HTS technology for optimizing the electrocatalytic activity of barium ferrite air electrodes for protonic ceramic cells

Barium ferrite-based perovskite oxides have emerged as promising parent materials for protonic ceramic cell (P-SOC) air electrodes owing to their low cost and broad applicability. However, conventional high-temperature calcination methods fail to yield a single-phase barium ferrite. Developing an appropriate synthesis process to optimize phase composition is thus crucial for enhancing its electrocatalytic activity. In this study, a high-temperature thermal shock (HTS) technique is proposed to optimize the phase composition of barium ferrite and further improve its electrocatalytic performance. HTS-BF comprises a Ba₂Fe₂O₅ phase and a minor BaFe₂O₄ phase. Compared to barium ferrite prepared via conventional high-temperature calcination, HTS-BF possesses a larger specific surface area and a higher concentration of oxygen vacancies, leading to significantly enhanced electrocatalytic activity. At 650 °C, HTS-BF-based single cell achieved a peak power density of 0.806 W cm⁻² and an electrolysis current density of 1.654 A cm⁻² at 1.3 V. In addition, HTS-BF-based single cell exhibited excellent durability, maintaining stable operation for over 100 h without noticeable degradation in both fuel cell and electrolysis modes. This work thus presents a rapid and efficient method for preparing barium ferrite-based air electrode materials and further enhances their electrocatalytic activity.