Influence of Y^3＋ doping on structure and electrochemical performance of layered Li1.05V3O8

• Published in: Transactions of Nonferrous Metals Society of China Vol. 17; no. 1; pp. 110 - 115
• Main Author: 刘丽英 田彦文 翟玉春 徐茶清
• Format: Journal Article
• Language: English
• Published: 2007
• Subjects: 导电性; 循环伏安图; 电化学; 锂电池
• ISSN: 1003-6326

LiOH.H2O, V2O5 and Y（NO3）3 were used as raw materials to synthesize the precursors containing Li, V and Y by liquid-state reaction, then the cathode materials Li1.05YxV3-xO8 （x=0, 0.002 5, 0.005, 0.01, 0.02, 0.1, 0.2） for lithium-ion battery were obtained by calcining the precursors. The influence of y^3＋ doping on structure, conductivity and electrochemical performance of Li1.05V3O8 were investigated by using XRD, cyclic voltammograms, AC impedance, etc. The results show that Li1.05YxV3-xO8 with different doping amounts have well-developed crystal structure of layered Li1.05V3O8 and lengthened interlayer distance of （100） crystal plane, y^3＋ can insert into crystal lattice completely when the doping amount is small and the impurity phase of YVO4 is found when x≥0.1. There is no change in the process of Li^＋ insertion-deinsertion with y^3＋ doping. The conductivity is clearly improved due to small amount of y^3＋ doping and it tends to increase first and then decrease with increasing doping amount. The initial discharge capacity and plateau potential are both enhanced with proper amount of y^3＋ doping. When x is 0.005, the first specific discharge capacity reaches 288.9 mA·h/g, 4.60 % larger than that of undoped sample （276.2 mA·h/g）. When x≤0.1, the average discharge plateau potentials are enhanced by about 0.15 V, which makes for higher energy density.