Non-aqueous electrolyte solution for lithium secondary battery and lithium secondary battery comprising the same

1. An additive for a non-aqueous electrolyte solution, the additive comprising a compound represented by Formula 1:

NC—(R) n —CN,  [Formula 1]

wherein in Formula 1, R is a cycloalkylene group having 5 carbon atoms, which is substituted with at least one cyano group (—CN); a haloalkylene group having 2 to 5 carbon atoms, which is substituted with at least one cyano group (—CN); or —R 2 —C(CN) 2 —R 3 —, wherein R 2 and R 3 are each independently an alkylene group having 1 to 3 carbon atoms, and at least one of R 2 and R 3 is an alkylene group having 1 carbon atom, and

n is an integer of 1 to 5.

2. The additive for a non-aqueous electrolyte solution of claim 1 , comprising at least one compound selected from the group consisting of compounds represented by Formulae 1e:

3. A non-aqueous electrolyte solution for a lithium secondary battery, the non-aqueous electrolyte solution comprising:

an ionizable lithium salt;

an organic solvent; and

an additive for a non-aqueous electrolyte solution,

wherein the additive for a non-aqueous electrolyte solution comprises a compound represented by Formula 1:

NC—(R) n —CN,  [Formula 1]

wherein in Formula 1, R is a cycloalkylene group having 3 to 5 carbon atoms, which is substituted with at least one cyano group (—CN); a haloalkylene group having 2 to 5 carbon atoms, which is substituted with at least one cyano group (—CN); or —R 2 —C(CN) 2 —R 3 —, wherein R 2 and R 3 are each independently an alkylene group having 1 to 3 carbon atoms, and at least one of R 2 and R 3 is an alkylene group having 1 carbon atom, and

n is an integer of 1 to 5.

4. The non-aqueous electrolyte solution for a lithium secondary battery of claim 3 , wherein the additive for a non-aqueous electrolyte solution comprises at least one compound selected from the group consisting of compounds represented by Formulae 1c and 1e:

5. The non-aqueous electrolyte solution for a lithium secondary battery of claim 3 , wherein the additive for a non-aqueous electrolyte solution is included in an amount of 0.5 wt % to 5 wt % based on a total weight of the non-aqueous electrolyte solution.

6. The non-aqueous electrolyte solution for a lithium secondary battery of claim 3 , wherein the lithium salt comprises Li + , as a cation, and any one selected from the group consisting of F − , Cl − , Br − , I − , NO 3 − , N(CN) 2 − , BF 4 − , ClO 4 − , AlO 4 − , AlCl 4 − , PF 6 − , SbF 6 − , AsF 6 − , BF 2 C 2 O 4 − , BC 4 O 8 − , (CF 3 ) 2 PF 4 − , (CF 3 ) 3 PF 3 − , (CF 3 ) 4 PF 2 − , (CF 3 ) 5 PF − , (CF 3 ) 6 P − , CF 3 SO 3 − , C 4 F 9 SO 3 − , CF 3 CF 2 SO 3 − , (CF 3 SO 2 ) 2 N − , (F 2 SO 2 ) 2 N − , CF 3 CF 2 (CF 3 ) 2 CO − , (CF 3 SO 2 ) 2 CH − , CF 3 (CF 2 ) 7 SO 3 − , CF 3 CO 2 − , CH 3 CO 2 − , SCN − , and (CF 3 CF 2 SO 2 ) 2 N − as an anion.

7. The non-aqueous electrolyte solution for a lithium secondary battery of claim 3 , wherein the organic solvent comprises any one selected from the group consisting of an ether compound, an ester compound, an amide compound, a linear carbonate compound, or a cyclic carbonate compound, or a mixture of two or more thereof.

8. A lithium secondary battery comprising:

a negative electrode;

a positive electrode;

a separator disposed between the negative electrode and the positive electrode; and

a non-aqueous electrolyte solution,

wherein the non-aqueous electrolyte solution comprises the non-aqueous electrolyte solution for a lithium secondary battery of claim 3 .