Multi-Physics Coupling Simulation of H2O–CO2 Co-Electrolysis Using Flat Tubular Solid Oxide Electrolysis Cells

Solid oxide electrolysis cells (SOECs) have emerged as a promising technology for efficient energy storage and CO2 utilization via H2O–CO2 co-electrolysis. While most previous studies focused on planar or tubular configurations, this work investigated a novel flat, tubular SOEC design using a comprehensive 3D multi-physics model developed in COMSOL Multiphysics 5.6. This model integrates charge transfer, gas flow, heat transfer, chemical/electrochemical reactions, and structural mechanics to analyze operational behavior and thermo-mechanical stress under different voltages and pressures. Simulation results indicate that increasing operating voltage leads to significant temperature and current density inhomogeneity. Furthermore, elevated pressure improves electrochemical performance, possibly due to increased reactant concentrations and reduced mass transfer limitations; however, it also increases temperature gradients and the maximum first principal stress. These findings underscore that the design and optimization of flat tubular SOECs in H2O–CO2 co-electrolysis should take the trade-off between performance and durability into consideration.