Optimizing of electrolyte thickness for solid oxide electrolytic cell considering current leakage and internal oxygen partial pressure at the oxygen electrode/electrolyte interface

Solid Oxide Electrolytic Cell (SOEC) offers a sustainable solution for efficient hydrogen production and stores energy from renewable energy. Increasing electrolyte thickness could reduce the current leakage and promote the hydrogen production . However, it can also cause high oxygen partial pressure , result in a hazardous situation. Therefore, ensuring oxygen partial pressure safety and minimizing current leakage are key points in designing electrolyte thickness. In this study, we chose the appropriate electrolyte thickness to balance hydrogen production losses, current leakage and safety. Firstly, a current leakage model for SOEC is introduced, an oxygen partial pressure security constraint model is presented as well. Then, the two optimization problems are formulated for both constant and varying input power application scenarios. Finally, the optimization model is used to calculate the ideal electrolyte thickness among three types material electrolytes, and maximize hydrogen production. The findings of this study show that the optimal electrolyte thickness could improve the hydrogen production rate significantly as the constant and varying power input. This means optimizing the electrolyte thickness, which is required to match the photovoltaic solar radiation in different regions, so as to achieve efficient hydrogen production. These results can make a valuable guiding to the design of SOEC. • A theoretical leakage current model for the SOEC in the electrolyte is proposed. • The analytical expression of leakage current for electrolyte thickness is obtained. • The oxygen partial pressure security constraint at anode–electrolyte is established. • Optimizing electrolyte balances leakage current and efficient hydrogen production. • Both constant and varying power input scenarios are discussed for optimization.