Solvent Molecule Design Enables Excellent Charge Transfer Kinetics for a Magnesium Metal Anode

Abstract

Lacking of suitable electrolytes is a fatal obstacle for the development of rechargeable magnesium batteries (RMBs). Herein, according to the design of a series of solvent molecules, we find 3-methoxypropylamine possesses a middle coordination ability that can be used as an effective solvent and realize a reversible Mg anode with traditional Mg salts. Mechanism study indicates, attributed to its unique solvated structure, energy barriers in both the charge transfer process and desolvation process are extremely low, thus leading to the fast charge transfer kinetics. The relationship between solvated structures and performances is precisely revealed for the first time in RMBs. Additionally, electrolytes with amine solvents possess outstanding water-resistant properties owing to strong hydrogen bonds between amine groups and water. This work proposes a universal design principle of solvent molecules for RMBs, inspiring a new thinking of developing advanced electrolytes in the view of solvents.