Porous Transport Layers with TiC-Coated Microporous Layers for Proton Exchange Membrane Water Electrolysis

The performance of a proton exchange membrane electrolyzer is greatly affected by the interfacial contact between the porous transport layer and the catalyst layer. Microporous layers have been widely used in proton exchange membrane fuel cells but have been less studied for proton exchange membrane water electrolysis. In this study, porous transport layers incorporated with microporous layers are developed by using a phase inversion/vacuum sintering method. Characterizations show that the microporous layers uniformly cover the surface of titanium felt without significantly changing its porosity. After vacuum sintering, titanium carbide (TiC) is formed, which is an efficient protective layer against corrosion under acidic conditions and high potential. Compared with a titanium felt reference, the sintered microporous layer-based porous transport layers display better hydrophilicity. Polarization experiments find that the addition of microporous layers decreases the contact resistance, improves the electrochemical performance, and reduces the mass transfer resistance at a high current density. Ex situ and in situ stability testing confirms the material's enhanced inertness against corrosion.