Acta Phys. -Chim. Sin. ›› 2006, Vol. 22 ›› Issue (02): 234-238.doi: 10.3866/PKU.WHXB20060221

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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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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