Electron Itinerancy Mediated by Oxygen Vacancies Breaks the Inert Electron Chain to Boost Lithium–Oxygen Batteries Electrocatalysis

Abstract

The synergistic effect of dopants and oxygen vacancies (V_o) in metal oxides is crucial for enhancing the adsorption and electron transfer processes in lithium–oxygen (Li–O₂) batteries; however, the underlying mechanisms remain unclear. Herein, Ru single-atom-modified TiO₂ nanorod array (Ru₁–TiO_2−x) electrocatalysts with abundant V_o were fabricated, serving as an efficient catalyst for Li–O₂ batteries. Experimental and theoretical investigations have demonstrated that V_o functions as an “electron pump”, facilitating electron itinerant behavior, while Ru₁ serves as an “electron buffer” to further activate the [Ru–O–Ti] electronic chain. This synergistic interplay endows Li–O₂ batteries with a highly active and stable bidirectional self-regulating capability during the process of circulation, exhibiting an ultra-low charge polarization (0.42V) and exceptional cycling stability (1680 h). V_o and Ru₁ synergistically modulate the d-band center at the Ti site to establish an adaptively tunable Ru–Ti dual-active site. This adjustment effectively balances the binding strength with the interface oxygen intermediate (^*O), thereby significantly reducing the activation barrier. The Hamiltonian layout further revealed the crucial role of remote orbital coupling in maintaining the structural stability. This study not only provides profound insights into V_o-dependent electron transfer kinetics but also proposes new strategies and theoretical guidance for the activation of inert materials.