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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (2): 104-108. 上一篇    下一篇

研究论文

AlF3包覆LiNi0.45Mn0.45Co0.10O2锂离子电池正极材料的结构表征和 电化学性能研究

林和成a,b 杨 勇*,a

  

  1. (a厦门大学化学系 固体表面物理化学国家重点实验室 厦门 361005)
    (b湖南科技学院生命科学与化学工程系 永州 425006)

  • 投稿日期:2008-07-07 修回日期:2008-08-26 发布日期:2009-01-28
  • 通讯作者: 杨勇

Structural Characterization and Electrochemical Performance of AlF3-coated LiNi0.45Mn0.45Co0.10O2 as Cathode Materials for Lithium Ion Batteries

Lin, Hecheng a,b Yang, Yong *,a

  

  1. (a State Key Laboratory of Physical Chemistry and Department of Chemistry, Xiamen University, Xiamen 361005)
    (b Department of Biological Science and Chemical Engineering, Hunan University of Science and Engineering, Yongzhou 425006)
  • Received:2008-07-07 Revised:2008-08-26 Published:2009-01-28
  • Contact: Yang, Yong

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通过共沉淀与固相反应法制备层状的LiNi0.45Mn0.45Co0.10O2, 并利用X射线衍射(XRD)和电子扫描显微镜(SEM)测定材料的结构和形貌. 在2.5～4.5 V范围内, 以0.1 C (28 mA•g－1)放电, LiNi0.45Mn0.45Co0.10O2正极材料的起始放电容量达到167.2 mAh•g－1, 但循环性能较差. 当采用AlF3包覆后, 材料的循环性能得到明显改善. 利用电化学阻抗谱(EIS)技术探索AlF3包覆对正极材料的电化学性能改善机理, 实验结果表明: AlF3包覆层能够阻止电解液对正极材料的溶解和侵蚀, 稳定其层状结构, 同时降低了电极界面阻抗. 因此AlF3包覆技术是一种改善LiNi0.45Mn0.45Co0.10O2材料电化学性能的有效方法和工具.

关键词: LiNi0.45Mn0.45Co0.10O2, AlF3, 正极材料, 锂离子电池

In this paper, layered-LiNi0.45Mn0.45Co0.10O2 was prepared by co-precipitation and solid state reaction methods. The crystal structures and morphology of the materials were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The LiNi0.45Mn0.45Co0.10O2 sample delivered the initial discharge capacity of 167.2 mAh•g－1 at 28 mA•g－1 (0.1 C) in the range of 2.5 to 4.5 V, but the cycle-life performance was relatively bad, which could be remarkably improved by AlF3 surface coating. Electrochemical impedance spectroscopy (EIS) was used to understand the possible mechanisms of improved electrochemical properties by the AlF3 coating. The results demonstrate that these coating layers could protect the dissolution and corrosion of LiNi0.45Mn0.45Co0.10O2 cathode materials in electrolyte, stabilize its layered-structure and reduce interface impedance. Therefore, the AlF3 coating technique is an effective method and tool to improve the electrochemical properties of LiNi0.45Mn0.45Co0.10O2 cathode material.

Key words: LiNi0.45Mn0.45Co0.10O2, AlF3, coating, cathode material, lithium-ion battery