| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative electrode material for a secondary battery which is formed of high crystalline particulates and has high bulk density and is excellent in kneading performance with a solvent by compressing and capacitively reducing graphite particles of specified crystal lattice constant, and setting them to a specific bulk density. SOLUTION: A crystal lattice constant Co(002) of high crystalline graphite particles of a carbon raw material used as a neagtive electrode material, is set to 0.670 to 0.673 nm. A desirable average particle diameter of the graphite particles is set not more than about 50 μm. These graphite particles are slightly turned into secondary particles, and are capacitively reduced, and bulk density is set to 0.3 to 1.0 g/cm<3> . In order to form the negative electrode material having high bulk density by being turned into secondary particles, for example, the graphite particles are compressed without using a pressure sensitive adhesive. Compression pressure is desirable to be about 0.2 to 10 kg/cm<2> . This negative electrode material is added to a solvent in which a binder is dissolved, and is sufficiently kneaded, and is formed as high concentration graphite particle slurry having the graphite particle concentration not less than 60 wt.%, and a negative electrode of a lithium ion secondary battery is adjusted by coating a current collecting body composed of metallic foil with this slurry. |
