Patent ID: 7816037

Claim:
An anode material for lithium ion secondary battery comprising a coated graphite powder, which is a graphite powder in which interior portions of fine pores are coated with a carbonized material of thermoplastic resin, wherein the coated graphite powder has: (1) a mesopore volume defined by IUPAC is 0.01 cc/g or less as calculated with the BJH method as viewed from desorption isotherm; (2) an average particle size as measured by a laser-scattering-particle-size-distribution measuring device ranges from 10 μm to 50 μm, and a ratio of standard deviation to the average particle size, σ/D, is 0.02 or less; (3) a peak strength ratio R of 1,360 cm −1 to 1,580 cm −1 is 0.4 or less as determined by a Raman spectrum analysis with a wavelength of 532 nm, where R=I 1360 /I 1580 ; (4) a rate of oxidation loss when oxidized in atmospheres of 400° C. and an air mass flow of 3 L/min. for one hour is 2 wt % or more; (5) a specific surface area is in the range of 1.6 m 2 /g to 3.1 m 2 /g as calculated based on BET with nitrogen as the absorptive; and (6) an average interlayer spacing d 002 of not more than 0.3380 nm and L(112) of not less than 5 nm as determined by the Gakushin-method for X-ray diffraction of carbon employing an X-ray diffraction device.