Multiphase-Field Simulation Studies of Coarsening in Ni-GDC SOFC Anode Microstructures and the Effect of Interfacial Energies

The long-term durability of solid oxide fuel cells (SOFCs) requires a comprehensive understanding of electrode degradation mechanisms. Performance degradation of nickel-gadolinium-doped ceria (Ni-GDC) electrodes, however, is not yet thoroughly understood, limiting their effective design and advance-
ment. Multiphase-field (MPF) simulation studies provide an effective method to understand the underlying microstructural changes and the resulting electrochemical property alterations in
SOFCs over time. In this study, we present quantitative simulations of nickel and GDC coarsening in SOFC anodes employing an MPF model utilizing focused ion beam-scanning electron microscopy-
reconstructed experimental 3D microstructures and reliable thermophysical parameters. The model is initialized with experimentally reconstructed pristine and preaged Ni-GDC microstructures and validated against aged experimental microstructures after 240 and 1100 operating hours. The model incorporates both surface and interface diffusivity to capture morphological evolutions. Key microstructural properties, mean particle size, three-phase boundary line density, tortuosity, and specific surface
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areas are evaluated to assess degradation. Furthermore, the influence of surface and interfacial energies on long-term degradation is investigated by considering distinct thermodynamic equilibrium contact angle scenarios at the triple junction and investigating layer formation around particles in Ni-GDC systems.