ELECTROLYTE FOR A LITHIUM RECHARGEABLE BATTERY, LITHIUM RECHARGEABLE BATTERY INCLUDING THE SAME, AND METHOD OF MANUFACTURING A LITHIUM RECHARGEABLE BATTERY

1 . A lithium rechargeable battery, comprising:

an electrode assembly;

a case accommodating the electrode assembly; and

an electrolyte in the case, wherein the electrolyte includes:

a lithium salt;

a non-aqueous organic solvent, the non-aqueous organic solvent including about 50 wt % or more of an ester-based solvent;

lithium difluoro(oxalato)borate; and

a first additive, the first additive including at least one selected from tris(trialkylsilyl)phosphate, tris(trialkylsilyl)phosphite, and tris(trialkylsilyl)borate.

2 . The lithium rechargeable battery as claimed in claim 1 , wherein the non-aqueous organic solvent includes about 50 wt % to about 90 wt % of the ester-based solvent.

3 . The lithium rechargeable battery as claimed in claim 1 , wherein the ester-based solvent includes at least one selected from an alkyl acetate, an alkyl propionate, and a cyclic ester.

4 . The lithium rechargeable battery as claimed in claim 3 , wherein the ester-based solvent includes the alkyl acetate, the alkyl acetate including at least one selected from methyl acetate, ethyl acetate, n-propyl acetate, and isopropyl acetate.

5 . The lithium rechargeable battery as claimed in claim 3 , wherein the ester-based solvent includes the alkyl propionate, the alkyl propionate including at least one selected from methyl propionate, ethyl propionate, n-propyl propionate, and isopropyl propionate.

6 . The lithium rechargeable battery as claimed in claim 3 , wherein the ester-based solvent includes the cyclic ester, the cyclic ester including at least one selected from γ-butyrolactone, decanolide, valerolactone, mevalonolactone, and caprolactone.

7 . The lithium rechargeable battery as claimed in claim 1 , wherein the non-aqueous organic solvent further includes at least one selected from a carbonate-based solvent, an ether-based solvent, a ketone-based solvent, an alcohol-based solvent, and an aprotic solvent.

8 . The lithium rechargeable battery as claimed in claim 7 , wherein:

the non-aqueous organic solvent includes the carbonate-based solvent, the carbonate-based solvent being a cyclic carbonate, and

the ester-based solvent and the cyclic carbonate are included in a weight ratio of about 4:1 to about 1:1.

9 . The lithium rechargeable battery as claimed in claim 1 , wherein the lithium difluoro(oxalato)borate is included in the electrolyte in an amount of about 0.1 wt % to about 5 wt %, based on a total weight of the electrolyte.

10 . The lithium rechargeable battery as claimed in claim 9 , wherein the lithium difluoro(oxalato)borate is included in the electrolyte in an amount of about 0.5 wt % to about 5 wt %, based on a total weight of the electrolyte.

11 . The lithium rechargeable battery as claimed in claim 1 , wherein the first additive includes the tris(trialkylsilyl)phosphate, the tris(trialkylsilyl)phosphate including at least one selected from tris(trimethylsilyl)phosphate, tris(triethylsilyl)phosphate, and tris(tripropylsilyl)phosphate.

12 . The lithium rechargeable battery as claimed in claim 1 , wherein the first additive includes the tris(trialkylsilyl)phosphite, the tris(trialkylsilyl)phosphite including at least one selected from tris(trimethylsilyl)phosphite, tris(triethylsilyl)phosphite, and tris(tripropylsilyl)phosphite.

13 . The lithium rechargeable battery as claimed in claim 1 , wherein the first additive includes the tris(trialkylsilyl)borate, the tris(trialkylsilyl)borate including at least one selected from tris(trimethylsilyl)borate, tris(triethylsilyl)borate, and tris(tripropylsilyl)borate.

14 . The lithium rechargeable battery as claimed in claim 1 , wherein the first additive is included in the electrolyte in an amount of about 0.1 wt % to about 5 wt %, based on a total weight of the electrolyte.

15 . The lithium rechargeable battery as claimed in claim 1 , wherein the electrolyte includes the lithium difluoro(oxalato)borate and the first additive in a weight ratio of about 1:0.5 to about 1:4.

16 . The lithium rechargeable battery as claimed in claim 1 , wherein the electrolyte further includes a second additive, the second additive including at least one selected from 1,3-propene sultone and vinylethylene carbonate.

17 . The lithium rechargeable battery as claimed in claim 16 , wherein the second additive is included in the electrolyte in an amount of about 0.1 wt % to about 5 wt %, based on a total weight of the electrolyte.

18 . The lithium rechargeable battery as claimed in claim 1 , wherein:

the electrode assembly includes a positive electrode plate and a negative electrode plate, the positive electrode plate including a positive active material and the negative electrode plate including a negative active material,

the positive active material includes a compound that reversibly intercalates and deintercalates lithium, and

the negative active material includes a material that reversibly intercalates/deintercalates lithium ions, lithium metal, an alloy of lithium metal, a material that dopes and dedopes lithium, or a transition metal oxide.

19 . An electrolyte for a lithium rechargeable battery, the electrolyte comprising:

a lithium salt;

a non-aqueous organic solvent, the non-aqueous organic solvent including about 50 wt % or more of an ester-based solvent;

lithium difluoro(oxalato)borate; and

a first additive, the first additive including at least one selected from tris(trialkylsilyl)phosphate, tris(trialkylsilyl)phosphite, and tris(trialkylsilyl)borate.

20 . A method of manufacturing a lithium rechargeable battery, the method comprising:

preparing an electrode assembly;

accommodating the electrode assembly in a case;

adding an electrolyte to the case; and

sealing the case,

wherein the electrolyte includes:

a lithium salt;

a non-aqueous organic solvent, the non-aqueous organic solvent including about 50 wt % or more of an ester-based solvent;

lithium difluoro(oxalato)borate; and

a first additive, the first additive including at least one selected from tris(trialkylsilyl)phosphate, tris(trialkylsilyl)phosphite, and tris(trialkylsilyl)borate.