Neutron Radiographic Investigations on the Effect of Hydrophobicity Gradients within MPL and MEA on Liquid Water Distribution and Transport in PEMFCs

In-Plane neutron radiography imaging technique was performed to investigate the effect of hydrophobicity gradients within catalyst layers (CLs) and cathode microporous layer (MPL) on water dynamics of polymer electrolyte membrane fuel cell (PEMFC) during operation. Effect of varying operating conditions (current density and relative humidity) of the inlet gases on the water content of the cells were evaluated. Hydrophobization of catalyst layers improved the membrane humidification, especially at more dry conditions. Implementation of more hydrophobic cathode MPL resulted in an increment of overall water content within the CLs and GDLs on anode and cathode side. Furthermore, the role of back diffusion transport mechanism on the water distribution was identified for the constructed cells in this study.