Negative active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same

A negative active material for a rechargeable lithium battery, comprising:

• a core including a silicon oxide represented by Chemical Formula 1;
• SiOx [Chemical Formula 1]
• wherein 0<x<2;
• and
• a surface-treatment layer surrounding a surface of the core and including a metal oxide represented by Chemical Formula 2,
• wherein an XPS peak representing an Si—O binding energy appears in a range of about 99 eV to about 110 eV in an X-ray photoelectron spectroscopic (XPS) analysis:
• MyOz [Chemical Formula 2]
• wherein, M is a metal selected from the group consisting of aluminum (Al), titanium (Ti), cobalt (Co), magnesium (Mg), calcium (Ca), potassium (K), sodium (Na), boron (B), strontium (Sr), barium (Ba), manganese (Mn), nickel (Ni), vanadium (V), iron (Fe), copper (Cu), phosphorus (P), scandium (Sc), zirconium (Zr), niobium (Nb), chromium (Cr), molybdenum (Mo), and a combination thereof,
• 0<y<5, and
• 0<z<20.

A method for preparing a negative active material for a rechargeable lithium battery, comprising:

• preparing a silicon oxide powder represented by Chemical Formula 1;
• SiOx [Chemical Formula 1]
• wherein 0<x<2.
• preparing a metal oxide precursor by mixing a metal or a metal alkoxide with water or an organic solvent;
• and
• mixing the silicon oxide powder and the metal oxide precursor in air atmosphere or a reduction atmosphere, and performing a heat treatment.

A method for preparing a negative active material for a rechargeable lithium battery, comprising:

• preparing a silicon oxide powder represented by Chemical Formula 1;
• SiOx [Chemical Formula 1]
• wherein 0<x<2.
• coating the silicon oxide powder with a metal oxide;
• and
• performing a heat treatment onto the silicon oxide coated with the metal oxide in air atmosphere or reduction atmosphere.