Nonaqueous electrolyte solution and lithium secondary battery using same

1. A non-aqueous electrolyte solution comprising:

a lithium salt;

a non-aqueous solvent;

a cyclic carbonate compound having an unsaturated bond in a concentration of 0.01 weight % to 8 weight %; and

a compound expressed by the following formula (Ic) in a concentration of 0.01 weight % to 5 weight %;

CF n H (3-n) CH 2 X 3   (Ic)

wherein n represents an integer of 1-3 and X 3 represents a group selected from the group consisting of the following formulae (Ic-1),(Ic-2) and (Ic-4),

—O—R 31   (Ic-1)

—O—Y 3 —O—R 32   (Ic-2)

and

wherein R 31 , R 32 and R 34 represent, independently of each other, an alkyl group having 1-20 carbon atoms that may be substituted by a halogen atom, and Y 3 represents a divalent hydrocarbon group having 1-10 carbon atoms that may be substituted by a halogen atom.

2. The non-aqueous electrolyte solution of claim 1 , comprising a compound of formula (Ic) wherein X 3 is the formula (Ic-2) wherein Y 3 is a divalent alkylene group having 1-10 carbon atoms that may be substituted by a halogen atom.

3. The non-aqueous electrolyte solution of claim 1 , comprising a compound of formula (Ic) wherein X 3 is the formula (Ic-4).

4. The non-aqueous electrolyte solution of claim 1 , wherein each of R 31 , R 32 and R 34 is an alkyl group having 1-20 carbon atoms substituted by 1-3 fluorine atoms.

5. The non-aqueous electrolyte solution of claim 1 , wherein the cyclic carbonate compound having an unsaturated bond is a compound or a plurality of compounds selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, divinyl ethylene carbonate, vinyl vinylene carbonate and methylene ethylene carbonate.

6. The non-aqueous electrolyte solution of claim 1 , wherein the compound of formula (Ic) is at least one selected from the group consisting of CFH 2 CH 2 OCH 2 CH 2 CH 2 OCH 2 CH 3 , CFH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 F, CF 3 CH 2 OCH 2 CH 2 OCH 2 CH 3 , CF 3 CH 2 OCH 2 CH 2 OCH 2 CF 3 , CFH 2 CH 2 OC(═O)OCH 2 CH 3 and CFH 2 CH 2 OC(═O)OCH 2 CH 2 F.

7. The non-aqueous electrolyte solution of claim 6 , wherein the non-aqueous solvent is vinylene carbonate.

8. The non-aqueous electrolyte solution of claim 7 , wherein the non-aqueous solvent comprises ethylene carbonate and ethyl methyl carbonate.

9. The non-aqueous electrolyte solution of claim 1 , wherein the compound of formula (Ic) is present in an amount of from 0.1 to 2 weight%.

10. The non-aqueous electrolyte solution of claim 1 , comprising a compound of formula (Ic) having an alkyl group having 1-20 carbon atoms substituted by a halogen atom.

11. The non-aqueous electrolyte solution of claim 1 , wherein R 31 , R 32 and R 34 represent, independently of each other, an alkyl group having 1-10 carbon atoms that may be substituted by a halogen atom.

12. The non-aqueous electrolyte solution of claim 1 , wherein R 31 , R 32 and R 34 represent, independently of each other, an alkyl group having 1-6 carbon atoms that may be substituted by a halogen atom.

13. The non-aqueous electrolyte solution of claim 1 , wherein R 31 , R 32 and R 34 represent, independently of each other, an alkyl group having 1-20 carbon atoms.

14. The non-aqueous electrolyte solution of claim 1 , wherein Y 3 represents a divalent hydrocarbon group having 1-6 carbon atoms that may be substituted by a halogen atom.

15. The non-aqueous electrolyte solution of claim 1 , wherein Y 3 represents a divalent hydrocarbon group having 1-4 carbon atoms that may be substituted by a halogen atom.

16. A lithium secondary battery comprising:

a non-aqueous electrolyte solution; and a positive electrode and a negative electrode capable of absorbing and desorbing lithium ions; wherein the non-aqueous electrolyte solution is the non-aqueous electrolyte solution of claim 1 .