| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a lithium ion secondary battery having large discharge capacity since charge capacity is large and initial discharge efficiency is high by forming a thermally decomposed carbon layer on a surface of a carbon particle by chemical evaporation processing, and using a negative electrode material having a prescribed characteristic. SOLUTION: A negative electrode material composed of a carbon particle and a thermally decomposed carbon layer formed by chemical evaporation processing by covering a surface of its carbon particle, is used as a negative electrode material to be used in a lithium ion secondary battery. In its negative electrode material, the specific surface area is set not more than 5m<2> /g, and a balanced adsorption moisture quantity is set not more than 0.3wt%. It is desirable that the carbon particle is formed by baking a condensate by methylene type bonding of aromatic sulfonic acid or its salt at 400 to 1100 deg.C, and an average particle diameter is 0.1 to 100μm, and a thickness of the thermally decomposed carbon layer is 0.1 to 2μm. |
