温度对LiCoO2中锂离子嵌脱过程的影响  

Effects of Temperature on the Intercalation-Deintercalation Process of Lithium Ion in LiCoO_2

作　　者：庄全超[1] 魏国祯[2] 许金梅[2] 樊小勇[2] 董全峰[2] 孙世刚[2] 

机构地区：[1]中国矿业大学材料科学与工程学院,徐州221116 [2]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,厦门361005

出　　处：《化学学报》2008年第7期722-728,共7页Acta Chimica Sinica

基　　金：国家重点基础研究和发展规划“973”项目(No.2002CB211804)资助项目

摘　　要：运用电化学阻抗谱(EIS)研究了LiCoO2正极在1mol/LLiPF6-EC(碳酸乙烯酯):DEC(碳酸二乙酯):DMC(碳酸二甲酯)和1mol/LLiPF6-PC(碳酸丙稀酯):DMC+5%VC(碳酸亚乙烯酯)电解液中0～30℃范围内的阻抗谱特征、固体电解质相界面(SEI)膜阻抗、电子电阻和电荷传递电阻等随温度的变化.结果表明,LiCoO2正极的阻抗谱特征随温度变化,当温度升高其低频区域在上述两种电解液中分别于10和20℃出现反映锂离子固态扩散的斜线.测得LiCoO2正极在上述两种电解液中,锂离子迁移通过SEI膜的离子跳跃能垒平均值分别为37.74和26.55kJ/mol;电子电导率的热激活化能平均值分别为39.08和53.81kJ/mol;嵌入反应活化能平均值分别为68.97和73.73J/mol.The temperature dependent properties of the impedance spectral characters, the electronic resistance, the resistances of the SEI （solid electrolyte interphase） film as well as the charge transfer reaction of the LiCoO2 electrode in 1 mol/L LiPF6-EC （ethylene carbonate）：DEC （diethyl carbonate）：DMC （dimethyl carbonate） and 1 mol/L LiPF6-PC （propylene carbonate）：DMC＋5% VC （vinylene carbonate） electrolyte solutions were studied and reported. The temperature was varied from 0 to 30℃. The studies of electro- chemical impedance spectroscopy （EIS） revealed that, the common EIS features of the LiCoO2 electrode in the 1 mol/L LiPF6-EC：DEC：DMC and 1 mol/L LiPF6-PC：DMC＋5% VC electrolyte solutions were related to the temperature, and a straight line reflecting solid state Li ion diffusion in the bulk of active mass appeared at 10 and 20℃, respectively. In 1 mol/L LiPF6-EC：DEC：DMC and 1 mol/L LiPF6-PC：DMC＋5% VC electrolyte solutions, the energy barriers for the ion jump relating to migration of lithium ions through the SEI film of the LiCoO2 electrode were determined to be 37.74 and 26.55 kJ/mol, the thermal active energy of the electronic conductivities to be 39.08 and 53.81 kJ/mol, and the intercalation-deintercalation reaction active energies to be 68.97 and 73.73 kJ/mol, respectively.

关 键 词：锂离子电池 LICOO2 固体电解质相界面膜 电子电阻 电荷传递电阻 

分 类 号：O614.111[理学—无机化学]