基于咪唑类离子液体含氟阴离子的调控制备高质子传导率的OPBI共混膜

Preparation of poly(aryl ether benzimidazole)blend membranes with high proton conductivity based on the regulation of fluorine-containing anions in imidazole ionic liquids

磷酸掺杂聚苯并咪唑(PA-PBI)被认为是最具发展潜力的高温质子交换膜材料之一,但如何制备出高质子传导率的膜材料,仍是PA-PBI高温质子交换膜所面临的挑战性难题。本文通过烷基化反应、离子交换反应,合成了阴离子为PF_(6)^(-)和BF_(4)^(-)的两种咪唑类离子液体([ViEtIm]PF_(6)、[ViEtIm]BF_(4)),通过与芳醚型聚苯并咪唑(OPBI)共混并采用流延法制备了[ViEtIm]PF_(6)/OPBI和[ViEtIm]BF_(4)/OPBI膜,进一步通过红外光谱、热重分析和SEM表征验证了离子液体与OPBI共混膜结构。对共混膜进行高温质子交换膜性能研究,结果表明,[ViEtIm]PF_(6)/OPBI膜综合性能优于[ViEtIm]BF_(4)/OPBI膜及原OPBI膜,特别是在质子传导率方面,[ViEtIm]PF_(6)/OPBI膜的质子传导率高达37.6 mS/cm,分别是[ViEtIm]BF_(4)/OPBI膜和原OPBI膜的1.5倍和4.3倍。

Phosphoric acid doped polybenzimidazole(PA-PBI)membrane is one of the most promising high-temperature proton exchange membrane materials.The preparation of membrane materials with high proton conductivity is a challenging problem of phosphoric acid doped polybenzimidazole high-temperature proton exchange membrane.In this work,two kinds of imidazole ionic liquids([ViEtIm]PF_(6) and [ViEtIm]BF_(4)) with anions of PF_(6)^(-) and BF_(4)^(-) were synthesized through alkylation reaction and ion exchange reaction. The blend membrane were prepared by casting method via co-blending ionic liquids and poly(aryl ether benzimidazole)(OPBI).The structure of the blend membrane was characterized by infrared spectroscopy,thermogravimetric analysis and SEM.The proton conductivity of[ViEtIm]PF_(6)/OPBI membrane is as high as 37.6 mS/cm,which is 1.5 times and 4.3 times that of[ViEtIm]BF_(4)/OPBI membrane and original OPBI membrane.In conclusion,the comprehensive performance of[ViEtIm]PF_(6)/OPBI membrane containing more fluorine structure is better than[ViEtIm]BF_(4)/OPBI membrane and original OPBI membrane,especially in proton conductivity.