【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.更多还原

【Abstract】 The temperature dependent properties of the impedance spectral characters,the electronic resis-tance,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 electrochemical 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.更多还原