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  • Modifying the Electrocataly...
    Li, Yawei; Van Cleve, Tim; Sun, Rui; Gawas, Ramchandra; Wang, Guanxiong; Tang, Maureen; Elabd, Yossef A.; Snyder, Joshua; Neyerlin, K. C.

    ACS energy letters, 06/2020, Letnik: 5, Številka: 6
    Journal Article

    Polymer electrolyte membrane fuel cell (PEMFC) electrodes with a 0.07 mgPt cm–2 Pt/Vulcan electrocatalyst loading, containing only a sulfonated poly­(ionic liquid) block copolymer (SPILBCP) ionomer, were fabricated and achieved a ca. 2× enhancement of kinetic performance through the suppression of Pt surface oxidation. However, SPILBCP electrodes lost over 70% of their electrochemical active area at 30% RH because of poor ionomer network connectivity. To combat these effects, electrodes made with a mix of Nafion/SPILBCP ionomers were developed. Mixed Nafion/SPILBCP electrodes resulted in a substantial improvement in MEA performance across the kinetic and mass transport-limited regions. Notably, this is the first time that specific activity values determined from an MEA were observed to be on par with prior half-cell results for Nafion-free Pt/Vulcan systems. These findings present a prospective strategy to improve the overall performance of MEAs fabricated with surface accessible electrocatalysts, providing a pathway to tailor the local electrocatalyst/ionomer interface.