Nonaqueous electrolytic solution and nonaqueous electrolyte secondary battery

A nonaqueous electrolytic solution, comprising:

• an electrolyte,
• a nonaqueous solvent, and
• a compound of formula (2):
• wherein R4, R5, and R6 are each independently a hydrogen atom, a cyano group, or an optionally halogen atom-substituted hydrocarbon group having 1 to 10 carbon atoms, with the proviso that R4 and R5 are not both hydrogen atoms,
• wherein the solution is suitable for a nonaqueous electrolyte secondary battery that comprises a negative electrode, a positive electrode, and a nonaqueous electrolytic solution, the negative electrode and the positive electrode being capable of storing and releasing metal ions.

A nonaqueous electrolytic solution, comprising:

• an electrolyte,
• a nonaqueous solvent,
• a compound of formula (1),
• and at least one compound selected from the group consisting of a halogen atom-containing cyclic carbonate, a monofluorophosphate, and a difluorophosphate,
• wherein formula 1 is:
• R1, R2, and R3 are each independently represent a hydrogen atom, a cyano group, or an optionally halogen atom-substituted hydrocarbon group having 1 to 10 carbon atoms,
• wherein the solution is suitable for a nonaqueous electrolyte secondary battery that comprises a negative electrode, a positive electrode, and a nonaqueous electrolytic solution, the negative electrode and the positive electrode being capable of storing and releasing metal ions.