Synthesis of LiVPO 4F with high electrochemical performance by sol-gel route

Abstract

LiVPO 4F was synthesized by a novel sol-gel method under Ar atmosphere using V 2O 5· nH 2O, LiF, NH 4H 2PO 4, 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 LiVPO 4F displays a triclinic structure with a space group of p ▪. The SEM results indicate that the particle size of LiVPO 4F is about 0.8 μm together with homogenous distribution. The optimal sintering temperature and sintering time are 600 °C and 20 h, respectively, in order to obtain pure triclinic LiVPO 4F with good electrochemical performance. LiVPO 4F 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 LiVPO 4F cathode materials with good electrochemical performance for lithium ion batteries.