A‐Site Defect Engineering Regulates Bimetallic Exsolution in Perovskite Oxide Boosting the Performance of Li–O2 Batteries

Abstract The application life of Lithium–oxygen (Li–O 2 ) batteries can be significantly affected by the formation and full decomposition of the discharge product Li 2 O 2 . After exsolution, the catalyst is designed to control the morphology and crystallinity of Li 2 O 2 enhanced reversibility. In the perovskite exsolution system, the large amount of A‐site defects are introduced to induce the activation of lattice oxygen and the formation of oxygen vacancy, and promote the bimetallic exsolution from La x Fe 0.8 Cu 0.1 Co 0.1 O 3 . When x = 0.70, the distribution density of CuCo alloy and Cu metal increases and the size is smaller. Through exsolution process, the resulting oxygen vacancy and more doped ions exsolved expose a significant number of active sites that enhance the charge transfer and catalytic activity. Therefore, the charge resistance ( R ct ) smaller and can be better decomposed due to the generated small‐size Li 2 O 2 with nano‐sheet morphology. Meanwhile, theoretical calculation shows that the exsolution of the catalyst enhances the adsorption of the intermediate LiO 2 that makes the surface mechanism more advantageous. The reversibility of the battery is improved, and the cycle stability reaches 195 cycles. This work can serve as a guide for the development of exsolution that directs the design of high efficiency cathode catalyst.