Improved Alkaline Electrode Configuration and CFD Modeling Comparison between Different Electrolysers

Alkaline electrolysis is the most industrially developed hydrogen production approach. Any improvements of alkaline electrolysers (AEL) are aimed at increasing the efficiency of the system. As a result, the most mature technology ‘classical’ AEL is developed further to Zero-gap AEL by compressing the porous electrodes on both sides of hydroxide anion exchange membrane (AEM) in order to reduce the current losses in the cell. In the present study, an improved AEL electrode configuration is proposed to provide a more compact design and lower electrical losses in the system. This was achieved by increasing the thickness of the electrodes by 10 times and adding hole’s structure. Here, three electrolyser designs: classical AEL, AEM, and an improved AEL were modeled by COMSOL Multiphysics software and compared in polarization curves, hydrogen production and efficiency. All designs feature identical active surface areas of 365 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for hydrogen production but vary in overall size. Both the classical AEL and AEM designs are with dimensions of 19 cm × 19 cm. In contrast, the improved AEL design has more compact dimensions of 5 cm × 5 cm, achieving the same hydrogen production capacity with a reduction of 53% and 73% in volume size, respectively. It was observed the lowest working temperature at 2.1V operating voltage is 21.3 °C for the new model comparing with AEL and AEM of 27.8 °C and 68 °C respectively. The findings emphasize the importance of design optimisation in enhancing the practicality of electrolyser technologies.