Anion Doping: A New Strategy for Developing High‐Performance Perovskite‐Type Cathode Materials of Solid Oxide Fuel Cells

Overcoming the sluggish activity of cathode materials is critical to realizing the wide‐spread application of intermediate‐temperature solid oxide fuel cells. Herein, a new way is reported to tune the performance of perovskite‐type materials as oxygen reduction electrodes by embedding anions (F − ) in oxygen sites. The obtained perovskite oxyfluorides SrFeO 3− σ − δ F σ and SrFe 0.9 Ti 0.1 O 3− σ − δ F σ (σ = 0.05 and 0.10) show improved electrocatalytic activity compared to their parent oxides, achieving area specific resistance values of 0.875, 0.393, and 0.491 Ω cm 2 for SrFeO 3− δ , SrFeO 2.95− δ F 0.05 , and SrFeO 2.90− δ F 0.10 , respectively, at 600 °C in air. Such improved performance is a result of the improved bulk diffusion and surface exchange properties due to anion doping. Moreover, favorable stability in performance is also demonstrated for the F − anion‐doped perovskites as oxygen reduction electrodes at 650 °C for a test period of ≈200 h. A combination of anion doping and cation doping may provide a highly attractive strategy for the future development of cathode materials.