Role of Patterned Wettability of Anode Porous Transport Layer in Enhancing Two-Phase Transport for Proton Exchange Membrane Electrolyzers

Green hydrogen production through proton exchange membrane (PEM) electrolyzers, powered by renewable energy sources and capable of operating at high current densities, has attracted considerable attention. However, two-phase transport within the anode porous transport layer (PTL) and catalyst layer (CL) significantly impacts the performance of PEM electrolyzers. In this work, the role of patterned wettability of the PTL is investigated in optimizing the gas distribution in the PTL, PTL/CL interface, and CL for PEM electrolyzers by a three-dimensional, two-phase, dual-scale pore network model. The dual-scale pore network modeling (PNM) approach analyzes the gas invasion process in the PTL, with a view to examining the impact of wettability on two-phase transport. Initially, gas invades larger pores at the PTL/CL interface, resulting in a rapid increase in the gas-phase saturation. As the invasion process continues, the rate of increase in the gas-phase saturation declines. By adjusting the width and ratio of hydrophobic regions in the PTL, gas-phase saturation can be effectively reduced. Notably, implementing patterned wettability with a hydrophilic/hydrophobic ratio of 3:1 and a width of 25 μm enhances water transport, reducing gas-phase saturation to 18%, which is over 14% lower than that observed for the PTL with original wettability.