| 摘要 |
PROBLEM TO BE SOLVED: To provide a large-capacity lithium ion secondary battery with excellent rate characteristics, cycle stability, and low-temperature characteristics, by making it possible to use an electrolytic solution containing PC(propylene carbonate) when using a graphite material for a negative electrode of a nonaqueous solvent secondary battery. SOLUTION: This nonaqueous solvent secondary battery is characterized by using the negative electrode using a graphite powder as carbon material and the electrolytic solution made by dissolving a lithium salt in a nonaqueous solvent containing propylene carbonate. The graphite powder contains boron and is made by graphitizing mesophase pitch in the existence of a boron compound in an atmospheric gas that contains nitrogen of 1 vol.% or less. With respect to the powder, in a spectrum obtained by X-ray photoelectron spectroscopy(XPS), the detected strength of a B1s peak appearing in a bound energy range from 186 eV to 187 eV is 0.02 or more when the bound energy of C1s is assumed to be 284.5 eV and the detected strength of the C1s peak to be 100, while the spacing d002 of crystal grains is 0.3360 nm or more in the C-axis direction in X-ray diffraction. |
