| 摘要 |
PURPOSE: Provided is a lithium secondary battery including a negative electrode comprising a copper core material, to which an active material made by mixing artificial graphite particles is fixed. CONSTITUTION: The lithium secondary battery comprises a positive electrode, a negative electrode and a non-aqueous electrolyte, wherein the negative electrode comprises a copper core material and a negative electrode material mixture layer fixed on the core material. The negative electrode material mixture layer includes an active material comprising a mixture of artificial graphite particles A and spherical graphite particles B. The artificial graphite particles A are isotropic artificial graphite particles including graphite structure oriented at random and having (1) an interplanar spacing d002 between the (002) planes obtained by a powder X-ray diffraction method being not more than 3.362, (2) a ratio I002/I110 of the peak intensity I002 attributed to the (002) plane to the peak intensity I110 attributed to the (110) plane, which are found from a diffraction pattern obtained by X-ray diffraction of the artificial graphite particles A molded into a pellet of 1.6 g/cm3 in density, being not more than 1,000, (3) a mean circularity of the particles being 0.85 to 0.95, (4) a particle diameter D50 corresponding to a volume fraction of 50% measured by a laser diffraction particle size distribution analyzer being 15 to 30 micrometer, and a ratio D10/D90 of a particle diameter D10 corresponding to a volume fraction of 10% to a particle diameter D90 corresponding to a volume fraction of 90% being 0.2 to 0.5, (5) a tap density after tapping of 900 times with a stroke length of 18 mm being not less than 1 g/cm3, and (6) a specific surface area measured by a BET method being not more than 1 m2/g. The spherical graphite particles B has (1) a mean circularity of the particles being 0.88 to 1, (2) a particle diameter D50 corresponding to a volume fraction of 50% measured by a laser diffraction particle size distribution analyzer being 5 to 15 micrometer, (3) an interplanar spacing d002 between the (002) planes obtained by a powder X-ray diffraction method being not more than 3.357, and (4) a specific surface area measured by a BET method being not more than 8 m2/g. |
