Effect of volume fractions and aging on Ni-GDC SOFC anode degradation and performance: multiphase-field simulations

Abstract Enhancing the performance and durability of solid oxide fuel cells (SOFCs) requires concurrent improvements in electrochemical activity and mechanical integrity, both strongly dependent on the initial anode microstructure and its degradation over long-term operation. This study presents a comprehensive degradation investigation for nickel-gadolinium doped ceria (Ni-GDC) SOFC anode microstructures, combining the generation of realistic synthetic microstructures and large-scale aging simulations. Synthetic microstructures are generated and quantitatively validated against experimental reconstructions of Ni-GDC employing an enhanced structure generator workflow that incorporates sintering-like morphological coalescence, resulting in digital twins for optimization studies. Representative synthetic microstructures are generated with systematically varying phase volume fractions and subjected to long-term (2000 h) aging using a validated multiphase-field model. Electrochemical performance descriptors, including triple-phase boundary (TPB), double-phase boundary (DPB) densities, phase tortuosities, and mechanical properties, such as elastic moduli and stress distributions resulting from thermal expansion coefficient mismatch between Ni and GDC, are collectively analyzed. The results provide detailed insights into the design of anode microstructures by highlighting trade-offs between initial and degradation-induced electrochemical and mechanical performance.