On the optimal cathode catalyst layer for polymer electrolyte fuel cells: Bimodal pore size distributions with functionalized microstructures

A high advancement has been achieved in the design of proton exchange membrane fuel cells (PEMFCs) since development thin-film catalyst layers (CLs). However, progress slowed down last decade due to difficulty reducing Pt loading, especially at cathode side, while preserving stack performance. This situation poses a barrier widespread commercialization cell vehicles, where performance and durability are needed reduced cost. Exploring technology limits is necessary adopt successful strategies that can allow improved PEMFCs for automotive industry. In this work, numerical model an optimized CL presented, which combines multiscale formulation mass charge transport nanoscale (∼10nm) layer scale id="m2">(∼1μ<mml:mi . The effect exterior oxygen ohmic resistances incorporated through mixed boundary conditions. features vertically aligned geometry equally spaced ionomer pillars, covered by thin nanoporous electron-conductive shell. interior surface cylindrical nanopores catalyzed with skin (atomic thickness), so triple phase points provided liquid water. results show need develop CLs bimodal pore size distributions functionalized microstructures maximize utilization water-filled facilitated compared films. Proton across must be assisted low-tortuosity regions, provide highways transport. Large secondary pores beneficial facilitate distribution water removal. Ultimate targets set U.S. Department Energy other governments optimization microstructure electrochemical area, reduction resistance from channel CL, increase activity (or maintaining similar alloys). Carbon-free supports (e.g., polymer or metal) preferred avoid corrosion enlarge durability.