Platinum group metal-free (PGM-free) catalysts are a low-cost alternative to expensive PGM catalysts for polymer electrolyte fuel cells. However, due to the low volumetric activity of PGM-free catalysts, the catalyst layer thickness of the PGM-free catalyst electrode is an order of magnitude higher than PGM based electrodes. The thick PGM-free electrodes suffer from increased transport resistance and poor water management, which ultimately limits the fuel cell performance. This manuscript presents the study of water management in the PGM-free electrodes to understand the transport limitations and improve fuel cell performance. In-operando neutron imaging is performed to estimate the water content in different components across the fuel cell thickness. Water saturation in thick PGM electrodes, with similar catalyst layer thickness to PGM-free electrodes, is lower than in the PGM-free electrodes irrespective of the operating conditions, due to high water retention by PGM-free catalysts. Improvements in fuel cell performance are accomplished by enhancing water removal from the flooded PGM-free electrode in three ways: (i) enhanced water removal with a novel microporous layer with hydrophilic pathways incorporated through hydrophilic additives, (ii) water removal through anode via novel GDL in the anode, and (iii) lower water saturation in PGM-free electrode structures with increased catalyst porosity.

无铂族金属（不含铂族金属）催化剂是聚合物电解质燃料电池中昂贵的铂族金属催化剂的低成本替代品。然而，由于不含PGM的催化剂的体积活性较低，不含PGM的催化剂电极的催化剂层厚度比基于PGM的电极高一个数量级。不含 PGM 的厚电极会受到运输阻力增加和水管理不良的影响，最终限制了燃料电池的性能。本手稿介绍了无铂族金属电极中的水管理研究，以了解传输限制并提高燃料电池性能。执行操作中中子成像来估计燃料电池厚度上不同成分中的水含量。由于无 PGM 催化剂的高保水性，无论操作条件如何，厚 PGM 电极（具有与不含 PGM 的电极相似的催化剂层厚度）的水饱和度都低于不含 PGM 的电极。燃料电池性能的改进是通过以下三种方式增强从淹没式无 PGM 电极的除水来实现的：(i) 使用具有通过亲水添加剂结合的亲水路径的新型微孔层来增强除水，(ii) 通过阳极通过新型微孔层除水。阳极中的 GDL，以及 (iii) 不含 PGM 的电极结构中水饱和度较低，催化剂孔隙率增加。