Proton Abstraction from DME n···X+ by OH-, O2-, and XO2-, for X = Li, Na, and K: Implications for Li-O2 Batteries.

The abstraction of a proton by OH-, O2-, and XO2- from DME n···X+, where X is Li, Na, or K, is studied using density functional theory. Both the gas phase and the solution phase are studied. In general, when explicit solvent molecules are added, the difference between the gas-phase and solution results becomes rather small. While the DME n···X+ binding energies differ significantly for various alkali cations, the reaction energies and transition-state energies are far less sensitive to the choice of an alkali cation. XO2- has a lower barrier height than OH-, which, in turn, has a lower barrier height than O2-. The reaction energies follow the same trends.