Direct methanol fuel cells using acid doped polybenzimidazole as a polymer electrolyte

Direct methanol fuel cells have been constructed and tested using phosphoric acid doped polybenzimidazole as a polymer electrolyte. These cells utilize unsupported Pt-Ru alloy catalysts for methanol oxidation and unsupported Pt as a catalyst for oxygen reduction. The doped polybenzimidazole electrolyte membrane provides suitable proton conductivity (>0.05 S/cm) and low methanol crossover rates (<10 mA/cm²) at temperatures up to 200°C. With catalyst loadings of 4 mg/cm², fuel cells operating at 200°C on atmospheric pressure reactants have produced over 0.18 W/cm²