Electrolyte for rechargeable lithium battery and rechargeable lithium battery comprising same
Disclosed is an electrolyte for a rechargeable lithium battery including 5 to 40 volume % of at least one fluorine-substituted ether compound represented by R1—O—R2 (wherein R1 and R2 are alkyl groups substituted with fluorine), having a substitution ratio of hydrogen with fluorine of 57 to 86%, a viscosity of 0.9 to 2.3 cp, and a boiling point of at least 88° C., and 60 to 90 volume % of a non-aqueous organic solvent having a flash point of at least 80° C.
1. An electrolyte for a rechargeable lithium battery, comprising:
5 to 40 volume % of at least one fluorine-substituted ether compound represented by R 1 —O—R 2 , wherein R 1 and R 2 are each independently an alkyl group substituted with fluorine, having a substitution ratio of hydrogen with fluorine of 57 to 86%, a total viscosity of 0.9 to 2.3 cp, and a boiling point of at least 88° C.;
60 to 90 volume % of a non-aqueous organic solvent having a flash point of at least 80° C.; and,
a compatibilizer selected from the group consisting of compounds represented by formulas 11 to 12:
CH 3 COOCH 2 (CF 2 ) 3 CF 2 H and (11)
CH 3 COOCH 2 CF 2 CF 2 H (12).
2. The electrolyte of claim 1 , wherein the fluorine-substituted ether compound is at least one selected from the group consisting of compounds represented by formulas 1 to 8:
HCF 2 (CF 2 ) 3 CH 2 OCF 2 CF 2 H (1)
CF 3 CF 2 CH 2 OCF 2 CFHCF 3 (2)
HCF 2 CF 2 CH 2 OCF 2 CF 2 H (3)
HCF 2 CF 2 CH 2 OCF 2 CFHCF 3 (4)
HCF 2 (CF 2 ) 3 CH 2 OCF 2 CFHCF 3 (5)
HCF 2 CF 2 OCH 2 CF 3 (6)
CF 3 CF 2 CH 2 OCF 2 CF 2 H and (7)
HCF 2 CF 2 CH 2 OCF 2 H (8).
3. The electrolyte of claim 1 , wherein the non-aqueous organic solvent is comprises at least one solvent selected from cyclic esters and cyclic carbonates.
4. The electrolyte of claim 1 , wherein the non-aqueous organic solvent is at least one selected from the group consisting of γ-butyrolactone, decanolide, valerolactone, mevalonolactone, ethylene carbonate, fluoroethylene carbonate, chloroethylene carbonate, propylene carbonate, chloromethylethylene carbonate, and fluoromethylethylene carbonate.
5. The electrolyte of claim 1 , wherein the compatibilizer is present in an amount of 0.01 to 10 wt % based on the total weight of the electrolyte.
6. An electrolyte for a rechargeable lithium battery, comprising:
5 to 40 volume % of at least one fluorine-substituted ether compound represented by R 1 —O—R 2 , wherein R 1 and R 2 are each independently an alkyl group substituted with fluorine, having a substitution ratio of hydrogen with fluorine of 57 to 86%, a viscosity of 0.9 to 2.3 cp and a boiling point of at least 88° C.;
20 volume % to 95 volume % of a high-flash point non-aqueous organic solvent having a flash point of at least 80° C.;
a positive amount up to 40 volume % of a low-viscosity non-aqueous organic solvent having a viscosity of 0.2 to 1.8 cP; and
a compatibilizer selected from the group consisting of compounds represented by formulas 11 to 12:
CH 3 COOCH 2 (CF 2 ) 3 CF 2 H and (11)
CH 3 COOCH 2 CF 2 CF 2 H (12).
7. The electrolyte of claim 6 , wherein the fluorine-substituted ether compound is at least one selected from the group consisting of compounds represented by formulas 1 to 8:
HCF 2 (CF 2 ) 3 CH 2 OCF 2 CF 2 H (1)
CF 3 CF 2 CH 2 OCF 2 CFHCF 3 (2)
HCF 2 CF 2 CH 2 OCF 2 CF 2 H (3)
HCF 2 CF 2 CH 2 OCF 2 CFHCF 3 (4)
HCF 2 (CF 2 ) 3 CH 2 OCF 2 CFHCF 3 (5)
HCF 2 CF 2 OCH 2 CF 3 (6)
CF 3 CF 2 CH 2 OCF 2 CF 2 H and (7)
HCF 2 CF 2 CH 2 OCF 2 H (8).
8. The electrolyte of claim 6 , wherein the high-flash point non-aqueous organic solvent is at least one solvent selected from cyclic esters and cyclic carbonates.
9. The electrolyte of claim 6 , wherein the high-flash point non-aqueous organic solvent is at least one selected from the group consisting of γ-butyrolactone, decanolide, valerolactone, mevalonolactone, ethylene carbonate, fluoroethylene carbonate, chloroethylene carbonate, propylene carbonate, chloromethylethylene carbonate, and fluoromethylethylene carbonate.
10. The electrolyte of claim 6 , wherein the low-viscosity non-aqueous organic solvent comprises one or more chain carbonates.
11. The electrolyte of claim 6 , wherein the low-viscosity non-aqueous organic solvent is at least one selected from the group consisting of diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, ethylpropyl carbonate, and ethylbutyl carbonate.
12. The electrolyte of claim 6 , wherein the compatibilizer is present in an amount of 0.01 to 10 wt % based on the total weight of the electrolyte.
13. A rechargeable lithium battery comprising:
an non-aqueous electrolyte comprising 5 to 40 volume % of at least one fluorine-substituted ether compound represented by R 1 —O—R 2 , wherein R 1 and R 2 are each independently an alkyl group substituted with fluorine, having a substitution ratio of hydrogen with fluorine of 57 to 86%, a viscosity of 0.9 to 2.3 cp, and a boiling point of at least 88° C.; and 60 to 90 volume % of a non-aqueous organic solvent having a flash point of at least 80° C.;
a positive electrode comprising a positive active material in which lithium intercalation reversibly occurs;
a negative electrode comprising a negative active material in which lithium intercalation reversibly occurs; and
a compatibilizer selected from the group consisting of compounds represented by formulas 11 to 12:
CH 3 COOCH 2 (CF 2 ) 3 CF 2 H and (11)
CH 3 COOCH 2 CF 2 CF 2 H (12).
14. The rechargeable lithium battery of claim 13 , wherein the fluorine-substituted ether compound is at least one selected from the group consisting of compounds represented by formulas 1 to 8:
HCF 2 (CF 2 ) 3 CH 2 OCF 2 CF 2 H (1)
CF 3 CF 2 CH 2 OCF 2 CFHCF 3 (2)
HCF 2 CF 2 CH 2 OCF 2 CF 2 H (3)
HCF 2 CF 2 CH 2 OCF 2 CFHCF 3 (4)
HCF 2 (CF 2 ) 3 CH 2 OCF 2 CFHCF 3 (5)
HCF 2 CF 2 OCH 2 CF 3 (6)
CF 3 CF 2 CH 2 OCF 2 CF 2 H and (7)
HCF 2 CF 2 CH 2 OCF 2 H (8).
15. The rechargeable lithium battery of claim 13 , wherein the non-aqueous organic solvent is at least one solvent selected from cyclic esters and cyclic carbonates.
16. The rechargeable lithium battery of claim 15 , wherein the non-aqueous organic solvent is at least one selected from the group consisting of γ-butyrolactone, decanolide, valerolactone, mevalonolactone, ethylene carbonate, fluoroethylene carbonate, chloroethylene carbonate, propylene carbonate, chloromethylethylene carbonate, and fluoromethylethylene carbonate.
17. The rechargeable lithium battery of claim 13 , wherein the compatibilizer is present in an amount of 0.01 to 10 wt % based on the total weight of the electrolyte.
18. The rechargeable lithium battery of claim 15 , wherein the battery is a lithium ion battery or a lithium polymer battery.
19. A rechargeable lithium battery comprising:
an electrolyte comprising 5 to 40 volume % of at least one fluorine-substituted ether compound represented by R 1 —O—R 2 , wherein R 1 and R 2 are each independently an alkyl group substituted with fluorine, having a substitution ratio of hydrogen with fluorine of 57 to 86%, a viscosity of 0.9 to 2.3 cp, and a boiling point of at least 88° C.; 20 volume % to 95 volume % of a high-flash point non-aqueous organic solvent having a flash point of at least 80° C.; a positive amount up to 40 volume % of a low-viscosity non-aqueous organic solvent having a viscosity of 0.2 to 1.8 cP;
a positive electrode comprising a positive active material in which lithium intercalation reversibly occurs; and
a negative electrode comprising a negative active material in which lithium intercalation reversibly occurs; and
a compatibilizer selected from the group consisting of compounds represented by formulas 11 to 12:
CH 3 COOCH 2 (CF 2 ) 3 CF 2 H and (11)
CH 3 COOCH 2 CF 2 CF 2 H (12).
20. The rechargeable lithium battery of claim 19 , wherein the organic fluoride ether compound is at least one selected from the group consisting of compounds represented by formulas 1 to 8:
HCF 2 (CF 2 ) 3 CH 2 OCF 2 CF 2 H (1)
CF 3 CF 2 CH 2 OCF 2 CFHCF 3 (2)
HCF 2 CF 2 CH 2 OCF 2 CF 2 H (3)
HCF 2 CF 2 CH 2 OCF 2 CFHCF 3 (4)
HCF 2 (CF 2 ) 3 CH 2 OCF 2 CFHCF 3 (5)
HCF 2 CF 2 OCH 2 CF 3 (6)
CF 3 CF 2 CH 2 OCF 2 CF 2 H and (7)
HCF 2 CF 2 CH 2 OCF 2 H (8).
21. The rechargeable lithium battery of claim 19 , wherein the high-flash point non-aqueous organic solvent is at least one solvent selected from cyclic esters and cyclic carbonates.
22. The rechargeable lithium battery of claim 21 , wherein the high-flash point non-aqueous organic solvent is at least one selected from the group consisting of γ-butyrolactone, decanolide, valerolactone, mevalonolactone, ethylene carbonate, fluoroethylene carbonate, chloroethylene carbonate, propylene carbonate, chloromethylethylene carbonate, and fluoromethylethylene carbonate.
23. The rechargeable lithium battery of claim 19 , wherein the low-viscosity non-aqueous organic solvent comprises one or more chain carbonates.
24. The rechargeable lithium battery of claim 19 , wherein the low-viscosity non-aqueous organic solvent is selected from the group consisting of diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, ethylpropyl carbonate, and ethylbutyl carbonate.
25. The rechargeable lithium battery of claim 19 , wherein the compatibilizer is present in an amount of 0.01 to 10 wt % based on the total weight of the electrolyte.
26. The rechargeable lithium battery of claim 19 , wherein the battery is a lithium ion battery or a lithium polymer battery.