Investigation of Gas Evolution on Nickel Wire Electrodes During Alkaline Water Electrolysis

The pursuit of higher current densities and device miniaturization intensifies gas evolution in alkaline water electrolysis, thereby reducing catalyst utilization and degrading system performance. In this work, a visualized alkaline electrolysis system was developed to investigate bubble dynamics on vertically oriented nickel wire electrodes. High-speed imaging coupled with a Yolov8 deep learning model enabled quantitative analysis of oxygen evolution behavior, revealing distinct bubble evolution modes such as isolated growth and coalescence. Systematic experiments demonstrated that current density, electrode diameter, and KOH concentration exert significant influences on bubble size distribution. Further correlation with electrochemical performance showed that increases in bubble population and size result in higher overpotentials, while bubble volume exhibits a strong linear relationship with the system’s ohmic resistance. These findings provide mechanistic insights into the coupling between bubble evolution and electrochemical performance, offering guidance for the design of efficient alkaline electrolyzers.