| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a graphite material for negative electrode which does not in effect contain a boron compound that is regarded as obstructing the performance improvement of a battery, and shows a steady and high discharge capacity. SOLUTION: (1), (A) This is a manufacturing method of a graphite material for lithium ion secondary battery negative electrode in which the graphite material, that has a specific graphite structure obtained by graphitization process of the carbon material under existence of a boron compound and has B4 C is (B) heat treated in the oxygen gas-contained atmosphere, and then (C) the boron oxide is cleaned and removed. (2) And further, (D) by decompression heat treatment, the remaining boron compound is removed. (3) After the (A), (B) steps, (C)' by performing decompression heat treatment, the boron oxide and the remaining boron compound are removed. (4) And also, the graphitization process is performed in argon atmosphere. And (5), (A) the carbon material is a milled carbon fiber from a mesophase pitch material. |
