Cross-scale transient analysis and optimization of electrode morphology evolution in direct-ammonia solid oxide fuel cells

Direct-ammonia solid oxide fuel cells (DA-SOFCs) represents a highly promising energy conversion technology, enabling direct utilization of ammonia (NH₃) as fuel. However, the industrial-scale deployment of SOFCs has been hindered by issues related to poor device durability, notably performance degradation resulting from electrode morphology evolution during long-term operation. In this study, a cross-scale trainset model is established, linking the pore scale with the macroscopic scale, thereby elucidating the mechanisms by which electrode morphology evolution affects performance degradation over long-term operation. Additionally, long-term performance optimization strategies are proposed. The model effectively captures the impact of electrode morphology evolution on NH₃ decomposition and long-term performance. The parametric analysis is conducted to explore the effects of various combinations of operating conditions, flow configurations, and microstructures on the Ni-pore interface area, active three-phase boundary length, NH₃ decomposition and cell performance over time. The findings indicate that the DA-SOFCs exhibits enhanced thermal stability at the cost of a slight reduction in performance relative to its H₂-fueled counterpart. Lowering the operating temperature can alleviate the performance degradation rate, but it also has a profound impact on the cell's overall performance throughout its lifespan. Based on the parametric analysis results, the optimal set of solutions that satisfy different maximum temperature gradient constraints are obtained using a data-driven multi-objective optimization algorithm. The optimal solutions ensure sufficient thermomechanical stability (degradation rate < 0.26 % kh^-1) while meeting the long-term performance requirements.