Effect of Sintering Process on Structure and Electrochemical Performances of Li₃V₂（PO₄）₃/C Cathode Material for Lithium Ion Batteries

Lithium vanadium phosphate（Li₃V₂（PO₄）₃） has become a potential and promising lithium ion battery cathode material due to its high energy density,good structural stability,safety performance and low temperature performance.The Li₃V₂（PO₄）₃/C samples were synthesized by carbothermal reduction method from ball-milling mixture of stoichiometric LiOH·H₂O,V₂O₅,NH₄H₂PO₄ and citric acid.The effects of calcination temperature and time on the structure and electrochemical properties of Li₃V₂（PO₄）₃ cathode materials were investigated by XRD and galvanostatic charge/discharge measurement.The optimum calcination process parameters for monoclinic Li₃V₂（PO₄）₃ cathode materials with excellent performances were obtained by several experiments.The results show that the Li₃V₂（PO₄）₃/C sample synthesized at 850 ℃ for 10 h has the most stable structure and the best electrochemical properties,respectively with the discharge capacity of 119 mAh/g for initial cycle and 118.7 mAh/g after 15 cycles,at 0.1 C and 3.0 ～ 4.3 V.The retention rate of discharge capacity is about 99.7%.