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A novel 2Li 3 V 2 (PO 4 ) 3 ·LiV 3 O 8 composite with short rod and thin plate shapes is synthesized through sol–gel method followed by hydrothermal and solid–state reaction. LiV 3 O 8 is used as an additive to improve the capacity of Li 3 V 2 (PO 4 ) 3 . In the composite cathode, active impurity phase Li 0.3 V 2 O 5 is also present, which has little impact on the whole electrochemical properties. The 2Li 3 V 2 (PO 4 ) 3 ·LiV 3 O 8 composite delivers a high initial capacity of 162.8 mAh g −1 at a current density of 100 mA g −1 in the voltage range of 2.0–4.3 V. Furthermore, the composite with high crystallinity also shows high electrochemical reversibility and good rate capability. The diffusion coefficient of Li ions in the composite is in the range of 10 −11 –10 −9 cm 2 s −1 obtained from galvanostatic intermittent titration technique. [ABSTRACT FROM AUTHOR]

Abstract: LiVO3 materials are synthesized by combustion method with oxalic acid as fuel. Owing to its relatively low crystallization and small particle size, the LiVO3 calcined at 450 °C for 2 h displays optimal electrochemical performances, delivering a high discharge capacity of 298.4 mAh g−1 and 262.5 mAh g−1 between 1.0 and 3.5 V at a current density of 50 mA g−1 and 500 mA g−1 respectively, and exhibiting good cyclic stability. In this work, the chemical diffusion coefficient of Li+ (D Li+) in the LiVO3 electrode is determined by electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT). The value calculated by EIS is in the range of 10−9–10−8 cm2 s−1, while it calculated by GITT is 10−9.5–10−8 cm2 s−1. [Copyright &y& Elsevier]

Abstract: Surface modified-LiV3O8 cathode materials with Al2O3 are successfully synthesized via a facile thermolysis process. The 0.5 wt.% Al2O3-coated LiV3O8 exhibits an enhanced cyclic stability at various charge–discharge current densities. At a current density of 100 mA g−1, it delivers an initial specific discharge capacity of 283.1 mAh g−1 between 2.0 and 4.0 V. Moreover, high capacities of 139.4 and 118.5 mAh g−1 are obtained at the 100th cycle at current densities of 2000 and 3000 mA g−1, respectively. The improved electrochemical performance is attributed to the Al2O3 coating, which can hinder the irreversible phase transformation and act as a protective layer to prevent the active material from direct contact with electrolyte. Furthermore, the formation of a Li–V–Al–O solid solution at the LiV3O8/Al2O3 interface provides a fast Li+ diffusion path which is of benefit to the electrochemical behaviors. [Copyright &y& Elsevier]

Abstract: LiVO3 is synthesized via a ball-milling route followed by a solid-state reaction at different temperatures. As cathode materials for lithium ion batteries, the electrochemical performances of LiVO3 are investigated by galvanostatic charge–discharge test and electrochemical impedance spectroscopy (EIS). The LiVO3 compound synthesized at 350 °C possesses the optimal performance, delivering an initial discharge capacity of 302.5 mAh g−1 between 1.0 V and 3.5 V at a current density of 50 mA g−1, and exhibiting a good cycling stability. Li-ion diffusion coefficient of 10−9.5–10−8 cm2 s−1 in the LiVO3 electrode is calculated by galvanostatic intermittent titration technique (GITT). The good performances can be attributed to its relatively low crystallization and small particle size. [Copyright &y& Elsevier]

Abstract: A NiO–graphene hybrid is synthesized by a liquid phase deposition method. As an anode material for lithium ion batteries, the cyclic stability and rate capability of NiO is significantly improved after the incorporation of graphene sheets. The NiO–graphene hybrid electrode delivers a capacity of 646.1mAhg−1 after 35cycles at a current density of 100mAg−1, corresponding to 86.3% capacity retention. When the current density is increased to 400 and 800mAg−1, it still maintains a capacity of 509 and 368.5mAhg−1, respectively. The thermodynamic and kinetic properties of NiO electrodes with and without graphene are investigated by galvanostatic intermittent titration technique. The relationship between the rate and voltage hysteresis is also discussed. The polarization of both the electrodes in all cases obeys ohmic rule in the present rate range. The incorporation of graphene sheets can partly reduce the voltage polarization thereby the voltage hysteresis with increasing the current density. However, the extrapolation to zero current ends up in an approximate residual voltage for both the NiO electrodes. [Copyright &y& Elsevier]