Ether Molecule Decomposition on MgM2O4 (M = Mn, Fe, Co) Spinel Surface: A First-principles Study

Abstract

The transition between MgM2O4 (M = Mn, Fe, Co) spinels (SPs) and MgMO2 rock salts (RS) has attracted considerable interest for cathode reactions in future magnesium battery applications. To improve the cycling performance, one should suppress the consumption of solvent molecules. In this study, we investigated ether solvent decomposition on MgM2O4 SP and MgMO2 RS surfaces using first-principles calculations. We found that the C–H bond dissociation of ether molecules on the SP surface was exothermic, while the C–H bond dissociation on RS and C–O bond dissociation on both SP and RS surfaces were endothermic, irrespective of the transition metal element. The products of C–H dissociation reactions at the SP surfaces have occupied states originating from SP surfaces inside the bandgap. As the SP surface is destabilized by C–H dissociation, the electrons at this level can be extracted as an oxidative current.

Keywords

• first-principles calculations
• mg-battery
• solvent decomposition
• mg-spinel