Patent attributes
A negative electrode for a lithium ion secondary battery comprising a material mixture layer comprising a carbonaceous material comprising a spherical natural graphite and a graphitized carbon fiber, wherein the material mixture layer has a carbon density of not less than 1.6 g/cm3; the spherical natural graphite has: (1) an interplanar spacing d002 between the (002) planes determined by an X-ray diffraction pattern of 0.3354 to 0.3357 nm, (2) a mean particle circularity of not less than 0.86, and (3) a mean particle size of 5 to 20 μm; the graphitized carbon fiber has: (1) a mean fiber length of 20 to 200 μm, and (2) a mean aspect ratio of 2 to 10; and the amount of the graphitized carbon fiber is 50 to 90% by weight of whole of the carbonaceous material.
