Unlocking the Orbital Interaction Mode in Li–O₂ Batteries

Understanding electrocatalyst-intermediate orbital interaction in oxygen evolution reactions (OER) is critical for designing high-performance lithium–oxygen (Li–O₂) batteries, yet remains a significant challenge. In this study, we employed a CdSe-based catalyst as a model cathode to deeply investigate the catalyst–intermediate interaction and its effect on OER activity. Compared to the 4d orbital electronic states of Cd in CdSe, electron transfer from CdSe to ZnS in the CdSe/ZnS heterojunction results in a downward shift of the Cd 4d suborbital energy levels. The differences in the Cd 4d orbital electronic states between CdSe and CdSe/ZnS cause distinct orbital interaction mode with LiO₂ intermediate, ultimately leading to variations in OER activity. Specifically, compared to the strong Cd 4d_xy–O 2P_x/y orbital interaction mode between CdSe and LiO₂, the weaker Cd 4d_z²–O 2P_y orbital interaction mode between CdSe/ZnS and LiO₂ significantly reduces the activation energy of the rate-determining step, thereby enhancing OER activity. This finding provides theoretical guidance for the design of OER electrocatalysts in Li–O₂ batteries.