| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative electrode material of a lithium ion secondary battery using inexpensive natural graphite which has high capacity while small in irreversible capacity and which has small reactivity with an electrolytic solution. SOLUTION: A graphite powder, a fusible organic powder (for example, pitch), and powders of boron oxide and/or boric acid are solid-mixed at a ratio of 1-10 pts.wt. of the fusible organic powder and 0.3-6 pts.wt. (in terms of B<SB>2</SB>O<SB>3</SB>) of the powders of boron oxide and/or boric acid based on 100 pts.wt. of the graphite powder, and an obtained mixture is heat-treated at 900°C-1,500°C under a non-oxidizing atmosphere to obtain a carbonaceous material powder produced by adhering non-graphite carbon and boron oxide to the graphite powder. The content of boron oxide in the material is 0.1-1.7 wt.% in B conversion. COPYRIGHT: (C)2009,JPO&INPIT
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