Simultaneous Improvement of Output Power and Durability of Ultra-Low Platinum Membrane Electrode Assemblies by Building a Stable Catalyst Layer Interfaces

Transferring high-activity catalysts from rotating disk electrodes (RDE) to membrane electrode assemblies (MEA) is the most effective approach for achieving large-scale commercialization of proton exchange membrane fuel cells (PEMFC). This study synthesizes a carbon-supported catalyst that can effectively transfer high oxygen reduction reaction (ORR) activity to the MEA. Experimental results indicate that, following hydrophobic treatment of the carbon support, the coverage of the ionomer on the carbon surface increased from 78.94% to 97.29%. The hydrophobic nature of the carbon support, combined with the uniform distribution of the ionomer, enhances the microphase separation area within the catalytic layer, thereby providing more space for oxygen transport to the catalyst's active sites. This improvement results in a 10.9% increase in the maximum output power of the ultralow platinum MEA. Meanwhile, in comparison to the electrochemical cycle, the relative humidity (RH) cycle exhibits a more pronounced attenuation of the output performance of the ultralow platinum MEA. The maximum output power of the MEA decreases by 30.3% after 50 RH cycles, whereas the maximum output power remains nearly unchanged after 10,000 cycles of catalyst accelerated aging. Utilizing hydrophobic carbon support can significantly enhance the durability of the ultralow platinum MEA. This is because hydrophobic carbon support mitigates the stress caused by water absorption expansion and dehydration shrinkage of the ionomer, leading to the formation of more stable interfaces between the ionomer and the catalyst.