( 1. 广西大学 化学化工学院, 南宁 530004；
2. 中国地质科学院 盐湖中心， 北京 100037)
摘 要: 为提高LiFePO4的充放电性能， 用Ni2+对LiFePO4进行掺杂。 采用电化学方法测量了Li1-xNixFePO4的充放电性能， 用X射线衍射和里特沃尔特方法表征了掺杂LiFePO4的晶体结构。 固相反应可制备单相
Li1-xNixFePO4 (x=0.00、 0.01、 0.02、 0.03、 0.05和0.07， 摩尔分数)。 研究表明： 少量镍离子掺杂能有效地提高LiFePO4的比容量和循环性能， 其中Li0.97Ni0.03FePO4具有更好的电化学性能， 放电比容量高出LiFePO4约30 mA·h/g， 其主要原因是镍离子掺杂不仅改变了晶体中原子间距离和位置， 引起晶胞收缩； 而且增加了LiFePO4中Fe3+/Fe2+共存态的浓度， 提高了材料的导电能力。
关键字: LiFePO4； 锂离子电池； 正极材料； 镍掺杂
（ 1. School of Chemistry and Chemical Engineering, Guangxi University,
Nanning 530004, China;
2. Research and Development Center of Saline Lake and Epithermal Deposits, Chinese Academy of Geological Science, Beijing 100037, China）
Abstract: To improve the performance of LiFePO4, single phase Li1-xNixFePO4 was prepared by solid state reaction (x=0.00, 0.01, 0.02, 0.03, 0.05 and 0.07, mole fraction). Crystal structure and charge/discharge performance of doped LiFePO4 were investigated by X-ray diffractrometry with the Rietveld method and electrochemical measurement, respectively. The results show that Ni2+ doping with low concentration can increase the capacity and cycle performances of LiFePO4, and Li0.97Ni0.03FePO4 has better performance than the others, whose discharge capacity is 30 mA·h/g higher than LiFePO4. Because Ni2+ doping not only causes the change of atomic position and distance and the shrinkage of crystal cell, but also increases the concentration of coexisted Fe3+/Fe2+ in LiFePO4， which increases the electrical conductivity of LiFePO4.
Key words: LiFePO4; lithium-ion battery; cathode material; Ni2+ doping
