Alkoxide-based magnesium electrolyte compositions for magnesium batteries

Abstract

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:
   R 4 R 5 R 6 SiO—Mg—X  (1c)
 
   
       wherein R 4 , R 5 , and R 6  are each bound to the silicon atom by a carbon atom and independently selected from hydrocarbon groups R′ having at least 1 and up to 12 carbon atoms and 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/or R 4 , R 5 , and R 6  are independently selected from groups OR′; X is a halide atom; and the bonds depicted between R 4 R 5 R 6 SiO 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 .- 10 . (canceled) 
     
     
         11 . The magnesium battery of  claim 1 , wherein said hydrocarbon groups have 1 to 6 carbon atoms. 
     
     
         12 . The magnesium battery of  claim 1 , wherein said hydrocarbon groups are unsubstituted straight-chained or branched alkyl groups. 
     
     
         13 . The magnesium battery of  claim 12 , wherein said unsubstituted straight-chained or branched alkyl groups have 1 to 6 carbon atoms. 
     
     
         14 . The magnesium battery of  claim 12 , wherein said unsubstituted straight-chained or branched alkyl groups are 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. 
     
     
         15 . (canceled) 
     
     
         16 . The magnesium battery of  claim 1 , wherein said hydrocarbon groups have at least 1 and up to 3 carbon atoms. 
     
     
         17 . The magnesium battery of  claim 1 , wherein said at least one heteroatom is selected from nitrogen, oxygen, sulfur, and silicon. 
     
     
         18 . (canceled) 
     
     
         19 . The magnesium battery of  claim 1 , wherein said electrolyte compound according to Formula (1c) is complexed with a Lewis acid compound. 
     
     
         20 . The magnesium battery of  claim 19 , wherein said Lewis acid compound is selected from compounds of aluminum, boron, iron, and titanium. 
     
     
         21 . The magnesium battery of  claim 20 , 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. 
     
     
         22 . The magnesium battery of  claim 1 , wherein said electrolyte further comprises a polar aprotic solvent non-reactive with components of the magnesium battery. 
     
     
         23 . The magnesium battery of  claim 22 , wherein said polar aprotic solvent includes at least one ether group. 
     
     
         24 . The magnesium battery of  claim 1 , further comprising a solid porous membrane positioned between the negative and positive electrodes.