Fabrication of PBI/SPOSS hybrid high-temperature proton exchange membranes using SPAEK as compatibilizer

Because of the harsh operating circumstances of high temperature over 100 °C and strong acidity, it is of great significance to explore some new methods on the developments of high-performance membrane materials using in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). In current work, with the assistance of newly designed sulfonated poly (aryl ether ketone) (SPAEK) compatibilizer, some hydrophilic and acidophilic polyhedral-oligosilsesquioxane nanoparticles bearing sulfuric acid groups (SPOSS) were successfully incorporated into a soluble arylether-type polybenzimidazole (Ph-PBI) matrix via an in situ sol-gel process to obtain a new family of hybrid membranes with an improved overall performance. As a result, these hybrid membranes exhibited enhanced acid absorption ability and doping levels at 120 °C, improved acid retention ability and attractive mechanical-dimensional stability. More importantly, the proton conductivity of a phosphoric acid doped hybrid membrane reached 126 mS cm−1 at 200 °C. This membrane was also suitable for membrane electrode assemblies (MEAs), and a maximum power density of 300 mW cm−2 could be achieved at 160 °C without humidity.