Influence of hydrophilic and hydrophobic double MPL coated GDL on PEFC performance

Gas diffusion layers (GDLs) coated with a hydrophobic microporous layer (MPL) have been commonly used to improve water management properties of polymer electrolyte fuel cells (PEFCs). In the present study, a novel hydrophilic and hydrophobic double MPL coated GDL was developed to further enhance the PEFC performance under both low and high humidity conditions. Under low humidity conditions, a thin hydrophilic layer using titanium dioxide coated on the hydrophobic MPL is effective to conserve the humidity of the MEA, while a hydrophobic intermediate MPL between the hydrophilic layer and the GDL substrate prevents the removal of water in the hydrophilic layer. Under high humidity conditions, a double MPL coated GDL is also effective to reduce flooding on the cathode catalyst layer, which results in a higher PEFC performance compared with that for a conventional hydrophobic MPL coated GDL.