Electrolyte solution for lithium secondary battery and lithium secondary battery including the same
An electrolyte solution for a lithium secondary battery includes an organic solvent, a lithium salt, and a pentaerythritol diphosphite-based compound including at least one substituent selected from the group consisting of a silyl group, a sulfonyl group, a phosphoryl group and a phosphino group. A lithium secondary including the electrolyte solution is provided.
1. An electrolyte solution for a lithium secondary battery, comprising:
an organic solvent;
a lithium salt; and
a pentaerythritol diphosphite-based compound comprising at least one substituent selected from the group consisting of a silyl group, a sulfonyl group, a phosphoryl group and a phosphino group
wherein the pentaerythritol diphosphite-based compound is represented by Chemical Formula 1:
wherein, in Chemical Formula 1, R 1 and R 2 are each independently hydrogen, a C 1 to C 10 alkyl group, —SiR 3 R 4 R 5 , —SO 2 R 6 , —P(OR 7 ) 2 or —P(O)(OR 8 ) 2 ,
at least one of R 1 and R 2 is —SiR 3 R 4 R 5 , —SO 2 R 6 , —P(OR 7 ) 2 or —P(O)(OR 8 ) 2 , and
R 3 to R 8 are each independently a substituted or unsubstituted C 1 to C 10 alkyl group, a substituted or unsubstituted C 6 to C 12 aryl group, or a substituted or unsubstituted 5 to 12 membered heteroaryl group.
2. The electrolyte solution for a lithium secondary battery according to claim 1 , wherein the pentaerythritol diphosphite-based compound comprises at least one of compounds represented by Chemical Formulae 2 to 5:
wherein, in Chemical Formulae 2 to 5, R 3 to R 8 are each independently a substituted or unsubstituted C 1 to C10 alkyl group, a substituted or unsubstituted C 6 to C 12 aryl group, or a substituted or unsubstituted 5 to 12 membered heteroaryl group.
3. The electrolyte solution for a lithium secondary battery according to claim 1 , wherein the pentaerythritol diphosphite-based compound is included in an amount from 0.1 wt % to 5.0 wt % based on a total weight of the electrolyte solution.
4. The electrolyte solution for a lithium secondary battery according to claim 1 , further comprising at least one additive selected from the group consisting of a cyclic carbonate-based compound comprising a double bond, a fluorine-substituted cyclic carbonate-based compound, a sultone-based compound and a cyclic sulfate-based compound.
5. The electrolyte solution for a lithium secondary battery according to claim 1 , wherein the organic solvent comprises at least one selected from the group consisting of ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate and diethyl carbonate.
6. A lithium secondary battery, comprising:
a case;
an electrode assembly comprising a cathode and an anode; and
the electrolyte solution for a lithium secondary battery of claim 1 injected into the case.