Electrolyte for rechargeable lithium battery and rechargeable lithium battery including the same
An electrolyte for a rechargeable lithium battery includes an organic solvent including C3 to C5 alkyl propionate, and the electrolyte further includes a lithium salt and a compound represented by Chemical Formula 1, wherein, in Chemical Formula 1, k, l, and m are independently integers of 0 to 20, k, l, and m are selected, so that Chemical Formula 1 has an asymmetric structure, n is an integer of 1 to 7, and R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are independently hydrogen, an alkyl group, an alkoxy group, or a fluoroalkyl group.
1. An electrolyte for a rechargeable lithium battery, the electrolyte comprising:
an organic solvent including C3 to C5 alkyl propionate;
a lithium salt; and
a compound represented by Chemical Formula 1:
wherein, in Chemical Formula 1,
k, l, and m are independently integers of 0 to 20, k, l, and m being selected so that Chemical Formula 1 has an asymmetric structure,
n is an integer of 1 to 7, and
R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are independently hydrogen, an alkyl group, an alkoxy group, or a fluoroalkyl group, and
wherein the compound represented by Chemical Formula 1 is included in an amount of about 0.05 wt % to about 10 wt % based on the total weight of the electrolyte for a rechargeable lithium battery.
2. The electrolyte as claimed in claim 1 , wherein the C3 to C5 alkyl propionate is included in an amount of about 10 volume % to about 80 volume % based on the total amount of the organic solvent.
3. The electrolyte as claimed in claim 2 , wherein the C3 to C5 alkyl propionate includes one or more of propyl propionate, N-butyl propionate, tert-butyl propionate, isobutyl propionate, N-pentyl propionate, 2-pentyl propionate, tert-pentyl propionate, or isopentyl propionate.
4. The electrolyte as claimed in claim 1 , wherein the compound represented by Chemical Formula 1 includes one or more of hexane tricyanide having an asymmetric structure, or pentane tricyanide having an asymmetric structure.
5. The electrolyte as claimed in claim 4 , wherein the electrolyte further includes succinonitrile.
6. The electrolyte as claimed in claim 1 , wherein in Chemical Formula 1, n is an integer of 1 to 5, and k, l, and m are independently integers of 0 to 10.
7. The electrolyte as claimed in claim 1 , wherein in Chemical Formula 1, n is an integer of 1 to 3, and k, l, and m are independently integers of 0 to 7.
8. The electrolyte as claimed in claim 1 , wherein in Chemical Formula 1, n is 1 or 2, k is 0, and l and m are independently integers of 1 to 5.
9. The electrolyte as claimed in claim 1 , wherein in Chemical Formula 1, k, l, and m are different integers from each other.
10. The electrolyte as claimed in claim 1 , wherein the lithium salt includes LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 3 C 2 F 5 ) 2 , LiC 4 F 9 SO 3 , LiClO 4 , LiAlO 2 , LiAlCl 4 , LiN(C x F 2x+1 SO 2 )(C y F 2y+1 SO 2 ), wherein x and y are natural numbers, LiCl, LiI, LiB(C 2 O 4 ) 2 , or a combination thereof.
11. The electrolyte as claimed in claim 1 , wherein a concentration of the lithium salt is about 0.1 M to about 2.0 M.
12. The electrolyte as claimed in claim 1 , wherein the electrolyte for a rechargeable lithium battery includes one or more additives selected from fluoroethylene carbonate, vinylethylene carbonate, succinonitrile, polysulfone, and a combination thereof.
13. A rechargeable lithium battery comprising:
a negative electrode including a negative active material,
a positive electrode including a positive active material, and
the electrolyte as claimed in claim 1 .
14. The rechargeable lithium battery as claimed in claim 3 , wherein the rechargeable lithium battery is operated at a voltage of about 4.4 V or greater.