LB-315锂离子电解液的热稳定性研究

Study on thermal stability of LB-315 lithium ion electrolyte

为研究LB-315锂离子电解液的热稳定性,采用TG-DTG技术研究了由LiPF_(6)、碳酸乙烯酯、碳酸甲乙酯、碳酸二甲酯和氟代碳酸乙烯酯构成的复合电解液的热行为。测定了不同升温速率(5、10和30℃/min)下LB-315的分解峰温,使用Kissinger方法计算了分峰后电解液中LiPF_(6)热分解反应的表观活化能和指前因子。采用热力学方程计算了LiPF_(6)分解反应的活化熵(ΔS≠)、活化焓(ΔH≠)和活化吉布斯自由能(ΔG≠)。结果表明LiPF_(6)在小于100℃区域对热较为稳定,其热分解反应的ΔS≠、ΔH≠和ΔG≠分别为-135.48 J/(K·mol)、39.6和95.60 kJ/mol。

In order to study the thermal stability of LB-315 lithium ion electrolyte,the thermal behavior of the composite electrolyte composed of LiPF_(6),ethylene carbonate,ethyl methyl carbonate,dimethyl carbonate and fluoroethylene carbonate was studied using TG-DTG technology.The decomposition peak temperature of LB-315 was measured at different heating rates(5,10 and 30℃/min),and the apparent activation energy and pre-exponential factor of LiPF_(6) thermal decomposition reaction in the electrolyte after peaking were calculated using Kissinger's method.The activation entropy(ΔS≠),activation enthalpy(ΔH≠)and activation Gibbs free energy(DG≠)of LiPF_(6) decomposition reaction were calculated using thermodynamic equations.The results show that ΔS≠,ΔH≠and ΔG≠of LiPF_(6) are-135.48 J/(K·mol),39.6 and 95.60 kJ/mol,respectively.