Ultra-thin acid-base compound high-temperature proton exchange membrane and preparation method thereof

The invention discloses an ultra-thin acid-base compound high-temperature proton exchange membrane and a preparation method thereof. The high-temperature proton exchange membrane is an acid-base composite membrane formed by blending carboxyl-containing polyimide and polybenzimidazole. The preparation method comprises the following steps: (1) taking 3, 5-diaminobenzoic acid, dianhydride and diamine as comonomers, and preparing carboxyl-containing polyimide through two stages of low temperature and heat treatment by a solution polycondensation method; (2) dispersing polybenzimidazole in a polar aprotic organic solvent, and mixing and dissolving carboxyl-containing polyimide with the polybenzimidazole to obtain a membrane preparation solution; and (3) blade-coating the membrane preparation solution on a dry and clean glass plate by using a glass rod through a solution casting method to form a membrane, and then performing post-treatment to obtain the ultrathin carboxyl-containing polyimide/polybenzimidazole blen