Enhanced low-humidity performance of electrochemical hydrogen compressors through efficient water management with Janus gas diffusion layers

Effective water management is crucial for high-performance electrochemical hydrogen compression (EHC) under low-humidity conditions. This work aims to design and optimize gas diffusion layers (GDLs) with multilayer microporous layers (MPLs) to enhance water transport and retention. An EP40-based hydrophilic substrate reduces bulk resistance and improves membrane hydration compared to conventional hydrophobic GDLs. Incorporating a Nafion-based MPL with 20 % Nafion content lowers contact resistance and further boosts proton exchange membrane hydration. A novel Janus GDL (JM-GDL), combining PTFE- and Nafion-based MPLs, enables spontaneous, directional water transport and reduces membrane ohmic resistance. Electrochemical tests and Lattice Boltzmann simulations demonstrate that MEAs with JM-GDL achieve 2.8 A/cm² current density and 1.0 MPa output pressure at 50 % relative humidity and 0.3 V within 300 s. This approach significantly improves EHC performance, providing strategic insights for advanced GDL design in low-humidity environments.