Redox shuttles for overcharge protection of lithium batteries

1. An electrolyte comprising:

an alkali metal salt;

a polar aprotic solvent; and

a redox shuttle additive that is an aromatic compound having at least one aromatic ring with four or more electronegative substituents, two or more oxygen atoms bonded to the aromatic ring, and no hydrogen atoms bonded to the aromatic ring; and

wherein:

the electrolyte solution is substantially non-aqueous; and

the redox shuttle additive has the Formula IA or IC:

X 1-8 are each independently selected from —F, —Cl, —Br, haloalkyl, —CN, or —NO 2 ; and

Y and Z are independently a group having a N, B, C, Si, S, or P atom, wherein the N, B, C, Si, S, or P atom is attached to at least one of the two or more oxygen atoms bonded to the aromatic ring.

2. The electrolyte of claim 1 wherein the redox shuttle additive has a redox potential of 3 V to 5.5 V in the electrolyte.

3. The electrolyte of claim 1 wherein the redox shuttle additive has two, three, or four oxygen atoms bonded to the aromatic ring.

4. The electrolyte of claim 1 wherein the electronegative substituents are selected from halogen, haloalkyl, —CN, or —NO 2 .

5. The electrolyte of claim 1 wherein the redox shuttle additive has the Formula IA:

6. The electrolyte of claim 5 wherein the redox shuttle additive has the structure selected from

wherein

each R 1 and R 3 is independently a hydrogen, an alkyl group, an aryl group, a haloalkyl group, or a haloaryl group;

each R 2 and R 4 is independently a halogen atom, an alkyl group, an aryl group, a haloalkyl group, or a haloaryl group;

M + is a cation; and

A − is an anion.

7. The electrolyte of claim 6 , wherein M + is an alkali metal cation and A − is a halide anion.

8. The electrolyte of claim 1 , wherein the redox shuttle additive has the Formula IC:

9. The electrolyte of claim 8 , wherein the redox shuttle additive has the structure selected from

wherein M + is a cation.

10. The electrolyte of claim 1 , wherein the redox shuttle additive is (tetrafluorobenzo-1,2-dioxyl)-pentafluorophenyl-borane, 1,2-bis(trimethylsiloxyl)tetrafluorobenzene, or a mixture thereof.

11. The electrolyte of 1, wherein the redox shuttle additive is a mixture of two or more aromatic compounds.

12. The electrolyte of claim 1 wherein the concentration of the redox shuttle additive ranges from 0.0005 wt % and 50 wt %.

13. The electrolyte of claim 1 wherein the alkali metal salt is a lithium salt.

14. The electrolyte of claim 1 wherein the alkali metal salt is Li[B(C 2 O 4 ) 2 ], Li[BF 2 (C 2 O 4 )], Li[PF 2 (C 2 O 4 ) 2 ], LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , Li[CF 3 SO 3 ], Li[N(CF 3 SO 2 ) 2 ], Li[C(CF 3 SO 2 ) 3 ], Li[N(SO 2 C 2 F 5 ) 2 ], lithium alkyl fluorophosphates, or a mixture of any two or more thereof.

15. The electrolyte of claim 1 , wherein the polar aprotic solvent is ethyl acetate, propyl acetate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, diethyl ether, methyl-acetate, gamma-butyrolactone, sulfolane, or a mixture of any two or more thereof.

16. The electrolyte of claim 1 further comprising an electrode stabilizing additive that can be reduced or polymerized on the surface of a negative electrode to form a passivation film on the surface of negative electrode.

17. The electrolyte of claim 1 further comprising an electrode stabilizing additive that can be oxidized or polymerized on the surface of positive electrode to form a passivation film on the surface of the positive electrode.

18. The electrolyte of claim 17 , further comprising an electrode stabilizing additive that can be reduced or polymerized on the surface of a negative electrode to form a passivation film on the surface of negative electrode.

19. The electrolyte of claim 18 wherein the electrode stabilizing additives are independently selected from 1,2-divinyl furoate, 1,3-butadiene carbonate, 1-vinylazetidin-2-one, 1-vinylaziridin-2-one, 1-vinylpiperidin-2-one, 1-vinylpyrrolidin-2-one, 2,4-diviny 1 -1,3-dioxane, 2-amino-3-vinylcyclohexanone, 2-amino-3-vinylcyclopropanone, 2-amino-4-vinylcyclobutanone, 2-amino-5-vinylcyclopentanone, 2-vinyl[1,2]oxazetidine, vinyl methyl carbonate, 2-vinylaminocyclohexanol, 2-vinylaminocyclopropanone, 2-vinyloxetane, 2-vinyloxy-cyclopropanone, 3-(N-vinylamino)cyclohexanone, 3,5-divinyl furoate, 3-vinylazetidin-2-one, 3-vinylaziridin-2-one, 3-vinylcyclobutanone, 3-vinylcyclopentanone, 3-vinyloxaziridine, 3-vinyloxetane, 3-vinylpyrrolidin-2-one, 4,4-divinyl-3-dioxolan-2-one, 4-vinyltetrahydropyran, 5-vinylpiperidin-3-one, allylglycidyl ether, butadiene monoxide, butyl vinyl ether, dihydropyran-3-one, divinyl butyl carbonate, divinyl carbonate, divinyl crotonate, divinyl ether, divinyl ethylene carbonate, divinyl ethylene silicate, divinyl ethylene sulfate, divinyl ethylene sulfite, divinyl methoxypyrazine, divinyl methylphosphate, divinyl propylene carbonate, ethyl phosphate, methoxy-o-terphenyl, methyl phosphate, oxetan-2-yl-vinylamine, oxiranylvinylamine, vinyl carbonate, vinyl crotonate, vinyl cyclopentanone, vinyl ethyl-2-furoate, vinyl ethylene carbonate, vinyl ethylene silicate, vinyl ethylene sulfate, vinyl ethylene sulfite, vinyl methacrylate, vinyl phosphate, vinyl-2-furoate, vinylcylopropanone, vinylethylene oxide, β-vinyl-γ-butyrolactone, (divinyl)(methoxy)(trifluoro)cyclotriphosphazene, (trivinyl)(difluoro)(methoxy)cyclotriphosphazene, (vinyl)(methoxy)(tetrafluoro)cyclotriphosphazene, (aryloxy)(tetrafluoro)(methoxy)cyclotriphosphazene, (diaryloxy)(trifluoro)(methoxy)cyclotriphosphazene compounds, 1,2-diphenyl ether, aryloxpyrrole, aryloxy ethylene sulfate, aryloxy pyrazine, aryloxy-carbazole trivinylphosphate, aryloxy-ethyl-2-furoate, 2-aryloxy-cyclopropanone, aryloxy-o -terphenyl, aryloxy-pyridazine, butyl-aryloxy-ether, divinyl diphenyl ether, (tetrahydro -furan-2-yl)-vinylamine, divinyl methoxybipyridine, methoxy-4-vinylbiphenyl, vinyl methoxy carbazole, vinyl methoxy piperidine, vinyl methoxypyrazine, allylanisole, vinyl pyridazine, 1-divinylimidazole, 3-vinyltetrahydrofuran, divinyl furan, divinyl methoxy furan, divinylpyrazine, vinyl methoxy imidazole, vinylmethoxy pyrrole, vinyl-tetrahydrofuran, 2,4-divinyl isooxazole, 3,4-divinyl-l-methyl pyrrole, aryloxyoxetane, aryloxy-phenyl carbonate, aryloxy-piperidine, aryloxy-tetrahydrofuran, 2-aryl-cyclopropanone, 2-diaryloxy-furoate, 4-allylanisole, aryloxy- carbazole, aryloxy-2-furoate, aryloxy-crotonate, aryloxy-cyclobutane, aryloxy-cyclopentanone, aryloxy-cyclopropanone, aryloxy-cycolophosphazene, aryloxy-ethylene silicate, aryloxy-ethylene sulfate, aryloxy-ethylene sulfite, aryloxy-imidazole, aryloxy-methacrylate, aryloxy-phosphate, aryloxy-pyrrole, aryloxy-quinoline, diaryloxy-cyclotriphosphazene, diaryloxy ethylene carbonate, diaryloxy furan, diaryloxy methyl phosphate, diaryloxy-butyl carbonate, diaryloxy-crotonate, diaryloxy-diphenyl ether, diaryloxy-ethyl silicate, diaryloxy-ethylene silicate, diaryloxy-ethylene sulfate, diaryloxyethylene sulfite, diaryloxy-phenyl carbonate, diaryloxy-propylene carbonate, diphenyl carbonate, diphenyl diaryloxy silicate, diphenyl divinyl silicate, diphenyl ether, diphenyl silicate, divinyl methoxydiphenyl ether, divinyl phenyl carbonate, methoxycarbazole, or 2,4- dimethyl-6-hydroxy-pyrimidine, vinyl methoxyquinoline, pyridazine, vinyl pyridazine, quinoline, vinyl quinoline, pyridine, vinyl pyridine, indole, vinyl indole, triethanolamine, 1,3-dimethyl butadiene, butadiene, vinyl ethylene carbonate, vinyl carbonate, imidazole, vinyl imidazole, piperidine, vinyl piperidine, pyrimidine, vinyl pyrimidine, pyrazine, vinyl pyrazine, isoquinoline, vinyl isoquinoline, quinoxaline, vinyl quinoxaline, biphenyl, 1,2-diphenyl ether, 1,2-diphenylethane, o-terphenyl, N-methyl pyrrole, naphthalene, or a mixture of any two or more thereof.

20. The electrolyte of claim 1 wherein the alkali metal salt is other than Li[B(C 2 O 4 ) 2 ], Li[BF 2 (C 2 O 4 )], or Li[PF 2 (C 2 O 4 ) 2 ], and the electrolyte further comprises about 0.001 to about 8 wt % of an electrode stabilizing additive that is Li[B(C 2 O 4 ) 2 ], Li[BF 2 (C 2 O 4 )], Li[PF 2 (C 2 O 4 ) 2 ], or a mixture thereof.

21. The electrolyte of claim 18 further comprising an electrode stabilizing additive that is a substituted or unsubstituted spirocyclic hydrocarbon containing at least one oxygen atom and at least one alkenyl or alkynyl group;

wherein the electrode stabilizing additive has the Formula V:

wherein

A 1 , A 2 , A 3 ,A 4 are independently O or CR 22 R 23 ; provided that A 1 is not O when G 1 is O, A 2 is not O when G 2 is O, A 3 is not O when G 3 is O, and A 4 is not O when G 4 is O;

G 1 , G 2 , G 3 , and G 4 are independently O or CR 22 R 23 ; provided that G 1 is not O when A 1 is O, G 2 is not O when A 2 is O, G 3 is not O when A 3 is O, and G 4 is not when A 4 is O;

R 20 and R 21 are independently a substituted or unsubstituted divalent alkenyl or alkynyl group;

R 22 and R 23 at each occurrence are independently H, F, Cl, Br, or a substituted or an unsubstituted alkyl, alkenyl, or alkynyl group.

22. The electrolyte of claim 21 wherein the electrode stabilizing additive is 3,9-divinyl-2, 4,8,10-tetraoxaspiro[5.5]undecane, 3,9-divinyl-2,4,8-trioxaspiro[5.5]undecane, 3,9-divinyl-2,4-dioxaspiro[5.5]undecane, 3,9-diethylidene-2,4,8,10-tetraoxaspiro [5.5]undecane, 3,9-diethylidene-2,4,8-trioxaspiro[5.5]undecane, 3,9-diethylidene -2,4-dioxaspiro[5.5]undecane, 3,9-dimethylene-2,4,8,10-tetraoxaspiro [5.5]undecane, 3,9-divinyl-1,5,7,11-tetraoxaspiro[5.5]undecane, 3,9-dimethyl ene-1,5,7,11-tetraoxaspiro [5.5]undecane, 3,9-diethylidene-1,5,7,11-tetraoxaspiro [5.5]undecane, or a mixture of any two or more thereof.

23. A method of preparing the electrolyte of claim 1 comprising combining an alkali metal salt; a polar aprotic solvent; and redox shuttle additive that is an aromatic compound having at least one aromatic ring with four or more electronegative substituents, two or more oxygen atoms bonded to the aromatic ring, and no hydrogen atoms bonded to the aromatic ring.

24. An electrolyte comprising:

an alkali metal salt;

a polar aprotic solvent; and

a redox shuttle additive that is an aromatic compound having at least one aromatic ring with four or more electronegative substituents, two or more oxygen atoms bonded to the aromatic ring, and no hydrogen atoms bonded to the aromatic ring; and

wherein:

the electrolyte solution is substantially non-aqueous; and

the redox shuttle additive has the Formula IB:

X 1-8 are each independently selected from —F, —Cl, —Br, haloalkyl, —CN, or —NO 2 ;

wherein:

Y and Z are independently selected from the following structures,

wherein

each R 1 , R 3 and R 5 is independently a hydrogen, an alkyl group, an aryl group, a halogen substituted alkyl group, or a halogen substituted aryl group;

each R 2 , R 4 and R 6 is independently a halogen atom, an alkyl group, an aryl group, a halogen substituted alkyl group, or a halogen substituted aryl group;

M + is a cation; and

A − is an anion.

25. The electrolyte of claim 24 wherein the redox shuttle additive has the structure:

and t is 0-8.

26. The electrolyte of claim 24 further comprising an electrode stabilizing additive that can be reduced or polymerized on the surface of a negative electrode to form a passivation film on the surface of negative electrode.

27. The electrolyte of claim 21 wherein each electrode stabilizing additive is present at a concentration of about 0.001 to about 8 wt %.

28. The electrolyte of claim 24 further comprising an electrode stabilizing additive that can be oxidized or polymerized on the surface of positive electrode to form a passivation film on the surface of the positive electrode.

29. The electrolyte of claim 28 , further comprising an electrode stabilizing additive that can be reduced or polymerized on the surface of a negative electrode to form a passivation film on the surface of negative electrode.