Evaluation of the dead-ended anode proton exchange membrane fuel cell's long-term performance under high and low atmospheric relative humidity

This study aims to elucidate how variations in oxidant (air) relative humidity modulate the long-term durability of dead-ended anode (DEA) proton exchange membrane fuel cells. Accelerated degradation experiments (10,000 cycles) are conducted on similar DEA fuel cells to assess their response under two distinct cathode relative humidity (RH C ) conditions: high (100%) and low (20%). According to results, both fuel cells exhibit performance deterioration, with elevated RH C amplifying the decline in maximum power density (MPD) due to catalyst degradation at high RH C . Specifically, the low-RH C condition yields approximately a 10% MPD reduction after 10,000 cycles, whereas the high-RH C condition experiences a substantially larger MPD decrease of 31.70%. The pronounced MPD loss at high humidity is concomitant with a 27.44% reduction in electrochemically active surface area (ECSA), while the low-humidity scenario shows about half the ECSA loss. Transmission electron microscopy corroborates these findings, revealing severe catalyst degradation at high RH C .