Porous Transport Layers for Proton Exchange Membrane Electrolysis Under Extreme Conditions of Current Density, Temperature, and Pressure

Abstract

Hydrogen produced via water electrolysis powered by renewable electricity or green H2 offers new decarbonization pathways. Proton exchange membrane water electrolysis (PEMWE) is a promising technology although the current density, temperature, and H2 pressure of the PEMWE will have to be increased substantially to curtail the cost of green H2. Here, a porous transport layer for PEMWE is reported, that enables operation at up to 6 A cm−2, 90 °C, and 90 bar H2 output pressure. It consists of a Ti porous sintered layer (PSL) on a low-cost Ti mesh (PSL/mesh-PTL) by diffusion bonding. This novel approach does not require a flow field in the bipolar plate. When using the mesh-PTL without PSL, the cell potential increases significantly due to mass transport losses reaching ca. 2.5 V at 2 A cm−2 and 90 °C. On the other hand, the PEMWE with the PSL/mesh-PTL has the same cell potential but at 6 A cm−2, thus increasing substantially the operation range of the electrolyzer. Extensive physical characterization and pore network simulation demonstrate that the PSL/mesh-PTL leads to efficient gas/water management in the PEMWE. Finally, the PSL/mesh-PTL is validated in an industrial size PEMWE in a container operating at 90 bar H2 output pressure.