Exploration of Novel Magnesium Battery Electrolytes based on Inorganic Salts

Abstract

We present a method to produce a novel magnesium/aluminum chloride complex (MaCC) electrolyte, involving a new promoter, CuCl 2 . The chemically formed electrolytic solution is observed to perform Mg deposition/dissolution with high coulombic efficiency. We further propose a new mechanism for MaCC synthesis, which suggests an alternative way to synthesize Mg-conductive electrolytes, by reacting metal chloride salts with nonaqueous suspensions of metallic magnesium.A set of preliminary experiments verifies that efficient Mg deposition/dissolution can be achieved from an electrolytic solution formed by direct reaction of FeCl 2 with a nonaqueous suspension of Mg powder.

Electrochemical Properties and Speciation in Mg(HMDS)2-Based Electrolytes for Magnesium Batteries as a Function of Ethereal Solvent Type and Temperature

“…Further investigations involved using glymes as higher boiling point solvents to replace THF. In these studies, the salt composition and concentration was held constant at Mg­(HMDS) 2 -2AlCl 3 and 0.35 M Mg. Diglyme electrolytes were initially very reactive with Mg metal, and we attribute this to the presence of a promoter, as elaborated in the Supporting Information. , The purification technique for the diglyme, as described in the Experimental Section, resulted in an electrolyte that was not corrosive to Mg metal. Thus, we kept this purification method consistent for all of the glyme electrolytes.…”

“…This is governed by the equilibrium chemistry within the magnesium electrolyte. Grignard reagents in ether can reversibly plate and strip magnesium and later, in the early 2000s, Aurbach and co-workers extended the electrolyte’s oxidative stability, with high efficiencies, by complexing a Grignard reagent with a strong Lewis acid. ,, Although these types of electrolytes are promising, the desire to remove the Grignard reagent from the solution has resulted in new generations of electrolytes. − ,,, …”

“…1,2,8 Although these types of electrolytes are promising, the desire to remove the Grignard reagent from the solution has resulted in new generations of electrolytes. [4][5][6]12,13,16 Of interest is magnesium bis(hexamethyldisilazide) (Mg-(HMDS) 2 )-based electrolytes and similar derivatives (see Figure 1). Both HMDSMgCl and Mg(HMDS) 2 are nonnucleophilic, thus making them compatible with electrophilic cathodes such as sulfur.…”