Effects of Ionomer Film Thickness and Water Content on Oxygen Permeation Properties of PEFC Cathode Catalyst

In order to promote the widespread use of Polymer Electrolyte Fuel Cell (PEFC), enhancing cell performance is necessary. One significant factor affecting cell performance is the oxygen permeability in the ionomer, which depends on its nano-scale structure. In this study, to investigate the relationship between structures of catalyst layers and cell performances, we analyzed the effects of film thickness and water content on the oxygen permeation properties of ionomer in the cathode catalyst layer of PEFC using molecular dynamics simulations. We constructed a system in which oxygen molecules permeated ionomer on a platinum (Pt) surface. We found that sulfonic acid groups have a significant effect on oxygen permeation in low water content conditions.