Preparation and electrochemical studies of Li3V2(PO4)3/Cu composite cathode material for lithium ion batteries

Li3V2(PO4)(3)/Cu composite cathode material was prepared via sol-gel method by adding of 1.8 wt% Cu powder into the precursor solution. The structural and physical properties, as well as the electrochemical performance of the material were compared with those of Cu-free Li3V2(PO4)(3). X-ray diffraction showed that Cu did not enter the crystal structure of Li3V2(PO4)(3). The Li3V2(PO4)(3)/Cu composite material had a higher electronic conductivity comparing with that of Cu-free Li3V2(PO4)(3). Electrochemical impedance spectroscopy showed that the adding of Cu decreased the charge transfer resistance of the electrode. In addition, the lithium diffusion coefficient was prominently enhanced from 1.3 x 10(-9) to 2.8 x 10(-8) cm(2) s(-1). Based on the these advantages, the Li3V2(PO4)(3)/Cu composite material exhibited much better cycling performance than the Cu-free Li3V2(PO4)(3). (C) 2009 Elsevier B.V. All rights reserved.