| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative active material constituting a lithium secondary battery with high storage characteristics, especially the high storage characteristics under high temperature, and its manufacturing method. SOLUTION: The negative active material is made of powdery carbon material, the carbon material is such a material that three parameters obtained by a powder X-ray diffraction method using CuKα line satisfy the following three conditions: (A) the ratio I110 /I002 of the intensity I110 of diffraction line from the (110) face and the intensity I002 of diffraction line from the (002) face; I110 /I002 <=0.015, (B) the half-value width W( deg.) of the peak in the (002) face; W>=0.2, and (C) the interlay distance d002 (nm); d002 >=0.337. The manufacturing method contains a raw material preparation process preparing a powdery raw carbon material satisfying prescribed conditions, and a crystallinity adjusting process for making the carbon material to satisfy the conditions (A) to (C) by changing the crystallinity of the carbon material. |
