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In this study, a new rugged catalyst layer (CL) structure is derived from a Nafion fiber mat to enhance the mass transport properties of polymer electrolyte membrane fuel cell. Nafion fiber mat is fabricated on a membrane surface by electrospinning technique and then a catalyst ink is sprayed on the fiber-coated membranes. With the Nafion fiber mat with 3.0 μm fiber diameter, a rugged CL supported on the fiber mat is formed, dictating the structural feature of the Nafion fiber mat. The resulting CL, which features an expanded outer CL surface, exhibits 21% improved power performance at 0.4 V under high humidity operation due to the increase of gas and water transport properties. These results demonstrate that Nafion fiber mat can be as an effective and scalable scaffold for the development of advanced CL.

H3PO4-doped polybenzimidazole (PBI) membranes have been employed for high temperature polymer electrolyte membrane fuel cell (HT-PEMFC). Although a thinner PBI membrane is beneficial in enhancing power performance, the use of thin PBI membrane has been hindered by its poor mechanical property and consequent difficulty in membrane handling during membrane electrode assembly (MEA) fabrication. Here, novel fabrication route to realize a thin PBI membrane (∼35 μm)-based HT-MEA is presented. The key feature of the process is to fabricate thin blend membrane of PBI and poly(ethylene glycol) (PEG) and laminate the blend membrane to anode gas diffusion electrode (GDE) followed by H3PO4 doping. The introduction of PEG to PBI film enables the tight bonding of the membrane to the GDE at a mild lamination temperature and mitigates the membrane expansion with the doping, preserving the tight interfacial bonding. Due to the lowered membrane thickness, the corresponding MEA exhibits a high power density of 264 mW cm-2 at 0.6 V. Therefore, the new fabrication strategy based on the blend of PBI/PEG is highly effective in improving both process and power performance of HT-MEA.