Li Yawei, Van Cleve Tim, Sun Rui, Gawas Ramchandra, Wang Guanxiong, Tang Maureen, Elabd Yossef A, Snyder Joshua, Neyerlin K C
Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States.
Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States.
ACS Energy Lett. 2020 Apr 29;5(6):1726-1731. doi: 10.1021/acsenergylett.0c00532. eCollection 2020 Jun 12.
Polymer electrolyte membrane fuel cell (PEMFC) electrodes with a 0.07 mg cm 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 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.
制备了仅含有磺化聚（离子液体）嵌段共聚物（SPILBCP）离聚物、铂/炭黑电催化剂负载量为0.07 mg/cm²的聚合物电解质膜燃料电池（PEMFC）电极，通过抑制铂表面氧化，其动力学性能提高了约2倍。然而，由于离聚物网络连通性差，SPILBCP电极在30%相对湿度下失去了超过70%的电化学活性面积。为了克服这些影响，开发了由Nafion/SPILBCP离聚物混合物制成的电极。混合Nafion/SPILBCP电极在动力学和质量传输限制区域内显著提高了膜电极组件（MEA）的性能。值得注意的是，这是首次观察到由MEA测定的比活性值与无Nafion的铂/炭黑体系先前的半电池结果相当。这些发现提出了一种改善由表面可及电催化剂制成的MEA整体性能的前瞻性策略，为定制局部电催化剂/离聚物界面提供了一条途径。
