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

摘要

LiVPO4F was synthesized by a novel sol-gel method under Ar atmosphere using V2O5·nH2O,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 0.8μm together with homogenous distribution.The optimal sintering temperature and sintering time are 600℃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.