Development of high-temperature PEMFC based on heteropolyacids and polybenzimidazole

Inorganic/organic composite membranes have been prepared from polybenzimidazole and two different heteropolyacids; namely phosphotungstic acid and silicotungstic acid. The membranes were characterized using SEM, XRD, and proton conductivity. The conductivity of the composite membrane was relatively high when compared to PBI membrane. The fuel cell performance with the composite membranes doped with phosphoric acid was investigated using hydrogen. It was found that pre-treatment of PWA and SiWA influenced the fuel cell performance and that the performance was enhanced with the use of the composite membrane. However, from the electrode polarization and crossover current data it was revealed that the expected high performance of the fuel cell was not achieved because of voltage losses associated with contact resistance and poor ionic conductivity in the catalyst layer. The best performance of the fuel cell was achieved with a 40% SiWA/PBI composite membrane.