Carbon coated Li3V2(PO4)3 from the single-source precursor, Li2(VO)2(HPO4)2(C2O4)•6H2O as cathode and anode materials for Lithium ion batteries

Monoclinic phase of Li3V2(PO4)(3) has been synthesized by thermal decomposition of a single source precursor, Li-2(VO)(2)(HPO4)(2)(C2O4)center dot 6H(2)O. This lithium vanadyl oxalatophosphate was obtained by a hydrothermal reaction at 120 degrees C and subsequent annealing at 800 degrees C in Argon atmosphere resulted in Li3V2(PO4)(3)-V2O3 composite material. Carbon coating has been achieved by the addition of sucrose to the precursor prior to thermal decomposition. Lithium intercalation/de-intercalation in the compound has been studied at different voltage ranges using galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy studies. The carbon coated sample has a BET surface area of 75 m(2) g(-1) and it shows good capacity retention in the voltage range of 2.5-4.3 V. In comparison, pristine Li3V2(PO4)(3) which has a lesser surface area of 5.4 m(2) g(-1) shows inferior electrochemical performance. Stable reversible lithium insertion into Li3V2(PO4)(3) forming Li5V2(PO4)(3) has also been observed when cycled in the voltage range of 1-3 V. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.