Alkoxide-based magnesium electrolyte compositions for magnesium batteries
Alkoxide magnesium halide compounds having the formula: RO—Mg—X (1) wherein R is a saturated or unsaturated hydrocarbon group that is unsubstituted, or alternatively, substituted with one or more heteroatom linkers and/or one or more heteroatom-containing groups comprising at least one heteroatom selected from fluorine, nitrogen, oxygen, sulfur, and silicon; and X is a halide atom. Also described are electrolyte compositions containing a compound of Formula (1) in a suitable polar aprotic or ionic solvent, as well as magnesium batteries in which such electrolytes are incorporated.
1. A magnesium battery comprising:
(i) a negative electrode comprising magnesium;
(ii) a positive electrode; and
(iii) an electrolyte positioned between the negative and positive electrodes, the electrolyte comprising a compound of the formula:
wherein R 1 , R 2 , and R 3 are independently selected from hydrogen atom and saturated and unsaturated hydrocarbon groups having at least 1 and up to 12 carbon atoms, wherein said hydrocarbon groups are optionally substituted with one or more fluorine atoms; X is a halide atom; and the bonds depicted between RO or X and Mg are understood to be predominantly ionic in nature.
2. The magnesium battery of claim 1 , wherein said negative electrode comprises elemental magnesium.
3. The magnesium battery of claim 1 , wherein said positive electrode is comprised of a transition metal oxide or transition metal sulfide material.
4. The magnesium battery of claim 1 , wherein said positive electrode is comprised of a material of the formula M x Mo 6 T 8 , wherein M is at least one metal selected from alkaline earth and transition metals, T is selected from at least one of sulfur, selenium, and tellurium, and x is a value of 0 to 2.
5. The magnesium battery of claim 4 , wherein T comprises at least sulfur.
6. The magnesium battery of claim 4 , wherein M is selected from Mg, Cu, Ni, and Ag.
7. The magnesium battery of claim 1 , wherein R 1 , R 2 , and R 3 are independently selected from hydrogen atom and saturated and unsaturated hydrocarbon groups having at least 1 and up to 6 carbon atoms, wherein said hydrocarbon groups may be substituted with one or more fluorine atoms.
8. The magnesium battery of claim 1 , wherein R 1 , R 2 , and R 3 are independently selected from hydrogen atom and unsubstituted straight-chained and branched alkyl groups.
9. The magnesium battery of claim 8 , wherein said unsubstituted straight-chained or branched alkyl group is selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, isopropyl, isobutyl, sec-butyl, t-butyl, 2-pentyl, 3-pentyl, 2-methylbut-1-yl, isopentyl, 1,2-dimethylprop-1-yl, 1,1-dimethylprop-1-yl, neopentyl, 2-hexyl, 3-hexyl, 2-methylpent-1-yl, 3-methylpent-1-yl, isohexyl, 1,1-dimethylbut-1-yl, 1,2-dimethylbut-1-yl, 2,2-dimethylbut-1-yl, 2,3-dimethylbut-1-yl, 3,3-dimethylbut-1-yl, 1,1,2-trimethylprop-1-yl, and 1,2,2-trimethylprop-1-yl groups.
10. The magnesium battery of claim 1 , wherein said electrolyte compound according to Formula (1) is complexed with a Lewis acid compound.
11. The magnesium battery of claim 10 , wherein said Lewis acid compound is selected from compounds of aluminum, boron, iron, and titanium.
12. The magnesium battery of claim 11 , wherein said Lewis acid compound is selected from AlX 3 , BX 3 , PX 3 , AlX 2 R 4 , FeX 2 , FeX 3 , SbX 3 , and TiX 4 , wherein X is independently selected from halogen atoms, and R 4 is a hydrocarbon group having 1 to 3 carbon atoms.
13. The magnesium battery of claim 1 , wherein said electrolyte further comprises a polar aprotic solvent non-reactive with components of the magnesium battery.
14. The magnesium battery of claim 13 , wherein said polar aprotic solvent includes at least one ether group.
15. The magnesium battery of claim 1 , further comprising a solid porous membrane positioned between the negative and positive electrodes.