Silicon carbon composite, negative electrode active material, negative electrode composition, negative electrode, and lithium secondary battery

A method for preparing a silicon carbon composite, the method comprising:

• performing a disproportionation reaction by heat treating a silicon oxide powder;
• etching the heat treated silicon oxide powder with an etchant;
• obtaining a porous silicon-based particle by pulverizing the etched silicon oxide powder;
• and
• forming a silicon carbon composite by reacting the porous silicon-based particle with a carbon source to form a carbon layer on a surface of the porous silicon-based particle, wherein the silicon carbon composite satisfies a condition of 3≤((B+C)/A)<4,
• wherein A is an intensity of peak A having a chemical shift value in the range of 20 ppm to −15 ppm in a 29Si-MAS-NMR spectrum, B is an intensity of peak B having a chemical shift value in the range of −20 ppm to −100 ppm in the 29Si-MAS-NMR spectrum;
• and C is an intensity of peak C having a chemical shift value in the range of −110 ppm to −140 ppm in the 29Si-MAS-NMR spectrum.

A method for preparing a silicon carbon composite, the method comprising:

• depositing silicon on a porous carbon particle by chemical vapor deposition,
• wherein the method optionally further comprises forming a carbon layer on a surface of the silicon deposited on the porous carbon particle,
• wherein the silicon carbon composite satisfies a condition of 3≤((B+C)/A)<4,
• wherein A is an intensity of peak A having a chemical shift value in the range of 20 ppm to −15 ppm in a 29Si-MAS-NMR spectrum, B is an intensity of peak B having a chemical shift value in the range of −20 ppm to −100 ppm in the 29Si-MAS-NMR spectrum;
• and C is an intensity of peak C having a chemical shift value in the range of −110 ppm to −140 ppm in the 29Si-MAS-NMR spectrum.