Advances in high-performance porous transport layers for proton-exchange-membrane water electrolyzers: A review

Abstract

Proton-exchange-membrane water electrolysis (PEMWE) is a leading technology for green hydrogen production, yet its performance and durability at high current densities are increasingly constrained by transport and interfacial losses within the porous transport layer (PTL). Positioned between the flow field and the catalyst layer, the PTL governs coupled two-phase water/oxygen transport, electronic conduction, heat dissipation, and mechanical support under harsh anodic conditions. In particular, the counter-current flow of liquid water and evolved oxygen, bubble nucleation and detachment dynamics, interfacial contact resistance, and corrosion-induced degradation collectively dictate cell efficiency and lifetime. This review summarizes recent advances in the development of high-performance Ti-based PTLs for PEMWE. Key thermal/electrical conduction and mass-transport mechanisms in PTLs, together with their influence on cell performance, are discussed. PTL performance can be improved through rational control of substrate microstructure, protective coatings, and surface modification. Two-phase transport can be enhanced by tuning pore architecture and wettability, while PTL–CL contact and catalyst utilization can be improved by introducing a microporous top layer. In addition, various PTL fabrication and processing strategies are comparatively discussed to highlight their respective advantages, limitations, and roles in enabling high-performance PEMWE operation.

Graphical abstract

Keywords

proton exchange membrane water electrolysis (PEMWE) / porous transport layer (PTL) / mass transport / microstructure / fabrication strategies

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