| 摘要 |
The present invention relates to a method for producing a graphite powder for negative electrode materials for lithium ion secondary batteries, which is characterized by comprising a step for graphitizing a mixture of a carbon starting material powder and a silicon carbide powder, and which is also characterized in that: the 90% particle diameter D90 of the silicon carbide powder in the volume-based cumulative particle size distribution by means of a laser diffraction method is 1-40 μm; the content ratio of silicon carbide in the total mass of the carbon starting material and the silicon carbide, namely (mass of silicon carbide)/(total mass of carbon starting material and silicon carbide), is 1-35% by mass; and the ratio of the 50% particle diameter D50 of the carbon starting material powder to the 50% particle diameter D50 of the silicon carbide powder in the volume-based cumulative particle size distribution by means of a laser diffraction method, namely (D50 of carbon starting material)/(D50 of silicon carbide), is 0.40-4.0. A production method of the present invention is able to provide, at low cost, a graphite powder for negative electrode materials for lithium ion secondary batteries, which has high capacity, high density and high capacity retention rate. |
