The Possibility of Intermediate–Temperature (120 °C)–Operated Polymer Electrolyte Fuel Cells using Perfluorosulfonic Acid Polymer Membranes

The technical possibility and possible issues of an intermediate–temperature–operated polymer electrolyte fuel cell (@120 °C) is investigated with an eye toward the launching of new fuel cell heavy–duty vehicles on the world market. Commercial perfluorosulfonic acid membrane and a commercial Pt catalyst supported on carbon are selected to clarify the possible issues in the fuel cells. The cell resistivity at high humidity is less than 0.1 Ω cm^–2. The mass activity (@ 0.85 V, Pt loading amount: 0.33 mg_Pt cm⁻²) approaches 850 A g_Pt ^–1. The high gas crossover rate through the membrane leads to decreased open circuit voltage, which necessitates the use of higher Pt loadings (>0.30 mg_Pt cm^–2) at the cathode to mitigate the effect of the mixed potential. Pt degradation during 120 °C operation at low humidity is found to be much lower than that during 80 °C operation at high humidity based on the results of load–cycle durability testing.