Manufacturing method of anode active material and secondary battery comprising the same

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/cm2, 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.