Laser fabricated micropattern of anode flow field enhances under-rib mass transport and performance in PEM water electrolysis

Proton exchange membrane water electrolysis is of great significance for the utilization of renewable energy and hydrogen energy storage, and the anodic gas-liquid two-phase flow limits the performance improvement. In this study, laser fabricated micropattern ribs of anode flow field are developed to enhance under-rib mass transport. The effects of rib surface microstructures on the two-phase transport, gas-liquid distribution, and electrolysis performance are comparatively studied. The results show that femtosecond laser processing can precisely fabricate microstructures on the rib surface. The microstructures enhance the gas-phobic effect on the anode rib surface, which is beneficial for bubble detachment, thereby reducing gas accumulation and accelerating liquid water supply. In addition, the use of dot-patterned microstructures can achieve efficient contact at the flow field/PTL interface and reduce the contact resistance. As a result, the electrolyzer with dot-patterned rib achieves the best electrolysis performance. At an electrolysis voltage of 2.0 V, the maximum current density (3.50 A cm−2) is 8.4% and 16.3% higher than that of the electrolyzer with channel-patterned rib (3.23 A cm−2) and the conventional rib (3.01 A cm−2).