Compression and Transport Coupling Behavior in Thin Gas Diffusion Layers for Polymer Electrolyte Membrane Fuel Cell

Compression and transport coupling behavior in gas diffusion layers (GDLs) influences the performance of membrane-electrode assemblies (MEAs) in polymer electrolyte membrane fuel cells (PEMFCs).Thin GDLs enhance volumetric power density and water removal, whereas their mechanical fragility and high compression sensitivity often lead to pore collapse and unstable interfacial contact.In this study, we investigated the effect of microstructures and gas permeability of GDLs on compression-related transport behavior by using three carbon-paper-based GDLs with identical microporous layers (MPLs) but different backing-layer thickness.Electrochemical analyses demonstrated that the MEA with intermediate GDL (GDL#B 215 m) showed the best performance with low charge-transfer and mass-transfer resistances.However, thin GDL (GDL#C 185 m) suffered from gas diffusion limitations and water condensation because of excessive MPL penetration and pore collapse, leading to the lower performance of MEA, and this tendency were more pronounced at > 1.5 Acm -2 .This study demonstrates that balancing between compression stability and gasdiffusion continuity play a critical role in optimizing MEA performance, providing practical design guidelines for engineering thin GDLs in high-performance MEAs in PEMFCs applications.