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过程工程学报 ›› 2015, Vol. 15 ›› Issue (3): 511-517.DOI: 10.12034/j.issn.1009-606X.215179

• 材料工程专栏 • 上一篇    下一篇

Electrochemical Behavior of La-doped LiFePO4/C Cathode Materials for Lithium Ion Batteries

王山 杨海涛 张立博 许洪亮 石丽丽   

  1. 中国科学院过程工程研究所多相复杂系统国家重点实验室 中国科学院过程工程研究所多相复杂系统重点实验室 中国科学院过程工程研究所多相复杂系统重点实验室 北京理工大学化工与环境学院 北京理工大学化工与环境学院
  • 收稿日期:2015-04-02 修回日期:2015-05-04 出版日期:2015-06-20 发布日期:2015-06-20
  • 通讯作者: 王山

Electrochemical Behavior of La-doped LiFePO4/C Cathode Materials for Lithium Ion Batteries

WANG Shan YANG Hai-tao ZHANG Li-bo XU Hong-liang SHI Li-li   

  1. State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences Beijing Key Laboratory of Environmental Science and Engineering, School of Chemical Engineering and Environment, Beijing Institute of Technology Beijing Key Laboratory of Environmental Science and Engineering, School of Chemical Engineering and Environment, Beijing Institute of Technology
  • Received:2015-04-02 Revised:2015-05-04 Online:2015-06-20 Published:2015-06-20
  • Contact: WANG Shan

摘要: Alien atom was used to obtain a series of LiFe1-xLaxPO4/C (x=0, 0.002, 0.005, 0.01, 0.015) cathode materials with the aim of investigating the influence of participation of La on the electrochemical behavior of LiFePO4/C. Combination of X-ray diffractometer, scanning electron microscope equipped with energy dispersive spectrometer and high resolution transmission electron microscope was applied. The results show that all the La-doped LiFePO4/C samples are olivine type crystals, La ion is sufficiently introduced into the network, and every element is well homogeneously distributed. There are many pore spaces on the surface of particles. The content of carbon in the prepared cathode materials remains 13.6% calculated by TGA/DTA curves, and the particles are wrapped by a uniformly and continuous carbon layer with the thickness of about 2 nm. Similarly, the content of Fe2P also keeps the same basically in all the cathode materials as a result of the similar ratio (2.35) of peak intensity at 36.5o and 37.1o from XRD. The increasing trend is most pronounced at doped 0.005 which presents the highest initial discharge capacity of 163 mA×h/g, lowest charge transfer resistance of 5.52 W, superior diffuse ability of lithium ion (10-11 cm2/s) and the best capacity retention current rate of about 93% after 50 cycles at 0.1 C.

关键词: LiFePO4, cathode material, lanthanum doping, lithium ion battery

Abstract: Alien atom was used to obtain a series of LiFe1-xLaxPO4/C (x=0, 0.002, 0.005, 0.01, 0.015) cathode materials with the aim of investigating the influence of participation of La on the electrochemical behavior of LiFePO4/C. Combination of X-ray diffractometer, scanning electron microscope equipped with energy dispersive spectrometer and high resolution transmission electron microscope was applied. The results show that all the La-doped LiFePO4/C samples are olivine type crystals, La ion is sufficiently introduced into the network, and every element is well homogeneously distributed. There are many pore spaces on the surface of particles. The content of carbon in the prepared cathode materials remains 13.6% calculated by TGA/DTA curves, and the particles are wrapped by a uniformly and continuous carbon layer with the thickness of about 2 nm. Similarly, the content of Fe2P also keeps the same basically in all the cathode materials as a result of the similar ratio (2.35) of peak intensity at 36.5o and 37.1o from XRD. The increasing trend is most pronounced at doped 0.005 which presents the highest initial discharge capacity of 163 mA×h/g, lowest charge transfer resistance of 5.52 W, superior diffuse ability of lithium ion (10-11 cm2/s) and the best capacity retention current rate of about 93% after 50 cycles at 0.1 C.

Key words: LiFePO4, cathode material, lanthanum doping, lithium ion battery

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