The Effect of Carbon Corrosion on Gas Diffusion Layer under Different Conditions

The gas diffusion layer (GDL) is a critical component of proton exchange membrane fuel cells (PEMFCs), playing a key role in mass transport, electrical conduction, and water management. In this study, accelerated stress testing (AST) was conducted to investigate the effects of operating potential, temperature, and potential of hydrogen (pH) value of electrolyte on carbon corrosion-induced degradation in the GDL. The results revealed that high potential conditions, particularly at 1.5 V vs. reversible hydrogen electrode (RHE), led to severe corrosion characterized by significant reductions in hydrophobicity (contact angle <125°) and increased in-plane resistivity (>40 mΩ cm). Additionally, the mechanical strength of the GDL exhibited a non-monotonic trend with pH, reaching a minimum at pH 3, which corresponds to the electrocapillary “zero charge potential.” Electrochemical performance deteriorated significantly when corroded GDLs were employed as cathodes, with a notable decrease in current density (1600 mA cm–2 @ 0.46 V). This work systematically elucidates the degradation mechanisms of GDLs under various simulated PEMFC operating conditions and provides insights for improving GDL durability in practical fuel cell applications.