Polybenzimidazoles via polyamidation: A more environmentally safe process to proton conducting membrane for hydrogen HT-PEM fuel cell

The article presents a new environmentally safe synthetic approach towards durable polybenzimidazole protonconducting membrane via polyamidation at ambient conditions and subsequent thermal heterocyclization of films cast from reaction solution followed by phosphoric acid doping. The method avoids exhausts, acid waste and inorganic salts, compared with the existing methods and technologies, allowing to minimize the negative environmental impact related to the process. The membrane possesses an excellent proton conductivity of 105 mS cm-1 and good mechanical properties and has been successfully tested in high temperature polymer electrolyte membrane fuel cells. An extremely low hydrogen crossover through the membrane of 0.040 mA cm-2 at 180 degrees C has been registered compared with quite high 4-5 mA cm-2 for Celazole (R) m-PBI.

Automated summary

This study introduces a new synthetic method for preparing an environmentally safe polybenzimidazole proton-conducting membrane with excellent performance, which has been successfully applied in high-temperature polymer electrolyte membrane fuel cells. Compared with existing methods, this approach can reduce negative environmental impact.