(166d) A Design of Gas Diffusion Media for Polymer Electrolyte Membrane Fuel Cells

Polymer exchange membrane (PEM) fuel cells are promising candidates to decarbonize transportation sector. They use hydrogen to produce electricity and water. The components must be optimized for either high efficiency or high current density operation. Micro-porous layers (MPL) that contact catalyst layer serve as layers that conduct electricity and heat, remove water and enable oxygen delivery to the active sites. The MPL is made of carbon black powder bound by hydrophobic agent. Commercially available MPLs are either impregnating the gas diffusion layer or are free-standing. Some feature cracks and inhomogeneous surfaces that are not favorable for thin (~10 micrometers) membranes that are currently being used in PEM fuel cells community. In this presentation I will summarize the effort into optimizing commercial MPLs and also designing novel MPLs using Teflon AF as a binder. We further try to understand the impact of MPL cracks on the PEM fuel cells durability, a topic that is of importance but has not been studied thoroughly in the field. We conclude that there is still room to advance MPLs to enable broader deployment of PEM fuel cells.