物理化学学报 >> 2009, Vol. 25 >> Issue (03): 406-410.doi: 10.3866/PKU.WHXB20090302

研究论文 上一篇    下一篇

温度对石墨电极性能的影响

庄全超 魏国祯 董全峰 孙世刚   

  1. 中国矿业大学材料科学与工程学院, 江苏 徐州 221116; 厦门大学化学化工学院化学系, 固体表面物理化学国家重点实验室, 福建 厦门 361005
  • 收稿日期:2008-09-24 修回日期:2008-12-15 发布日期:2009-03-02
  • 通讯作者: 庄全超; 孙世刚 E-mail:zhuangquanchao@126.com;sgsun@xmu.edu.cn

Influence of Temperature on the Performance of a Graphite Electrode

 ZHUANG Quan-Tiao, WEI Guo-Zhen, DONG Quan-Feng, SUN Shi-Gang   

  1. School of Materials Science and Engineering, China University of Mining&Technology, Xuzhou 221116, Jiangsu Province, P. R. China; State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China
  • Received:2008-09-24 Revised:2008-12-15 Published:2009-03-02
  • Contact: ZHUANG Quan-Chao; SUN Shi-Gang E-mail:zhuangquanchao@126.com;sgsun@xmu.edu.cn

摘要:

运用电化学阻抗谱(EIS)并结合循环伏安法(CV)研究了石墨电极25和60 ℃时在1 mol·L-1 LiPF6-EC(碳酸乙烯酯):DEC(碳酸二乙酯):DMC(碳酸二甲酯)电解液中, 以及60 ℃时在1 mol·L-1 LiPF6-EC:DEC:DMC+5%VC(碳酸亚乙烯酯)电解液中的首次阴极极化过程. 发现高温下(60 ℃)石墨电极在1 mol·L-1 LiPF6-EC:DEC:DMC电解液中可逆循环容量衰减的主要原因在于其表面无法形成稳定的固体电解质相界面(SEI)膜. 实验结果显示, VC添加剂能够增进高温下石墨电极表面SEI膜的稳定性, 进而改进石墨电极的循环性能.

关键词: 锂离子电池, 石墨电极, 电化学阻抗谱, SEI膜

Abstract:

The first lithiation of a graphite electrode in 1 mol·L-1 LiPF6-EC (ethylene carbonate):DEC(diethyl carbonate):DMC(dimethyl carbonate) electrolyte at 25 and 60 ℃, and in 1 mol·L-1 LiPF6-EC:DEC:DMC+5% VC (vinylene carbonate) electrolyte at 60 ℃ were investigated by electrochemical impedance spectroscopy (EIS) combined with cyclic voltammetry (CV). It was found that deterioration of the graphite electrode's electrochemical performance was mainly caused by the unstable solid electrolyte interphase (SEI) film on the electrode's surface in 1 mol·L-1 LiPF6-EC:DEC:DMC electrolyte at 60 ℃. However, the use of VC as an additive to the above electrolyte significantly improved the electrochemical performance of the graphite electrode, which was attributed to an improvement in the stability of the SEI filmthat formed on the graphite electrode's surface.

Key words: Lithium ion battery, Graphite electrode, Electrochemical impedance spectroscopy, SEI film

MSC2000: 

  • O646