Physics-based Modeling of Degradation in Alkaline Water Electrolysis Cells due to Reverse Currents

The operation of water electrolyzers with renewable energies means that long-term operation also involves several start-up/shut-down cycles of the system. In particular, for alkaline water electrolyzers (AWE) it is known that shut-down leads to reverse currents, which causes electrochemical degradation and thereby reducing the efficiency. In this work, a modeling framework is proposed and implemented for the electrochemical degradation of nickel electrodes in AWE stacks under start-up/shut-down (SU/SD) operation, and it is achieving good agreement with experiments. Such a model can be used for digital twins of electrolysis plants as well as optimizing its operation.