物理化学学报 >> 2010, Vol. 26 >> Issue (06): 1499-1506.doi: 10.3866/PKU.WHXB20100608

电化学 上一篇    下一篇

电解液组成对尖晶石LiMn2O4中锂离子嵌脱过程的影响

邱祥云, 庄全超, 王红明, 崔永丽, 方亮, 孙世刚   

  1. 中国矿业大学材料科学与工程学院, 江苏 徐州 221116; 固体表面物理化学国家重点实验室, 厦门大学化学化工学院化学系, 福建 厦门 361005
  • 收稿日期:2009-10-29 修回日期:2010-02-19 发布日期:2010-05-28
  • 通讯作者: 庄全超, 孙世刚 E-mail:zhuangquanchao@126.com; sgsun@xmu.edu.cn

Influence of Electrolyte Composition on the Intercalation-Deintercalation Process of Lithium Ion in Spinel LiMn2O4

QIU Xiang-Yun, ZHUANG Quan-Chao, WANG Hong-Ming, CUI Yong-Li, FANG Liang, SUN Shi-Gang   

  1. School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, P. R. China; State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China
  • Received:2009-10-29 Revised:2010-02-19 Published:2010-05-28
  • Contact: ZHUANG Quan-Chao, SUN Shi-Gang E-mail:zhuangquanchao@126.com; sgsun@xmu.edu.cn

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摘要：

运用电化学阻抗谱(EIS)研究了尖晶石LiMn2O4正极在1 mol·L-1 LiPF6-EC(碳酸乙烯酯)|DEC(碳酸二乙酯)|DMC(碳酸二甲酯), 1 mol·L-1 LiPF6-EC|DEC|EMC(碳酸甲乙酯)和1 mol·L-1 LiPF6-EC|DMC三种不同电解液中, -20 - 20 ℃范围内的阻抗谱特征随温度的变化. 研究结果表明, 温度强烈影响尖晶石LiMn2O4正极的阻抗谱特征, 而电解液组成对尖晶石LiMn2O4正极阻抗谱特征的影响较小, 但电解液组成对锂离子在尖晶石LiMn2O4正极中嵌入脱出过程相关动力学参数影响较大. 测得尖晶石LiMn2O4正极在上述三种电解液中, 锂离子迁移通过固体电解质相界面(SEI)膜的离子跳跃能垒平均值分别为7.60、16.40 和18.40 kJ·mol-1; 电子电导率的热激活化能平均值分别为44.77、35.47和68.06 kJ·mol-1;嵌入反应活化能平均值分别为52.19、46.19和69.86 kJ·mol-1.

关键词: 锂离子电池, 尖晶石LiMn2O4, 固体电解质相界面膜, 电子电阻, 电荷传递电阻

Abstract:

Variations in the impedance spectra of the commercially available spinel LiMn2O4 electrode from -20 to 20 ℃ were investigated by electrochemical impedance spectroscopy (EIS) in 1 mol·L-1 LiPF6-EC (ethylene carbonate)|DEC (diethyl carbonate)|DMC (dimethyl carbonate), 1 mol·L-1 LiPF6-EC|DEC|EMC (ethyl methyl carbonate) and 1 mol·L -1 LiPF6-EC |DMC electrolyte solutions. We found that the impedance spectral characteristics of the spinel LiMn2O4 electrode was strongly influenced by temperature and only slightly influenced by the electrolyte composition. However, the electronic resistance and the resistance of the SEI filmas well as the charge transfer reaction resistance of the spinel LiMn2O4 electrode were strongly influenced by the electrolyte composition. In 1 mol·L-1 LiPF6-EC|DEC|DMC, 1 mol·L-1 LiPF6-EC|DEC|EMC and 1 mol·L-1 LiPF6-EC|DMC electrolyte solutions, the energy barriers for the ion jump relating to the migration of lithium ions through the solid electrolyte interphase (SEI) film of the spinel LiMn2O4 electrode were determined to be 7.60, 16.40, and 18.40 kJ·mol-1. The thermal active energies of the electronic conductivities were 44.77, 35.47, and 68.06 kJ·mol-1 and the intercalation-deintercalation reaction active energies were 52.19, 46.19, and 69.86 kJ·mol-1, respectively.

Key words: Lithium-ion battery, Spinel LiMn2O4, Solid electrolyte interphase film, Electronic resistance, Charge transfer reaction resistance