Carbon coated Li3V2(PO4)3 from the single-source precursor, Li2(VO)2(HPO 4)2(C2O4)·6H2O as cathode and anode materials for Lithium ion batteries

Abstract

Monoclinic phase of Li3V2(PO4)3 has been synthesized by thermal decomposition of a single source precursor, Li2(VO)2(HPO4)2(C2O 4)·6H2O. This lithium vanadyl oxalatophosphate was obtained by a hydrothermal reaction at 120 °C and subsequent annealing at 800 °C in Argon atmosphere resulted in Li3V2(PO 4)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 m2 g-1 and it shows good capacity retention in the voltage range of 2.5-4.3 V. In comparison, pristine Li3V2(PO 4)3 which has a lesser surface area of 5.4 m2 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. © 2013 Published by Elsevier Ltd. All rights reserved.