Self-Supporting Microporous Layers (MPLs) for PEM Fuel Cells

Abstract

The main requirements of a gas diffusion layer (GDL) of polymer electrolyte membrane fuel cells (PEMFC) are the provision of a gas and water transport as well as a significant electrical and thermal conductivity. The development of membrane electrode assemblies (MEA) for a wide temperature range (-20°C until +130°C) still favours membranes that require a certain level of humidification for sufficient proton conductivity. The PEMFC diffusion media and their influence on water management is of crucial importance for these conditions, however, the detailed structure relations and especially the influence of the micro porous layer (MPL) needs further investigation. An important function of the cathode side MPL at high temperature operation of PEMFCs is the prevention of membrane drying. However, a flooding of porous structures in the GDL or catalyst layers at lower temperatures has to be avoided under all operation conditions.