Pt/ionomer interface engineering via hydrogen-bonding polyols towards enhanced PEMFC performance

The performance of polymer electrolyte membrane fuel cells (PEMFCs) is governed by the interfacial structure between carbon-supported platinum (Pt/C) catalysts and ionomers in the cathode catalyst layer. Although short-side-chain ionomers (SSCs) like Aquivion offer high proton conductivity and oxygen permeability compared to conventional long-side-chain ionomers (LSCs), their dense sulfonate groups poison Pt active sites, thereby limiting oxygen reduction reaction (ORR) activity. Herein, we report a hydrogen-bonding strategy to engineer the Pt/SSC interface via ethylene glycol (EG) incorporation to mitigate Pt poisoning. Characterizations confirm EG–sulfonate hydrogen bonds, reducing ionomer layer thickness and coverage and alleviating Pt poisoning. Electrochemical measurements reveal that EG introduction promotes proton and oxygen transport, leading to higher power densities. EG incorporation also improves water management, as evidenced by high frequency resistance (HFR) analysis. The universality of this strategy is validated using other polyols. This work presents a promising approach to Pt/ionomer interface engineering towards high-performance PEMFCs.