Modeling the Effects of the Cathode Micro-Porous Layer on the Performance of a PEM Fuel Cell

In this study, a model was developed to evaluate the role of the micro-porous layer (MPL) and the effects of its properties on the liquid water saturation levels in the cathode porous media and the performance of a proton exchange membrane (PEM) fuel cell. The results validated that the fuel cell performance was improved by adding an MPL between the macro-porous gas diffusion layer (GDL) and the catalyst layer (CL) in the cathode side. The MPL, due to its high hydrophobicity, increases the liquid water pressure in the cathode to the levels much higher than those in the anode resulting in an increased back-transport rate of liquid water from the cathode to the anode. The more hydrophobic the MPL is, the higher liquid pressure increases, and, consequently, the higher driving force is created across the membrane to drive water from the cathode to the anode.