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

Hydrogen produced via water electrolysis powered by renewable electricity or green H-2 offers new decarbonization pathways. Proton exchange membrane water electrolysis (PEMWE) is a promising technology although the current density, temperature, and H-2 pressure of the PEMWE will have to be increased substantially to curtail the cost of green H-2. Here, a porous transport layer for PEMWE is reported, that enables operation at up to 6 A cm(-2), 90 degrees C, and 90 bar H-2 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 degrees 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 H-2 output pressure.

Automated summary

This study presents a porous transport layer for PEMWE, allowing operation at higher current density, temperature, and H-2 output pressure, reducing the cost of green H-2 production and extending the operational range of the electrolyzer. Extensive physical characterization and pore network simulation demonstrate efficient gas/water management in the PEMWE.