Characterization of gas diffusion layer transport properties by limiting current approach

The high performance of hydrogen fuel cells requires an efficient transport of product/reactants in the porous electrodes. An important role in the transport processes plays a gas diffusion layer (GDL) – a key part of the fuel cell electrode. In this work, we studied gas transport properties of commercially available GDLs using a limiting current technique. Average relative diffusivities of oxygen and hydrogen for different commercially available GDLs were measured in operating fuel cell. An elaborate analysis of oxygen and hydrogen transport provided important insights into gas diffusion performance and water saturation of GDL at different current densities. Water transport was found to be governed by the GDL thickness. Structural study of GDL by scanning electron microscopy and mercury intrusion porosimetry techniques was performed. Fuel cell performance of GDLs at different relative humidities was studied and analyzed in the framework of transport and structural properties.