Effects of Wide Temperature Range and Porous Media Parameters on Alkaline Electrolyzer Performance under Multiphysics Coupling

Alkaline water electrolysis is a mature commercial hydrogen production technology; however, the unclear impact mechanisms of wide-temperature operating conditions and porous media parameters on electrolyzer performance restrict its efficient operation. This study establishes an electricity-gas-liquid-heat multiphysics coupling model to systematically analyze the effects of temperature, electrode, and diaphragm characteristics on electrolyzer performance. Results show that multiphysics coupling causes significant nonlinear polarization behavior: the bubble effect remarkably increases polarization, whereas moderate heating can partially offset this negative impact. Temperature affects the electrolysis process in a dual manner: heating improves efficiency but exacerbates bubble-induced polarization. High temperature exerts different influences on hydrogen and oxygen production: the hydrogen generation rate exhibits a peak, whereas the oxygen generation rate continuously increases with rising temperature. This is the result of the combined effects of the enhanced activity of the temperature-induced oxygen evolution reaction and the change in gas solubility. Sensitivity analysis of porous media parameters reveals that diaphragm parameters affect electrolyzer performance 1.5 to 3 times more significantly than do electrode parameters, highlighting the importance of optimizing diaphragm parameters. This study clarifies the critical role of temperature management and porous media parameters in optimizing electrolysis efficiency, providing a reference for parameter selection and performance improvement.