Integrated Multiscale Structural Engineering of Fe–N–C Electrocatalysts and Device Components for High-Performance PEMFCs

Abstract

Achieving high power density in practical proton-exchange membrane fuel cells (PEMFCs) using platinum-group-metal (PGM)-free catalysts remains a central challenge. This study demonstrates that an atomically dispersed iron catalyst (Fe–N–C), integrated with multiscale structural engineering, enables a single cell to achieve a peak power density of 0.583 W cm^–2 under practical H₂/air conditions, which is over 40% higher than that of the pristine Fe–N–C system. At the catalyst level, encompassing both atomic and meso scales, a soft-templating approach is employed to construct mesoporous architectures and induce geometric deformation of active sites via concave curvature, thereby enhancing site accessibility, mass transport, and intrinsic activity. Further strain modulation tailors the geometric and electronic configuration of Fe–N₄ sites, optimizing the adsorption–desorption behavior of ORR intermediates. At the membrane electrode assembly (MEA) and single cell levels, a porous hydrophobic metal foam replaces the conventional flow field, effectively improving water management and oxygen transport within thick catalyst layers. Overall, this work establishes a multiscale structural engineering strategy that offers a promising route toward high-performance PEMFCs.