Gas diffusion layers (GDLs) play a critical role in proton exchange membrane fuel cells (PEMFCs) by enabling reactant transport, electron conduction, and effective water management; however, cathode flooding and mass transport limitations continue to restrict performance and durability, particularly at high current densities. Recent studies have demonstrated notable performance improvements through the optimization of GDL characteristics such as porosity, wettability, and pore architecture, with peak power densities approaching 1.7 W cm –2 . This review uniquely provides a comparison between commercial GDLs and findings from recent studies, highlighting key differences in material characteristics, design approaches, and observed performance, while identifying the practical limitations that hinder large-scale adoption. Particular emphasis is placed on the trade-offs between enhanced water management and essential requirements such as electrical conductivity, mechanical strength, cost, and scalable manufacturing. The review also examines fabrication strategies, from conventional carbon paper and cloth substrates to emerging scalable techniques such as spray coating and roll-to-roll processing, with a focus on reproducibility and industrial relevance. By addressing the gap between reported improvements and real-world deployment constraints, this review outlines key challenges and design priorities for next-generation GDLs, providing actionable insights to accelerate the broader implementation of PEMFC technologies in sustainable energy systems.
Li et al. (Mon,) studied this question.