Electrochemical and thermodynamic analysis of alkaline water electrolysis: Design and performance optimization

This study employs an electrochemical thermodynamic model to analyze the performance of an alkaline water electrolysis (AWE) system. The model is numerically solved using MATLAB to investigate the effects of key design parameters, including electrode thickness, electrode porosity, electrolyte concentration, electrode spacing, membrane thickness, and membrane porosity. Additionally, the study examines the influence of operating conditions such as temperature and pressure. A comparative analysis is conducted on the second-law efficiency of two high-pressure hydrogen production systems utilizing AWE: one integrating a high-pressure feed pump with AWE, and the other combining AWE with a high-pressure compressor. The results highlight the critical role of ohmic electrode resistance in cell performance, emphasizing the need for accurate modeling based on cell and electrode design. Notably, very thin or highly porous electrodes exhibit high ohmic resistance, leading to reduced AWE cell efficiency. Based on second-law efficiency analysis, the feed pump-coupled AWE system outperforms the AWE-compressor system across the pressure range of 0–100 bar, at an inlet temperature of 60 °C and a current density of 0.6 A/cm².