Polybenzimidazole-based Polymers of Intrinsic Microporosity Membrane for High-Temperature Proton Conduction

Anhydrous proton conducting polymer membrane materials have raised much attention in the application of high-temperature proton-exchange membranes (HT-PEMs) fuel cells, which convert chemical energy into electrical energy. Polybenzimidazole-based polymers, as typically materials for HT-PEMs, its compact structure results in a small larger fractional free volume (FFV), which is not conducive to the adsorption and retention of proton carriers. Herein, a series of polybenzimidazole-based polymers of intrinsic microporosity (PIM-PBIs) were synthesized. PIM-PBIs possess the benzimidazole units and porous structures, and have good thermal stability and large specific surface area (100 similar to 400 m(2)/g). PIM-PBIs are further embedded in polyvinylidene fluoride (PVDF) to form mixed matrix membranes for high-temperature proton conduction. The resulting membrane exhibits high proton conductivity of 90.11 mS cm(-1) at 140 degree celsius and high phosphoric acid (PA) retention rate of 90.0 %. This work provides a facile method for the precise design and preparation of proton-conducting porous materials.