Engineering hierarchical pores in FeCo-N-C catalysts to construct advanced cathode catalyst layers for AEMFCs with alleviated water management

Water (H 2 O) management limitations within the cathode catalyst layer (CCL), particularly for precious-metal-free metal/nitrogen-doped carbon (M-N-C) catalysts, severely constrain the performance of anion-exchange membrane fuel cells (AEMFCs). To address this challenge, we implement precision pore-structure engineering at the catalyst-intrinsic level. Three hierarchically porous FeCo-N-C catalysts were synthesized, enabling the fabrication of CCLs with tailored pore architectures. The CCL prepared from the macroporous-open catalyst (o-CCL) exhibits an optimized pore structure, characterized by a restructured distribution of hydrophilic hierarchical pores along with a high porosity of 54.7% and a low tortuosity of 1.61. Simulations and experimental measurements collectively confirm that the optimized o-CCL achieves improved H 2 O distribution, enhanced gas-liquid flow velocity, and reduced oxygen (O 2 ) transport resistance. These structural advantages collectively lead to a notable improvement in AEMFC performance. The o-CCL, with an electrode area of 5 cm 2 , achieves peak power densities of 684 mW cm −2 in H 2 /air and 1153 mW cm −2 in H 2 /O 2 . This study demonstrates that pore-structure engineering at the catalyst particle level offers a viable strategy to alleviate the H 2 O-O 2 transport conflict in AEMFCs and improve overall cell performance.