Modeling of Solid-Oxide Electrolyser Cells: From H2, CO Electrolysis to Co-Electrolysis

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 H-2 and CO, individually, as electrochemically active species. Also, a multi-step elementary heterogeneous reaction mechanism for the thermo-catalytic H-2/CO2 electrode chemistry, along with the dusty gas model (DGM) to account for multi-component diffusion of ideal gases through porous media, are used. The model is geometry independent. Results pertaining to detailed chemical processes within the cathode, electrochemical behavior and irreversible losses during SOEC operation are demonstrated.