PREPARATION METHOD OF SOFT CARBON AND LITHIUM-ION SECONDARY BATTERY

A preparation method of soft carbon comprises heating heavy oil to raw coke under a condition of 480°C-550°C, heating the raw coke to 850°C-900°C at a first heating rate of 3°C/min to 5°C/min and holding the temperature for 4 hours or more to obtain a carbon-containing material, grinding and grading the carbon-containing material to obtain a carbon-containing powder, heating the carbon-containing powder to 1030°C-1220°C at a second heating rate of 3°C/min to 10°C/min and holding the temperature for 4 hours or more to obtain a carbon material powder,; and adding pitch to the carbon material powder, and then heating it to 1030°C-1220°C at a third heating rate of 0.90°C/min to 1.25°C/min and holding the temperature for 5 hours or more to obtain soft carbon.