Patent ID: 8790825

Claim:
A negative active material for a rechargeable lithium battery, comprising an innermost core consisting essentially of a silicon oxide represented by Chemical Formula 1; SiO X [Chemical Formula 1] wherein 0<x<2; and a surface-treatment layer surrounding the innermost core and including a metal oxide represented by Chemical Formula 2, wherein the metal of the metal oxide is included in an amount of from about 0.1 wt % to about 20 wt % based on the total weight of the negative active material for a rechargeable lithium battery: M y O z [Chemical Formula 2] wherein M is aluminum (Al), 0<y<5, and 0<z<20; wherein the negative active material has a ratio (E 1 /E 0 ) of a Si—O binding energy E 1 of the negative active material to a Si—O binding energy E 0 of the core of from about 1.005 to about 1.02 in an X-ray photoelectron spectroscopic (XPS) analysis.