Recent Advances in Barium Cobaltite‐Based Perovskite Oxides as Cathodes for Intermediate‐Temperature Solid Oxide Fuel Cells

Abstract Solid oxide fuel cells (SOFCs) are considered as advanced energy conversion technologies due to the high efficiency, fuel flexibility, and all‐solid structure. Nevertheless, their widespread applications are strongly hindered by the high operational temperatures, limited material selection choices, inferior long‐term stability, and relatively high costs. Therefore, reducing operational temperatures of SOFCs to intermediate‐temperature (IT, 500–800 °C) range can remarkably promote the practical applications by enabling the use of low‐cost materials and enhancing the cell stability. Nevertheless, the conventional cathodes for high‐temperature SOFCs display inferior electrocatalytic activity for oxygen reduction reaction (ORR) at reduced temperatures. Barium cobaltite (BaCoO 3‐δ )‐based perovskite oxides are regarded as promising cathodes for IT‐SOFCs because of the high free lattice volume and large oxygen vacancy content. However, BaCoO 3‐δ ‐based perovskite oxides suffer from poor structural stability, inferior thermal compatibility, and insufficient ionic conductivity. Herein, an in‐time review about the recent advances in BaCoO 3‐δ ‐based cathodes for IT‐SOFCs is presented by emphasizing the material design strategies including functional/selectively doping, deficiency control, and (nano)composite construction to enhance the ORR activity/durability and thermal compatibility. Finally, the currently existed challenges and future research trends are presented. This review will provide valuable insights for the development of BaCoO 3‐δ ‐based electrocatalysts for various energy conversion/storage technologies.