Electrolyte for rechargeable lithium battery and rechargeable lithium battery including the same
An electrolyte for a rechargeable lithium battery includes a non-aqueous organic solvent, a lithium salt, and an additive. The additive includes a gamma butyrolactone compound substituted with at least one F atom at the α-position.
1. A rechargeable lithium battery, comprising:
a positive electrode comprising a positive active material;
a negative electrode comprising a negative active material comprising a Si-based active material selected from the group consisting of:
Si;
SiO x wherein 0<x<2;
Si—Y alloys wherein Y is an element selected from the group consisting of alkali metals, alkaline-earth metals, group 13 through group 16 elements, transition elements, rare earth elements, and combinations thereof, but Y is not Si;
carbon-coated SiO x wherein 0<x<2;
Si—C composites; and
combinations thereof; and
an electrolyte comprising:
a non-aqueous organic solvent;
a lithium salt; and
an additive comprising a compound represented by Chemical Formula 1:
wherein:
each of X 1 and X 2 is independently a halogen or hydrogen, provided that at least one of X 1 and X 2 is F,
each of R 1 through R 3 is hydrogen, and
R 4 is selected from the group consisting of unsubstituted butyl groups, and unsubstituted hexyl groups.
2. The rechargeable lithium battery of claim 1 , wherein the additive is selected from the group consisting of α,α-difluoro-γ-butyl gammabutyrolactone, α,α-difluoro-γ-hexyl gammabutyrolactone, and combinations thereof.
3. The rechargeable lithium battery of claim 1 , wherein the additive is present in the electrolyte in an amount of about 0.5 to about 10 parts by weight based on 100 parts by weight of the non-aqueous organic solvent and the lithium salt.
4. The rechargeable lithium battery of claim 1 , wherein the additive is present in the electrolyte in an amount of about 2 to about 10 parts by weight based on 100 parts by weight of the non-aqueous organic solvent and the lithium salt.
5. The rechargeable lithium battery of claim 1 , wherein the Si-based active material is selected from the group consisting of:
Si;
SiO x wherein 0<x<2;
carbon-coated SiO x wherein 0<x<2;
Si—C composites; and
combinations thereof.
6. The rechargeable lithium battery of claim 1 , wherein the Si-based active material comprises the carbon-coated SiO x wherein 0<x<2.
7. The rechargeable lithium battery of claim 1 , wherein the negative active material further comprises a carbon-based active material.
8. The rechargeable lithium battery of claim 7 , wherein the carbon-based active material comprises graphite.
9. The rechargeable lithium battery of claim 1 , wherein the negative active material comprises a combination of the Si-based active material and a carbon-based active material, the Si-based active material is present in the negative active material in an amount of about 1 wt % to about 99 wt %, and the carbon-based active material is present in the negative active material in an amount of about 1 wt % to about 99 wt %.
10. The rechargeable lithium battery of claim 1 , wherein the negative active material comprises a combination of the Si-based active material and a carbon-based active material, the Si-based active material is present in the negative active material in an amount of about 10 wt % to about 90 wt %, and the carbon-based active material is present in the negative active material in an amount of about 10 wt % to about 90 wt %.