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无机材料学报

无机材料学报

• 研究论文 • 上一篇    下一篇

钛离子掺杂对LiFePO4结构和性能的影响

文衍宣1, 郑绵平2, 童张法1, 粟海锋1, 薛敏华1   

  1. 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
  • 收稿日期:2004-12-20 修回日期:2005-02-28 出版日期:2006-01-20 网络出版日期:2006-01-20

Effect of Ti4+ Ion Doping on the Performance and Structure of Lithium Iron Phosphate

WEN Yan-Xuan1, ZHENG Mian-Ping2, TONG Zhang-Fa1, SU Hai-Feng1, XUE Min-Hua1   

  1. 1. School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China; 2. R&D Center of Saline Lake and Epithermal Deposits, Chinese Academy of Geological Science, Beijing 100037, China
  • Received:2004-12-20 Revised:2005-02-28 Published:2006-01-20 Online:2006-01-20

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摘要： 为提高LiFePO4的充放电性能, 用Ti(Ⅳ)对LiFePO4进行掺杂. 用电化学方法测量了Li1-xTixFePO4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
可以制备单相Li1-xTixFePO4(x=0.00、0.01、0.02、0.03、0.05和0.07, 摩尔分数), 其中Li0.98Ti0.02FePO4具有更好的电化学性能, 在80mA/g的充放电电流下, 第2次的放
电比容量为136.606mAh/g, 循环20次后为128.388mAh/g. 研究表明, 少量钛离子掺杂不仅改变了原子间距和位置、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, 从而能有效地提高LiFePO4的比容量和循环性能.

关键词: 锂离子电池, 正极材料, LiFePO4

Abstract: In order to improve the performance of LiFePO4, Li1-xTixFePO4(x=0.00, 0.01, 0.02, 0.03, 0.05 and 0.07,mol fraction) with Ti(Ⅳ) dopant was prepared. Crystal structure and charge/discharge
performance of Ti(Ⅳ) doped LiFePO4 were investigated by X-ray diffraction using the Rietveld method and electrochemical measurement, respectively. Single phase Li1-xTixFePO4
can be prepared by solid state reaction. Li0.98Ti 0.02FePO4 shows higher capacity than LiFePO4 through the research on Li1-xMxFePO4. As Li0.98Ti0.02PO4 is
charged and discharged at 80mA/g, its 2nd and 20th discharge capacity is 136.606 and 128.388mAh/g, respectively. The results show that low concentration Ti(Ⅳ) dopant can increase
the capacity and cycle performances of LiFePO4. because it 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: lithium ion battery, cathode material, LiFePO4

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