Abstract: An anode for a lithium secondary battery includes an anode current collector, and an anode active material layer formed on at least one surface of the anode current collector. The anode active material layer includes an anode active material and an anode binder. The anode active material includes a plurality of composite particles, each of the composite particles include a silicon-based active material particle, and a solid electrolyte interphase (SEI) layer formed on at least a portion of a surface of the silicon-based active material particle. A relative standard deviation of thickness values of the SEI layer of the composite particles, which are measured by an X-ray photoelectron spectroscopy (XPS) from 9 different composite particles among the plurality of composite particles after repeating 100 cycles of charging and discharging is 20% or less.

Abstract: An anode active material for a secondary battery according to an embodiment of the present application includes lithium-silicon composite oxide particle. The lithium-silicon composite oxide particles include at least one selected from the group consisting of Li2SiO3 and Li2Si2O5 and have a phase fraction ratio defined by Equation 1 of 1.0 or less. A content of particles having a diameter of less than 3 ?m is 5 vol % or less based on a total volume of the lithium-silicon composite oxide particles.

Abstract: An anode active material for a secondary battery includes a plurality of composite particles. The composite particles include carbon-based particles containing pores therein. A silicon-containing coating layer is formed inside the pores or on a surface of the carbon-based particles. A surface oxide layer is formed on the silicon-containing coating layer. The surface oxide layer contains silicon oxide. A silicon oxidation number ratio of the composite particle is predefined.