高等学校化学学报 ›› 2005, Vol. 26 ›› Issue (11): 2073.

• 研究论文 • 上一篇    下一篇

锂离子电池电解液中甲醇杂质对石墨电极性能影响机制的电化学阻抗谱研究

庄全超1,3, 陈作锋1, 董全峰1,2, 姜艳霞1, 周志有1, 孙世刚1   

  1. 1. 固体表面物理化学国家重点实验室,厦门大学化学系,厦门361005;
    2. 厦门大学宝龙电池研究所,厦门361005;
    3. 西北核技术研究所,西安710024
  • 收稿日期:2004-12-29 出版日期:2005-11-10 发布日期:2005-11-10
  • 基金资助:

    国家“九七三”计划项目(批准号:2002CB211804)资助

Effects of Methanol Contaminant in Electrolyte on Performance of Graphite Electrodes for Li-ion Batteries Studied via Electrochemical Impedance Spectroscopy

ZHUANG Quan-Chao1,3, CHEN Zuo-Feng1, DONG Quan-Feng1,2, 1, JIANG Yan-Xia1, ZHOU Zhi-You1   

  1. 1. State Key Lab for Physical Chemistry of Solid Surfaces,Department of Chemistry,Xiamen University,Xiamen 361005,China;
    2. Powerlong Battery Research Institute,Xiamen University,Xiamen 361005, China;
    3. Northwest Institute of Nuclear Technology,Xi'an 710024,China
  • Received:2004-12-29 Online:2005-11-10 Published:2005-11-10

摘要: 运用电化学阻抗谱和循环伏安法研究了在1mol/LLiPF6-EC/DEC/DMC电解液中,不同甲醇杂质含量对石墨电极性能的影响及其机制.结果表明,甲醇对石墨电极性能的影响与电解液中甲醇的含量有关;其对石墨电极性能的影响机制为甲醇在2.0V左右还原生成的甲氧基锂沉积在石墨电极表面上,形成一层初始SEI膜,影响了EC的还原分解成膜过程.

关键词: 锂离子电池, 石墨电极, 电解液, 甲醇杂质, 电化学阻抗谱

Abstract: Electrochemical performance of graphite electrode cycled vs.Li in 1 mol/L LiPF6-EC/DEC/DMC(1:1:1, volume ratio) electrolyte solution,which contains different concentrations of methanol,was investigated by cyclic voltammetry and electrochemical impedance spectroscopy(EIS) in the process of first lithiation.It was demonstrated that methanol contaminant caused the deterioration of the electrochemical performance of graphite electrodes,which depends markedly on the concentration of methanol.Based on the experimental results and analysis,a mechanism of the deterioration of the electrochemical performance of graphite electrode caused by methanol contaminant was proposed.The methanol was reduced to lithium methoxide,that deposited on graphite electrode surface to form initial SEI(solid electrolyte interphase) near 2.0 V,which resulted in ethylene carbonate excess decomposition and poor passive ability of the SEI ultimately formed.

Key words: Lithium-ion batteries, Graphite electrode, Electrolyte, Methanol contaminant, EIS

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