Li₂MoO₄ Tailored Anion-enhanced Solvation Sheath Layer Promotes Solution-phase Mediated Li-O₂ Batteries

The high overpotential of Li-O₂ batteries (LOBs) is primarily triggered by sluggish charge transfer kinetics at the reaction interfaces. A typical LiBr redox mediator (RM) catalyst can effectively reduce the battery's overpotential. However, it is prone to shuttling and corroding the Li anode, leading to RM loss and reduced energy efficiency. To address these challenges, we introduced Li₂MoO₄ into the LiBr-containing electrolyte to promote the solution-phase mediated LOBs. This addition tailors the anion-enhanced Li⁺ solvation sheath layer and forms a robust anion-derived solid electrolyte interphases (SEI) on the Li anode. The robust SEI effectively mitigates the corrosion of soluble Br₃⁻/Br₂ and attacks by highly reactive oxygen species. Additionally, the dispersed and high-density Li₂MoO₄ exhibits strong adsorption capabilities for O₂/LiO₂ and Br-related species during the discharge/charge process, thereby promoting the growth and decomposition of Li₂O₂ in the solution phase and inhibiting the shuttle effect of Br-related species in LOBs. Consequently, the LOBs demonstrate exceptional cycling stability (415 cycles) and high energy efficiency (86.2 %), paving the way for the sustainable development and practical application of these battery systems.