Membranes, Electrodes, and Membrane-Electrodes Assemblies Analyzed before and after Operation by Atomic Force Microscopy

Material-sensitive and conductive atomic force microscopy was applied to the investigation of cross sections of membraneelectrode-assemblies (MEA) at operating conditions, 80% relative humidity and 75°C, before and after operation. The ionomer content inside the electrodes could be measured due to their characteristic mechanical, chemical and physical properties. By surface potential measurements across MEAs after degrading fuel cell operation, a severe influence of the re-deposited platinum on the potential distribution was found.