Investigating Bubble-Induced Overpotential, Current Non-Uniformity, and Gas Cross-over in Flow-based Water Electrolyzers: A Numerical Study

Abstract

The transition towards a sustainable energy landscape necessitates efficient and scalable technologies for renewable energy storage. Water electrolysis, a process that converts electrical energy into chemical energy stored in hydrogen, holds immense potential for integration with intermittent renewable sources. However, the performance and efficiency of water electrolyzers are impeded by the complex multiphase flow dynamics involving bubble nucleation, growth, and transport within the electrochemical cell. This study employs state-of-the-art three-dimensional multiphase flow simulations to unravel the intricate interplay between bubbles and the electrochemical processes in a parallel-electrodes flow-based electrolyzer (PE-FBE). By accurately capturing bubble-electrolyte interfaces, the simulations quantify the detrimental effects of bubbles on overpotentials, current density distribution, and gas crossover. Crucially, the impact of critical parameters, including flow rate, bubble nucleation size, surfactant addition, and applied current, on these performance metrics is systematically investigated. The findings reveal strategies to mitigate bubble-induced losses, enhance current uniformity, and improve hydrogen purity, paving the way for optimized electrolyzer designs and efficient renewable energy storage.