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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).

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

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

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 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 (

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

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.

Hot topic of research today is to overcome the irreversible capacity loss (ICL) in high capacity anodes used in Li-ion battery. Several attempts have been exploited to overcome the ICL issue, but all of them involved time consuming and inevitable electrolyte decomposition. Here, we attempted to utilize the octahedral site of spinel cathode ( ex. LiMn 2 O 4 ) for the compensation of ICL when paired with conversion type anode, α-Fe 2 O 3 nanorods. The performance of Li 1.26 Mn 2 O 4 /α-Fe 2 O 3 nanorods cell is compared with similar configurations fabricated without any electrode treatment and α-Fe 2 O 3 treated one. Amongst, LiMn 2 O 4 treated assembly showed promising results as compared with anode treated configuration.

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.

Anatase TiO2 microcubes with a unique (0 0 1) facets, single crystalline nature and highly uniform mesoporous morphology are shown to yield an excellent performance as efficient insertion anode material for lithium-ion battery application in both half cell (Li/TiO2) and full-cell (LiMn2O4/TiO2) assemblies. This material displays a stable reversible capacity of ~150 mA h g–1 (current density of 150 mA g–1) after 250 cycles with capacity retention of ~73% in the half-cell configuration. In full-cell assembly with spinel LiMn2O4 it shows remarkable ~74% retention of the initial capacity after 1000 cycles at 2 C rate, with an operating potential of ~2.2 V which is the one of the most stable performances shown for anatase TiO2 based Li-ion batteries in a full-cell assembly. We also highlight and discuss the effective contributions of mesopores and single crystalline nature along with the highly exposed (0 0 1) facets towards such efficient Li-insertion/extraction processes over a long duration as revealed from cycling stability.

Aqueous rechargeable Lithium ion batteries (ARLBs) are considered as the safest alternatives to match the performance of current Li-ion energy storage devices. Herein, we report the configuration of a full cell ARLB with Na1.16V3O8 crystalline rods and LiMn2O4 as electrodes that deliver high efficiency and excellent rate performance. In this study Na1.16V3O8 crystalline rods synthesized by one step hydrothermal method were used as the anode and solid microspheres of LiMn2O4 synthesized by a sol–gel synthesis followed by a heat-treatment using LiOH were used as the cathode. The performance of this fabricated full cell was optimized to operate between 0 V to 2.3 V in aqueous electrolytes to deliver an energy density of ~240 Wh/kg that was found to be better than most of the current lithium ion batteries which are based on non-flammable electrolytes. The device fabricated in this study exhibits a round trip efficiency of ~50% at the end of 100 cycles with a current density of 500 mA g−1. Furthermore, the charge storage mechanism in Na1.16V3O8 rods was also studied to corroborate its suitability as a potential anode material for aqueous rechargeable lithium ion batteries. Keywords: Aqueous rechargeable lithium ion battery (ARLB), Na1.16V3O8 (NVO), Microspheres, Rods, Full-cell

Research activities on the development of organic Na-ion hybrid electrochemical capacitors (NICs) are described in this review. In particular, more emphasis is given on the development of battery type electrodes (faradaic mechanism), for example, hard carbons, Na2Ti3O7, etc. Also, equal importance is given for the exploration of non-faradaic type counter electrodes derived from bio-mass and polymer precursors. In the recent past, Mxenes have attracted attention as promising candidates for cathodes and anodes for electrochemical energy storage devices. Accordingly, efficient utilization of such Mxenes as positive and negative electrodes in an NIC assembly is given along with their synthetic procedure. Furthermore, the symmetric configuration of other Na-ion based organic supercapacitor is also given in detail.

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 report a new electrochemical procedure to suppress the irreversible capacity loss (ICL) from high capacity anodes, specifically for high capacity anodes that undergo either alloying or conversio...

Novel materials with high lithium-storage capacities are indispensable to substantially increase the gravimetric and volumetric energy densities of lithium-ion batteries. In this context, metal thiophosphites (MTPs) possessing a layered structure are considered ideal candidates to serve as alkali-ion hosts. Herein, the lithium storage properties of layered tin thiophosphite (SnPS3) crystals have been investigated in coin-cell configuration. The results reveal that SnPS3 undergoes a conversion and alloying reaction to deliver high lithiation capacities. The SnPS3 anode delivered a significant lithiation capacity of ∼800 mAh g-1 at a specific current of 100 mA g-1. Moreover, the layered structure was able to accommodate the volume changes upon (de)lithiation as evident from its excellent cycling stability. Additionally, the SnPS3 anode demonstrated excellent rate capability as well and delivered ∼315 mAh g-1 at a high specific current of 2 A g-1. Furthermore, the lithium-storage mechanism was investigated through cyclic voltammetry and ex situ X-ray diffraction and X-ray photoelectron spectroscopy studies. Studies of SnPS3 anode in a full cell configuration by coupling with commercial LiNi0.33Co0.33Mn0.33O2 cathode are also presented. The outstanding electrochemical performance demonstrated by the SnPS3 anode calls for further research into this novel class of metal thiophosphites for energy storage applications. National Research Foundation (NRF) Accepted version National Research Foundation of Singapore (NRF) Investigatorship award number NRF2016NRF-NRFI001-22.

We report a facile low-temperature synthesis of graphitic carbons with a spherically shaped morphology (CO-CS) and high purity by the modified catalytic chemical vapour deposition using vegetable cooking oil as a carbon source. The excellent Li-insertion properties are noted with high reversibility (∼369 mA h g−1) in the half-cell assembly, which is very close to the theoretical capacity of graphite. Further explored the suitability to be used as an anode in the practical configurations, the intercalation type LiFePO4 and double layer forming activated carbon (AC) have been used as the cathodes toward the fabrication of Li-ion battery (LIB) and Li-ion capacitor (LIC), respectively. Prior to the LIC assembly, CO-CS has been pre-lithiated electrochemically. Both LiFePO4/CO-CS and AC/CO-CS assemblies display a maximum energy density of ∼337 and ∼108 W h kg−1 (based on an active material loading), respectively. The obtained values are better than those of the state-of-the-art LIB and LIC based on a graphitic anode. A decent cycle-ability is also registered for both cases. NRF (Natl Research Foundation, S’pore)

We report the possibility of recycling carbonaceous materials (GC) from used/spent Li‐ion batteries (LIBs) and re‐using the material again as a negative electrode. In addition to LIB, the possibility of using them in Li‐ion capacitor (LIC) configuration with activated carbon is also explored. First, the carbonaceous materials are recovered from the mechanical treatment and subsequent leaching process. After the successful recovery, the Li‐insertion properties are studied in half‐cell assembly and it exhibits very decent electrochemical activity. While re‐using GC as an anode, large irreversibility is noted compared to fresh usage. Therefore, the elimination of such irreversible capacity is desperately required prior to the fabrication of either LIBs or LICs. Full‐cell LIB is assembled with olivine phase LiFePO4 cathode and the configuration delivers a maximum energy density of ∼313 Wh kg−1. Similarly, the GC is used as an anode in LIC assembly with commercial activated carbon. The LIC displays an energy density of ∼112 Wh kg−1 with decent cycling profiles. National Environmental Agency (NEA) Submitted/Accepted version 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). SM would like to thank the grant award from NEA (National Environmental agency) on Singapore – CEA Alliance for Research in Circular Economy (SCARCE), award number USS-IF-2018-4.

Sodium-ion batteries (SIBs) have received renewed interest in recent years and are projected as an alternative to the existing lithium-ion battery (LIB) system. Research on SIBs is impelled by the low cost and abundant supply of sodium resources, the similar electrochemistry of SIBs and LIBs and the competing electrochemical performance achieved in recent years. Significant progress has been made in the development of alloying anodes for SIBs which offer high gravimetric and volumetric energy densities when compared to the conventional intercalation based anodes. Recent progress in the field of advanced operando and ex situ characterization techniques as well as theoretical computational studies has shed light on the sodiation mechanism of these alloying anodes. Herein, we review the recent developments in alloying anodes for SIBs. Primarily Sn, Sb, and P based alloying anodes are focused on and the progress in Bi, Ge and Si is also discussed. We focus on the sodiation mechanism of these alloying anodes, recently revealed by means of advanced experimental and computational tools, to enable the design of efficient strategies for enhanced electrochemical performance. We also discuss synthetic methodologies and novel approaches adopted for alloying anodes to mitigate the challenges faced during the (de)sodiation cycles. The future outlook and issues to be addressed to realize the practical implementation of alloying anodes are also discussed. NRF (Natl Research Foundation, S’pore) Accepted version

A facile one-pot solvothermal route has been developed to synthesize phase pure M x C 2 O 4 ⋅2H 2 O (M = Mn, Co; 0 x ⩽ 1) microstructures without employing any hard/soft template and their electrochemical performance in lithium-ion batteries has been systematically investigated. Morphology, microstructure and composition of the synthesized materials are characterized by field emission-scanning electron microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy. Anhydrous micron-sized MnC 2 O 4 and CoC 2 O 4 exhibits specific reversible discharge capacity of ∼800 and 950 mA h g −1 respectively, at 1 C-rate. MnC 2 O 4 exhibited good cycling stability while CoC 2 O 4 showed severe capacity fading phenomenon after 40 cycles, thereafter attaining 400–600 mA h g −1 for all C-rates. Interestingly, mixed solid solution having Co 0.52 Mn 0.48 C 2 O 4 composition improved the specific reversible discharge capacity to a stable value of ∼1000 mA h g −1 (1 C-rate), which is one of the highest reported values for such oxalates. The cycling stability of this mixed metal oxalate is remarkably better than its individual constituents at most C-rates. The Mn 2+ substitution into CoC 2 O 4 lattice has led to the synergistic modification of the electrochemical performances, thus making it a promising anode candidate for future LIBs.

This review describes the overall research activities focused on developing high-performance Li-ion batteries (LIBs) fabricated with various TiO2 polymorphs as insertion anodes. Although several polymorphs of TiO2 have been reported, only the anatase, rutile, bronze, and brookite phases have proven promising. The bronze phase's lower insertion potential, high reversibility and high current performance makes it an attractive candidate for constructing high power and high energy density Li-ion power packs. In addition, the bronze phase exhibits superior performance over the conventional, commercialized spinel Li4Ti5O12 anodes when coupled with the olivine phase LiFePO4. This exceptional behavior of the bronze phase opens new avenues for the development of high power LIBs capable of powering zero emission transportation and grid storage.

We first report the possible utilization of carbon-coated Li 3 V 2 (PO 4 ) 3 (LVP-C) phase as insertion type anode and cathode in Lithium-ion hybrid electrochemical capacitor (Li-HEC) applications with activated carbon (AC) counter electrode. Conventional sol–gel technique is utilized to prepare LVP-C and characterized by various techniques like powder X-ray diffraction, field emission scanning electron microscopy and high resolution transmission electron microscopy. Li-cycling studies are performed in half-cell assembly to evaluate the optimum mass loading for the fabrication of Li-HEC. A reversible capacity of ∼125 and ∼91 mAh g −1 is noted (current density of 100 mA g −1 ) when LVP-C is employed as cathode (3–4.3 V vs. Li) and anode (1–3 V vs. Li), respectively. Li-HEC is constructed in an organic electrolyte and tested in two configurations, using LVP-C as positive electrode and AC as the negative electrode (LVP-C/AC) and the second one composed of AC as the positive electrode and LVP-C as the negative electrode (AC/LVP-C). The LVP-C/AC and AC/LVP-C Li-HECs delivered maximum energy densities of ∼27 and ∼25 Wh kg −1 , respectively.

We demonstrate the significance of nanostructuring on the reversible Li-insertion into octahedral sites of the nickel substituted spinel Li[Ni 0.5 Mn 1.5 ]O 4 . One dimensional nanofibers (50–250 nm diameter) of the Li[Ni 0.5 Mn 1.5 ]O 4 were prepared by a single spinneret electrospinning and their performance was compared with powders synthesized via a conventional solid state approach. Li-diffusion coefficient of electrospun fibers was an order of magnitude higher (5.8 × 10 −11 cm 2 s −1 ) than that of conventional powders (1.22 × 10 −12 cm 2 s −1 ). Galvanostatic studies revealed a much improved capacity and rate performance for electrospun fibers. The fibers delivered a reversible capacity of ∼87 mAh g −1 after 150 cycles at 1C rate compared to negligible capacity for solid-state prepared material. Finally, the performance of this nanostructured spinel phase as an anode in aqueous rechargeable Li-ion system was demonstrated to require a strongly alkaline electrolyte.

In the present review, we describe the development of a high energy density LIB fabricated with all 1D nanofibers as the anode and cathode, as well as a separator-cum-electrolyte prepared by an electrospinning technique without compromising the power capability and cycle life. Such a unique assembly certainly enables realizing the advantages of using 1D nanostructures in practical LIBs, irrespective of the anode or cathode in the presence of gelled polyvinylidene fluoride-co-hexafluoropropylene as the separator-cum-electrolyte. Outstanding cycling profiles with high power densities were noted for all the configurations evaluated. This excellent performance opens up new avenues for the development of high performance Li-ion power packs with a long cycle life and high energy and power densities to drive zero emission transportation applications in the near future, and opens up new research activities in this field as well.

Outstanding sodium and lithium storage capability is successfully demonstrated in ultrathin NiO nanosheets (4–5 nm in thickness) synthesized via a facile solvothermal process followed by annealing in air. For sodium storage, the NiO nanosheets deliver a high reversible specific capacity of 299 mA h g −1 at a current density of 1 A g −1 , and the capacity still remains up to 154 mA h g −1 at 10 A g −1 . Upon charge/discharge cycling, the specific capacity maintains to be as high as 266 mA h g −1 during the 100th cycle at 1 A g −1 . Such sodium storage capability of NiO nanosheets is by far one of the best reported for transition metal oxides. For lithium storage, the cell achieves a high reversible specific capacity of 1242 and 250 mA h g −1 at 0.2 and 15 A g −1 , respectively. The capacity for lithium storage maintains to be 851 mA h g −1 during the 170th cycle at 2 A g −1 . The present results demonstrate that ultrathin NiO nanosheets are highly attractive for fast sodium/lithium diffusion with high-rate capability for rechargeable sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs).

Aqueous electrolyte-based asymmetric electrochemical capacitors (AECs) are promising in the field of energy storage because of their wider potential windows compared to the symmetric capacitors and higher ionic conductivity compared to the organic electrolytes. Most of the research works on AECs are directed towards cathode materials, while anode materials have rarely been investigated. Herein, a novel AEC is constructed, in which two highly conductive and lightweight graphitic substrates, graphene framework and graphene foam, are hybridized with Fe3O4@C core–shell nanoparticles (anodes) and mesoporous Co(OH)2 nanosheets arrays (NAs) (cathodes), respectively. The as-assembled AEC device shows extended cell voltage (0.0–1.6 V) and excellent cycle stability (72% retention after 8000 cycles). More importantly, a high specific energy of 75 W h kg−1 is achieved at a specific power of 400 W kg−1. Even at a 10.3 s charge/discharge rate, specific energy as high as 33 W h kg−1 can be retained.

Since there has been a notable improvement in the performance of graphene-supported tin-based lithium ion battery anodes, they have become a viable alternative to state of the art graphite anodes. However, currently these anodes are produced by energy-demanding thermal processes and generate lithium chloride or other wastes. In this research, we demonstrate the formation of efficient and stable lithium ion battery anodes based on sodium stannate-coated reduced graphene oxide. Coating is performed at low temperatures and when a sodium peroxostannate precursor is used, the process can be carried out with zero waste discharge. Thermal treatment is required only for the solid material. The anode exhibited a charge capacity of 610 mA h g−1 after 140 cycles at 100 mA g−1. This is the first characterization of a sodium stannate-based anode for LIBs.

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.

3D high surface area porous carbon is seen to form via self assembly of porous graphene sheets by direct pyrolysis of an oligomer salt tailored for the realization of molecular level activation. The oligomer salt was derived from 4-amino benzoic acid as the monomer by a facile free radical polymerization process. Incorporation of the functional groups ( COONa) eliminate the need for any external activating agents (KOH, ZnCl 2 , etc.) and also render high degree of sub-nanoscale homogeneity. This oligomer derived carbon (ODC) exhibits efficient performance in non-aqueous charge storage application namely Li-ion hybrid electrochemical capacitor (Li-HEC) owing to its high surface area, 3D interconnectivity and an appropriate pore size distribution. The Li-HEC fabricated with ODC based electrodes delivered a maximum energy density of ∼63 Wh kg −1 with spinel Li 4 Ti 5 O 12 as the anode.

Research activities on the development of one-dimensional (1D) nanostructures and their successful implementation in the fabrication of high-performance practical Li-ion batteries (LIBs) are described. Although numerous 1D-structured materials have been explored for use in LIBs as anodes, cathodes, and separator-cum-electrolytes, only a very limited number of studies report the practical assembly of LIBs using these components. As a result, the salient features of using 1D materials in charge-storage devices have not been realized from an application perspective. Exceptional battery performance is reported when all-1D-based electro-active materials are used to fabricate LIBs. Using all-1D nanostructures not only provides high power capability, energy density, and durability, it also opens up new avenues for developing high-performance next-generation Li-ion power packs.

Owing to the high theoretical sodiation capacities, intermetallic alloy anodes have attracted considerable interest as electrodes for next-generation sodium-ion batteries (SIBs). Here, we demonstrate the fabrication of intermetallic Fe–Sb alloy anode for SIBs via a high-throughput and industrially viable melt-spinning process. The earth-abundant and low-cost Fe–Sb-based alloy anode exhibits excellent cycling stability with nearly 466 mAh g–1 sodiation capacity at a specific current of 50 mA g–1 with 95% capacity retention after 80 cycles. Moreover, the alloy anode displayed outstanding rate performance with ∼300 mAh g–1 sodiation capacity at 1 A g–1. The crystalline features of the melt-spun fibers aid in the exceptional electrochemical performance of the alloy anode. Further, the feasibility of the alloy anode for real-life applications was demonstrated in a sodium-ion full-cell configuration which could deliver a sodiation capacity of over 300 mAh g–1 (based on anode) at 50 mA g–1 with more than 99% Coulombic efficiency. The results further exhort the prospects of melt-spun alloy anodes to realize fully functional sodium-ion batteries. Accepted version

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.

High energy density Li-ion hybrid electrochemical capacitors (Li-HEC) are fabricated with 3 D architectured high surface area porous carbon (HSPC) derived from the poly(acrylamide-co-acrylic acid) potassium salt in a single step without any activating agent. The obtained HSPC exhibits high specific surface area of 1490 m2 g−1 and characterized with several analytical techniques. Li-HEC is fabricated with insertion type Li4Ti5O12 anode by adjusting the mass balance based on the single electrode performance with Li. The Li-HEC delivered the maximum energy density of ∼55 Wh kg−1, which is much higher than commercially available activated carbon (∼36 Wh kg−1). Further HSPC based Li-HEC delivered excellent cycleability and rendered ∼87% of initial value after 2000 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 loa...

A scalable electrospinning technique is used to synthesize 1D TiO2 nanofibers for Li-ion battery applications. Oxygen deficiency (TiO2−δ) in anatase phases is created by treating the nanofibers in the H2 atmosphere with various temperature conditions. Structural and morphological features of both pure and oxygen deficient phases are analyzed by X-ray diffraction and scanning electron microscopy, respectively. Li-insertion properties of such nanofibers are evaluated in half-cell configuration at high current rate of 150 mA g–1 and found that there is no improvement in the reversible capacity after H2 treatment. Improved cycling profiles are noted for such deficient phases compared with pure TiO2 nanofibers. ac impedance spectra were also conducted to validate the electrical conductivity profiles of the electrospun TiO2 nanofibers.

We report the preparation of highly crystalline Li3V6O16 rods (LVO-1 rods) and their use as anode materials in aqueous rechargeable lithium ion batteries (ARLBs) for the first time. Half-cell ARLBs with LVO-1 as an anode material deliver a higher initial capacity of >120 mA h g−1 at high current rates and a higher round trip efficiency of 52% at the end of 100 cycles at a current density of 500 mA g−1. ARLBs with LVO-1 rods as anodes exhibited an excellent rate and cycling performance.

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.

One dimensional TiO2-B nanorods are synthesized by a conventional hydrothermal approach under highly concentrated alkali hydroxide solutions. Various characterization techniques such as X-ray diffraction, Raman studies, BET surface area measurements, scanning electron microscopy and transmission electron microscopy (TEM) are utilized. Electrochemical Li-insertion properties are evaluated by means of half-cell configuration (Li/TiO2-B) which delivered a discharge capacity of 195 mA h g−1 at a current density of 150 mA g−1 under ambient temperature conditions. The test cell, Li/TiO2-B, displayed good cycling profiles up to 500 cycles with columbic efficiency over 99.5%. Full-cell, LiMn2O4/TiO2-B, is fabricated and tested both in conventional liquid and PVdF-HFP membranes at a current density of 150 mA g−1 and exhibited an excellent cycleability up to 1000 cycles at an operating potential of ∼2.5 V. The results demonstrate the improved electrochemical performance and durability of one dimensional nanostructures i.e. TiO2-B nanorods and electrospun membranes during prolonged cycling. In addition, ex-situ TEM analysis revealed the retention of nanorod morphology along with the crystalline structure after 1000 cycles in full-cell assembly, which ensures excellent long-term cycleability of TiO2-B anodes.

A facile and bottom-up approach has been presented to prepare 2D Ni-MOFs based on cyanide-bridged hybrid coordination polymers. After thermally induced sulfurization and selenization processes, Ni-MOFs were successfully converted into NiS and NiSe2 nanoplates with carbon coating due to the decomposition of its organic parts. When evaluated as anodes of Li-ion batteries (LIBs) and Na-ion batteries (NIBs), NiS and NiSe2 nanoplates show high specific capacities, excellent rate capabilities, and stable cycling stability. The NiS plates show good Li storage properties, while NiSe2 plates show good Na storage properties as anode materials. The study of the diffusivity of Li(+) in NiS and Na(+) in NiSe2 shows consistent results with their Li/Na storage properties. The 2D MOFs-derived NiS and NiSe2 nanoplates reported in this work explore a new approach for the large-scale synthesis of 2D metal sulfides or selenides with potential applications for advanced energy storage.

Exceptional Li-ion battery performance is presented with the oxide component of the anode was extracted from red mud by simple magnetic separation and applied directly without any further processing. The extracted material has γ-Fe2 O3 as the major phase with inter-dispersed phases of Ti, Al, and Si oxides. In a half-cell assembly, the phase displayed a reversible capacity (∼697 mA h g(-1) ) with excellent stability upon cycling. Interestingly, the stability is rendered by the multiphase constitution of the material with the presence of other electrochemically inactive metal oxides, such as Al2 O3 , SiO2 , and Fe2 TiO4 , which could accommodate the strain and facilitate release during the charge-discharge processes in the electrochemically active maghemite component. We fabricated the full-cell assembly with eco-friendly cathode LiMn2 O4 by adjusting the mass loading. Prior to full-cell assembly, an electrochemical pre-lithiation was enforced to overcome the irreversible capacity loss obtained from the anode. The full-cell delivered a capacity of ∼100 mA h g(-1) (based on cathode loading) with capacity retention of ∼61 % after 2000 cycles under ambient conditions.

We report the synthesis and electrochemical performance of one-dimensional TiO2–graphene composite nanofibers (TiO2–G nanofibers) by a simple electrospinning technique for the first time. Structural and morphological properties were characterized by various techniques, such as X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and BET surface area analysis. Lithium insertion properties were evaluated by both galvanostatic and potentiostatic modes in half-cell configurations. Cyclic voltammetric study reveals the Li-insertion/extraction by a two-phase reaction mechanism that is supported by galvanostatic charge–discharge profiles. Li/TiO2–G half-cells showed an initial discharge capacity of 260 mA h g–1 at current density of 33 mA g–1. Further, Li/TiO2–G cell retained 84% of reversible capacity after 300 cycles at a current density of 150 mA g–1, which is 25% higher than bare TiO2 nanofibers under the same test conditions. The cell also exhibits promising high rate behavior with a discharge capacity of 71 mA h g–1 at a current density of 1.8 A g–1.

Hollondite type -MnO2 nanorods are prepared by hydrothermal route at 160 � C for 8 h. The structural and morphological properties are examined by X-ray diffraction, BET surface area, scanning electron microscopy and high resolution transmission electron microscopy. Half-cells (Li/-MnO2) are fabricated to study the Li-cycling behavior in both galvanostaic and potentiostatic modes. The -MnO2 delivers a stable reversible capacity of ∼80 mA h g −1 at constant current 50 mA g −1 up to 50 cycles when cycled between 1.5–3.8 V versus Li. The hybrid electrochemical capacitor is fabricated using -MnO 2 nanorods (as anode) and activated carbon (as cathode) in non-aqueous medium and cycled between 0–3 V. The hybrid electrochemical capacitor exhibited a stable specific discharge capacitance of 28 F g −1 at high current (60 mA g −1 ). Further, hybrid electrochemical capacitor displayed a maximum energy and power densities o f9Whk g −1 and 87 W kg −1

This paper presents an overview of the various types of lithium salts used to conduct Li(+) ions in electrolyte solutions for lithium rechargeable batteries. More emphasis is paid towards lithium salts and their ionic conductivity in conventional solutions, solid-electrolyte interface (SEI) formation towards carbonaceous anodes and the effect of anions on the aluminium current collector. The physicochemical and functional parameters relevant to electrochemical properties, that is, electrochemical stabilities, are also presented. The new types of lithium salts, such as the bis(oxalato)borate (LiBOB), oxalyldifluoroborate (LiODFB) and fluoroalkylphosphate (LiFAP), are described in detail with their appropriate synthesis procedures, possible decomposition mechanism for SEI formation and prospect of using them in future generation lithium-ion batteries. Finally, the state-of-the-art of the system is given and some interesting strategies for the future developments are illustrated.

Nano-size (≤100 nm) TiP 2 O 7 is prepared by the urea assisted combustion synthesis, at 450 and 900 °C. The compound is characterized by powder X-ray diffraction, Rietveld refinement, high resolution transmission electron microscopy and surface area methods. Lithium cycling properties by way of galvanostatic cycling and cyclic voltammetry (CV) showed a reversible and stable capacity of 60 (±3) mAh g −1 (0.5 mole of Li) up to 100 cycles, when cycled at 15 mA g −1 between 2–3.4 V vs. Li. Non-aqueous hybrid supercapacitor, TiP 2 O 7 (as anode) and activated carbon (AC) (as cathode) has been studied by galvanostatic cycling and CV in the range, 0–3 V at 31 mA g −1 and exhibited a specific discharge capacitance of 29 (±1) F g −1 stable in the range, 100–500 cycles. The Ragone plot shows a deliverable maximum of 13 Wh kg −1 and 371 W kg −1 energy and power density, respectively.

Sodium-ion batteries (SIBs) are considered as complementary alternatives to lithium-ion batteries for grid energy storage due to the abundance of sodium. However, low capacity, poor rate capability, and cycling stability of existing anodes significantly hinder the practical applications of SIBs. Herein, ultrathin two-dimensional SnS2 nanosheets (3-4 nm in thickness) are synthesized via a facile refluxing process toward enhanced sodium storage. The SnS2 nanosheets exhibit a high apparent diffusion coefficient of Na(+) and fast sodiation/desodiation reaction kinetics. In half-cells, the nanosheets deliver a high reversible capacity of 733 mAh g(-1) at 0.1 A g(-1), which still remains up to 435 mAh g(-1) at 2 A g(-1). The cell has a high capacity retention of 647 mA h g(-1) during the 50th cycle at 0.1 A g(-1), which is by far the best for SnS2, suggesting that nanosheet morphology is beneficial to improve cycling stability in addition to rate capability. The SnS2 nanosheets also show encouraging performance in a full cell with a Na3V2(PO4)3 cathode. In addition, the sodium storage mechanism is investigated by ex situ XRD coupled with high-resolution TEM. The high specific capacity, good rate capability, and cycling durability suggest that SnS2 nanosheets have great potential working as anodes for high-performance SIBs.

International audience; The development of portable devices, electric vehicles and renewable energies has motivated research works about energy storage for years. Existing lithium-ion batteries cannot reach sufficient energy density to address the needs for such applications. One of the issues limiting the energy density is the low specific capacity of the graphite anode (372 mAh.g$^{-1}$). Mixed-transition metal oxides with a spinel structure (AB$_2$O$_4$$-$A, B transition metals) appear as a promising solution to replace graphite with a higher theoretical capacity (between 750 and 1000 mAh.g$^{-1}$). Nanostructuration of these compounds was studied to maintain mechanical stability and to enhance lithiation kinetics. ZnFe$_2$O$_4$ is an interesting substitute to graphite as the storage mechanism gives rise to a theoretical capacity of 1001 mAh.g$^{-1}$ and among various oxides, ZnFe$_2$O$_4$ is cheap, abundant and non-toxic. Compared with oxides like Fe$_2$O$_3$ , the combination of two transition metals contributes to lower the working voltage vs. Li/Li$^+$ (1.5V for ZnFe$_2$O$_4$ vs. 2.1V for Fe$_2$O$_3$). ZnFe$_2$O$_4$ nanoparticles were synthesized by laser pyrolysis. In this process, an aerosol containing precursors droplets produced by a nebulizer, is flown into the reactor with a carrier gas. In the reactor, a 10.6 $\mu$m-CO$_2$ laser beam decomposes the precursors to obtain nanopowders which are then collected on a filter. The key advantage of laser pyrolysis is the ability to obtain nanomaterials in large scale with a high purity while controlling the grain size with the appropriate parameters. Solutions containing Zn(NO$_3$)$_2$ .6H$_2$O and Fe(NO$_3$)$_3$.9H$_2$O dissolved in deionized water were used for the synthesis of ZnFe$_2$O$_4$ nanoparticles. Ethylene was used as sensitizer gas to absorb the CO$_2$ laser and allow the decomposition of the precursors whereas air and argon were tested as carrier gases. Powders of different morphologies and crystallinities were obtained and characterized by XRD, SEM, EDX, HRTEM and XPS. ZnO and Fe$_2$O$_3$ were also synthesized to compare their electrochemical performances with those of ZnFe$_2$O$_4$. All the results were compared with literature.