Silicon-based negative electrode active material and method for preparing the same

A negative electrode active material comprising:

• silicon-based nanoparticles;
• and
• a carbonized water-soluble polymer on the silicon-based nanoparticle,
• wherein the silicon-based nanoparticle having the carbonized water-soluble polymer thereon has a diameter in the range of 30 nm to 800 nm,
• wherein the carbonized water-soluble polymer is included in 3% by weight to 20% by weight with respect to a total weight of the silicon-based nanoparticles,
• wherein the silicon-based nanoparticles include any one material selected from the group consisting of SiO, SiM and a combination thereof, and M includes any one selected from the group consisting of Ni, Co, B, Cr, Cu, Fe, Mn, Ti, Y and a combination thereof,
• wherein the carbonized water-soluble polymer is prepared by carbonizing a water-soluble polymer having a weight average molecular weight of 90,000 to 2,000,000,
• wherein the water-soluble polymer is carboxymethylcellulose (CMC).