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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This is the first report of the utilization of TiNb2O7 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 TiNb2O7 nanofibers that can be characterized by XRD with Rietveld refinement, SEM, and TEM. The lithium insertion properties of such electrospun TiNb2O7 are evaluated in the half-cell configuration (Li/TiNb2O7) 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 TiNb2O7 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/TiNb2O7 Li-HEC delivers a good cyclability of 3000 cycles with about 84 % of the initial value. [ABSTRACT FROM AUTHOR]

The synthesis of carbon-coated Li3Nd3W2O12 (C-Li3Nd3W2O12), a low voltage insertion anode (0.3 V vs. Li) for a Li-ion battery, is reported to exhibit extraordinary performance. The low voltage reversible insertion provides an increase in the energy density of Li-ion power packs. For instance, C-Li3Nd3W2O12 delivered an energy density of ≈390 Wh kg−1 (based on cathode mass loading) when coupled with an LiMn2O4 cathode with an operating potential of 3.4 V. Furthermore, excellent cycling profiles are observed for C-Li3Nd3W2O12 anodes both in half and full-cell configurations. The full-cell is capable of delivering very stable cycling profiles at high current rates (e.g., 2 C), which clearly suggests the high power capability of such garnet-type anodes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we report the influence of carbon coating on the electrochemical performance of hollow structured SnO2 electrospun nanofibers. The electrospun nanofibers are subjected to plasma enhanced chemical vapour deposition for a conformal carbon coating of ∼6nm 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. 0.005-0.8V and 0.005-2.5V 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 SnO2, 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 SnO2 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. [Copyright &y& Elsevier]

Prelithiated, electrospun α-Fe 2 O 3 nanofibers display an exceptional cycleability when it is paired with commercial LiMn 2 O 4 cathode in full-cell assembly. The performance of such α-Fe 2 O 3 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.

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.

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., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)