A mathematical model to analyze solid oxide electrolyzer cells (SOECs) for hydrogen production

• A numerical model is developed for Solid Oxide Electrolysis Cells.
• The model couples kinetics at the micro-scale level with macro-scale phenomena.
• Model is validated with experimental data for SOEC running on H2–H2O.
• Electrochemical behavior and irreversible losses during SOEC operation are reported.
• Efficiency analysis and limiting current behavior of the SOEC system are studied.

In this analysis, we report an in-house model to describe the complex fundamental and functional interactions between various internal physico-chemical phenomena of a SOEC. Electrochemistry at the three-phase boundary is modeled using a modified Butler–Volmer approach that considers H2 as the electrochemically active species. Also, a multi-step elementary heterogeneous reaction mechanism for the thermo-catalytic H2 electrode chemistry, dusty-gas model to account for multi-component diffusion through porous media, and plug flow model for flow through the channels are used. Results pertaining to detailed chemical processes within the cathode, electrochemical behavior and irreversible losses during SOEC operation are demonstrated. Furthermore, efficiency analysis is performed and limiting current behavior of the SOEC system is investigated.