Synthesis and Electrochemical Performance of Li<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> Cathode Materials by Microwave-Assisted Carbothermal Reduction Method

Abstract

The lithium vanadium phosphate (Li3V2(PO4)3) cathode materials were synthesized by microwave- assisted carbothermal reduction method. The effects of microwave heating time and Li/V molar ratio on the structure and electrochemical performance of the prepared samples were investigated. The results show that the perfect crystal growth and good electrochemical performance ( first charge / discharge specific capacity of 160.8 mAh•g-1/151.3 mAh•g-1 and discharge decay rate of 7.90% after 30 cycles ) of the Li3V2(PO4)3 were obtained under the optimal conditions of heating time 11 min and Li/V molar ratio 3.05:2.0. The voltage values appeared at the oxidation and reduction peaks of the cyclic voltammetry curves were proved to be basically consistent with those appeared at the charge / discharge curves. The lithium ion diffusion coefficient was determined to be 2.320 ×10-9 cm2•s-1 by electrochemical impedance spectroscopy and mathematical models derived from simulative equivalent circuit.