Effect of hydrophobicity of gas diffusion layer in calcium cation contamination in polymer electrolyte fuel cells

To understand the effect of gas diffusion layer (GDL) in cation contamination in polymer electrolyte fuel cells (PEFCs), three membrane electrode assembly (MEA) configurations were soaked in a cationic (Ca2+) solution, with the major difference being whether catalyst coated membrane (CCM) was exposed (either completely or partially) to the cationic solution or separated by the GDL and gasket. Significant performance drop was observed with the CCMs which were in direct or partial contact with the Ca2+ solution, however, no significant change in performance occurred where the CCM was separated by the GDL and gasket. It seems that the GDL acts as a barrier to the transport of Ca2+ solution into the CCM, possibly due to very highly hydrophobic nature of the GDL, especially in the microporous layer (MPL) next to the catalyst layers. When a wetting agent was added to the cationic solution to increase the wettability of the GDL, a drop in the performance was observed which verified that the hydrophobicity of the GDL and the MPL hindered the transport of Ca2+ solution into the CCM.