METHOD OF PRODUCING AMORPHOUS CARBON MATERIAL FOR THE NEGATIVE ELECTRODE OF LITHIUM ION SECONDARY BATTERY, AND LITHIUM ION SECONDARY BATTERY

摘要

An amorphous carbon material for lithium-ion secondary battery negative electrode is capable of reducing capacity degradation due to repeated charge and discharge cycles, storage while being charged, or floating charge. A method for producing an amorphous carbon material for a negative electrode of a lithium-ion secondary battery includes the steps of: pulverizing and classifying a raw coke composition obtained from a heavy-oil composition undergone coking by delayed coking process to obtain powder of the raw coke composition, the raw coke composition having a H/C atomic ratio that is a ratio of hydrogen atoms H and carbon atoms C of 0.30 to 0.50 and having a micro-strength of 7 to 17 mass%; giving compressive stress and shear stress to the powder of the raw coke composition to obtain a carbonized composition precursor; and heating the carbonized composition precursor under an inert atmosphere at a temperature from 900°C to 1,500°C so that a size of a crystallite Lc(002) is in a range of 2 nm to 8 nm, the size being calculated from a (002) diffraction line obtained by X-ray wide-angle diffractometry.