Gas diffusion layers (GDLs) are vital components in Polymer Electrolyt Membrane Fuel Cells (PEMFC) modulating all relevant transport processes comprising fuel, oxidants, reaction products, electricity and heat. Gas diffusion layers serve as a functional interface between the gas distribution compartments (structural cell parts, macroscopic scale) and the electrochemically active catalyst layers (reaction layers, processes occurring at the nanoscale). GDLs direct fuels and oxidants to the active sites whilst removing heat and reaction products and electrically wiring the reaction layers with the current collectors.
