Morphology and performance evolution of anode microstructure in solid oxide fuel cell: A model-based quantitative analysis

The morphological evolution caused by Ni coarsening is one of the main causes of performance degradation in solid oxide fuel cell (SOFC) anode. In this study, we perform a model-based quantitative analysis to investigate the influences of morphological evolution on SOFC performance and durability. A phase-field model is developed to track the temporal evolution of microstructure as inputs of an electrode numerical model for evaluating the electrochemical performance degradation over time. After model validation, parametric simulations are conducted. It is found that Ni coarsening manifests mainly in two aspects: the reduction of total three-phase boundary (TPB) length, and the lengthening of single TPB. Based on the quantified microstructure parameters, the overpotential increase caused by Ni coarsening is obtained. Besides, the results highlight the importance of Ni content on the temporal evolution. The performance analysis provides an optimal range of Ni content, which can maintain a relatively low overpotential during the whole process.