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Aqueous asymmetric supercapacitors (ASC) is considered to fulfill the safety and high energy-power requirements simultaneously towards building next-generation storage devices. One of the most attractive electrolytes is multiple ion-based water-in-salt (WIS) solutions, which are steadily conquering the field of rechargeable batteries/capacitors. Stabilizing the pH value is one of the efficient ways to improve the energy density of the charge storage system by widening the operating potential. In this line, we report that acetate ions could help to neutralize the pH of sodium(I)bis(fluorosulfonyl)imide-based WIS electrolyte by diluting the free water molecules without any precipitation or recrystallization, and allow to widen the operating potential window from ~2.7 to 3.1 V. The Physico-chemical properties of mixed anions-based electrolytes are explored from confocal-Raman and Nuclear magnetic resonance studies. In addition, we performed ab-initio density functional theory calculations to study the co-ordination environment. Apparently, the acetate (OAcˉ) ions show a stronger interaction with Na+ ion compared to weakly coordinating imide (FSIˉ) analogues. The Na0.44MnO2 and prosopis juliflora derived activated carbon (PJAC) based ASC, and PJAC based symmetric supercapacitor (SSC) using mixed WIS electrolyte is cycled up to 5000 times. Further, the influence of environmental conditions (60 and −20 °C) is also studied in detail for the WIS based electrolyte for both ASC and SSC. National Research Foundation (NRF) This research is supported by grants from the National Research Foundation, Prime Minister's Office, Singapore under its Campus of Research Excellence and Technological Enterprise (CREATE) programme under the Singapore-HUJ Alliance for Research and Enterprise Ltd (SHARE), NEW-CREATE which is joint research programme between the Hebrew University of Jerusalem (HUJ, Israel) and Nanyang Technological University (NTU, Singapore). ROR acknowledges the Department of Science & Technology (DST), Science & Engineering Research Board (SERB) for the Early Career Research Award (ECR/2016/000041). VA acknowledges financial support from the SERB, a statutory body of the DST, Govt. of India, through the Ramanujan Fellowship (SB/S2/RJN-088/2016).

This paper reports a simple method to recycle plastic-bottle and Li-ion-battery waste in one process by forming valuable coordination polymers (metal-organic frameworks, MOFs). Poly(ethylene terephthalate) from plastic bottles was depolymerized to produce an organic ligand source (terephthalate), and Li-ion batteries were dissolved as a source of metals. By mixing both dissolution solutions together, selective precipitation of an Al-based MOF, known as MIL-53 in the literature, was observed. This material can be recovered in large quantities from waste and presents similar properties of purity and porosity to as-synthesis MIL-53. This work illustrates the opportunity to form hybrid porous materials by combining different waste streams, laying the foundations for an achievable integrated circular economy from different waste cycle treatments (for batteries and plastics). Ministry of National Development (MND) National Environmental Agency (NEA) Published version This research was funded by the National Environmental Agency (NEA, Singapore) and the Ministry of National Development (MND, Singapore) with the “Singapore–CEA Alliance for Research in Circular Economy (SCARCE, award number USS-IF-2018-4)”, which is a joint laboratory set up between Nanyang Technological University (NTU, Singapore) and the French Alternative Energies and Atomic Energy Commission (CEA, France).

End-of life Li-ion batteries can be a source of valuable materials to rebuild new batteries or for other applications. In this way, we propose to precipitate metals from a dissolution solution of Li-ions batteries (LiBs) as hybrid organic–inorganic materials (metal–organic frameworks, MOFs), well known in many fields due to their specific properties (high porosity, large surface area and sometimes thermal and chemical stability). From raw LiBs containing Al, Cu, Mn, Ni, or Co mainly, a selective precipitation of different metals as MOFs has been possible. The use of a carboxylate ligand allowed complete precipitation of Al from the solution, whereas using a bipyridine ligand changes the selectivity to precipitate Cu as MOFs. This work shows that formation of different MOFs in a multi-metallic solution can be obtained depending on the precipitating agent. Ministry of National Development (MND) National Environmental Agency (NEA) Submitted/Accepted version Authors are grateful to Joseph Lautru and Xavier Le Goff for their help to characterize materials and to grant award from NEA (National Environmental agency, Singapore) and Ministry of National development (MND, Singapore) titled “Singapore –CEA Alliance for Research in Circular Economy (SCARCE, award number USS-IF-2018-4)”, which is a joint lab set up between Nanyang Technological University (NTU, Singapore) and the French Alternative Energies and Atomic Energy Commission (CEA, France).”

Battery cathode materials operating on multivalent‐ion intercalation are prone to short operational lifetimes, traditionally explained to be due to poor solid‐state diffusion. Here, we overcome this problem by using a conversion‐type cathode material and demonstrate the benefits in a FeVO4 host structure. The rechargeable Zn‐ion battery exhibits stability for an unprecedented operational lifetime of 57 days with a high capacity of 272 mAh g−1 (60 mA g−1) over 140 cycles. We use a combination of synchrotron‐based XAS, SRXTM, Raman, XRD and HRTEM techniques to elucidate the cathode material evolution at multilength‐scale for understanding the Zn‐ion storage mechanism. We further highlight the benefits of using a low‐salt concentration electrolyte and pH‐consideration analysis in aqueous battery development, the optimization of which leads to a 4‐fold increase in battery performance as compared to conventional high‐salt concentration electrolyte formulations. National Research Foundation (NRF) Accepted version This work was financially supported by the National Research Foundation of Singapore (NRF) Investigatorship Award Number NRFI2017-08/NRF2016NRF-NRFI001-22.

A concept is proposed for the recycling of Li-ion batteries with an open-loop method that allows to reduce the volume of wastes and simultaneously to produce valuable materials in large amounts (Metal-Organic Frameworks, MOFs). After dissolution of Nickel, Manganese, Cobalt (NMC) batteries in acidic solution (HCl, HNO3 or H2SO4/H2O2), addition of organic moieties and a heat treatment, different MOFs are obtained. Solutions after precipitation are analyzed by inductively coupled plasma and materials are characterized by powder X-Ray diffraction, N2 adsorption, thermogravimetric analysis and Scanning electron microscope. With the use of Benzene-Tri-Carboxylic Acid as ligand, it has been possible to form selectively a MOF, based on Al metallic nodes, called MIL-96 in the literature, and known for its interesting properties in gas storage applications. The supernatant is then used again to precipitate other metals as MOFs after addition of a second batch of ligands. These two other MOFs are based on Cu (known as HKUST-1 in the literature) or Ni-Mn (with a new crystalline structure) depending of conditions. This method shows promising results at the lab scale (15 g of wastes can be converted in 10 g of MOFs), and opens interesting perspectives for the scaled-up production of MOFs. Ministry of National Development (MND) National Environmental Agency (NEA) Submitted/Accepted version This research was funded by NEA (National Environmental agency, Singapore) and Ministry of National development (MND, Singapore) titled “Singapore –CEA Alliance for Research in Circular Economy (SCARCE, award number USS-IF-2018-4)”, which is a joint lab set up between Nanyang Technological University (NTU, Singapore) and the French Alternative Energies and Atomic Energy Commission (CEA, France).

We report the synthesis and Li-storage properties of two-dimensional Co0.33In2.67S2.29Se1.71 as an anode for Li-ion battery applications. Chemical vapour transport technique is adopted to prepare high quality Co0.33In2.67S2.29Se1.71 single crystals with high yield. Li-storage properties are assessed using a half-cell configuration in which the cell is cycled in the alloying region (0.005–1 V vs. Li) that provides better characteristics than the extended region (i.e. allowing the materials to undergo a conversion pathway) in terms of cycling stability and retention. This logically think us to evaluate the suitability of the prepared negative electrode to fabricate the practical cell i.e. full-cell with olivine phase LiFePO4 cathode. The irreversible capacity loss observed in the negative electrode is effectively tackled by using an electrochemical pre-treatment with Li and subsequently assembled the full-cell by adjusting the loading of LiFePO4. The practical-cell, LiFePO4/pre-treated Co0.33In2.67S2.29Se1.71 displayed a very decent electrochemical activity and exhibits a maximum energy density of ∼103 Wh kg−1 (including dead mass weight). National Research Foundation (NRF) Accepted version This work was financially supported by National Research Foundation of Singapore (NRF) Investigatorship award number: NRF2016NRF-NRFI001-22. VA thank the financial support from Science & Engineering Research Board (SERB), a statutory body of the Department of Science & Technology, Govt. of India through Ramanujan Fellowship (SB/S2/RJN-088/2016).

We report the facile and low temperature synthesis of one dimensional graphitic fibers with hollow structured morphology (VO-CF) by modified chemical vapor deposition using vegetable oil as a carbon source. Graphitization of the prepared phase is validated with various analytical tools. Prior to the fabrication of charge storage devices like Li-ion battery (LIB) and Li-ion capacitor (LIC), Li-insertion properties of VO-CF is studied in half-cell assembly. Mass adjustment between the electrodes are very crucial and adjusted for aforesaid energy storage devices. Pre-treatment or pre-lithiation is carried out using an electrochemical approach in Swagelok fittings with Li. LIB assembly with LiFePO4 delivered a maximum energy density of ∼233 Wh kg−1 whereas the LIC displayed the energy density of ∼112 Wh kg−1 when paired with activated carbon electrode. Both LIB and LIC assemblies rendered very decent cycling profiles for extended 500 and 10000 cycles, respectively. NRF (Natl Research Foundation, S’pore)

VS4 anode materials with controllable morphologies from hierarchical microflower, octopus-like structure, seagrass-like structure to urchin-like structure have been successfully synthesized by a facile solvothermal synthesis approach using different alcohols as solvents. Their structures and electrochemical properties with various morphologies are systematically investigated, and the structure–property relationship is established. Experimental results reveal that Li+ ion storage behavior in VS4 significantly depends on physical features such as the morphology, crystallite size, and specific surface area. According to this study, electrochemical performance degrades on the order of urchin-like VS4 > octopus-like VS4 > seagrass-like VS4 > flower-like VS4. Among them, urchin-like VS4 demonstrates the best electrochemical performance benefiting from its peculiar structure which possesses large surface area that accommodates the volume change to a certain extent, and single-crystal thorns that provide fast ele...

High-charge-capacity sodium-ion battery anodes made of Sb2Te3@reduced graphene oxide are reported for the first time. Uniform nano-coating of graphene oxide is carried out from common sol of peroxotellurate and peroxoantimonate under room temperature processing. Reduction by hydrazine under glycerol reflux yields Sb2Te3@reduced graphene oxide. The electrodes exhibit exceptionally high volumetric charge capacity, above 2300mAhcm-3 at 100mAg-1 current density, showing very good rate capabilities and retaining 60% of this capacity even at 2000mAg-1. A comparison of sodiation and lithiation shows that lithiation exhibits better volumetric charge capacity, but surprisingly only marginally better relative rate capability retention at 2000mAg-1. Tellurium-based electrodes are attractive due to the high volumetric charge capacity of Te, its very high electric conductivity, and the low relative expansion upon lithiation/sodiation.

We report the synthesis of TiS2 by chemical vapour transport and evaluated as insertion host for Na-ion battery. The half-cell assemblies are fabricated to study the Na-insertion properties. The Na/TiS2 cell displayed a reversible capacity of ∼146 mAh g–1 at 0.1 C rate which corresponds to ∼0.61 mol. Na. Excellent cycling stability, and rate performance are noted for TiS2. Cyclic voltammetry and impedance measurements supports the charge storage mechanism and interfacial properties, respectively. Operando studies are also conducted to ensure the structural stability of the insertion host. Furthermore, the Li-insertion properties are also conducted to support the electrochemical activity of the host matrix prepared by chemical vapour transport.

In this work, orthorhombic Li3VO4 with the controllable morphology has been synthesized by tuning the solvent composition (volume ratios of ethanol to deionized water) in a solvothermal approach. The resulting Li3VO4 samples with various morphologies (coral-shaped particle, self-assembled hierarchical microsphere, cube-like particle, sheet-like structure) show then different electrochemical performances when employed as anodes for Li-ion battery applications. The Li3VO4 with self-assembled hierarchical microsphere morphology (volume ratio of ethanol to deionized water at 15:15) exhibits the best electrochemical performance. The subsequent carbon coating process on microsphere samples is claimed to significantly improve both the capacities at both low (350–430 mAh g−1 at 100 mA g−1) and high current (180–350 mAh g−1 at 2 A g−1) conditions, and their excellent cycling stability. MOE (Min. of Education, S’pore) Accepted version

In this work, -Co(OH)2 nanosheets are explored as efficient pseudocapacitive material for the fabrication of 1.6 V class high energy supercapacitors in asymmetric fashion. As-synthesized -Co(OH)2 nanosheets displayed an excellent electrochemical performance owing to the unique structure, morphology and reversible reaction kinetics (fast Faradic reaction) in both three electrode and asymmetric configuration (with activated carbon, AC). For example, in three electrode set-up, -Co(OH)2 exhibits a high specific capacitance of ~675 F g-1 at scan rate of 1 mV s-1. In asymmetric supercapacitor, -Co(OH)2||AC cell delivers a maximum energy density of 37.3 Wh kg-1 at a power density of 800 W kg-1. Even at harsh conditions (8 kW kg-1), the energy density of 15.64 Wh kg-1 is registered for -Co(OH)2||AC assembly. Such an impressive performance of -Co(OH)2 nanosheets in asymmetric configuration reveals the emergence of pseudo-capacitive electrode towards the fabrication of high energy electrochemical charge storage systems.

We report a microwave-assisted solvothermal process for the preparation of magnetite (Fe3O4, ca. 5 nm)-anchored reduced graphene oxide (rGO). It has been examined as a prospective conversion-type negative electrode for multiple energy storage applications, such as Li-ion batteries (LIBs) and Li-ion capacitors (LICs). A LiFePO4/Fe3O4-rGO cell is constructed and capable of delivering an energy density of approximately 139 Wh kg−1 with a notable cyclability (ca. 76 %) after 500 cycles. Prior to the fabrication of a LIB, the Fe3O4-rGO is electrochemically pretreated to eliminate the irreversible capacity loss. In addition to the LIB, a high-energy LIC is also fabricated by using the pre-lithiated Fe3O4-rGO composite as the anode and commercial activated carbon as the cathode. This LIC registered a maximum energy density of approximately 114 Wh kg−1 with good cyclability. For both the LIB and LIC, the mass loading between the electrodes was adjusted based on the performance with metallic Li. The improved electrochemical performance of Fe3O4-rGO over existing materials is a promising development in the quest for novel, fast, low cost, and efficient energy storage systems without compromising the eco-friendliness

Activated carbon (AC) with high surface area (1,901 m2 g−1) is synthesized from bio-waste orange (Citrus sinensis) peel for fabrication of high specific energy lithium ion capacitors (LICs). The composition, structure and electrochemical properties of orange peel derived AC (OP-AC) are characterized by elemental analyzer, field emission-scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammogram, charge-discharge and impedance studies. Fabricated LIC using the high surface area OP-AC with pre-lithiated graphite (LiC6) delivered specific energy of ∼106 Wh kg−1. In addition, LIC configuration with Li4Ti5O12 was also fabricated and observed to be capable of delivering the specific energy of ∼35 Wh kg−1. Symmetric configuration of OP-AC with aqueous and organic solutions was also made for comparison purpose. A systematic improvement from the specific energy of ∼7 to 106 Wh kg−1 is noted from aqueous to LIC assembly. The findings open up the possibility of developing high specific energy LICs from abundant, low-cost, sustainable biomass waste.

Coconut shell derived mesoporous carbon (CS-AC) is explored as prospective supercapacitor component in Li-ion and Na-ion capacitors (LIC and NIC) along with pre-lithiated/sodiated natural plant derived hard carbon (HC) as battery element. Though, there is no obvious variation from the capacitive properties of CS-AC, but an obvious difference is evident for battery component in single electrode configuration. Based on such performance, the mass loading has been adjusted during the fabrication of LIC and NIC. Prior to this, HC is pre-lithiated/sodiated for LIC/NIC assembly. The CS-AC and pre-treated HC based materials registered the maximum energy density of ∼121 and ∼82 Wh kg−1 for LIC and NIC assemblies, respectively. An excellent long-term cycleability of ∼83% retention is noted for LIC after 8000 cycles, whereas NIC showed inferior performance (∼60%) under similar testing conditions. Multilayer surface film is the main reason for such performance which has been clearly revealed from the impedance measurements. First, the CS-AC is prepared by hydrothermal carbonization and subsequent chemical activation with ZnCl2 to yield high specific surface area and pore volume of 1795 m2 g−1 and 2.2 cm3 g−1, respectively, in which 71% originated from mesoporous region.

The development of anodes with high capacity, long cycle life and good rate capability is essential to expedite the commercialization of sodium-ion batteries for practical applications, including grid storage and electric vehicles (EV). Herein, we report the facile solvothermal synthesis of nanostructured iron distannide (FeSn2) intermetallic particles as an alloy-type anode and the improvement of its cycle life by fabricating FeSn2-graphite composites by a ball-milling process. The influence of graphite concentration on the sodium storage properties is studied. The composite anode delivered over 400 mAh g−1 sodiation capacity over 200 cycles at a specific current of 100 mA g−1. In addition, the composite anode exhibited excellent rate performance at higher current rates. This result would certainly pave the way for the development of high-performance anodes that would realize low-cost sodium-ion batteries with a longer calendar life.

The commercialization of Na-ion batteries demands the development of technologically feasible and economically viable electrodes, in particular anodes. Herein, we report the facile synthesis of nanostructured FeSn 2 by a hydrothermal route and the formulation of composites with different carbonaceous materials like Super P, graphite, and graphene via high-throughput ball-milling. The influence of the carbonaceous matrix on the electrochemical performance of the alloy anode is investigated in half-cell assembly. Amongst, FeSn 2 -Graphite composite exhibits excellent cycling stability with a reversible capacity of 333 mAh g −1 obtained after 100 cycles at a specific current of 100 mA g −1 . The composite also displayed a good rate performance even at high current rates of 1 A g −1 which is a desirable feature for high power applications such as hybrid electric vehicles. The outstanding electrochemical performance of the composite anodes is ascribed to the effective encapsulation of the alloy particles in the carbonaceous matrix, which sustains the volume change and facilitates excellent Na-storage capability.

We report the fabrication of high energy Li-ion capacitor (LIC) using teak wood sawdust derived mesoporous activated carbon (AC-HBP) with electrochemically pre-lithiated graphite (LiC6). Three interesting supercapacitor assemblies are constructed using AC-HBP to realize the high energy density. Amongst, AC-HBP paired with LiC6 delivered a maximum energy density of ∼111 Wh kg−1 compared to Li4Ti5O12 in LIC (∼53 Wh kg−1) and AC-HBP (∼37 Wh kg−1) in symmetric configurations. This excellent energy density is mainly ascribed to the tailored mesoporous nature (∼67%) of the high surface area activated carbon (2108 m2 g−1) obtained via hydrothermal carbonization process in the presence of processing agent, benzene tetracarboxylic acid followed by physico-chemical activation.

We report on the synthesis of a high rate NaTi2(PO4)3/graphene composite for use as an anode material for high power Na-ion hybrid capacitors with the following characteristics; (1) reduction of the particle size of NaTi2(PO4)3 to the nanometer scale in order to reduce the Na+ ion diffusion length, (2) chemical bonding between NaTi2(PO4)3 nanoparticles and graphene in order to improve electrical conductivity, and (3) interconnected nanoporous structures in order to allow easy access of Na+ ions to NaTi2(PO4)3. For this, the NaTi2(PO4)3/rGO microsphere composite was prepared via a facile spray drying method using a solution mixture of graphene oxide, NaH2PO4·2H2O, Ti(OC2H5)4 and NH4H2(PO4)3, in which all the components of the titanium were present as ionic species in order to facilitate the chemical bonding between NaTi2(PO4)3 and rGO in the composite. The NaTi2(PO4)3/rGO microsphere composite had a Ti–O–C bond between NaTi2(PO4)3 nanoparticles (

A remarkable improvement in energy density was found using Se-substituted two-dimensional TiS2 (TiSe0.6S1.4) as the insertion matrix in a Li-ion capacitor (LIC) assembly with activated carbon (AC) as the counter electrode. Chemical vapor transport was successfully used to synthesize high quality TiSe0.6S1.4 with near-100% crystallinity and subsequently employed as a battery component in LICs. Prior to LIC fabrication, the Li-insertion properties were assessed in single-electrode configuration with metallic Li. Single-electrode performance is crucial for adjusting the mass loading of AC and TiSe0.6S1.4 to realize the maximum energy density. Accordingly, an AC/TiSe0.6S1.4-based LIC delivered an energy density of ∼50 W h kg−1 with a good cyclability of 5000 cycles. Few undesirable side reactions with the electrolyte counterpart were observed for TiSe0.6S1.4, as supported by the impedance measurements.

Herein, we report, for the first time, the possibility of using TiS2 as an insertion host for the fabrication of high energy and high power Li-ion capacitors with commercial activated carbon (AC). The Li-insertion and PF6− adsorption/desorption properties are determined using Li in TiS2 and AC electrodes, respectively, which is very useful to balance the mass loading between the electrodes to realize maximum energy. Under balanced loading, the AC/TiS2 based LIC delivers a maximum energy density of ∼49 W h kg−1. Upon long-term cycling, the AC/TiS2 based LIC experiences a marginal fade in density; specifically ∼76% of its initial value is retained after 2000 cycles. Prior to this, a nearly 100% crystalline TiS2 insertion host was prepared via chemical vapor transport with high yield.

Electrocatalysts are one of the most important parts for oxygen evolution reaction (OER) to overcome the sluggish kinetics. Herein, amorphous Fe–Ni–P–B–O (FNPBO) nanocages as efficient OER catalysts are synthesized by a simple low-cost and scalable method at room temperature. The samples are chemically stable, in clear contrast to reported unstable or even pyrophoric boride samples. The Fe/Ni ratio of the FNPBO nanocages can be continuously adjusted to optimize the OER catalytic performance. The FNPBO nanocages composed of multicomponent elements can weaken the metal–metal bonds, thus rearranging the electron density around the catalytic metal atom centers and reducing the energy barrier for intermediate formation. Hence the optimized FNPBO (Fe6.4Ni16.1P12.9B4.3O60.2) catalyst shows superior intrinsic electrocatalytic activity for OER. The low overpotential to afford the current density of 10 mA cm–2 (236 mV), the small Tafel slope (39 mV dec–1), and the high specific current density (26.44 mA cm–2) at a given overpotential of 300 mV make a sharp contrast to state-of-the-art RuO2 (327 mV, 136 mV dec–1, and 0.028 mA cm–2, respectively). NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Accepted version

International audience; Le besoin urgent de réduction des émissions de gaz à effet de serre stimule le développement de procédés de production d'énergie bas carbone utilisant des sources renouvelables dont le caractère intermittent nécessite de disposer de systèmes de stockage performants permettant de lisser les fluctuations de production. Les systèmes de stockage nomades de l'énergie font également l'objet de nombreuses recherches dans le cadre du développement de la mobilité électrique. Ainsi, la communauté scientifique tente d'améliorer les performances des dispositifs existants en étudiant des matériaux innovants permettant de débloquer certains verrous technologiques auxquels se heurtent les concepts actuels de batterie. Parmi les solutions prometteuses, les matériaux nanostructurés avancés occupent une place de choix dans la perspective de relever ce défi, et les nouveaux procédés capables de synthétiser des nanoparticules à façon sont donc appelés à jouer un rôle clé dans l'essor de ces technologies. En ce qui concerne les batteries Li-ion, la technologie actuelle est confrontée d'une part aux problèmes de sécurité induits par la formation de dendrites de Li, et d'autre part à la limitation de la capacité liée à la nature des matériaux d'électrodes utilisés. Il conviendrait ainsi d'utiliser des matériaux fonctionnant à des potentiels différents où le risque de formation de dendrite est réduit, et qui montreraient des capacités spécifiques élevées. Parmi les solutions alternatives, les matériaux d'alliage ou de conversion pourraient répondre à ce cahier des charges mais ils souffrent de variations volumiques importantes lors des cyclages qui mènent à la ruine des électrodes. De plus, leur conductivité électronique est parfois limitée. L'utilisation de matériaux nanostructurés pour l'élaboration des électrodes pourrait permettre de contourner des limitations en accommodant mieux les contraintes liées à l'expansion volumique, en favorisant la diffusion des Li + au coeur de l'électrode, et en multipliant les chemins de percolation électrique. Dans ce travail, le procédé de pyrolyse laser est utilisé pour synthétiser d'une part des nanoparticules d'oxydes mixtes ZnFe2O4 de morphologie contrôlée, ainsi que des nuances d'oxydes d'étain SnO2 dopés ou associés à du graphène. Ces deux matériaux de conversion présentent en effet des capacités spécifiques élevées de l'ordre de 1000 à 1500 mAh.g-1 , respectivement (à comparer aux 372 mAh.g-1 du graphite actuellement utilisé à l'anode). Le choix du métal de transition dans les structures spinelles AB2O4 permet de surcroît de modifier le potentiel de fonctionnement du dispositif typiquement entre 0,5 et 1,6 V vs Li + /Li (à comparer au 0,4 V utilisé dans les batteries graphite actuelles). Dans les deux cas, nos travaux ont montré que la nanostructuration permettait de conserver une capacité importante après plusieurs centaines de cycles charge/décharge. Dans le cas de la ferrite de zinc, une différence de comportement en termes de rétention de la capacité a pu être mise en évidence au bénéfice d'une distribution de taille bimodale. Dans le cas de l'oxyde d'étain, le dopage à l'azote a permis d'améliorer les performances en cyclage au meilleur niveau de l'état de l'art [1], et l'association avec le graphène en une seule étape de pyrolyse laser a permis d'obtenir des rétentions de capacité exceptionnelles notamment lors des cyclages rapides.

We report all carbon-based high energy Li-ion capacitor from environmentally threatening bio-source, prosopis juliflora. The pyrolyzed carbon exhibits a few layers of graphene-like structure and tubular morphology with multiple inherent heteroatoms like N, S, and Ca. Presence of such heteroatoms are certainly beneficial to the betterment of electrical conductivity, and pore generation which eventually results in an enhancement in capacity/capacitance of carbonaceous materials. The electrochemical pre-lithiation strategy is used to mitigate the irreversibility observed, and eventually employed as a negative electrode in a hybrid configuration. This LIC delivered a high energy density of ∼216 and 185 Wh kg−1 at ambient (25 °C) and elevated temperature (55 °C) conditions, respectively. Further, ∼94% initial capacity is retained after 5000 cycles with minimum fading of 0.0013% per cycle at ambient temperature. This results clearly demonstrate that the surface functionality and heteroatom doping with tubular structure synergistically facilitates the Li+ and electron transport properties to realize higher energy density for this fascinating all carbon-based Li-ion capacitor. National Research Foundation (NRF) This study was supported by the National Research Foundation of Korea grant funded by the Korea government (Ministry of Science, ICT) (No. NRF-2011-C1AAA0010030538). Also, the work was financially supported by NTU-HUJ Create Phase II which is a joint research programme between the Hebrew University of Jerusalem (HUJ, Israel) and Nanyang Technological University (NTU, Singapore) with CREATE (Campus for Research Excellence and Technological Enterprise) funding from National Research Foundation of Singapore (NRF,Singapore). VA thank the financial support from the Science & Engineering Research Board (SERB), a statutory body of the Department of Science & Technology, Govt. of India through Ramanujan Fellowship (SB/S2/RJN-088/2016).

To facilitate the commercialization of sodium-ion batteries (SIBs), advanced electrode materials with high sodiation capacities and enhanced cycling stabilities are essential. Herein, we investigate the effect of Fe incorporation into SnSb to generate a new ternary nanocrystalline composite based anode, which improves the cycling stability and performance of SIBs. We ensure a high-throughput synthetic approach via a rapid-solidification technique for efficient and industrially viable Fe–Sn–Sb alloy synthesis. Interestingly, the new ternary system possesses nanocrystalline domains that helped to alleviate the stresses induced upon the sodiation/desodiation reactions and thereby enhanced the performance. The Fe1.0–SnSb anode delivered a capacity of ∼500 mA h g−1 at a specific current density of 50 mA g−1 for over 120 cycles and a full-cell was designed, which could deliver one of the highest reported energy densities of ∼826 W h kganode−1. The promising electrochemical results assert the significance of microstructural engineering of alloying anodes and open up new avenues of research into rapidly solidified alloys for energy storage applications. NRF (Natl Research Foundation, S’pore) Accepted version

Considering the high safety, low-cost and high capacity, aqueous zinc ion batteries have been a potential candidate for energy storage ensuring smooth electricity supply. Herein, we have synthesized inverse opal manganese dioxide constructed by few-layered ultrathin nanosheets by a solution template method at mild temperature. The ultrathin nanosheets with the thickness as small as 1 nm are well separated without obvious aggregation. Used as cathode material for aqueous zinc ion batteries, the few-layered ultrathin nanosheets combined with the inverse opal structure guarantee excellent performance. A high specific discharge capacity of 262.9 mAh·g−1 is retained for the 100th cycle at a current density of 300 mA·g−1 with a high capacity retention of 95.6%. A high specific discharge capacity of 121 mAh·g−1 at a high current density of 2,000 mA·g−1 is achieved even after 5,000 long-term cycles. The ex-situ X-ray diffraction (XRD) patterns, selected-area electron diffraction (SAED) patterns and high-resolution transmission electron microscopy (HRTEM) results demonstrate that the discharge/charge processes involve the reversible formation of zinc sulfate hydroxide hydrate on the cathode while in-plane crystal structure of the layered birnessite MnO2 could be maintained. This unique structured MnO2 is a promising candidate as cathode material for high capacity, high rate capability and long-term aqueous zinc-ion batteries. NRF (Natl Research Foundation, S’pore) Accepted version

We first report the fabrication of all one dimensional (1D) active materials based Li-ion power packs using conversion type anode (α-Fe2O3). Electrospining procedure has been used to prepare all the 1D nanostructures. Half-cell studies are performed with metallic Li to ascertain the electrochemical activity of the individual components. In order to overcome irreversible capacity loss (ICL) in α-Fe2O3, the high voltage cathode has been over lithiated electrochemically (Li1.33Ni0.5Mn1.5O4) prior to the full-cell assembly. The combined advantages of 1D nanostructure and a new over lithiation concept certainly provides the less amount of active material loading to mitigate ICL. On the other hand, all based cell Li1.33Ni0.5Mn1.5O4/1 M LiPF6 gelled PVdF-HFP/α-Fe2O3 delivered an energy density of ∼193 Wh kg−1 with working potential of ∼3.27 V and rendered ∼88% of initial reversible capacity after 60 cycles.

TiO2-reduced graphene oxide (rGO) nanocomposite (TiO2-rGO) is fabricated by microwave-assisted forced hydrolysis and examined as prospective electrode for energy storage applications, especially in Li-ion battery (LIB) and Li-ion capacitor (LIC). First, the uniformly distributed nanoscopic TiO2 particulates (∼3 nm) over rGO nanosheets is evaluated as anode in half-cell assembly to ascertain the Li-insertion behavior and found that ∼0.68 mol Li (∼227 mAh g−1) is reversible. Then, “rocking-chair” type LIB is fabricated with spinel LiMn2O4 cathode, and the LiMn2O4/TiO2-rGO assembly exhibits high capacity (∼120 mAh g−1 at 0.1 C rate), good rate capability (∼53 mAh g−1 at 1 C rate), and excellent cycleability (∼90% initial reversible capacity after 1000 cycle) as well. Similarly, the LIC is also constructed with activated carbon cathode, and such configuration delivered a maximum energy density of ∼50 Wh kg−1 with ∼82% retention after 4000 cycles. The synergistic effect of both rGO and anatase nanoparticles provides excellent energy efficiency and battery performance in different kind of Li-ion based energy storage devices.