Mitigating the Degradation of Electrodes in Alkaline Water Electrolysis during Shutdown Mode by Interrupting Reverse Current

Abstract

Alkaline water electrolysis (AWE) is a promising technology for large-scale hydrogen production using renewable energy sources (RES). However, AWE integrated with RES experiences shutdown mode due to their intermittency, resulting in reverse current through open flow path of high ionic conductivity. This induces irreversible phase changes, which lead to electrode degradation and inevitably reduce the performance of the AWE. Therefore, it is important to examine the degradation mechanism and identify effective methods to reduce reverse current in AWE. In this work, we developed AWE system which impedes hydroxide ion transfer using deionized (DI) water circulation when it undergoes a shutdown mode. Cutting off the flow of ionic charges prevents the electrodes from forming irreversible phase change, making long-term operation possible while securing durability. We examined how reduced ionic conductivity mitigates the side effects of reverse current using phase characterization and electrochemical performance tests. Based on these results, we established an optimal way to impede hydroxide ion transfer in shutdown condition of an AWE system integrated with RES. Our findings will overcome fatal shortcomings and operate more efficiently in AWE industry.