Evaluation of a start-stop protocol and its impact on the degradation of high-temperature proton exchange membrane fuel cells

The limited durability of high-temperature proton exchange membrane fuel cells (HT-PEMFCs) hinders their commercial viability. This study delves into the performance degradation of two high-temperature membrane-electrode assemblies (HT-MEAs) under start-stop conditions via 90 and 100-hour accelerated stress tests. The degradation mechanisms were assessed through polarization curve measurements, current and temperature density profiles, and electrochemical impedance spectroscopy (EIS) analysis. These findings were substantiated by literature utilizing a similar methodology. Voltage degradation results and EIS spectra revealed a post-50 cycle total degradation rate of 3,600.00 μV/cycle for HT-MEA1 and 2,396.16 μV/cycle for HT-MEA2. The outcomes underscore a notable decline in membrane integrity and a substantial increase in ohmic resistance, as well as anode and cathode charge transport resistance, alongside heightened overall mass transport resistance, particularly evident after the initial 10 cycles, attributed to phosphoric acid leaching, redistribution, and anode and cathode catalyst poisoning.