Manufacturing method of anode active material and secondary battery comprising the same
The present invention relates to a method for preparing an anode active material including the steps of: obtaining graphite byproduct particles that have not been spheroidized in a step of pulverizing and spheroidizing flaky graphite particles; preparing coated particles by liquid phase mixing the graphite byproduct particles with composite particles to coat the surface of the graphite byproduct particles with the composite particles; spheroidizing the coated particles by performing an isostatic pressing process thereon; and pulverizing the coated particles and coating the surface thereof with amorphous carbon to prepare spherical graphite.
1 . A method for preparing an anode active material, the method comprising the steps of:
obtaining graphite byproduct particles having a particle size of 3 to 6 μm in a step of pulverizing and spheroidizing flaky graphite particles having a particle size of 30 to 200 μm;
preparing coated particles by liquid phase mixing the graphite byproduct particles with composite particles to coat a surface of the graphite byproduct particles with the composite particles;
spheroidizing the coated particles by performing an isostatic pressing process thereon in conditions of a pressure of 40 to 500 kgf/cm 2 , a temperature of 10 to 150° C., and a time of 1 to 10 hours, using a mixed fluid of water with 5 to 10 vol % of hexane; and
pulverizing the coated particles and coating a surface of the coated particles with amorphous carbon to prepare spherical graphite.
2 . The method for preparing an anode active material according to claim 1 , wherein the composite particles include any one of silicon (Si), tin (Sn), antimony (Sb), aluminum (Al), germanium (Ge), zinc (Zn), lead (Pb), or a mixture of two or more thereof, or an oxide of the above components, or a mixture of two or more of the oxides.