Tailoring a Three-Phase Microenvironment for High-Performance Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells

ZP Zhao and MD Hossain and CC Xu and ZJ Lu and YS Liu and SH Hsieh and I Lee and WP Gao and J Yang and BV Merinov and W Xue and ZY Liu and JX Zhou and ZT Luo and XQ Pan and F Zaera and JH Guo and XF Duan and WA Goddard and Y Huang, MATTER, 3, 1774-1790 (2020).

DOI: 10.1016/j.matt.2020.09.025

Despite tremendous progress in catalyst development for rate-limiting cathodic oxygen reduction reaction (ORR), reducing Pt usage while meeting performance requirements in practical proton exchange membrane fuel cells (PEMFCs) remains a challenge. The ORR in PEMFCs occurs at a catalyst-electrolyte-gas three-phase interface. A desirable interface should exhibit highly active and available catalytic sites, as well as allow efficient oxygen and proton feeding to the catalytic sites and timely removal of water to avoid interface flooding. Here, we report the design of a three-phase microenvironment in PEFMCs, showing that carbon surface chemistry can be tuned to modulate its interaction with the ionomers and create favorable transport paths for rapid delivery of both reactants and products. With such an elaborate interfacial design, for the first time we have demonstrated PEMFCs with all key ORR catalyst performance metrics, including mass activity, rated power, and durability, surpassing the US Department of Energy targets.

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