Manipulating Electron Delocalization of Metal Sites via a High-Entropy Strategy for Accelerating Oxygen Electrode...

High-entropy perovskite oxides, in which the B-type metal site of perovskite oxides (ABO₃) is occupied by over five kinds of transition metal ions, show promising applications in energy storage and conversion fields. Herein, high-entropy perovskite oxides (LaSr(5TM)O₃) composed of Cr, Mn, Fe, Co, and Ni at the B-type metal site are prepared as oxygen electrocatalysts for Li-O₂ batteries. The presence of compressive strain in LaSr(5TM)O₃ effectively regulates the 3d orbit occupancy of the active Co site (Co²⁺ → Co³⁺) and lifts the energy level of the Co d-band center, thus leading to enhanced adsorption toward the LiO₂ intermediate on Co sites. Furthermore, the high electron-drawing capability of Cr sites ensures sufficient electron exchange and further strengthens the adsorption of LiO₂. As expected, the Li-O₂ battery with a LaSr(5TM)O₃ electrode delivers a low overpotential (0.79 V) and superior cyclability (226 cycles). This study provides a meaningful strain strategy to improve the electrocatalytic activity of multicomponent oxides via fabricating high-entropy materials.