LITHIUM-DOPED SILICON-BASED NEGATIVE ELECTRODE ACTIVE MATERIAL, METHOD OF PRODUCING THE SAME, METHOD OF POST-TREATING THE SAME, AND NEGATIVE ELECTRODE AND SECONDARY BATTERY INCLUDING THE SAME

Provided are a lithium-doped silicon-based negative electrode active material, a method of producing the same, and a negative electrode and a lithium secondary battery including the same. According to an exemplary embodiment of the present invention, a method of producing a negative electrode active material for a secondary battery including: a) a metal doping process of mixing a silicon-based material and a metal precursor and performing a heat treatment to dope the silicon-based material with a metal; and b) an acid gas treatment process of treating the metal-doped silicon-based material in an acid gas atmosphere to remove residual metal may be provided.