APPLICATION OF AC-IMPEDANCE IN FUEL-CELL RESEARCH-AND-DEVELOPMENT

In applying ac impedance to fuel cells and their porous (gas diffusion ) electrodes the emphasis lies on different fuel cell components, and their properties, according to the fuel cell type. The focus has been directed at the electrode/electrolyte interface in MCFC and PAFC, wher eas in SOFC and PEMFC the ionic/electronic conductivity of the electro lyte or the characteristics of its composite with the electrocatalyst is of primary interest. The limitations of ac impedance in fuel cell a pplication are in part due to difficulties of interpretation and in pa rt due to experimental difficulties because of the generally fast elec trode reaction kinetics. Further research directions are indicated.