Abstract: An anode active material for a lithium secondary battery comprising magnesium-silicon composite oxide particles comprising MgSiO3 and silicon and having a ratio of magnesium to total magnesium, silicon, and oxygen of about 0.07 to about 0.17. A secondary lithium battery comprising the anode active material is provided having enhanced capacity and lifespan.

Abstract: An anode active material for a lithium secondary battery according to embodiments of the present disclosure includes composite particles including carbon-based particles including pores, and a silicon-containing coating formed on a surface of the carbon-based particles, wherein the composite particles have an equivalent porosity of 5 to 25.1%, which is defined by Equation 1 below: Equivalent ? porosity ? ( % ) = ( 1 - W c ? a ? r ? b ? o ? n D c ? a ? r ? b ? o ? n + W S ? i D Si W c ? a ? rbon + W Si D P ) * 1 ? 0 ? 0 [ Equation ? 1 ] In Equation 1, Dcarbon is a density (g/cm3) of carbon, DSi is a density (g/cm3) of silicon, DP is a density (g/cm3) of the composite particles measured by a helium (He) pycnometer, WSi is a weight (g) of silicon included in the composite particles, and Wcarbon is a weight (g) of carbon included in the composite particles.

Abstract: An anode active material for a secondary battery according to an embodiment includes a plurality of a silicon-based active material particle being doped with a metal element and including pores. An average of porosity values measured for each of 10 different silicon-based active material particles among the plurality of the silicon-based active material particle is in a range from 0.2% to 9.0%.