First-principles Calculation Study on the Mechanism of Oxygen Reduction Reaction at the SrO/La0.5Sr0.5FeO3-δ/Air Three-phase Boundary

Solid oxide fuel cells (SOFCs) have attracted significant attention in the renewable energy field due to their high-efficiency and clean energy conversion capabilities. The Sr segregation phenomenon occurring on the electrode surface is often regarded as the main cause of performance degradation. However, recent studies have shown that a small amount of SrO deposition can actually enhance performance, indicating that the mechanism by which SrO affects the oxygen reduction reaction (ORR) activity remains unclear. First-principles calculations reveal that the SrO/LSF/air three-phase boundary significantly reduces the oxygen vacancy formation energy and the ORR activation energy, thereby enhancing electrocatalytic performance. Furthermore, by simulating the change in boundary length with varying deposition amounts, it was discovered that a small amount of SrO deposition forms a large number of SrO/LSF/air three-phase active boundaries, whereas excessive SrO deposition covers these active boundaries, inhibiting ORR activity. This reveals the mechanism by which the SrO/LSF/air threephase boundary promotes ORR activity at SOFC cathodes, providing a theoretical basis for optimizing electrode design.