Magnesium-based electrolyte compositions and uses thereof

Patent metadata

Field	Value
Publication number	US-2019020058-A1
Application number	US-201816033087-A
Country	US
Kind code	A1
Filing date	Jul 11, 2018
Priority date	Jul 11, 2017
Publication date	Jan 17, 2019
Grant date	—

Abstract

Methods of making magnesium-based compositions are disclosed. The methods include the addition of a metallic magnesium powder to a magnesium salt, a metal halide and a solvent. The methods provide compositions with advantageous properties that make them useful as electrolytes for battery applications.

First claim

What is claimed is:

1 . A method of making a composition, the method comprising:
adding a magnesium salt, a metal halide and metallic magnesium to a solvent to provide a mixture; stirring the mixture; and filtering the mixture to provide a composition, wherein the composition has a molar ratio of magnesium to the metal of the metal halide of from about 1:3 to about 1:0.

2 . The method of claim 1 , wherein the solvent comprises an ethereal solvent, a sulfone solvent, acetonitrile, carbonate, dimethylforamide (DMF), dimethyl sulfoxide (DMSO), or a mixture thereof.

3 . The method of claim 1 , wherein the metal halide comprises aluminum halide, boron halide, gallium halide, or a combination thereof.

4 . The method of claim 1 , wherein the metallic magnesium is present in the mixture at from about 0.1 mg/mL to about 40 mg/mL.

5 . The method of claim 1 , wherein the magnesium salt is present in the mixture at from about 0.5 mg/mL to about 600 mg/mL.

6 . The method of claim 1 , wherein the metal halide is present in the mixture at from about 0.5 mg/mL to about 320 mg/mL.

7 . The method of claim 1 , wherein the mixture is stirred for at least 5 hours prior to filtering.

8 . The method of claim 1 , wherein the mixture is stirred at a temperature range of from about 15° C. to about 80° C.

9 . The method of claim 2 , wherein the ethereal solvent comprises tetrahydrofuran (THF), dimethoxyethane (DME), diglyme (DMG), triglyme, tetraglyme, 1,4-dioxane, or a combination thereof.

10 . The method of claim 2 , wherein the sulfone solvent comprises dipropyl sulfone, ter-butyl sulfone, or a combination thereof.

11 . The method of claim 2 , wherein the carbonate comprises propylene carbonate, ethylene carbonate, fluoroethylene carbonate, ethyl methyl carbonate, 4-Vinyl-1,3-dioxolan-2-one, diethyl carbonate, or a combination thereof.

12 . The method of claim 1 , wherein the composition has a magnesium concentration of from about 1 mg/mL to about 50 mg/mL.

13 . The method of claim 1 , wherein the composition has a metal concentration, the metal being that of the metal halide, of from about 0.1 mg/mL to about 65 mg/mL.

14 . The method of claim 3 , wherein the composition has a molar ratio of magnesium to aluminum of
(a) from about 2.2:1 to about 4:1,
wherein the ethereal solvent is THF,
(b) from about 1.2:1 to about 3:1,
wherein the ethereal solvent is DME, or
(c) from about 1:1.21 to about 1:3,
wherein the ethereal solvent is DMG.

15 . The method of claim 1 , wherein the composition has a magnesium concentration of
(a) from about 1 mg/mL to about 20 mg/mL,
wherein the ethereal solvent is THF,
(b) from about 10 mg/mL to about 30 mg/mL,
wherein the ethereal solvent is DME,
(c) from about 3 mg/mL to about 20 mg/mL,
wherein the ethereal solvent is DMG, or
(d) from about 3 mg/mL to about 20 mg/mL,
wherein the solvent is dipropyl sulfone/THF at a 1/1 (v/v) ratio.

16 . The method of claim 3 , wherein the composition has an aluminum concentration of
(a) from about 0.1 mg/mL to about 0.5 mg/mL,
wherein the ethereal solvent is THF,
(b) from about 1 mg/mL to about 10 mg/mL,
wherein the ethereal solvent is DME, or
(c) from about 0.5 mg/mL to about 5 mg/mL,
wherein the ethereal solvent is DMG.

17 . The method of claim 1 , wherein the magnesium salt comprises magnesium chloride (MgCl 2 ), magnesium(II) bis(trifluoromethane sulfonyl) imide (Mg(TFSI) 2 ), magnesium bis(hexamethyldisilazide) (Mg(HMDS) 2 ), or a combination thereof.

18 . The method of claim 1 , wherein the metal halide is aluminum chloride (AlCl 3 ).

19 . The method of claim 1 , wherein the composition comprises less than 50 ppm water.

20 . The method of claim 1 , wherein the composition has a Coulombic efficiency of greater than 90%.

21 . The method of claim 1 , wherein the composition has an overpotential of less than 200 mV.

22 . The method of claim 1 , wherein the metallic magnesium is in the form of a powder.

23 . The method of claim 1 , wherein the method further comprises adding an ionic liquid to the solvent or mixture.

24 . A battery comprising:
the composition of claim 1 ; a cathode; and an anode.

25 . The battery of claim 24 , wherein the composition comprises an ionic liquid and the cathode comprises sulfur.

Assignees

• Liu Tianbiao
• Univ Utah State

Inventors

• Liu Tianbiao

Classifications

• H01M2300/0045

  Room temperature molten salts comprising at least one organic ion · CPC title

• H01M10/054 Primary

  Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium · CPC title

• H01M10/056

  characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes · CPC title

• H01M2300/0088

  Composites · CPC title

• H01M2300/0022

  Room temperature molten salts · CPC title