| 摘要 |
To improve battery characteristics by an optimum combination of an electrolytic solution and a negative electrode active material. An electrolytic solution of a nonaqueous electrolyte secondary battery contains a metal salt, and an organic solvent having a heteroatom and satisfying, regarding an intensity of a peak derived from the organic solvent in a vibrational spectroscopy spectrum, Is>Io, when an intensity of an original peak of the organic solvent is represented as Io and an intensity of a peak resulting from shifting of the original peak is represented as Is. As a negative electrode, any of the following (1) to (5) is used: (1) a graphite whose G/D ratio, which is a ratio of G-band and D-band peaks in a Raman spectrum, is not lower than 3.5; (2) a carbon material whose crystallite size, calculated from a half width of a peak appearing at 2θ=20 degrees to 30 degrees in a X-ray diffraction profile measured by X-ray diffraction method, is not larger than 20 nm; (3) silicon element and/or tin element; (4) a metal oxide configured to occlude and release lithium ions; or (5) a graphite whose ratio (long axis/short axis) of long axis to short axis is 1 to 5. |
