Gas–Liquid Decoupling Transport by Self-Draining in the Anode of Anion Exchange Membrane Fuel Cells

Abstract

The gas–liquid decoupling transport represents a fundamental challenge in anode catalytic layers of anion exchange membrane fuel cells (AEMFCs), where water exhibits a paradoxical duality: as an essential transport medium for hydroxide ions (OH^–), yet as a kinetic-limiting product requiring immediate expulsion. Herein, we report a biomimetic capillary-driven water management strategy to achieve gas–liquid decoupling transport by engineering a hierarchically porous carbon nanofiber layer (CNL) as a self-draining anode catalytic layer (SD-ACL). The SD-ACL achieves anisotropic mass transport through structurally decoupled pathways: promoting rapid through-plane gas transport with a hydrophobic porous network while driving spontaneous in-plane water drainage via capillary action. As a result, the SD-ACL-fabricated membrane electrode assemble (MEA) achieved a high peak power density of 1150.3 mW cm^–2 at high humidity with excellent durability, which was 2.3 times higher than that of the traditional one. Moreover, the SD-ACL could enhance nonprecious metal-anode-based AEMFCs by 57.5%, offering a promising strategy to achieve high-performance platinum-group metal-free (PGM-free) AEMFC technology.