| 摘要 |
Provided are: a nonaqueous electrolyte solution for secondary batteries, which has sufficient cycle characteristics and excellent withstand voltage characteristics that enable charging and discharging at a higher voltage; and a lithium ion secondary battery. A nonaqueous electrolyte solution for secondary batteries, which contains a lithium salt, a medium that is mainly composed of a specific fluorine-containing ether compound, and a specific ligand compound containing a specific phosphoric acid ester compound. The ratio of the total number of moles of oxygen atoms (NO) in the phosphonyl groups in the phosphoric acid ester compound relative to the total number of moles of lithium atoms (NLi) derived from the lithium salt, namely NO/NLi is 1 or more, and the ratio of the total number of moles of atoms (NA) in the ligand compound, said atoms being coordinated to the lithium atoms, relative to the above-described NLi, namely NA/NLi is 4-8. A lithium ion secondary battery which uses this nonaqueous electrolyte solution. |
