| 摘要 |
A graphite material for a negative electrode of a lithium ion secondary cell is capable of suppressing capacity degradation caused by the repetition of charging and discharging cycles, storage in a charged state, floating charging and the like. A graphite material for a negative electrode of a lithium ion secondary cell, in which Lc (112), which is a crystallite size in a c-axis direction calculated from a (112) diffraction line measured using powder X-ray diffraction method, is within 4.0 nm to 30 nm, a carbon-derived spectrum appearing in electron spin resonance spectroscopy, which is measured using an X band, is in a range of 3200 gauss (G) to 3400 gauss (G), a relative signal intensity ratio (I4.8K/I40K) of the signal intensity (I4.8K) of the spectrum measured at a temperature of 4.8 K to the signal intensity (I40K) of the spectrum measured at a temperature of 40 K is within 1.5 to 3.0, and DeltaHpp, which is a line width of the spectrum calculated from a primary derivative spectrum of the temperature of 4.8 K, is within 20 gauss (G) to 40 gauss (G). |
