Translating insights from experimental analyses with single-crystal electrodes to practically-applicable material development strategies for controlling the Pt/ionomer interface in polymer electrolyte fuel cells

Ionomers are used in polymer electrolyte fuel cells (PEFCs) catalyst layers to improve proton conduction. Recent analytical studies have clarified that the adsorption of the ionomer on the surface of a Pt catalyst deteriorates the catalytic activity for the oxygen reduction reaction and oxygen transport properties near the catalyst surface. These findings have led to the development of new materials, such as mesoporous carbon support and highly oxygen-permeable ionomer, which are now commercially used. In this review article, we summarize recent analytical studies of the Pt/ionomer interface focusing on half-cell experiments with single-crystal electrodes. We also present promising approaches for mitigating ionomer adsorption, as well as the remaining challenges in the application of these approaches to PEFCs.

Automated summary

Ionomers are used in fuel cells to enhance proton conduction, but their adsorption onto Pt catalysts can deteriorate their catalytic activity and oxygen transport properties. Recent analytical studies have focused on the Pt/ionomer interface and have led to the development of new materials to mitigate ionomer adsorption. However, challenges remain for their application in fuel cells.