A comprehensive review on assembly design strategies on proton exchange membrane applications

Proton exchange membranes (PEMs) are widely used in fuel cells, electrolyzers, and electrolytic dehumidifiers. Despite significant improvements in material preparation, operational performance and durability for these applications remain impractical, mainly due to poor multilayer structures and component design. This paper reviews recent ideas on improving the assembly design for three types of PEM applications, focusing on aspects of configuration optimization of the membrane electrode assembly and microstructured anode/cathode materials. Well-designed interfaces in catalyst layers (CLs) and diffusion layers (DLs), and between multilayers, are critical for reducing contact resistance and enhancing water management. Modification of catalyst/ionomer interfaces, such as order-structured CLs and patterned PEM/CLs, can improve catalyst utilization and notably reduce loading. Combining multiple CLs and DLs with different porosity or hydrophobicity, or using metal-based DLs (metal fiber or foam) is also feasible. Another approach receiving much attentions is to improve the common plate-and-frame structure to a plate-less one. Eliminating bipolar plates with ridge grooves or integrating the flow field with DLs can improve the reaction, and reduce mass transfer and interface ohmic resistances. Stack compactness can also be enhanced. From the microstructure of materials to the macrostructure of assembly configurations, this review pointed out systematical guidance for further research to achieve well-designed PEM assemblies. • We reviewed research on assembly design strategies for various PEM applications. • This review ranges from materials' microstructure to assemblies' macrostructure. • Well-designed interfaces between catalyst and diffusion layers, and between PEMs are critical. • Modification of catalyst/ionomer interfaces can improve utilization and reduce loading. • Elimination of bipolar or flow field plates can reduce mass transfer and ohmic resistances.