Effect of Cation Contamination of Gas Diffusion Layer on Water Management and Performance of PEMFCs

ABSTRACT The efficient and stable operation of proton exchange membrane fuel cells (PEMFCs) in practical applications can be adversely affected by various contaminants. This study delves into the impact of Cr₂(SO₄)₃ contamination on the gas diffusion layer (GDL) and PEMFC performance, systematically analyzing the physicochemical property changes and their correlation with electrochemical performance. The results indicate that after post‐treatment, the GDL surface exhibited exposed carbon fibers, cracks, and large pores in the microporous layer (MPL), with a noticeable detachment of PTFE. There was a marked reduction in C and F element signals, an increase in O element signals, deposition of Cr₂(SO₄)₃, formation of C=O and C=C bonds, appearance of Cr₂(SO₄)₃ characteristic peaks, and changes in pore structure—all suggesting significant alterations in the GDL's surface morphology, structure, and chemical composition. The decline in mechanical strength and thermal stability, and increased surface roughness and resistance negatively impacted fuel cell performance. At high current densities, the emergence of water flooding increased mass transfer resistance from 0.1 Ω cm² to 1.968 Ω cm², with a maximum power density decay rate reaching 71.17%. This study reveals the significant negative impact of Cr₂(SO₄)₃ contamination on GDL and fuel cell performance, highlighting that changes in surface structure, reduced hydrophobicity, and increased mass transfer resistance are primary causes of performance degradation. The findings provide crucial insights for improving GDL materials, optimizing fuel cell manufacturing and operation processes, and addressing contamination issues in practical applications.