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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, for the first time, the possibility of using tavorite type LiVPO4F as insertion electrode for Li-ion capacitor configuration with carbonaceous counterpart i. e. activated carbon (AC) in organic medium. Carbothermal reduction process is successfully employed to prepare LiVPO4F and the as-prepared material is subsequently characterized using various analytical techniques. Single electrode studies are conducted to estimate the optimum mass loading between two electrodes. A reversible capacity of 120 mAh g–1 is obtained when cycled between 3–4.5 V vs. Li at current density of 50 mA g–1. This has been further studied as cathode in a Li-ion capacitor configuration with AC. The LiVPO4F/AC configuration delivered the maximum energy density of 30 Wh kg–1. A good cycleability is also evidenced, for instance, ∼90 % of the initial value is retained after 1000 cycles.

In this paper, we report the influence of carbon coating on the electrochemical performance of hollow structured SnO 2 electrospun nanofibers. The electrospun nanofibers are subjected to plasma enhanced chemical vapour deposition for a conformal carbon coating of ∼6 nm thickness without destroying the one dimensional morphological features of the fiber mats. Li-storage properties are evaluated in half-cell configuration between two different potential windows i.e. 0.005-0.8 V and 0.005-2.5 V vs. Li. The potential regions tested corresponds to the alloying/de-alloying and alloying/de-alloying & conversion reactions for former and latter cases, respectively. Very high reversibility over 3.6 moles of Li is feasible for both bare and carbon coated SnO 2 , without an obvious difference between the electrochemical profiles noted during cycling. In contrary, huge differences in the electrochemical performances are observed for bare and carbon coated SnO 2 when the test cell is cycled for conversion reaction. This result clearly shows the importance of carbon coating for conversion reaction compared to alloying/de-alloying reaction.

We report the fabrication of high energy Li-ion capacitors (LICs) using conversion type Mn3O4 octahedrons anchored to few layer graphene (Mn3O4-G) as the negative electrode with activated carbon (AC) as the positive one. First, the Mn3O4-G composite is prepared via a hydrothermal approach using commercially available graphene nanosheets. Li-storage studies of both electrodes (AC and Mn3O4-G) are conducted in single electrode/half-cell configuration with metallic Li to assess the mass balance. Prior to the fabrication of LICs, Mn3O4-G is pre-lithiated in Swagelok fittings with Li and subsequently paired with the desired loading of AC. The AC/Mn3O4-G based LIC delivered a maximum energy density of ∼142 W h kg−1 with excellent cyclability of 9000 cycles with ∼80% retention. This result certainly provides new avenues for the development of high energy LICs using conversion type negative electrodes rather than traditional insertion type anodes.

We first report the multi-couple reaction in all vanadium redox flow batteries (VRFB) while using biomass (coconut shell) derived mesoporous carbon as electrode. The presence of V 3þ /V 4þ redox couple certainly supplies the additional electrons for the electrochemical reaction and subsequently provides improved electrochemical performance of VRFB system. The efficient electro-catalytic activity of such coconut shell derived high surface area mesoporous carbon is believed for the improved cell performance. Extensive power and electrochemical studies are performed for VRFB application point of view and described in detail.

In the present work, we present the successful fabrication of a 2.4 V Li-ion cells with NASICON-type carbon-coated LiTi2(PO4)3 [C-LiTi2(PO4)3] as the cathode and pre-lithiated graphite (LiC6) as the anode . This class of 2.4 V Li-ion cell, C-LiTi2(PO4)3/LiC6, is capable of delivering charge and discharge capacities of approximately 108 and 113 mAh g−1 [based on C-LiTi2(PO4)3 loading] at 0.05 mA cm−2 at ambient temperature. A good cyclability over 100 cycles is also observed for the low-cost and ecofriendly configuration, which is certainly capable of powering various portable electronic devices. The LiTi2(PO4)3 nanoparticles are prepared by firstly using a Pechini-type polymerizable-complex method and subsequently carbon coating by decomposing glucose.

We report on the Na-insertion/extraction properties of NASICON type carbon-coated LiTi 2 (PO 4 ) 3 (C-LiTi 2 (PO 4 ) 3 ) in aqueous medium. Sub-micron sized LiTi 2 (PO 4 ) 3 particles are synthesized by a pechini type polymerizable complex method and subsequently coated with carbon. Na-insertion properties are evaluated in a three electrode configuration and it was found that ∼1.32 mol of Na (capacity of ∼91 mA h g −1 ) could be reversibly inserted/extracted at 1 C rate. High power capability of C-LiTi 2 (PO 4 ) 3 is also demonstrated with good capacity retention characteristics.

We report the extraordinary performance of an Li-ion battery (full-cell) constructed from one-dimensional nanostructured materials, i.e. nanofibers as cathode, anode, and separator-cum-electrolyte, by scalable electrospinning. Before constructing such a one-dimensional Li-ion battery, electrospun materials are individually characterized to ensure its performance and balancing the mass loading as well. The insertion type anode TiNb2O7 exhibits the reversible capacity of ∼271 mAh g–1 at current density of 150 mA g–1 with capacity retention of ∼82% after 100 cycles. Under the same current density, electrospun LiMn2O4 cathode delivered the discharge capacity of ∼118 mAh g–1. Gelled electrospun polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) nanofibers membrane is used as the separator-cum-electrolyte in both half-cell and full-cell assembly which exhibit the liquid like conductivity of ∼2.9 mS cm–1 at ambient conditions. Full-cell, LiMn2O4|gelled PVdF-HFP|TiNb2O7 is constructed by optimized mass loa...

We report the extraordinary performance of carbon-coated sodium super ion conductor (NASICON)-type LiTi2 (PO4 )3 as an ideal host matrix for reversible insertion of both Li and Na ions. The NASICON-type compound was prepared by means of a Pechini-type polymerizable complex method and was subsequently carbon coated. Several characterization techniques such as XRD, thermogravimetric analysis (TGA), field-emission (FE) SEM, TEM, and Raman analysis were used to study the physicochemical properties. Both guest species underwent a two-phase insertion mechanism during the charge/discharge process that was clearly evidenced from galvanostatic and cyclic voltammetric studies. Unlike that of Li (≈1.5 moles of Li), Na insertion exhibits better reversibility (≈1.59 moles of Na) while experiencing a slightly higher capacity fade (≈8 % higher than Li) and polarization (780 mV) than Li. However, excellent rate capability profiles were noted for Na insertion relative to its counterpart Li. Overall, the Na insertion properties were found to be superior relative to Li insertion, which makes carbon-coated NASICON-type LiTi2 (PO4 )3 hosts attractive for the development of next-generation batteries.

We report the synthesis and electrochemical performance of one dimensional NiO nanofibers by simple electrospinning technique and subsequently heat treated at 800 °C to yield single phase material. After the heat treatment, thickness and crystal size electrospun NiO is found ∼1 μm and 100 nm, respectively. The electrospun nanofibers are subjected to various characterizations such as X-ray diffraction with Rietveld refinement, scanning electron microscopy and transmission electron microscopy (TEM). Half-cell assembly is used to evaluate the Li-uptake properties and found maximum reversible capacity of ∼784 mA h g −1 at current density of 80 mA g −1 with operating potential of ∼1.27 V vs. Li. The test cell rendered good cycleability and exhibits capacity retention of over 75% of reversible capacity after 100 cycles. The conversion mechanism of metallic nanoparticles (Ni 0 ) are validated though ex-situ TEM measurements. Rate performance studies are also conducted and delivered good cycling properties under such high current studies.

Prelithiated, electrospun α‐Fe2O3 nanofibers display an exceptional cycleability when it is paired with commercial LiMn2O4 cathode in full‐cell assembly. The performance of such α‐Fe2O3 nanofibers is mainly due to the presence of unique morphology with porous structure, appropriate mass balance, and working potential. Also, synthesis technique cannot be ruled out for the performance.

Prelithiated, electrospun α-Fe2O3 nanofibers display an exceptional cycleability when it is paired with commercial LiMn2O4 cathode in full-cell assembly. The performance of such α-Fe2O3 nanofibers is mainly due to the presence of unique morphology with porous structure, appropriate mass balance, and working potential. Also, synthesis technique cannot be ruled out for the performance. NRF (Natl Research Foundation, S’pore) Published version

Nano-sized NASICON type LiTi2(PO4)3 particles are prepared by a Pechini type polymerizable complex method and subsequently coated with carbon.

We report for the first time the synthesis and extraordinary performance of a high voltage spinel LiNi(0.5)Mn(1.5)O4 fiber cathode in all one dimensional (1D) architecture. Structural and morphological features are analyzed by various characterization techniques. Li-insertion/extraction properties are evaluated in a half-cell assembly (Li/LiNi(0.5)Mn(1.5)O4) and subsequently in full-cell configuration with an anatase TiO2 fiber anode. In both half- and full-cell assemblies, gelled polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) is used as the separator-cum-electrolyte. All the one dimensional components used for fabricating Li-ion cells are prepared by a simple and scalable electrospinning technique. The full-cell, LiNi(0.5)Mn(1.5)O4/gelled PVdF-HFP/TiO2 delivered the reversible capacity of ∼ 102 mA h g(-1) at 0.1 C rate with an operating potential of ∼ 2.8 V. Excellent rate capability and stable cycling profiles are noted for such a full-cell assembly with a capacity retention of ∼ 86% after 400 cycles.

We report the extraordinary performance of an Li-ion battery (full-cell) constructed from one-dimensional nanostructured materials, i.e. nanofibers as cathode, anode, and separator-cum-electrolyte, by scalable electrospinning. Before constructing such a one-dimensional Li-ion battery, electrospun materials are individually characterized to ensure its performance and balancing the mass loading as well. The insertion type anode TiNb2O7 exhibits the reversible capacity of ∼271 mAh g(-1) at current density of 150 mA g(-1) with capacity retention of ∼82% after 100 cycles. Under the same current density, electrospun LiMn2O4 cathode delivered the discharge capacity of ∼118 mAh g(-1). Gelled electrospun polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) nanofibers membrane is used as the separator-cum-electrolyte in both half-cell and full-cell assembly which exhibit the liquid like conductivity of ∼2.9 mS cm(-1) at ambient conditions. Full-cell, LiMn2O4|gelled PVdF-HFP|TiNb2O7 is constructed by optimized mass loading of cathode with respect to anode and tested between 1.95 and 2.75 V at room temperature. The full-cell delivered the reversible capacity of ∼116 mAh g(-1) at current density of 150 mA g(-1) with operating potential and energy density of ∼2.4 V and ∼278 Wh kg(-1), respectively. Further, excellent cyclability is noted for such configuration irrespective of the applied current densities.

This is the first report of the utilization of TiNb2 O7 as an insertion-type anode in a lithium-ion hybrid electrochemical capacitor (Li-HEC) along with an activated carbon (AC) counter electrode derived from a coconut shell. A simple and scalable electrospinning technique is adopted to prepare one-dimensional TiNb2 O7 nanofibers that can be characterized by XRD with Rietveld refinement, SEM, and TEM. The lithium insertion properties of such electrospun TiNb2 O7 are evaluated in the half-cell configuration (Li/TiNb2 O7 ) and it is found that the reversible intercalation of lithium (≈3.45 mol) is feasible with good capacity retention characteristics. The Li-HEC is constructed with an optimized mass loading based on the electrochemical performance of both the TiNb2 O7 anode and AC counter electrode in nonaqueous media. The Li-HEC delivers very high energy and power densities of approximately 43 Wh kg(-1) and 3 kW kg(-1) , respectively. Furthermore, the AC/TiNb2 O7 Li-HEC delivers a good cyclability of 3000 cycles with about 84% of the initial value.

We report the extraordinary lithium storage performance of porous LiMn2O4 hollow nanofibers synthesized by electrospinning technique. The electrospun LiMn2O4 hollow nanofibers retained 87% of initial reversible capacity after 1250 cycles at the 1 C rate. Further, excellent cycling profiles at 55 °C and cubic spinel to tetragonal phase transformation are also noted.

One HEC of a material: The use of trigol-reduced graphene oxide nanosheets as cathode material in hybrid lithium-ion electrochemical capacitors (Li-HECs) results in an energy density of 45 Wh kg(-1) ; much enhanced when compared to similar devices. The mass loading of the active materials is optimized, and the devices show good cycling performance. Li-HECs employing these materials outperform other supercapacitors, making them attractive for use in power sources.

Free-standing carbon nanofibres (CNFs) are prepared by the carbonization of poly-acrylonitrile using a simple electro-spinning technique. The electro-spun fibres are studied as an anode material for lithium-ion batteries in half-cell configurations. The fibres showed an initial discharge capacity of 826 mAh g−1 at a current density of 200 mA g−1 and exhibited an appreciable capacity profile during cycling. The Li-storage mechanism has been explained based on the cyclic voltametric and galvanostatic cycling results.

Bring on the power: A high-performance insertion-type LiCrTiO4 anode is synthesized by solid-state-reaction methods. Reversible insertion of almost one mole of lithium is achieved in the half-cell configuration. The picture shows a TEM image of LiCrTiO4 with superimposed cyclic voltammetric traces of a LiMn2O4/LiCrTiO4 cell.

A simple and efficient sol–gel/electrospinning technique is employed for the preparation of high aspect ratio CuO nanofibers. Characterizations studies including X-ray diffraction, scanning electron microscopy, High-resolution-transmission electron microscopy are employed to analyze the crystal structure, and morphology of electrospun CuO nanofibers. Electrochemical lithium storage properties are evaluated in half-cell configurations at room temperature between 0.005 and 3 V vs Li. Cyclic voltammetry is used to study the reaction mechanism during charge–discharge process. Electrospun CuO nanofibers delivered stable reversible capacity of 452 mAh g–1 at current density of 100 mA g–1 in half-cell configuration (Li/CuO nanofibers). The cell displayed the very stable cycling behavior up to 100 cycles at current density of 100 mA g–1. Rate capability studies of CuO nanofibers are conducted and presented. Our studies have shown that the enhanced cycleability of CuO electrospun nanofibers are due to the fibrous morphology formed by nanoscopic CuO particles which could not only increase the electrode/electrolyte contact area but also enables the facile partial reduction of Cu2O into metallic particles (Cu0).

We successfully demonstrated the performance of novel, one-dimensional electrospun nanofibers as cathode, anode and separator-cum-electrolyte in full-cell Li-ion configuration. The cathode, LiMn2O4 delivered excellent cycle life over 800 cycles at current density of 150 mA g(-1) with capacity retention of ~93% in half-cell assembly (Li/LiMn2O4). Under the same current rate, the anode, anatase phase TiO2, rendered ~77% initial reversible capacity after 500 cycles in half-cell configuration (Li/TiO2). Gelled electrospun PVdF-HFP exhibits liquid-like conductivity of ~3.2 mS cm(-1) at ambient temperature conditions (30 °C). For the first time, a full-cell is fabricated with enitrely electrospun one-dimensional materials by adjusting the mass loading of cathode with respect to anode in the presence of gelled PVdF-HFP membrane as a separator-cum-electrolyte. Full-cell LiMn2O4|gelled PVdF-HFP|TiO2 delivered good capacity characteristics and excellent cyclability with an operating potential of ∼2.2 V at a current density of 150 mA g(-1). Under harsh conditions (16 C rate), the full-cell showed a very stable capacity behavior with good calendar life. This clearly showed that electrospinning is an efficient technique for producing high performance electro-active materials to fabricate a high performance Li-ion assembly for commercialization without compromising the eco-friendliness and raw material cost.