Successfully incorporating Gd³⁺ ions into the A-site of BaFeO_3-δ by sol-gel method, has resulted in the formation of cobalt-free Gd_xBa_1-xFeO_3-δ (x= 0.1, 0.2, 0.3, and 0.4) perovskites with a stable cubic symmetric structure. The analysis of oxygen vacancy and electrical conductivity reveals that the higher conductivity of Gd_0.3Ba_0.7FeO_3-δ (GBF0.3) promotes the oxygen reduction reaction activity while ensuring enough oxygen vacancy, resulting in the higher electrochemical performance. At 800°C, the polarization resistance of GBF0.3 symmetrical cell and the maximum power density of the GBF0.3 single cell are 0.019 Ω cm² and 0.99 W cm^-2, respectively. Furthermore, the single cell can operate stably for 117 hours under 1.2 A cm^-2. Therefore, it holds great promise as a novel cathode candidate for solid oxide fuel cells (SOFCs).
 

solid oxide fuel cells, Cobalt-free cathode material, Barium ferrites, Gd-doping