轨道交通车用锂离子电容器低温有机电解液研究

Research on the low temperature organic electrolytes for lithium-ion capacitors for rail transit vehicle

在常规六氟磷酸锂(LiPF_(6))/碳酸乙烯酯(EC)+碳酸甲乙酯(EMC)有机电解液体系中添加碳酸二甲酯(DMC)或乙酸乙酯(EA)溶剂,组成电解液;测试了各组电解液25℃、-25℃、-40℃时的电导率,结果显示EC+EMC+EA三元体系电解液电导率最高。使用三元碳酸酯基电解液的商业化3.8 V 1 Ah锂离子电容器在-40℃、10 C倍率放电时的容量为25℃、66 C倍率放电容量的84.6%~100%,显著提升了锂离子电容器低温高倍率充放电性能。

Dimethyl carbonate(DMC)or ethyl acetate(EA)solvents were added to the conventional lithium hexafluorophosphate(LiPF_(6))/ethylene carbonate(EC)+ethyl methyl carbonate(EMC)organic electrolyte system to form the electrolyte;the conductivities of the electrolytes of each group were tested at 25℃,-25℃,and-40℃,and the results showed that the electrolyte of the EC+EMC+EA ternary system had the highest conductivity.The capacity of commercialized 3.8 V 1 Ah lithium-ion capacitor using ternary carbonate-based electrolyte at-40℃,10 C multiplicative discharge is 84.6%~100%of the capacity of 25℃,66 C multiplicative discharge,which significantly improves the performance of lithium-ion capacitor in low-temperature high-multiplicative charging and discharging.