A novel multi-physics coupled heterogeneous single-cell numerical model for solid oxide fuel cell based on 3D microstructure reconstructions

As one of the most prevailing tools, numerical modeling plays a unique role in understanding the multi-physics interactions in Solid Oxide Fuel Cells (SOFCs) during operation at elevated temperatures. Unfortunately, a dynamic heterogeneous single-cell model in actual sizes has not been reported yet for predicting cell performance. In this work, a three-dimensional (3D), multi-physics coupled dynamic heterogeneous single-cell model is proposed based on 3D reconstructions of all SOFC components using the focused ion beam-scanning electron microscopy (FIB-SEM) technique. The simulations are conducted based on tetrahedral meshes in COMSOL coordinated with custom codes for automated feature recognition, equation assignment, and solutions. The current-voltage curves and Electrochemical Impedance Spectroscopy (EIS) predicted by the model are in good agreement with the experimental data. The factors affecting the polarization characteristics under different conditions are analyzed systematically. The model then is applied in quantifying the performance degradation in a SOFC caused by nickel phase coarsening and agglomeration in the anode functional layer (AFL) after 7000 h operation. The proposed single-cell model is flexible and can be superimposed with other fields and domains and incorporate inputs from multi-scale simulations, which leads to a potential platform for future SOFC optimization to improve overall electrochemical performance.