Mechanism of mediated alkali peroxide oxidation and triplet versus singlet oxygen formation.

Aprotic alkali metal-O batteries face two major obstacles to their chemistry occurring efficiently, the insulating nature of the formed alkali superoxides/peroxides and parasitic reactions that are caused by the highly reactive singlet oxygen (O). Redox mediators are recognized to be key for improving rechargeability. However, it is unclear how they affect O formation, which hinders strategies for their improvement.

Deactivation of redox mediators in lithium-oxygen batteries by singlet oxygen.

Non-aqueous lithium-oxygen batteries cycle by forming lithium peroxide during discharge and oxidizing it during recharge. The significant problem of oxidizing the solid insulating lithium peroxide can greatly be facilitated by incorporating redox mediators that shuttle electron-holes between the porous substrate and lithium peroxide. Redox mediator stability is thus key for energy efficiency, reversibility, and cycle life.

DABCOnium: An Efficient and High-Voltage Stable Singlet Oxygen Quencher for Metal-O Cells.

Singlet oxygen ( O ) causes a major fraction of the parasitic chemistry during the cycling of non-aqueous alkali metal-O batteries and also contributes to interfacial reactivity of transition-metal oxide intercalation compounds. We introduce DABCOnium, the mono alkylated form of 1,4-diazabicyclo[2.2.