物理化学学报 >> 2006, Vol. 22 >> Issue (02): 234-238.doi: 10.3866/PKU.WHXB20060221

研究简报 上一篇    下一篇

尖晶石锂锰氧化物电极首次脱锂过程的EIS研究

庄全超; 樊小勇; 许金梅; 陈作锋; 董全峰; 姜艳霞; 黄令; 孙世刚   

  1. 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； 厦门大学宝龙电池研究所, 厦门 361005； 西北核技术研究所, 西安 710024
  • 收稿日期:2005-07-11 修回日期:2005-09-11 发布日期:2006-01-22
  • 通讯作者: 孙世刚 E-mail:sgsun@xmu.edu.cn

Electrochemical Impedance Spectroscopic Study of the First Delithiation of Spinel Lithium Manganese Oxide

ZHUANG Quan-chao; FAN Xiao-yong; XU Jin-mei; CHEN Zuo-feng; DONG Quan-feng; JIANG Yan-xia; HUANG Ling; SUN Shi-gang   

  1. Department of Chemistry, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, P. R. China； Xiamen University-Powerlong Battery Research Institute, Xiamen 361005, P. R. China； Northwest Institute of Nuclear Technology, Xi′an 710024, P. R. China
  • Received:2005-07-11 Revised:2005-09-11 Published:2006-01-22
  • Contact: SUN Shi-gang E-mail:sgsun@xmu.edu.cn

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摘要： 研究了尖晶石锂锰氧化物电极首次脱锂过程中的电化学阻抗特征. 通过选取适当的等效电路拟合实验所得的电化学阻抗谱数据, 获得了首次脱锂过程中固体电解质相界面膜(SEI膜)的电阻、电容以及电荷传递电阻、双电层电容等随电极极化电位的变化规律.

关键词: 锂离子电池, 尖晶石锂锰氧化物电极, 电化学阻抗谱, SEI膜

Abstract: The first delithiation of the spinel LiMn2O4 electrode was studied using electrochemical impedance spectroscopy (EIS). Appropriate equivalent circuits were proposed to fit the experimental EIS data. Based on the fitting results, the variation of the capacitance and the resistance of SEI (solid electrolyte interphase) film, the resistance of charge transfer, and the capacitance of double layer along with the increase of polarization potential were quantitatively analyzed. The results demonstrated that the resistance and the thickness of the SEI film formed on the spinel LiMn2O4 electrode were both increased with the increase of polarization potential in the first delithiation of the spinel LiMn2O4 electrode; The charge transfer resistance decreases below 4.15 V and increases above 4.15 V, corresponding to the two-step reversible (de)intercalation of lithium between LiMn2O4 and λ-MnO2; The double layer capacitance was influenced by both the state of the spinel LiMn2O4 electrode(different polarization potential) and the two-step reversible (de)intercalation of lithium.

Key words: Li-ion batteries, Spinel lithium manganese oxide electrode, Electrochemical impedance spectroscopy, SEI film