Disclosed herein is a silicon-based anode active material, comprising a silicon phase, a SiOx (0 < x < 2) phase and a carbon dioxide phase. Also disclosed is a secondary batteru, which comprises a cathode comparising a cathode active material, an anode active material comprising an anode active material, and a separator, wherein the anode active material comproises a silicon phase, an SiOx (O < x < 2) phase and a silicon dioxide phase.