Orbital Charge Exchange Transition Conceptually Activates Multi-Bifunctional Li–O₂ and Li–CO₂ Pathways at Deep and Shallow Energy Levels in Li–Air Batteries

In Li-air batteries (LABs), the deep and shallow orbital distributions of reactants in Li–O₂ and Li–CO₂ pathways in ambient air pose a conceptual predicament for designing cathode catalysts that can precisely activate multi-functional electrocatalysis at different energy levels with a large energy gap. Following the design guideline of optimizing deep and shallow band structures, an orbital charge exchange transition strategy was applied to tailor the electronic structure of Ce₂Mo₃O₁₂ as a potential catalyst. Theoretical investigation predicts the oxygen vacancy-induced ligand rearrangement tendency and the orbital charge exchange transition from a f-p-f super exchange between Ce─O─Ce sites to a f-p-d double exchange mode between Ce─O─Mo hetero-sites. This motivates the low-lying Ce 2e orbitals for Li–O₂ pathways and gains a charge-filled shallow Mo d-band for Li–CO₂ pathways. Importantly, the XANES and related electronic and crystal structure analysis, quantitative electrocatalysis investigation and high battery performance perfectly identify the reliability of the theoretical prediction. Consequently, the Ce₂Mo₃O₁₂ cathode exhibited stable operation for nearly 600 cycles in ambient air with excellent humidity tolerance and an impressive energy density of 1560 Wh kg⁻¹ for pouch cells as power sources of electric devices, marking a significant step for the practical application of LABs.