Structural Design of Gas Diffusion Layer to Mitigate Carbon Corrosion in Proton Exchange Membrane Fuel Cells

Abstract

Unsteady-state operating conditions of proton exchange membrane fuel cells (PEMFCs) such as startup-shutdown processes and voltage reversal will cause local ultrahigh potential, resulting in carbon corrosion of gas diffusion layer (GDL). To mitigate performance degradation, in this paper, a novel wavy microporous layer (MPL) was prepared by gelatinous MPL slurry on the surface of GDL. Due to the wave shape and rough surface, the corrosion region of GDL was transferred from MPL to the macroporous substrate. By morphology characterization, GDL containing common MPL (com-GDL) exhibited a serious structural destruction. In contrast, GDL containing wavy MPL (wavy-GDL) revealed a high structural stability. In the electrochemical testing of the samples, the performance of fresh wavy-GDL was higher than that of fresh com-GDL. After being corroded, the performance of the com-GDL was reduced by more than 20%. While the degradation of the wavy-GDL was less than 10%, realizing effective mitigation of corrosion. In summary, this paper pointed out a novel strategy to improved durability of PEMFCs, and the findings are helpful to promote the carbon corrosion mitigation strategy for other devices at high potential.

Keywords: Proton exchange membrane fuel cell, Gas diffusion layer, Selective carbon corrosion, Durability