Recent advances in perovskite oxide electrocatalysts for Li-O2 batteries

Abstract

Lithium-oxygen batteries (LOBs) have been anticipated as promising energy-storage devices; however, their practical application is plagued by low energy efficiency, small capacity, and the short cycle life. When applied as air cathodes for LOBs, perovskite oxides exhibit an enormous potential for favorable battery performance due to their catalytic activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Their tunable compositions, diverse structures and unique electronic properties allow flexible manipulation of their catalytic activity. This mini-review comprehensively describes recent advances in perovskite oxide electrocatalysts for LOBs. First, the energy-storage mechanism of LOBs and crucial catalytic descriptors of perovskites for the ORR/OER are analyzed. Then, several ingenious tactics to promote the catalytic activity of perovskite oxides are highlighted. A discussion of synthetic protocols for the preparation of perovskite oxides follows, including how the nanostructure, morphology and composition of perovskite oxides can be controlled by different methods and the effect of these on catalytic performance. Additionally, A-/B-/O-site regulation, oxygen vacancies, and the composites of perovskites and functional materials are thoroughly investigated. Finally, we summarize the challenges and outlook of perovskite oxide electrocatalysts for LOBs.