in terms of electrochemical activity and kinetic reversibility towards the vanadium redox reactions, and the markedly high energy density measured (up to 95.8 % at 25 mAcm-2) in a laboratory scale flow device.

Resume : The rapidly growing number of applications for micro-electromechanical systems (MEMS) and microelectronic devices has resulted in an increasing demand for lightweight batteries with high lifetime and high energy density. All-solid-state lithium-ion batteries (LIB) feature low self-discharge and a good long-term stability. Furthermore, compared to LIB based on liquid electrolyte, all-solid-state LIB show reduced net weights and volumes, and are inherently safer [1-3]. A challenge of all-solid-state LIB is the relatively low power density. In order to overcome this issue electrode surface areas have to be increased using 3D structures like trenches, pores, nanowires or nanotubes as templates or active electrode materials [2-4], resulting in high demands on the applied coating technologies. Atomic Layer Deposition (ALD) is capable to meet these demands due to its excellent step-coverage, film thickness control and uniformity across the substrate. In this context, we present results on electrode film deposition as well as LIB device characterization. Tested electrodes were single layers of titanium or cobalt oxide deposited on silicon substrates. The titanium oxide was grown by thermal ALD using titanium tetrachloride (TiCl4) and water, while the cobalt oxide was deposited with pulsed chemical vapor deposition (CVD) using dicarbonylcyclop¬entadienylcobalt(I) [CpCo(CO)2] and hydrogen. The achieved layers were applied as cathode materials in home-made cells (of Swagelok® or button type) with glass fiber separator, 1 M LiPF6 solution in a mixture of ethylene (EC) and dimethyl carbonate (DMC), and a lithium counter electrode. Layers (resp. cells) were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Based on these methods we will show and discuss the cell and electrode characteristics and compare it with the behavior of commercial button cells. Thus, according to peak potentials (U_p) and their potential difference delta U_p measured in CV experiments, the deposited TiO2 layer consisted at least partially of anatase phase, which was in line with XRD results. The relatively broad Ti3+/Ti4+ peaks shifted with increased scan rate v from 0.05 to 10 mV/s resulting in higher potential differences, revealing quasi-reversible kinetics. As expected for diffusion processes (here: Li+ intercalation and de-intercalation), both peak currents (I_p) increased linearly with the square root of the applied scan rate. EIS results seemed to indicate a higher micro-scale surface inhomog¬eneity than commercial materials. Thus, the ALD TiO2 process has to be further improved. [1] M. Roberts, P. Johns, J. Owen, D. Brandell, K. Edstrom, G. El Enany, C. Guery, D. Golodnitsky, M. Lacey, C. Lecoeur, H. Mazor, E. Peled, E. Perre, M.M. Shaijumon, P. Simon, P.-L. Taberna, 3D Lithium Ion Batteries - from Fundamentals to Fabrication. J. Mater. Chem. 21 (2011) pp. 9876 [2] J.G. Kim, B. Son, S. Mukherjee, N. Schuppert, A. Bates, O. Kwon, M.J. Choi, H.Y. Chung, S. Park, A review of lithium and non-lithium based solid state batteries, J. Power Sources 282 (2015) pp. 299 [3] J.F.M. Oudenhoven, L. Baggetto, P.H.L. Notten, All-Solid-State Lithium-Ion Microbatteries: A Review of Various Three-Dimensional Concepts. Adv. Energy Mater. 1 (2011) pp. 10 [4] X. Meng, X.-Q. Yang, X. Sun, Emerging Applications of Atomic Layer Deposition for Lithium-Ion Battery Studies. Adv. Mater. 24 (2012) pp. 3589

Resume : One critical challenge facing flexible and wearable technology is how to develop safe, robust , reliable and low-cost flexible energy storage units with high performance. However, the widely-investigated lithium-ion batteries usually suffer from intrinsic safety, cost and reliability issues, while the applications of supercapacitors are restricted by relatively low energy density. Here we demonstrate a highly safe and rechargeable solid-state zinc-ion battery constructed by a novel hierarchical polymer electrolyte (HPE) and ?-MnO2 nanofibres/carbon nanotube (CNT) composite cathode. The hierarchical electrolyte is synthesized by grafting polyacrylamide (PAM) on gelatin chains that is filled in the network of polyacrylonitrile (PAN) electrospun fiber membrane. The gelatin-g-PAM based hydrogel significantly enhance the ionic conductivity and water retention of the HPE film, while the PAN fiber membrane efficiently reduces the possibility of short circuit of the battery besides a further improvement in strength. With a highly porous three-dimensional structure and a high level of water retention in polymeric networks, the HPE film showed a high ionic conductivity of 1.76×10?2 S·cm?1 at room temperature while maintaining good flexibility and mechanical strength.This solid-state battery demonstrates delivers high energy density (7.47 mWh cm?3), high specific capacity (280mAh/g at 0.2C) and good cycling stability (97% capacity retention after 1000cycles at 9C rate). More importantly, this battery offers greatly enhanced safety and possess the capability to work under some severe conditions, such as being bent, hammered, punctured, tailored?burned or even washed in water. In addition, multiple solid-state zinc-ion batteries could be integrated in series to power a commercial smart watch and wearable pulse senor, demonstrating promising potential for more practical wearable applications. This work may offer a new platform for the advancement of flexile and wearable energy storage technologies.

Resume : Ionic liquid electrolytes may find application in next-generation batteries. Even if they don?t replace conventional solvents, they may contribute to the ion mobility within the electrolyte. Task-specific ionic liquids are designer materials that are made to exercise specific functions like ion complexation. Introduction of task-specificity into ionic liquids however is often performed using elaborate reaction conditions and expensive reagents. We report the synthesis of task-specific imidazolium ionics and ionic liquids with key functionalities of organic molecules from electro- and coordination chemistry. Products are highly functional and potentially suitable for high technology applications even though they are formed without elaborate reactions from cheap and potentially green reagents. Our goal is to make progress towards economically competitive and sustainable task-specific ionic liquids for electrolyte applications.

Resume : Lithium-ion batteries are the most popular choice as source of energy for nomad technologies. In this context, the use of lithium metal as material for negative electrode has emerged as a solution to improving the energy density and capacity of actual systems. However, the dendritic growth phenomenon that induces the formation of dead lithium and short circuit of the battery with eventual fire risks is the main obstacle for its commercialization [1]. On the other hand, the use of ionic liquids (ILs) as a promising choice to improve safety and suppress dendrite growth because of their characteristic properties such as retarded flammability, high thermal stability, and high ionic conductivity has been reported [2]. In this work, X-ray photoelectron spectroscopy (XPS) coupled to electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) have been used to study the side reactions between lithium electrode and imidazolium-based ILs. The impact of C1C6ImTFSI and C1C6ImFSI ILs has been studied showing an enhanced stability when using FSI as anion forming a homogeneous SEI layer. Finally, the lithium surface evolution under aging in equilibrium condition as well as under polarization depending on electrolyte composition will be discussed. [1] Y. Takeda, O. Yamamoto and N. Imanishi, Electrochemistry 84(4) 210?218 (2016) [2] N. Schweikert, A. Hofmann, M. Schulz, M. Scheuermann, S. Boles, T. Hanemann, H. Hahn, S. Indris, Journal of Power Sources 228 (2013) 237-243

Resume : This study has illustrated the analysis of key battery components ? namely, anode, cathode, and separator ? at low accelerating voltages, revealing additional information beyond the reported structures in batteries. This low kV imaging of Li-ion batteries allowed an increased image fidelity on the extent of particle cracking, the observation of inhomogeneous binder distributions, binder strings and the detection of cubic and spherical shaped objects. The binder strings became visible between particles in the cathode and anode material and spanned lengths of 20nm up to 3µm. The electron beam exposure quickly lead to melting and disappearance of the strings. This indicates, that the strings might be polymeric. The observed cubic shaped objects in the cathode were of a few 10nm lateral extent and the ones in the separator about 10µm in size. They disappeared after cycling and were melting during direct electron exposure or even disappeared when using to high accelerating voltages. In contrast, in the anode spherical objects ranging from 20nm up to 40nm in lateral extend were observed. Surprisingly, they did not disappear after cycling, but instead fused to a more closed layer around the anode particles. Voltages of 1kv down to 100V were used. It was demonstrated that highly nonconductive material can be imaged without further conductive treatment and differences of the micro and nanostructure before and after aging of the battery can be observed.

Resume : There is an ever-increasing interest in energy storage devices that not only store energy but which are also flexible, stretchable or structural. These mechanical requirements demand new electrode materials and architectures. Owing to their unique combination of excellent electrical conductivity (3.5x10^5S/m), high-performance mechanical properties (specific tensile strengths of 1,5GPa/SG, modulus of 60GPa/SG and toughness of 80J/g) and high surface area (260m2/g) carbon nanotube fibers is considered as highly appealing candidate material for flexible energy storage. Here we present a simple method to fabricate large scale all-solid EDLCs made by CNT fibers and a polymer electrolyte (PE) membrane. Electrochemical measurements show high performance of all-solid devices with the maximum gravimetric capacitance, energy density and power densities of 28F/g, 11.4Wh/kg and 46kW/kg very similar to those obtained using pure IL, and which can be taken as a benchmark to evaluate the efficiency of the EDLC assembly process. The EDLC devices can be repeatedly bent and folded 180° without degradation of their properties. In addition, mechanical tests of CNT fibers/PE membrane composite shows specific strength and modulus of 39MPa/SG and 577MPa/SG for a fiber mass fraction of 11wt.%, similar to a structural thermoplastic and with higher specific strength than copper. Further optimization of fabrication method and SC composition open a great perspective to use these materials as structural EDLC.

Resume : Understanding the degradation of graphite anodes plays a major role in the improvement of Li-ion batteries. One possible cause of degradation are inhomogeneities in the electrodes as they may lead to a variation in local charging/discharging rates. Subsequently, local Li plating or a locally extreme state of charge (SOC) result in a loss of capacity. In our contribution, we demonstrate the detection of two-dimensional variances on the sub-mm scale in the composition of the graphite anodes in pouch cells by lock-in thermography (LIT). For this purpose, we combined LIT measurements with scanning electron microscopy (SEM) and Raman spectroscopy mapping to link differences in the heat emission to those in the structure of the graphite. Finally, we used the nondestructive character of LIT to investigate the aging of graphite composite anodes in pouch cells. The aged cells show a typical ring pattern in lock-in thermography images, which can be explained by the help of Raman spectroscopy. We attribute this pattern to the different contact due to the formation of gas during operation, which also leads to inhomogeneous degradation of the graphite electrode.

Resume : Zinc-air batteries (ZABs) are promising candidates for next-generation electrochemical energy storage. They offer a high theoretical specific energy (1086 Wh?kg-1) and energy density (6093 Wh?l-1) and are based on abundant materials. But over time, the performance of the cell is degraded due to a parasitic reaction between the alkaline electrolyte (KOH) and CO2. Furthermore, local depletion of electrolyte at the electrode interface contributes to the passivation of zinc. We have developed continuum models based on the principles of electrochemical thermodynamics and kinetics to simulate the performance of metal-air batteries. Using this approach, we investigate transient and spatially resolved changes in cell potential, electrolyte concentrations, and multi-phase volume fractions. We analyze the performance of ZABs with KOH electrolytes to show how the electrolyte influences overall cell performance. We then expand our analysis to include new aqueous electrolytes, such as pH neutral ZnCl2-NH4Cl. The ZnCl2-NH4Cl electrolyte is not susceptible to the same parasitic reactions as KOH and could extend the life of the battery. The stability of aqueous zinc-ligand complexes can shift strongly with even small changes in pH, affecting the composition of the discharge product and the overall energy density of the cell. Our simulations show that pH gradients can develop, which may accelerate the degradation of the catalyst. We discuss how the composition of the electrolyte and the architecture of the cell can be adjusted to maintain a stable, neutral pH over cycling. This work is supported by the European Commission Horizon 2020 project ZAS! (Zinc Air Secondary Batteries Based on Innovative Nanotechnology for Efficient Energy Storage).

Resume : In recent years, supercapacitors (SCs), an electrochemical energy storage device, have emerged as an alternative to solve excessive energy consumption and depletion of fossil fuels. Although SCs possess excellent cycling stability, high power density and specific capacitance, the performance of SCs has been restricted for their low energy density. The characteristics of SCs are dependent on their electrode materials, configurations and morphologies. In the case of electrode materials, Binary transition metal sulfides (BTMSs) such as CuCo2S4 have several key advantages; rich redox reactions, the synergistic effects by interaction between diverse metal compound, better specific capacitance and electrical conductivity than single transition metal oxides. In particular, the ball-in-ball structure of the electrode material can decide diffusion/transport paths of electrons, the specific surface area and the active sites for electrochemical reactions. Herein, we successfully synthesized the CuCo2S4 novel ball-in-ball multi-shell nanostructures via uniform CuCo2-glycerate nanospheres as precursor for SCs. The structural and chemical compositions of CuCo2-glycerate and CuCo2S4 were confirmed through SEM, TEM, XRD and FT-IR. In addition, their electrochemical performances were investigated by CV and galvanostatic charge/discharge measurements.

Resume : Energetically autonomous electronics for Internet of Things, off-grid and renewable energy generation are demanding for cheap and environmental friendly energy storage devices. In this field, supercapacitors (SC) can assist batteries when large power handling is requested. In particular, research efforts are oriented towards fabrication of performing, non-toxic and flexible SCs easily implementable in different electronic systems. Cellulose fibers and conductive polymers mixtures can provide the 3D electrode structure needed to improve SCs energy storage capacity together with the requested mechanical and sustainability properties. Herein, we make use of poly(3,4-ethylenedioxythiophene) (PEDOT) enriched cellulose fibers and imidazolium-based ionic liquid (EMIM-ES) to fabricate flexible SCs in a quick and upscalable way. The good electronic and ionic conductivities proven by PEDOT-cellulose bulky electrodes (140S/cm, 20mS/cm respectively) and their 3D structure allow obtaining specific capacitances above 150F/g. The large voltage window provided by the use of an ionic liquid make possible to reach power and energy densities as high as 100kW/kg and 10Wh/kg (normalized by PEDOT mass). These electrochemical performances are maintained even after 45000 charging and discharging cycles and under different bending radius. The obtained results foster to mass-production of disposable and recyclable SCs.

Resume : The development of innovative processes leading to reduced electrode production cost and environmental pollution is needed to enable lithium ion batteries for automotive and other large-scale applications. Water-soluble binders could enable greener and cheaper Li-ion battery manufacturing by eliminating the standard fluorine-based formulations and associated to that, reduced use of volatile organic compounds. The main issue however is that water-based dispersion are difficult to stabilize requiring additional processing complexity and additives. Herein, we will show that mechanochemical conversion of a regular PEDOT:PSS water solution produces a supramolecular hydrogel that meets most of the requirements as binder for lithium battery electrodes. The conversion is realized by ball milling in the presence of metallic Iron. Released Fe-ions are complexed by sulfonate groups of the PSS chain resulting in a stable coordination network. Slow corrosion of Fe combined with continuous milling produces a homogeneous polymer-metal framework that incorporates all the originally contained water (of up to 98% by mass). The supramolecular hydrogel has suitable rheology (viscosity of 2000 to 4000 mPas) to be applied as a lithium battery binder. When including also the electrode constituents (anode and cathode materials, conductive carbon and additives) the mechanochemical processing induces in situ gelation as well as fine mixing of the components. The corresponding battery slurries are stable, show no phase segregation (over several months) and produce highly uniform thin (25 μm) to very thick (500 μm) films in a single coat, with no material migration even upon slow drying. Cyclic voltammetry confirmed that the PEDOT:PSS gel formulations have good anodic stability (up to 4.5 V vs. Li/Li+ ). The cathodic stability is also demonstrated with first cycle irreversible processes attributed to the redox on the PEDOT chain. Physicochemical characterization confirmed that the electrical conductivity is preserved upon metal- induced gelation enabling higher power in the fabricated electrodes. Active materials such as Si, Sn, graphite, Al (negatives) but also LiCoO2, LiMn2O4, LiFePO4 and carbon-sulfur composites (positives) have been successfully tested in half and full cells. The electrochemical analysis demonstrated that improved power performances with similar to enhanced cycling stability was obtained using PEDOT:PSS gel binders when compared to standard aqueous binder formulation (including pristine PEDOT:PSS solution). Overall, the mechanochemically synthesized PEDOT:PSS metal-ligand supramolecular hydrogels, when applied as binder for lithium-ion batteries, show net advantages given the simple aqueous processing, excellent dispersion stability, preserved electrical conductivity, enhanced structural integrity and adhesion of the prepared electrodes as well as improved power and cycling stability performances[1]. [1] A. Vlad et al., (2017) submitted.

Resume : Graphite has been the anode material of choice for lithium ion batteries (LIB) due to its practical and economic advantages. However, in the face of strong demands to improve LIB performance, molybdenum disulfide has been spotlighted as a future candidate because of its high theoretical capacity, which at 680mAh/g is about two times higher[1]. In addition, MoS2 is a layered material and provides a potential solution to the volume expansion problem during the charging process, as typically observed in silicon anode materials[2]. But owing to the low ionic and electronic conductivity of MoS2 the lithium ions cannot be inserted/extracted effectively, resulting in high capacity fading and low rate capability. Composite structuring with carbon-based materials can be a solution for the abovementioned shortcomings of MoS2 as anode material[3]. In this work molybdenum disulfide was synthesized by a one-step solvothermal reaction in ethylene glycol solvent at 200oC. The carbon source, ethylene glycol, was trapped inside layers of MoS2 during the solvothermal synthesis step and subsequently carbonized at 800oC to yield a carbon/MoS2 composite. Another carbon/MoS2 composite was prepared from sucrose, which was dissolved in ethylene glycol solvent and annealed at the same temperature. The carbon/MoS2 composites were fully characterized, and a reasonable amount of MoO2 was identified in the composite. For the new carbon/MoS2 composite system it was essential to provide an optimum non-aqueous electrolyte, which would form a solid electrolyte interphase (SEI) and influence overall cycling performance. Based on the well-known 1 M LiPF6 electrolyte in LIB, several additives werestudied, such as fluoroethylene carbonate (FEC), vinylene carbonate (VC), ethylene sulfite (ES), propylene sulfite (PS), diethylsulfite (DES), and dimethylsulfite (DMS). The electrolytemixtures contain 3wt% VC and 5wt% FEC or FEC + DMC (1:1) showed good cycling performances of MoS2 with improved specific capacity and rate capability. In situ electrochemical dilatometry was combined with cyclic voltammetry, and volume expansion phenomena during lithiation/delithiation were precisely monitored. Finally, the carbon/MoS2 composites, originated from ethylene glycol and sucrose, showed great potential as a new alternative to graphite as anode material. They demonstrated specific capacity of 1288 mAh/g at 60th cycle. Further, their rate performance was 566 mAh/g at a C-rate of 2C. Full cells combined with LiCoO2 were also fabricated to demonstrate practical electrochemical performance. References: [1] T. Stephenson, Z. Li, B. Olsen, and D. Mitlin, ?Lithium ion battery applications of molybdenum disulfide (MoS2 ) nanocomposites,? Energy Environ. Sci., vol. 7, no. 1, pp. 209?231, 2014. [2] Z. Zeng, X. Zhang, K. Bustillo, K. Niu, C. Gammer, J. Xu, and H. Zheng, ?In Situ Study of Lithiation and Delithiation of MoS2 Nanosheets Using Electrochemical Liquid Cell Transmission Electron Microscopy,? 2015. [3] H. Shu, F. Li, C. Hu, P. Liang, D. Cao, and X. Chen, ?The capacity fading mechanism and improvement of cycling stability in MoS2 -based anode materials for lithium-ion batteries,? Nanoscale, vol. 8, no. 5, pp. 2918?2926, 2016. Acknowledgements: This work was financially supported by The Austrian Research Promotion Agency (FFG) in the research program of energy under Grant No. 5131261. We acknowledge gratefully the supports of TEM- and XPS investigation from Vienna University of Technology, Austria.

Resume : Development of the Internet of Things (IoT) will lead to an exponential growth in wireless sensor networks and autonomous microsystems, however, improvements in energy storage is a critical aspect in order to enable future applications. Currently, planar thin-film lithium and Li-ion batteries are at present commercially available but have limited capacity (< 0.3mAh/cm2). Therefore, in order to meet the future demands in terms of power and energy density the need for all-solid-state 3D Li-ion microbatteries arises. Here, we present a novel thin-film solid-state composite electrolyte (SCE), manufactured by combining molecular layer deposition (MLD) with atomic layer deposition (ALD). The SCE consists of a nanoporous insulator that provides both mechanical stability and a high effective internal surface area. The internal surface of the nanoporous matrix is coated with nanometer thin layers of a Li-compound that supplies the necessary Li ions. The enhanced ion transport at the interface between the surface of the insulator and the Li-compound is exploited to make a SCE with enhanced ionic conductivity. In this work, nanoporous alumina matrices were obtained through different post-treatments of alucone deposited by MLD. The alumina matrix was functionalized for Li-ion conduction by ALD. An enhancement in ionic conductivity of up to a few orders of magnitude was observed compared to the pure Li-compounds. Thus, this novel approach could open up new paths regarding design and development of future thin-film solid-state electrolytes.

Resume : A study of the synthesis feasibility of two different gel polymer electrolytes based each one in methyl methacrylate (MMA) and 1-Vinyl-2-pyrrolidone (VP) monomers, respectively, by using a common ion liquid i.e. 1-(2-hydroxyethyl)-3-methyl imidazolium tetrafluoroborate ([HEMIm][BF4]) as the conductive plasticizer, has been done. A novel PVP/[HEMIm][BF4] solid-state and self-standing ion gel electrolyte has been successfully prepared. The thermal stability, FTIR-ATR and optical transmittance analysis, ionic conductivity and electrochemical stability of the prepared PVP/[HEMIm][BF4] solid-state ion gel has been determined, being the thermal degradation of PVP/[HEMIm][BF4] ion gel in two steps with the first one at above 200 °C and the main one over 390 °C. This solid-state ion gel is transparent, showing an optical transmittance with a maximum value of 90% in the visible wavelength region from 370 to 770 nm. The synthesized PVP/[HEMIm][BF4] solid-state ion gel exhibits an electrochemical stability window of ca. 5.0 V and an acceptable ionic conductivity of ? = 5.7 10?3 S cm?1 at room temperature. Finally, a symmetrical pseudocapacitive supercapacitor has been assembled and characterized using this PVP/[HEMIm][BF4] solid-state ion gel?glass/ITO/PEDOT/PVP/[HEMIm][BF4]/PEDOT/ITO/glass. It is found that the supercapacitor shows a typical areal specific capacitance of 3.1 mF cm?2, a maximum energy density of 2.5 ?Wh cm?2, and an areal specific power density of ca. 1 mW cm?2.

Resume : Lithium-vanadium phosphate (Li3V2(PO4)3) based composite electrodes, having NASICON-type structure, have been found as capable to provide extremely fast lithium transport properties. Their structural, morphology and surface characteristics as well as electrochemical properties have been studied by a combination of methods: X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), laser diffraction particle size distribution (PSD), as well as electrochemical methods: potentiostatic (PITT) and galvanostatic (GITT) intermittent titration techniques, electrochemical impedance spectroscopy (EIS), and constant current chronopotentiometry. There were found significant differences in the rate of lithium diffusion depending on the lithiation stage. According to the PITT, GITT and EIS data, lithium diffusion coefficients drop abruptly by 2?3 orders of magnitude (from 10-9 to 10-12 cm2?s-1) in the 4.3?4.4 V potential range vs Li/Li+. Observed phenomenon was attributed to the LiV2(PO4)3?V2(PO4)3 phase transition. The electrochemical extraction/insertion of two lithium equivalents can occur at ultra-high rates (up to 320 C) from/into structurally more accessible Li2 and Li3 sites, while the de/intercalation of the third lithium equivalent from/into the Li1 position is supposedly hindered kinetically. For the electrochemical data analysis special theoretical models were developed and applied. These models take into account geometry and phase structure of the diffusion space, as well as the properties of the phase boundary interfaces. Morphology parameters of the material were obtained by SEM, PSD and BET methods, and introduced into the mathematical data processing procedures. Authors wish to thank Russian Science Foundation (project #15-13-10006), and Russian Foundation for Basic Research (projects #16-33-00328, #16-03-00023, #16-33-00211) for financial support of the work.

Resume : The computational study of chemical reactions in complex, wet environments is critical for applications in many fields. It is often essential to study chemical reactions in the presence of an applied electrochemical potentials, including complex electrostatic screening coming from the solvent [Andreussi et al. J. Chem. Phys. 136, 064102 (2012)]. A solvation library is presented to handle solutes and surfaces in contact with neutral and ionic solutions in electronic structure calculations. The interface between the quantum-mechanical solute and surrounding environment is described by a fully continuum and differentiable permittivity function of the atomic coordinates. Thanks to the features of a recently developed generalized Poisson solver based on Interpolating Scaling Functions [Fisicaro et al. J. Chem. Phys. 144, 014103 (2016)], the library holds very high accuracy and parallel efficiency keeping computational efforts and runtime at vacuum level. It allows for the exact treatment of molecular or slab-like geometries. The whole library has been extensively calibrated and tested on neutral and ionic solutes in aqueous environment as well as on solid-liquid interfaces by means of contact angle benchmark. A study of reaction barriers on a cadmium sulfide-water interface proves the feasibility and advantages of such explicit/implicit scheme at the atomic scale in terms of accuracy and computational efforts.

Resume : Next generation batteries that are currently attracting most attention in research and development are Lithium-ion batteries (LiB). LiB?s have the highest energy density of all known systems and are thus the best choice for rechargeable micro-battery applications. Liquid electrolyte LiB?s present limitations in safety, size and design, thus all-solid state devices are predominantly considered to overcome these restrictions. These new high efficient batteries require optimum design parameters to acquire excellent performance, high-energy density, cost effectiveness and improvements in lifetime and safety. Specifically, flexible high-power sources have gained much attention, as they enable the development of applications such as implantable, bendable and wearable electronic devices. Here, we explore optimization methods and novel materials in all solid state batteries in order to enhance performance with extended cycling by tuning thin film deposition parameters. We report on high voltage cathode materials to increase the energy density and we make use of several substrate materials to study the behavior of flexible thin film batteries. Combining several optimization approaches such as the ones reported here will lead to improvements in performance, lifetime and enable form-factors for future Li-ion micro-batteries in the electronic industry. This project has received funding from the EU Horizon 2020 research and innovation programme under the MSCA grant agreement No 658057.

Resume : During the last years a lot of research have been focused on batteries studies, these being one of the most important key for the technology development. Lithium-ion batteries are widely used throughout the world for portable electronic devices and mobile phones and show a great potential for more demanding applications like electric vehicles [1]. In the same time, Na-ion batteries gain more and more attention due to the abundance of Na worldwide and the significant cost-effective advantages [2]. The aim of this work is to present new carbon/Si-based materials synthesized by environmental friendly processes which could be successfully used as anodes for Li and Na-ion batteries, Si being one of the materials with the highest theoretical capacity (4000 mAh/g vs. Li). For this study, two one-pot carbon/Si-based materials with different textural characteristics were synthesized and treated at different temperatures (600/750/900oC). The STEM images present small (2÷5 nm) and very well distributed particles in the carbon support, which favors the diffusion of the electrolyte during the electrochemical tests, and so, the performances are improved. We want to report an excellent cycling capability for C/Si-based materials vs. Na, with a reversible capacity up to 350 mhA/g, after 900 cycles.The same materials tested vs. Li, present a reversible capacity higher than 1000 mAh/g, after 200 cycles. [1] A. Casimir, H. Zhang, O. Ogoke, J.C.Amine, J.Lu, G.Wu, ?Silicon-based anodes for lithium-ion batteries: Effectiveness of materials synthesis and electrode preparation?- Nano Energy, 27(2016)359?376. [2] A. Jahel, C. M. Ghimbeu, A. Darwiche, L. Vidal, S. Hajjar-Garreau, C. Vix-Guterl, and L. Monconduit, ?Exceptionally highly performing Na-ion battery anode using crystalline SnO 2 nanoparticles confined in mesoporous carbon - J. Mater. Chem, vol. A, 2015, 3, 11960.

Resume : A kinetically controlled surface modification technique, mainly based on hydrolysis and condensation reactions of titanium butoxide in an ethanol based environment, was used to initiate heterogeneous nucleation and growth of an amorphous TiO2 shell on commercial LiNi0.5Mn1.5O4 (LNMO) powders. The effects of annealing temperatures from 500 to 850oC on the morphology, crystal structure and battery performance of TiO2 surface modified LNMO (LNMO@TiO2) cathode powders were investigated. TEM images show changes in surface morphology as well as crystallite size and shape for LNMO@TiO2 samples annealed at different temperatures. FTIR results reveal changes in ordering/disordering and Rietveld refinement of XRD results indicate differences in lattice parameters of LNMO@TiO2 for different temperatures. Higher annealing temperatures were found to cause lattice expansion and LiNi0.5Mn1.5-xTixO4 secondary phase formation. Galvanostatic charge-discharge measurements of LNMO@TiO2 vs Li/Li half cells cycled 200 times between 3.4 to 4.9 V at 0.5 C using EC/DMC electrolyte show superior cyclic stability compared to bare LNMO samples. Annealing at 500oC results in the highest discharge capacity for the first few cycles; while 800oC provides a high cyclic stability but a lower initial discharge capacity. This project receives the support of the European Union, the European Regional Development Fund ERDF, Flanders Innovation & Entrepreneurship and the Province of Limburg (project 936)

Resume : Development of electrolyzers converting electricity into chemical energy is one of the current topics in energy-related chemistry. We have focused on alcohol electrosynthesis using ubiquitous carboxylic acids, which are some of the main components of biomass-derived materials, to storage renewable electricity. We previously reported that oxalic acid (OX), a divalent carboxylic acid, is efficiently converted into glycolic acid (GC), a monovalent alcohol, on anatase TiO2 through four-electron reduction in a two-compartment electrolyzer (Energy Environ. Sci. 2015, 8, 1456-1462.). However, we believe that the two-compartment electrolyzer is not an ideal for the alcohol electrosynthesis because the reaction solution includes electrolyte (e.g. Na2SO4) that cannot be automatically separated, which prevents continuous operation of the electrolysis. One idea to solve this problem is to employ a polymer electrolyte electrolyzer for the alcohol electrosynthesis, which does not require electrolytes in reaction solution. To date, however, there is no report on the alcohol electrosynthesis from the carboxylic acids using the polymer electrolyte electrolyzer. In this study, we report on a fabrication of a novel polymer electrolyte electrolyzer for the alcohol electrosynthesis, named as ?polymer electrolyte alcohol synthesis cell (PEAEC)?. Firstly, we prepared a new cathode, metal mesh tightly connected with porous anatase TiO2 catalyst, which has both catalytic activity for carboxylic acid and substrate diffusivity, by employing a hydrothermal reaction. The PEAEC was constructed using the TiO2 cathode, Nafion, and IrO2-loaded carbon. 100% conversion of the OX was observed by applying bias between both electrodes of the PEAEC.

Resume : Thin film MnO2 deposits have been observed to exhibit excellent electrochemical energy storage properties. A method has been developed at the University of Newcastle for the comprehensive assessment of both the deposition process, and the resulting charge storage capacity of the deposited material. This method uses a systematic combination of the electrochemical quartz crystal microbalance (EQCM) with electrochemical assessment techniques cyclic voltammetry (CV), step potential electrochemical spectroscopy (SPECS) and electrochemical impedance spectroscopy (EIS). Cyclic voltammetry was conducted with a 25 mV/s sweep rate from 0 - 0.8V for 250 cycles. By doing this, the capacitive performance of the material was determined. By recording the mass change throughout the experiment it was possible assess faradaic and non-faradaic process occurring on the surface of the electrode which will affect the charge storage mechanism as well as observation of sample stability throughout cycling. SPECS and EIS immediately followed the cycling which allowed for the observation of the maximum charge storage capability of the material and the mechanism in which the material stores energy. The impedance data allowed detailed analysis of the charge transfer mechanism and the various interfacial resistances and capacitance processes which occur at the electrode-electrolyte interface. This technique has allowed for significantly greater understanding of the charge storage process and can be used as a powerful tool in various aspects of electrochemical analysis.

Resume : LiFe0.4Mn0.6PO4 (LFMP) is a promising material for Li-ion batteries because it operates at 3.4?4.1V vs. Li+/Li. This voltage is not so high as to decompose the organic electrolyte but is not so low as to sacrifice energy density. However, as other olivine type compounds, LFMP also has low conductivity. The improvement of the electrochemical properties of cathode materials can be achieved by using conducting polymer, such as poly-3,4-ethylenedioxythiophene/polystyrene sulfonate (PEDOT:PSS). PEDOT:PSS which can act both as electron conducting additive and as an effective binder, provides enhanced electrochemical performance of the electrodes. Recently [1] we have shown that employment of polymer dispersion PEDOT:PSS along with carboxymethylcellulose (CMC) as additive to LFP-based cathode material greatly improved the specific capacity and C-rate performance of electrodes. In this work we give a deeper insight on the positive role of PEDOT:PSS/CMC binder in electrochemical performance of LFMP cathode material by investigation of role of morphology and evaluation and comparative analysis of the kinetic parameters by CV and EIS methods. The significant decrease of interfacial charge transfer resistance and the increase of Li+ effective diffusion coefficient were found. These parameters are responsible for observed improvement of electrochemical performance. [1] R.V. Apraksin, S.N. Eliseeva, E.G. Tolstopjatova, A.M. Rumyantsev, V.V. Zhdanov, V.V. Kondratiev, Mater. Lett. 176 (2016) 248?252. Acknowledgments The authors would like to thank the Center for X-ray Diffraction Methods and the Interdisciplinary Center for Nanotechnology of Research park of Saint-Petersburg State University.

Resume : Perovskite oxides have brought a significant zeal as energy conversion materials for metal–air battery and solid-oxide fuel-cell electrodes considering their unique physical and electronic properties. Amongst these inherent properties is the structural stability of the cation loop in perovskites that can hold mobile oxygen ions under electrical polarization. In conjunction with optical property, oxygen ion mobility and vacancies having been exhibited to play a typify role in photocatalysis but their function in charge storage has yet to be revealed. We interrogate the mechanism of redox pseudocapacitance for bismuth-based perovskite, BiFeO3. Herein we report a simple wet chemical synthesis of BiFeO3 fine particulates by self propagating combustion and investigate pseudocapacitive and photocatalytic properties favouring its applications in green energy fields. It has been demonstrated both as energy conversion and storage material. The phase evaluation, chemical features, structural and optical properties of the synthesized material have been analysed using scanning electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The capacitive behavior has been found to be significantly higher than that of metal oxide based electrode, which is mainly due to the redox active BiFeO3 nanoparticles. A specific capacitance of about 274 F g-1 at a current density of 1 A g-1 and good cycling stability, suitable for supercapacitor application. The material also elucidate a high efficiency for photocatalytic degradation towards aromatic organic dye Crystal violet under solar light illumination. Photocatlytic investigation reveals that very fast degradation of Crystal violet dye with the degradation rate of 99.5 % within the short time interval of 50 min, supporting that BiFeO3 could be a multifunctional novel material for electrochemical energy storage and solar energy conversion.

Resume : Electrochemically rechargeable zinc-air batteries require active oxygen evolution reaction (OER) catalysts for the charging process. Precious metals, such as Ru and Ir, are recognized as the most active OER electrocatalysts, but have limited applicability to zinc-air batteries due to their high cost. Cheaper alternatives, such as transition metal oxides catalysts in powder form, need to be mixed with binders and conductive additives before coating onto the gas diffusion layer (GDL) during fabrication of the air electrode, which adds complexity to electrode fabrication. As such, an effective way to produce and coat OER catalysts onto the air electrode is highly desired. In this study, Co and Fe were co-electrodeposited onto the GDL to produce Co-Fe OER catalysts with various Co/Fe ratios. Electron microscopy was used to investigate the morphology and composition of the electrodeposited Co-Fe films. OER catalytic activity was studied using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronopotentiometric measurements in a 6 M KOH solution. The electrochemical tests demonstrate that the Co/Fe ratio not only influences deposit morphology, but also affects electrochemical performance. The fabricated OER catalysts were then assembled into a zinc-air battery for discharge-charge cycling tests. Preliminary results show that the discharge-recharge efficiency is 57% at a current density 5 mA/cm2. In addition, electrodeposited Co-Fe is structurally stable during battery cycling and shows strong adhesion to the GDL substrate.

Resume : Nickel oxides, hydroxides as well as oxyhydroxides are excellent electrode materials for pseudo capacitors due to their high specific capacity. Although there are many studies in the literature on the production of these compounds by chemical or electrochemical routes, production of these electroactive compounds directly on nickel metal is still a challenge. Production of these compounds directly on nickel metal is highly preferable since the pathway of electrons produced during the reactions is extremely shortened when compared to composite layers produced by mixing electroactive nickel compounds with suitable polymer blends. One of the methods of producing electroactive nickel oxides on nickel is anodic oxidation of them in molten KOH. The aim of this study is to investigate the capacitive behavior two different porous nickel substrates (nickel foam and self-standing nickel nanowires) that are produced by anodic oxidation in molten KOH. For this purpose, commercially available nickel foam and self-standing nickel nanowires produced in our laboratories using AAO templates are used. For anodic oxidation studies in KOH, temperature, duration and anodization potential are selected as experimental parameters. The produced oxides are structurally characterized with XRD, SEM and Raman Spectroscopy. The relations between their structure and capacitance behaviour are determined with cycling voltammetry and chronopotentiometry in KOH solutions. Differences between the capacitance of different substrates are evaluated mainly concentrating on the structure and morphology of both substrates and the nature of the electroactive nickel oxides formed on them. Acknowledgements: This study is supported financially by 115M129 – TUBITAK 1001 Project and 2515 COST Action MP1407.

Resume : KVPO4F fluoride-phosphate with the KTiOPO4-type structure has been tested as a cathode material for K-ion rechargeable battery. The material was synthesized via freeze-drying and solid-state methods in two steps. First, vanadium phosphate VPO4 was obtained via freeze-drying from NH4VO3 and NH4H2PO4 followed by annealing in Ar flow at 850 oC. The product was mixed with KHF2 and annealed in Ar flow 625 oC to produce a phase-pure KVPO4F, as demonstrated by powder XRD and TG methods. Optimal conditions for the deposition of electrodes were selected and the half-cells with metallic K as the anode and KVPO4F as the cathode were assembled. By optimizing various parameters we obtained an optimal cell KVPO4F (freeze-drying method):pVdF:Carbon Super P(70:15:15 wt %)/0.4 M KPF6 in EC:PC (5:7)/K with the reversible cyclic voltammetry curves with 4.8 and 5.1 V cutoff. By investigation of galvanostatic cycling data we found that the charge and discharge curves emphasize the cycling ability at the indicated rates and the capacitance value achieved 35 and 60 % of theoretical capacity. But capacity evolution upon cycling showed that after 35 cycles, the moderate capacity drop was around 40%.

Resume : Two dimensional (2D) transition metal dichalcogenides such as WS2 of 2H phase are emissive in the visible range, has been attracted tremendously for optoelectronic studies, whereas metallic 1T phase, without any emission property, attracted for energy storage and catalysis application. However, widespread applications of WS2 are hampered by its low yield production due to its reluctance towards intercalation and exfoliation in liquid phase. Here we have synthesized bi-to-few layers WS2 in solution from bulk WS2 by Li-ion intercalation technique using Lithium halide. In the process, a group of lithium halides (LiCl, LiBr, LiI) has been employed for the first time to intercalate WS2 by lithium followed by mild sonication to exfoliate in dispersive polar solvents. A highest concentration of 19 mg/ml has been obtained using LiI as an exfoliating agent due to its lower lattice energy compared to other alkali halides and small size of the cation. The structural and morphological characterisation of the as synthesized material was done by TEM, AFM, RAMAN, XRD, XPS techniques. Charge storage ability of WS2 flakes is investigated by integrating a flexible solid state symmetric supercapacitor using acetylene black as a conducting filler and PVA-H3PO4 mixture as gel electrolyte. The fabricated supercapacitor shows a high (18 mF/cm2) areal capacitance at a current density of 0.1 mA/cm2. Cycle stability of the devices is measured by running cyclic charge-discharge experiment up to 1000 cycles. Almost 85% of specific capacitance is retained after 1000 cycles using this material, indicating WS2 as a potential candidate for real energy storage device application. The device also shows good energy density (1.14 µWh/cm2) at a current density of 0.1 mA/cm2. The flexibility of the device is also demonstrated by conducting CV experiment at different bending angle.

Resume : Anions ? from a chemical point of view ? are at the opposite end of the standard reduction potential series from lithium, and therefore, show interesting possible applications in battery systems. The general working principle of such an anion battery is based on the reduction of the cathodic material and the oxidation of the anodic material via anion transport through the electrolyte. But for obtaining an anion battery a good ionic conduction is required throughout all parts of the cell such as cathode, electrolyte and anode to assure the migration of chloride ions or fluoride ions. Our work is focussed on understanding anion migration and to develop new materials with good halogenide conduction. In this presentation, the latest advances to understand anion migration using electrochemical techniques will be shown.

Resume : The design and improvement of the cathode materials for Li-ion batteries requires detailed knowledge on the crystal structure at different charge/discharge states and comprehensive understanding of the processes occurring at the nanoscale or even atomic scale level, as many electrode materials demonstrate highly inhomogeneous non-equilibrium behavior. Advanced transmission electron microscopy (TEM) is by far the most suitable and direct tool to look at the materials down to atomic scale. Recent progress in the quantitative electron diffraction methods and aberration-corrected scanning TEM imaging will be illustrated here with the examples of atomic structure investigation of various cathode materials. Electron diffraction tomography provides quantitative diffraction data enabling reliable structure solution and refinement from extremely small crystallites, typically smaller than 1 micrometer. Electron diffraction data can be acquired at very low electron dose, enabling investigation of the materials sensitive to the electron beam irradiation damage, such as polyanion and mixed-anion Li-ion battery cathodes, particularly in their charged state. The capabilities of quantitative electron diffraction in locating Li atoms and refining the occupancy of the Li positions will be demonstrated using the (Li,K)VPO4F, Li2FePO4F and LiMn0.5Fe0.5PO4 materials. Aberration-corrected scanning transmission electron microscopy (STEM) techniques deliver the information on the local structure with sub-Å resolution. High angle annular dark field STEM (HAADF-STEM) imaging provides clear visualization of the cation positions, whereas annular bright field STEM (ABF-STEM) shows the location of the “light” elements, such as O and Li. HAADF-STEM method has been applied to the Li-Ru-Ti-O and Li-Ru-Sn-O systems to investigate the capacity and voltage fade in the layered rock-salt type oxides because of the cumulative local structure changes upon continuous electrochemical cycling. Direct observation of O-O “peroxo” dimers in A2-xIrO3 (A = Li, Na) and O vacancy formation in LixFe0.56TeO6 with the ABF-STEM method helps to establish the fundamental relation between the anionic redox process and the evolution of the O-O bonding in the layered oxides.

Resume : A striking increase in the demand for a sustainable means of transport, not based on the internal combustion engines, has made the need for better batteries greater than ever before. Many automotive manufacturers now believe that limitations in the performance of current lithium-ion batteries still represent the greatest barrier to the electrification of transport. The energy density of lithium batteries is currently restricted by the cathode material, delivering ~ 160-190 mAh g-1.1 New high-energy-density cathode materials are much sought after to meet the increasing requirements of consumer electronics, electric vehicles and grid energy storage. The so called lithium-rich layered oxide materials (e.g. Li1-x[Li0.2Mn0.6Ni0.2]O2), exceed the conventional limit of charge storage as far more lithium (x ≈ 1, corresponding to 310 mAh g-1) can be extracted than can be accounted for through transition metal oxidation (x ≈ 0.4). The source of this “extra capacity” has been explained previously by a number of models including oxygen loss, electrolyte decomposition and anion redox. Recently, by combining a series of techniques, we and others have identified and quantified the charging process in Li[Li0.2Ni0.2Mn0.6]O2 with direct experimental evidence of a dominate O redox process balanced with a minor contribution from oxygen loss when these materials are charged beyond 4.4 V.2-7 This contribution will present the results which underpin this conclusion and also discuss the requirements necessary to form holes on the oxygen in these compounds. The conclusions of this work and that of other researchers working to understand anion redox provide us with a guidance which can be used to discover future higher energy density cathode materials. References 1. Goodenough, J. B.; Kim, Y. Chem Mater 2010, 22, (3), 587-603. 2. Luo, K.; Roberts, M. R.; Hao, R.; Guerrini, N.; Pickup, D. M.; Liu, Y. S.; Edstrom, K.; Guo, J. H.; Chadwick, A. V.; Duda, L. C.; Bruce, P. G. Nat Chem 2016, 8, (7), 684-691. 3. Luo, K.; Roberts, M. R.; Guerrini, N.; Tapia-Ruiz, N.; Hao, R.; Massel, F.; Pickup, D. M.; Ramos, S.; Liu, Y. S.; Guo, J.; Chadwick, A. V.; Duda, L. C.; Bruce, P. G. J Am Chem Soc 2016, 138, (35), 11211-8. 4. Koga, H.; Croguennec, L.; Menetrier, M.; Mannessiez, P.; Weill, F.; Delmas, C. J Power Sources 2013, 236, 250-258. 5. Koga, H.; Croguennec, L.; Menetrier, M.; Mannessiez, P.; Weill, F.; Delmas, C.; Belin, S. J Phys Chem C 2014, 118, (11), 5700-5709. 6. Sathiya, M.; Rousse, G.; Ramesha, K.; Laisa, C. P.; Vezin, H.; Sougrati, M. T.; Doublet, M. L.; Foix, D.; Gonbeau, D.; Walker, W.; Prakash, A. S.; Ben Hassine, M.; Dupont, L.; Tarascon, J. M. Nat Mater 2013, 12, (9), 827-835. 7. Seo, D. H.; Lee, J.; Urban, A.; Malik, R.; Kang, S.; Ceder, G. Nat Chem 2016, 8, (7), 692-7.

Resume : Perovskite oxides have attracted significant attention as energy conversion materials for metal–air battery and solid-oxide fuel-cell electrodes owing to their unique physical and electronic properties. Amongst these unique properties is the structural stability of the cation array in perovskites that can accommodate mobile oxygen ions under electrical polarization. Despite oxygen ion mobility and vacancies having been shown to play an important role in catalysis, their role in charge storage has yet to be explored. In this presentation we investigate the mechanism of oxygen-vacancy-mediated redox pseudocapacitance for a nanostructured perovskites. Thi work represents the most emerging exampes of anion-based intercalation pseudocapacitance energy storagae, as well as, elucidation of oxygen intercalation mechanism in perovskite oxides that enabel fast energy storage. Whereas previous pseudocapacitor and rechargeable battery charge storage studies have focused on cation intercalation, the anion-based mechanism presented here offers a new paradigm for electrochemical energy storage that has not be fully explored.

Resume : The design of new materials for electrochemical devices is a pivotal question for the development of renewable energies and their storage. Recently, the prevailing paradigm that materials for energy storage devices such as Li-ion batteries (LIBs) or water splitting were relying on cationic redox has been challenged by numerous observations that lattice oxygen from the active materials can be involved during the oxidation processes at high potential. Since these early observations, much was done to understand the physical origin of the oxygen activation in transition metal oxides in order to control it; the major physical descriptors for triggering the anionic redox will be covered in this presentation. Moreover, the main challenge remains now to implement materials demonstrating anionic redox into practical devices, and for this the control of the electrochemical interface with the electrolyte as well as the kinetics associated with this redox must be understood. For that, we can learn from the electrocatalysis field for which mastering the reactivity of surface oxygen is critical. Throughout this presentation, examples will be taken from both fields, LIBs and electrocatalysis, to give an overview of the major challenges remaining to master the anionic redox and makes its promises true.

Resume : Hard carbons (hereafter called HC) microstructure is relevant in the capacity provided by those negative electrodes for sodium ion batteries [1,2], since sodium ions are stored in the defects, turbostratic domains and microporosity of HC. Moreover, the relationship between electrolyte characteristics (electrochemical stability and compatibility with the sodiation, sodium ion solvation …) and the mechanism of storage justifies the evaluation of several electrolytes for HC [3,4]. Furthermore, negative electrode capacity can be largely increased by composites produced from HC and Na-alloying metals, keeping an intimate contact [5,6]. In this work, we have approached the preparation of M-Sn-HC (M= transition metal) nanocomposites by an original and cost-saving method which involves reduction of divalent tin and metal salts. In order to obtain the nanocomposite, HC particle size has been decreased to the nanoscale. We have subsequently evaluated the cycling properties of such electrodes (with different loads of the Ni-Sn part) and two electrolytes with different solvents (EC/PC 1/1 v/v and THF). In this presentation, we will report for the first time the use of such nanocomposite electrodes in sodium ion batteries (theoretically reaching twice the capacity of HC) and the impact of the electrolyte in their electrochemical performances. References : (1) J. M. Stratford, P. K. Allan, O. Pecher, P.A. Charter, C.P. Grey, Chem. Comm. 52 (2016) 12430-12433. (2) V. Simone, A. Boulineau, A. de Geyer, D. Rouchon, L. Simonin, S. Martinet, Journal of Energy Chemistry 25 (5) (2016) 761-768 . (3) S. Komaba, W. Murata, T. Ishikawa, N. Yabuuchi, T. Ozeki, T. Nakayama, A. Ogata, K. Gotoh, K. Fujiwara, Adv. Funct. Mater. 21 (2011) 3859-3867. (4) G.G. Eshetu, S. Grugeon, H. Kim, S. Jeong, L. Wu, G. Gachot, S. Laruelle, M. Armand, S. Passerini, Chem. Sus. Chem. 9 (5) (2016) 462-471. (5) Y. Kim, K.-H. Ha, S.M. Oh, K.T. Lee, Chem. Eur. J. 20 (2014) 11980-11992. (6) M.S. Balogun, Y. Luo, W. Qju, P. Liu, Y. Tong, Carbon 98 (2016) 162-178.

Resume : Na-ion based cathode materials are getting more attention recently ever since they were firstly investigated in 1980´s [1] due to the Na natural abundance, geographical distribution, low cost and similar intercalation chemistry to lithium.[2,3] Na layered oxides are playing an important role as reliable positive electrode materials for Na ion batteries, mainly for stationary applications. Their outstanding electrochemical properties, structural simplicity and scalable synthesis method are some of the most important reasons to study them.[4] NaxMnO2 has been considered as one of the most versatile systems, although some issues as the Jahn-Teller distortion effect which could cause loss of capacity and multiple step plateaus.[5] Our group has investigated how by substituting Mn with different quantities of Fe, the electrochemical performance of the new materials can be improved and better cyclability achieved. We will present an electrochemical comparative study of the synthesized phases with Mn:Fe ratio from 0.34:0.67 [6,7] up to 0.8:0.2 Mn content. In situ synchrotron X-ray diffraction data will be discussed. References: [1] C. Delmas, et al. Physica, 1980, 99B, 81. [2] V. Palomares, et al. Energy Environ. Sci. 2012, 5, 5884. [3] V. Palomares, et al. Energy Environ. Sci., 2013,6, 2312. [4] M. Han, et al. Energy Environ. Sci. 2015, 8, 81. [5] X. Ma et al. JES, 2011,158 (12) A1307. [6] E. Gonzalo, et al. J. Mater. Chem. A 2014, 2, 18523. [7] N. Katcho, et al. Adv. Energy Mater. 2016, 1601477.

Resume : Sodium ion battery (SIB) has gained great attention in recent times owing to the high abundance of sodium on earth’s crust, suitable redox properties and similar electrochemical behaviour as that of lithium.[1] However, development of efficient anode materials remain a big challenge for the successful implementation of this technology. [2] Herein, we report the synthesis and electrochemical performance of a composite of antimony oxide (Sb2O3) microstructures encapsulated in graphene hydrogel, interconnected by a network of carbon nanotubes. The composite is synthesized through a facile hydrothermal method. The composite electrode, with 3-dimensional encapsulation by graphene, and ‘wired’ with multiwalled carbon nanotubes, exhibit improved electrochemical performance with steady specific capacity and long cycle life. Further, SnSb-based nanoarchitectured electrodes with a carbon nanotube shell is synthesized through electrodeposition technque and the composite electrode showed excellent electrochemical performance with minimal volume expansion, resulting in improved cycling performance. The results are discussed and the key challenges are addressed. References [1] N. Yabuuchi, K. Kubota, M. Dahbi, and S. Komaba. Chem. Rev., 114, 11636 (2014). [2] D. Buchholz, A.Moretti, R.Kloepsch, S. Nowak, V.Siozios, M. Winter, and S.Passerini, Chem. Mater., 25, 142 (2013).

Resume : SIBs have attracted significant interest during the last decade due to their cost-effectiveness compared to LIBs since sodium is the 6th most abundant element in the earth’s crust to a depth of 16 km.[1-3] Additionally, SIBs undergo reactions that are similar to those of LIBs in terms of ion intercalation and solid-state diffusion, phase transitions, surface film formation, and interfacial charge transfer processes, thereby facilitating the R&D process. The development of high-energy and high-power density sodium-ion batteries is a great challenge for modern electrochemistry. The main hurdle to wide acceptance of sodium-ion batteries lies in identifying and developing suitable new electrode materials. O3-type layered structured transition metal oxides appear to be attractive based on the success of using layered LiMO2 cathodes in LIBs. However, the relationships between transition metal composition and the electrochemical and related structural properties in O3-type layered NaMO2 compounds have not been systematically studied. In this study, to determine whether the same trade-off relationship applies to Na[Ni1-x-yCoxMny]O2 cathodes, we investigated the effect of transition metal composition on the electrochemical, structural, and thermal properties of micron-sized layered Na[NixCoyMnz]O2 (x=1/3, 0.5, 0.6, and 0.8) cathodes. In addition, we introduce a composition-graded cathode material that exhibits excellent electrochemical performances and safety. This work is a pronounced step forward in the development of new Na ion insertion cathodes. References [1] B. Scrosati, J. Hassoun, Y. K. Sun, Energy Environ. Sci. 2011, 4, 3287. [2] V. Etacheri, R. Marom, R. Elazari, G. Salitra, D. Aurbach, Energy Environ. Sci. 2011, 4, 3243. [3] J. Emsley, Nature’s Building Blocks, Oxford University Press, Oxford, UK 2011.

Resume : For future battery systems Na+ is a good choice as alternative ion to Li+. Due to the massive sodium abundance on earth Na+ based systems promise to be suitable for large scale applications. Additionally the Na+ ion is quite mobile in numerous systems, sometimes even more mobile than Li+. Most recently, all-solid-state batteries appeared as a promising concept to obtain high energy densities and stabilities, but are currently relying on Li+ as charge carrier and face serious interface issues. The combination of these two aspects – all-solid-state Na+ batteries - is seldomly realised up to now. We build functional cells with NaCoO2 cathodes, solid electrolytes and metallic Na anodes. These model cells help to investigate interface phenomena as well as the electronic structure within Na+ based battery systems. In this contribution we present the comparative study of two NaCoO2/electrolyte interfaces by XPS using a surface science approach, allowing us to detect cathode interface reactions. Presence of reaction layers will be discussed in conjunction with overpotential in all-solid-state battery cycling. The Na-β´´-Al2O3 electrolyte, known for a long time, shows strong interface reactions in contact with NaCoO2 electrodes resulting in high overpotential for the NaCoO2/Na β´´ Al2O3/Na cell. By replacing the Na β´´ Al2O3 with a NASICON-type electrolyte, the cell overpotential is significantly reduced.

Resume : Cubic garnets Li(7−3x)AlxLa3Zr2O12 (LLAZO) exhibit high conductivity and are envisioned as electrolyte materials for all-solid-state batteries. To better understand the role of Al3+, we investigated different Al-doped LLAZO prepared by conventional solid-state reaction. Cubic phase was formed at 900°C, confirmed by X-ray diffraction. Based on 6Li, 7Li and 27Al MAS NMR spectroscopies, we identified for different Al doping levels the Li and Al site occupancies and investigated their mobility by 7Li static NMR with variable temperature. Ionic conductivity measurements on pellets were also performed using electrochemical impedance spectroscopy. Li and Al site occupancies were found dependent on Al doping levels and strongly impact ionic mobility. From our measurements, garnet with x=0.35 exhibits higher ionic conductivity than with x=0.24. Al ions were mainly found at octahedral sites (96h) for x=0.35 whereas they were mainly on tetrahedral sites (24d) for x=0.24. More vacancies were also found on tetrahedral sites for x=0.35, that could facilitate [octa-tetra-octa] diffusion pathway. The latter have been shown to be more favorable energetically, i.e more mobility. Some pellets were sintered using Spark Plasma Sintering (SPS) and further investigated. We found that SPS modifies the material as Li and Al site occupancies were different compared to non-sintered powders. Al occupancy on octahedral sites was increased for x=0.24 at levels comparable to non-sintered powders at x=0.35.

Resume : This contribution focuses on Li7La3Zr2O12 (LLZO) garnet, which is one of the most promising ceramic electrolytes given its high Li-ion conductivity, wide electrochemical stability and chemical compatibility with Li metal. An innovative dual-substitution strategy will be presented to fine-tune the number of charge carriers in LLZO according to the stoichiometry Li7-3x+yGaxLa3Zr2-yScyO12 [1]. Solid state NMR characterization reveals a unique cationic distribution in the dual-substituted garnet, improving its ion transport properties. Li-ion conductivity values up to 1.8 mS·cm-1 at 300 K, with an activation energy of 0.29 eV, were obtained for a specific substitution level, representing the fastest garnet conductor reported [1]. Implementation of these garnet electrolytes in a full cell device, using LiFePO4 cathode and Li metal anode, shows promising performance as constant capacities were extracted from the cathode active material [2]. However, prolonged cycling led to charge inconsistencies and to abrupt cell failure originated from the deposition of Li metal dendrites within the ceramic electrolyte [2]. The mechanisms of dendrite formation and propagation will be discussed in detail. Finally, initial results on the development of composite garnet-polymer electrolyte membranes will be also reported. [1] L. Buannic, et. al., Chem. Mater., DOI: 10.1021/acs.chemmater.6b05369, (2017). [2] F. Aguesse et al., ACS Appl. Mater. Interfaces, DOI: 10.1021/acsami.6b13925, (2017).

Resume : Solid state electrolytes (SSEs) with high Li conductivity can significantly improve Li ion accumulators in terms of electrochemical efficiency, thermal and mechanical stability, and environmental compatibility, leading to an enhanced range of applications for these high energy density batteries. Compounds crystallizing in the structure of NaZr2(PO4)3 (NZP) are regarded as promising SSEs, mainly because of their three-dimensional diffusion network enabling fast transport of Li ions through well defined channels. Starting from LiTi2(PO4)3, we analyzed a large variety of NZP compounds by systematically screening the relevant parts of the periodic table, replacing atoms on the Ti and P sublattices by isovalent elements. The influence of these elemental substitutions on structural stability, preferred Li sites, ionic mobility, migration paths and diffusion mechanisms were analyzed by means of a combined approach of multiple computational methods with different levels of accuracy, ranging from static energy landscape and molecular dynamics simulations with ionic bond valence potentials to density functional theory calculations combined with the nudged elastic band method.

Resume : The application of lithium-ion batteries to electric vehicles and stationary systems brings challenges in terms of scale-up, guaranteed safety and longevity. Modern liquid electrolytes, toxic, flammable and reactive, are one of the limiting components inducing important safety issues in case of internal cell failure or leakage. Due to inactivity of ceramic solid electrolytes, all-solid-state batteries seem to fully meet safety requirements. Among all solid electrolyte materials investigated, garnet-type ceramics are promising candidates as they offer high Li-ion conductivity (10-4 S/cm – 10-3 S/cm) and good chemical compatibility with Li metal anodes and oxide-based cathode materials. However, rigid ceramics do not support dense packing with perfect contact between particles. Accordingly, high resistance of ceramic separators and composite cathodes originates from slow grain boundary ion transport. This is the main barrier to implementation of safe ceramic electrolytes. Here we synthesized and characterized the highly conductive doped cubic Li7La3Zr2O12 phase through various synthesis routes (solid-state, co-precipitation, sol-gel). The synthesis parameters were optimized to obtain the lowest possible particle size for further densification. Various densification methods were applied to maximize the ionic conductivity and approach the implementation of Li7La3Zr2O12 in all-solid cell.