Synthesis of LiVPO4F with high electrochemical performance by sol-gel route

LiVPO4F was synthesized by a novel sol-gel method under Ar atmosphere using V2O5 center dot nH(2)O, LiF, NH4H2PO4, and citric acid as starting materials, and its physicochemical properties were characterized using X-ray diffractometry ( XRD), SEM, and electrochemical methods. The XRD patterns show that LiVPO4F displays a triclinic structure with a space group of p1. The SEM results indicate that the particle size of LiVPO4F is about 0.8 mu m together with homogenous distribution. The optimal sintering temperature and sintering time are 600 degrees C and 20 h, respectively, in order to obtain pure triclinic LiVPO4F with good electrochemical performance. LiVPO4F has the discharge capacity of 134 mA.h/g in the range of 3.0-4.4 V at the first cycle, and the discharge capacity remains 125 mA.h/g after 30 cycles. The sol-gel method is suitable for the preparation of LiVPO4F cathode materials with good electrochemical performance for lithium ion batteries.