COMPOSITE NEGATIVE ELECTRODE ACTIVE MATERIAL, METHOD FOR PREPARING SAME, NEGATIVE ELECTRODE COMPRISING SAME, AND SECONDARY BATTERY

A composite negative electrode active material including silicon-containing oxide particles; and a metal distributed on the surface, inside, or both on the surface and inside of the silicon-containing oxide particles, in which an average value of aggregate diameters measured by a specific method is 65 nm or less. The composite negative electrode active material can have a uniform and small aggregate diameter to minimize deterioration of service life performance of the composite negative electrode active material caused by volume expansion and contraction of silicon during charging and discharging.