Mesoscale regulation of ordered membrane electrode assemblies for hydrogen-electric energy interconversion systems

Hydrogen-electric energy interconversion systems represented by proton exchange membrane fuel cells and PEM water electrolyzers are key technologies for clean energy conversion. However, their widespread commercialization is hindered by challenges such as high cost and limited durability, largely attributed to inefficient catalyst utilization and multiphase transport limitations in conventional membrane electrode assemblies (MEAs). In recent years, ordered MEAs have emerged as a promising strategy to rationally structure the catalyst layer (CL), proton exchange membrane, and gas diffusion layer (GDL) at the mesoscale, thereby enabling ordered pathways for proton, electron, gas, and water transport. This paper reviews the design and regulation strategies of ordered membrane electrodes from the mesoscale perspective, focusing on the ordered structures of the CL, PEM, GDL and their effects on cell performance. The optimization of the reaction interface, the construction of long-range ordered proton transport channels and the design of hierarchical porous GDLs have resulted in significant advancements in the field. The paper concludes with a discussion of the current challenges in research and offers a perspective on future directions, including scale-up preparation, long-term stability assessment and multi-scale coupling mechanism research.