Synthesis and characterization of triclinic structural LiVPO4F as possible 4.2 V cathode materials for lithium ion batteries
来源期刊：中南大学学报(英文版)2007年第3期
论文作者：钟胜奎 尹周澜 王志兴 陈启元
文章页码：340 - 343
Key words：lithium ion batteries; cathode material; LiVPO4F; carbon-thermal reduction method
Abstract: A potential 4.2 V cathode material LiVPO4F for lithium batteries was prepared by two-step reaction method based on a carbon-thermal reduction (CTR) process. Firstly, V2O5, NH4H2PO4 and acetylene black are reacted under an Ar atmosphere to yield VPO4. The transition-metal reduction is facilitated by the CTR based on C→CO transition. These CTR conditions favor stabilization of the vanadium as V3+ as well as leaving residual carbon, which is useful in the subsequent electrode processing. Secondly, VPO4 reacts with LiF to yield LiVPO4F product. The property of the LiVPO4F was investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and electrochemical measurement. XRD studies show that LiVPO4F synthesized has triclinic structure(space group ), isostructural with the naturally occurring mineral tavorite, LiFePO4·OH. SEM image exhibits that the particle size is about 2 μm together with homogenous distribution. Electrochemical test shows that the initial discharge capacity of LiVPO4F powder is 119 mA.h/g at the rate of 0.2C with an average discharge voltage of 4.2V (vs Li/Li+), and the capacity retains 89 mA.h/g after 30 cycles.
基金信息：the National Natural Science Foundation of China
