A H2SO4 Loaded Polybenzimidazole (PBI) Membrane for High Temperature PEMFC

Abstract Sulfuric acid loaded polybenzimidazole (PBI) membranes were prepared with loading levels up to 10.58 (acid molecule per repeat unit of PBI) and characterized with Fourier transform infrared spectroscopy. Ionic conductivity of the PBI–H 2 SO 4 membrane was found greater than that of the PBI–H 3 PO 4 membrane. Through plane conductivity of a PBI–H 2 SO 4 membrane with loading level 9.65 was >0.2 S cm –1 at 150 °C. However, the conductivity of PBI–H 2 SO 4 membrane increased greatly with increasing relative humidity. Membrane electrode assemblies using PBI–H 2 SO 4 membrane exhibited better power density performances with pre‐humidified H 2 and air than that with none‐humidified gases. Polymer electrolyte membrane fuel cells with PBI–H 2 SO 4 membrane in a single cell fixture demonstrated a peak power density >0.35 W cm –2 with H 2 and air.