Long life lithium batteries with stabilized electrodes
View Patent ↗The present invention relates to non-aqueous electrolytes having electrode stabilizing additives, stabilized electrodes, and electrochemical devices containing the same. Thus the present invention provides electrolytes containing an alkali metal salt, a polar aprotic solvent, and an electrode stabilizing additive. In some embodiments the additives include a substituted or unsubstituted cyclic or spirocyclic hydrocarbon containing at least one oxygen atom and at least one alkenyl or alkynyl group. When used in electrochemical devices with, e.g., lithium manganese oxide spinel electrodes or olivine or carbon-coated olivine electrodes, the new electrolytes provide batteries with improved calendar and cycle life.
1. An electrolyte comprising:
an alkali metal salt;
a polar aprotic solvent; and
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 electrolyte is substantially non-aqueous.
2. The electrolyte of claim 1 , wherein the electrode stabilizing additive contains 1, 2, 3, 4, 5, or 6 oxygen atoms.
3. The electrolyte of claim 1 , wherein the electrode stabilizing additive has 1 or 2 alkenyl groups.
4. The electrolyte of claim 1 , wherein the electrode stabilizing additive has the Formula I:
wherein
X 1 , X 2 , X 3 , and X 4 are independently O or CR 3 R 4 ; provided that X 1 is not O when Y 1 is O, X 2 is not O when Y 2 is O, X 3 is not O when Y 3 is O, and X 4 is not O when Y 4 is O;
Y 1 , Y 2 , Y 3 , and Y 4 are independently O or CR 3 R 4 ; provided that Y 1 is not O when X 1 is O, Y 2 is not O when X 2 is O, Y 3 is not O when X 3 is O, and Y 4 is not O when X 4 is O;
R 1 and R 2 are independently a substituted or unsubstituted divalent alkenyl or alkynyl group; and
R 3 and R 4 at each occurrence are independently H, F, Cl, a substituted or an unsubstituted alkyl, alkenyl, or alkynyl group.
5. The electrolyte of claim 4 , wherein at least one of X 1 , X 2 , X 3 , and X 4 is O.
6. The electrolyte of claim 4 , wherein X 1 is O.
7. The electrolyte of claim 4 , wherein each of X 1 , X 2 , X 3 , and X 4 is O.
8. The electrolyte of claim 4 , wherein R 1 and R 2 are the same.
9. The electrolyte of claim 8 , wherein R 1 and R 2 are each CH—CH═CH 2 , C═CH 2 , or C═CHCH 3 .
10. The electrolyte of claim 4 , wherein at each occurrence R 3 and R 4 are each H.
11. The electrolyte of claim 4 , wherein the 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-dimethylene-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.
12. The electrolyte of claim 1 , wherein the stabilizing additive is present in an amount of about 0.0005 to about 15 wt %.
13. The electrolyte of claim 1 , wherein the stabilizing additive is present in an amount of about 0.0005 to about 2 wt %.
14. The electrolyte of claim 1 , wherein the alkali metal salt is a lithium salt.
15. The electrolyte of claim 1 , wherein the alkali metal salt is Li[(C 2 O 4 ) 2 B], Li(C 2 O 4 )BF 2 , LiPF 2 C 4 O 8 , LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiCF 3 SO 3 , Li(CF 3 SO 2 ) 2 N, Li(CF 3 SO 2 ) 3 C, LiN(SO 2 C 2 F 5 ) 2 , lithium alkyl fluorophosphates, or a mixture of any two or more thereof.
16. The electrolyte of claim 1 , wherein the alkali metal salt is lithium (chelato)borate.
17. The electrolyte of claim 1 , wherein the alkali metal salt is Li(C 2 O 4 )BF 2 , Li[(C 2 O 4 ) 2 B], or a mixture of any two or more thereof.
18. 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, dimethyl ether, diethyl ether, methyl-acetate, gamma-butyrolactone, or a mixture of any two or more thereof.
19. An electrolyte comprising:
an alkali metal salt;
a polar aprotic solvent; and
an electrode stabilizing additive having Formula II:
wherein,
X 1 and X 2 are independently O, CHR 3 , CHR 4 , or CR 3 R 4 ; provided that X 1 is not O when Y 1 is O, and X 2 is not O when Y 2 is O;
Y 1 and Y 2 are independently O, CHR 3 , CHR 4 , or CR 3 R 4 ; provided that Y 1 is not O when X 1 is O and Y 2 is not O when X 2 is O;
R 1 and R 2 are independently a substituted or unsubstituted divalent alkenyl or alkynyl group;
R 3 and R 4 at each occurrence are independently H, F, Cl, a substituted or an unsubstituted alkyl, alkenyl, or alkynyl group; and
wherein the electrolyte is substantially non-aqueous; and
the electrode stabilizing additive is 2,4-diviynl-tetrahydropyran, 2,5-divinyl-tetrahydropyran, 2,6-divinyl-tetrahydropyran, 2,5-divinyl-[1,4]dioxane, 2,5-divinyl-[1,3]dioxane, 2-ethylidene-5-vinyl-[1,3]dioxane or a mixture of any two or more thereof.
20. A method of making the electrolyte of claim 1 , the method comprising combining
an alkali metal salt;
a polar aprotic solvent; and
an electrode stabilizing additive that is a spirocyclic hydrocarbon containing at least one oxygen atom and at least one alkenyl or alkynyl group.
21. An electrolyte comprising:
an alkali metal salt;
a polar aprotic solvent;
a first 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; and
a second electrode stabilizing additive that is capable of stabilizing an anode;
wherein the electrolyte is substantially non-aqueous.
22. The electrolyte of claim 21 wherein the second electrode stabilizing additive is selected from vinyl ethylene carbonate, vinyl carbonate, a lithium (chelato)borate, a lithium(chelato)phosphate, a cyclotriphosphazene, or a mixture of any two or more thereof.
23. The electrolyte of claim 22 , wherein the lithium(chelato)borate is selected from Li(C 2 O 4 ) 2 B, Li(C 2 O 4 )BF 2 , or a mixture thereof.
24. The electrolyte of claim 22 , wherein the lithium(chelato)phosphate is LiPF 2 C 4 O 8 .
25. The electrolyte of claim 22 , wherein the cyclotriphosphazene is selected from P-ethoxy-P,P′,P″-pentafluorocyclotriphosphazene, P,P′-diethoxy-P,P′,P″-tetrafluorocyclotriphosphazene, P-phenoxy-P,P′,P″-pentafluorocyclotriphosphazene, P,P′,P″-hexamethoxycyclotriphosphazene, P-phenoxy-P′-(prop-2-ene-oxy)-P,P′,P″-pentafluorocyclotriphosphazene, or mixtures of any two or more thereof.
26. The electrolyte of claim 21 , wherein the second electrode stabilizing additive is present between about 0.01 wt % and about 15 wt %.
27. The electrolyte of claim 21 , wherein the alkali metal salt is other than Li(C 2 O 4 ) 2 B, Li(C 2 O 4 )BF 2 , or LiPF 2 C 4 O 8 .