物理化学学报 >> 2004, Vol. 20 >> Issue (06): 582-586.doi: 10.3866/PKU.WHXB20040606

研究论文 上一篇    下一篇

铬离子掺杂对LiFePO4电化学性能的影响

倪江锋;周恒辉;陈继涛;苏光耀   

  1. 北京大学化学与分子工程学院，北京　100871；湘潭大学化学学院，湘潭　411105
  • 收稿日期:2003-12-10 修回日期:2004-02-05 发布日期:2004-06-15
  • 通讯作者: 周恒辉 E-mail:hhzhou@chem.pku.edu.cn

Effect on the Electrochemical Performance of Lithium Iron Phosphate by Cr3＋ Ion Doping

Ni Jiang-Feng;Zhou Heng-Hui;Chen Ji-Tao;Su Guang-Yao   

  1. College of Chemistry and Molecular Engineering, Peking University, Beijing　100871;College of Chemistry, Xiangtan University, Xiangtan　411105
  • Received:2003-12-10 Revised:2004-02-05 Published:2004-06-15
  • Contact: Zhou Heng-Hui E-mail:hhzhou@chem.pku.edu.cn

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摘要： 采用机械球磨和共沉淀的方法合成了两种Cr3＋掺杂的LiFePO4. 通过对合成样品的XRD、SEM及其电化学性能（循环性能、大电流放电性能）的研究表明，少量Cr3＋的掺杂未影响到LiFePO4的晶体结构，但显著改善了它的电化学性能，在低放电倍率（0.1 C）时，机械球磨掺杂和共沉淀掺杂Cr3＋的LiFePO4的放电容量分别为144和158 mAh•g－1，而当放电倍率提高到2 C时，两种掺杂的LiFePO4仍分别具有110和130 mAh•g－1的放电容量，且循环性能良好.同时表明通过铁源共沉淀掺杂是一条改善离子掺杂效果的有效途径.

关键词: 磷酸亚铁锂, 共沉淀, 离子掺杂, 电子导电率, 嵌锂容量, 正极材料

Abstract: Two different methods(mechanical ball-milling and co-precipitation)were applied to prepare lithium iron phosphate(LiFePO4) containing low concentration(1％, mole fraction) Cr3＋ ion dopant. The samples were characterized by X-ray diffraction and scanning electron microscope, and their electrochemical performances were investigated including cycling behavior and large current discharging. The results indicate that the Cr3＋ ion dopant does not affect the structure of the material but considerably improves its kinetics in terms of capacity delivery and cycle performance. At a low discharging rate (0.1 C), LiFePO4 samples doping via mechanical ball-milling and co-precipitation are capable of delivering reversible specific capacities of 144 mAh•g－1 and 158 mAh•g－1 respectively, with fairly stable cycleability. Even at a 2 C discharging rate, they can show capacities of 110 mAh•g－1 and 130 mAh•g－1 respectively, too. The results also confirm that doping via co-precipitation with Fe sources is an effective method to improve the ion doping effect.

Key words: Lithium iron phosphate, Co-precipitation, Ion doping, Electronic conductivity, Lithium intercalation capacity, Positive electrode material