| 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–H2SO4 membrane was found greater than that of the PBI–H3PO4 membrane. Through plane conductivity of a PBI–H2SO4 membrane with loading level 9.65 was >0.2 S cm–1 at 150 °C. However, the conductivity of PBI–H2SO4 membrane increased greatly with increasing relative humidity. Membrane electrode assemblies using PBI–H2SO4 membrane exhibited better power density performances with pre‐humidified H2 and air than that with none‐humidified gases. Polymer electrolyte membrane fuel cells with PBI–H2SO4 membrane in a single cell fixture demonstrated a peak power density >0.35 W cm–2 with H2 and air. |
