Abstract:

The development of electrolytes for liquid aluminum electrolytic capacitors is mainly focused on the branched polycarboxylic acids and their salts, but the high-temperature stability and low-temperature performance of the electrolytes still need to be improved. To address this shortcoming, three ether-based branched carboxylic acids (EBCS₁, EBCS₂, EBCS₃) that have both skeletal structures and ether groups were prepared, and characterized with NMR and FT-IR spectrum. Then, the electrolyte system was optimized to be 70% ethylene glycol and 10% γ-butyrolactone with an optimal content of EBCS boiled at 140℃, with which an electrical conductivity of 1.8mS/cm and spark voltage greater than 550V were achieved. The assembled capacitors demonstrated excellent performance judging from the resultant capacity, loss, equivalent series resistance, leakage current, low-temperature impedance and high-temperature lifetime, and thus have a good commercialization prospect.

Key words: branched polycarboxylic acids, skeleton structure, ether group, low temperature impedance, high temperature life

摘要：

液态铝电解电容器电解质的发展目前主要集中在支链多元羧酸及其盐，但相应电解液的高温稳定性及低温性能均有待提高。为了解决这一问题，本文通过将骨架结构和醚基相结合，制备了3种骨架结构醚基支链型羧酸（EBCS₁、EBCS₂、EBCS₃），并采用核磁共振波谱和红外光谱对其进行了表征确认。然后通过电解液合成体系的优化，确定了在140℃的烧煮温度下，溶剂体系选用70%乙二醇和10% γ-丁内酯，3种EBCS电解质的最佳含量分别为3.5%、3.5%、3%时电解液具有最优的电性能，电导率均能达到1.8mS/cm，闪火电压均高于550V。将3种电解液装配成铝电解电容器，其室温下的容量、损耗、等效串联电阻ESR和漏电流均优于市售电容器，同时在低温阻抗测试和高温寿命实验中性能表现优异，具有较大的市场应用潜力。

关键词: 支链多元羧酸, 骨架结构, 醚基, 低温阻抗, 高温寿命