Electrochemical Performances of Yttrium Doped Li3V2–XYX(PO4)3/C Cathode Material for Lithium Secondary Battery

Abstract

In this study, the Li3V2–X YX(PO4)3 compounds have been synthesized by a simple solid state method. In addition, a polyurethane was added to apply carbon coating on the surface of the Li3V2–X YX(PO4)3 particles for enhancement of the electrical conductivity. The crystal structure and morphology of the synthesized Li3V2–XYX(PO4)3/C (LVYP/C) was investigated using an X-ray diffraction (XRD) and a scanning electron microscopy (SEM) systematically. The electrochemical performance of synthesized material, such as the initial capacity, rate capability, cycling performance and EIS was evaluated. The sizes of synthesized particle ranged from 1 to 5 μm. The Li3V2–XYX(PO4)3/C (X = 0.02) delivered the initial discharge capacity of 171.5 mAh · g–1 at 0.1C rate. It showed a capacity retention ratio of 73.0% at 1.0C after 100th cycle. The electrochemical impedance spectroscopies (EIS) results revealed that the charge transfer resistance of the material decreases by Y doping.