To provide a carbon material for negative electrodes which improves cycle properties and initial efficiency by adding specified amounts of boron and silicon.
Boron or a boron compound, together with silicon or a silicon compound, is added to and mixed with a material of a carbon material such as pitch coke, petroleum type coke, graphite, etc., whose particle size is adjusted as necessary, and the resultant mixture is heat-treated. The temperature for the heat treatment is controlled to be finally 2400°C or higher. The particle size of the obtained already heat-treated carbon material is adjusted to be required particle size by pulverizing and sieving processes and to give a carbon material for a negative electrode for a desired lithium secondary battery. The added boron exists as boron carbide in the carbon material, and the added silicon exists as silicon carbide. The addition amounts of boron and silicon are controlled so as to be 1-20 wt.%, 0.01-20 wt.%, respectively, in the carbon material after heat treatment.
SASAKI AKITO
TANAKA TAKAHIRO
ITO MASAYUKI
TAKEUCHI TADASHI
OKUBO HIROSHI
| JPS62249164A | 1987-10-30 | |||
| JPS62148956A | 1987-07-02 | |||
| JPS59137944A | 1984-08-08 |
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