Electrolyte for lithium secondary battery and lithium secondary battery including the same
An electrolyte for a lithium secondary battery according to exemplary embodiments may include a lithium salt; an organic solvent; and an additive including a lactone compound having an epoxy group. Accordingly, it is possible to provide an electrolyte for a lithium secondary battery having excellent high-temperature characteristics and a lithium secondary battery including the electrolyte.
1 . An electrolyte for a lithium secondary battery comprising:
a lithium salt;
an organic solvent; and
an additive including a lactone compound represented by Formula 1 below:
In Formula 1, X is a substituted or unsubstituted C 1 -C 5 alkylene group,
wherein the substituted C 1 -C 5 alkylene group is the alkylene group in which at least one hydrogen of the alkylene group is substituted with substituent selected from the group consisting of a halogen, a C 1 -C 6 alkyl group, a C 2 -C 6 alkenyl group, an amino group, a C 1 -C 6 alkoxy group, a C 3 -C 7 cycloalkyl group, and a 5- to 7-membered heterocycloalkyl group.
2 . The electrolyte for the lithium secondary battery according to claim 1 , wherein the X is an unsubstituted C 1 -C 3 alkylene group.
3 . The electrolyte for the lithium secondary battery according to claim 1 , wherein the lactone compound represented by Formula 1 includes 2,3-epoxy-γ-butyrolactone.
4 . The electrolyte for the lithium secondary battery according to claim 1 , wherein the additive is included in an amount of 0.1% to 10% by weight based on a total weight of the electrolyte.
5 . The electrolyte for the lithium secondary battery according to claim 1 , wherein the additive is included in an amount of 0.5% to 5% by weight based on the total weight of the electrolyte.
6 . The electrolyte for the lithium secondary battery according to claim 1 , wherein the electrolyte further comprises at least one auxiliary additive selected from the group consisting of a cyclic carbonate compound, a fluorine-substituted cyclic carbonate compound, a sultone compound, a cyclic sulfate compound and an oxalatophosphate compound.
7 . The electrolyte for the lithium secondary battery according to claim 6 , wherein the at least one auxiliary additive is included in an amount of 1% to 10% by weight based on the total weight of the electrolyte.
8 . The electrolyte for the lithium secondary battery according to claim 6 , wherein a weight ratio of the at least one auxiliary additive to a weight of the additive in the electrolyte is 0.5 to 10.
9 . The electrolyte for the lithium secondary battery according to claim 1 , wherein the organic solvent includes a cyclic carbonate solvent and a linear carbonate solvent.
10 . A lithium secondary battery comprising:
a cathode which comprises a lithium metal oxide as a cathode active material;
an anode disposed to face the cathode; and
the electrolyte for the lithium secondary battery according to claim 1 .
11 . The lithium secondary battery according to claim 10 , wherein the cathode active material includes a lithium metal oxide containing nickel.
12 . The lithium secondary battery according to claim 10 , wherein the anode includes a silicon-based active material as an anode active material.