Nonaqueous electrolytic solution and nonaqueous electrolyte secondary battery using the same

1. A nonaqueous electrolytic solution, comprising an electrolyte, a nonaqueous solvent, an aromatic carboxylate ester (I) and a compound (II),

the aromatic carboxylate ester (I) being represented by formula (2):

wherein

A 2 is an optionally substituted aryl group,

n 2 is an integer of 1 or 2,

a 2 is an integer of 1 or 2,

when a 2 is 1, R 4 is a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 12 carbon atoms or an optionally substituted aryl group, with the proviso that when n 2 is 2, R 4 is an optionally substituted aryl group, and

when a 2 is 2, R 4 is a single bond, an optionally substituted aliphatic hydrocarbon group having 1 to 12 carbon atoms or an optionally substituted arylene group, and A 2 s may be the same as or different from each other, with the proviso that when n 2 is 2, R 4 is an optionally substituted arylene group,

the compound (II) being at least one selected from the group consisting of fluorine-containing cyclic carbonates, sulfur-containing organic compounds, phosphonate esters, cyano group-containing organic compounds, isocyanate group-containing organic compounds, silicon-containing compounds, aromatic compounds other than those of formula (2), carboxylate esters represented by formula (3) below, cyclic compounds having a plurality of ether bonds, monofluorophosphate salts, difluorophosphate salts, borate salts, oxalate salts and fluorosulfonate salts,

wherein

R 5 is a hydrocarbon group having 1 to 4 carbon atoms, and

R 6 is an ethyl group, an n-propyl group or an n-butyl group.

2. The nonaqueous electrolytic solution according to claim 1 , wherein a 2 in formula (2) is 1.

3. The nonaqueous electrolytic solution according to claim 1 , wherein A 2 in formula (2) is a phenyl group.

4. The nonaqueous electrolytic solution according to claim 1 , wherein the nonaqueous electrolytic solution contains the aromatic carboxylate ester represented by formula (2) in 0.001 mass % to 10 mass %.

5. The nonaqueous electrolytic solution according to claim 1 , wherein the nonaqueous electrolytic solution comprises 0.001 mass % to 20 mass % of the at least one compound selected from the group consisting of fluorine-containing cyclic carbonates, sulfur-containing organic compounds, phosphonate esters, cyano group-containing organic compounds, isocyanate group-containing organic compounds, silicon-containing compounds, aromatic compounds other than those of formula (2), carboxylate esters represented by formula (3), cyclic compounds having a plurality of ether bonds, monofluorophosphate salts, difluorophosphate salts, borate salts, oxalate salts and fluorosulfonate salts.

6. The nonaqueous electrolytic solution according to claim 1 , wherein n 2 in formula (2) is 1.

7. The nonaqueous electrolytic solution according to claim 1 , wherein R 4 in formula (2) is a phenyl group.

8. The nonaqueous electrolytic solution according to claim 1 , wherein the aromatic carboxylate ester (I) is benzyl phenyl acetate.

9. The nonaqueous electrolytic solution according to claim 1 , wherein the compound (II) is a fluorine-containing cyclic carbonate.

10. The nonaqueous electrolytic solution according to claim 9 , wherein the fluorine-containing cyclic carbonate is monofluoroethylene carbonate.

11. The nonaqueous electrolytic solution according to claim 8 , wherein the compound (II) is a fluorine-containing cyclic carbonate.

12. The nonaqueous electrolytic solution according to claim 11 , wherein the fluorine-containing cyclic carbonate is monofluoroethylene carbonate.