Negative electrode active materials, preparation methods thereof, and lithium rechargeable batteries

A negative electrode active material, comprising:

• a silicon-carbon composite particle including a plurality of silicon nanoparticles and amorphous carbon;
• wherein:
• the plurality of silicon nanoparticles are included in an amount of about 56 wt % to about 64 wt % and the amorphous carbon is included in an amount of about 36 wt % to about 44 wt % based on a total weight of the silicon-carbon composite particle;
• the silicon-carbon composite particle includes closed pores therein;
• a pore volume of a surface of the silicon-carbon composite particle measured by a BJH method is less than about 0.02 cm3/g;
• and
• a volume of the closed pores of the silicon-carbon composite particle calculated by Equation 1 is about 0.015 cm3/g to about 0.05 cm3/g:
• Volume
• ⁢
• of
• ⁢
• closed
• ⁢
• pores
• ⁢
• in
• ⁢
• a
• ⁢
• particle
• =
• (
• (
• theoretical
• ⁢
• density
• )
• -
• (
• true
• ⁢
• density
• )
• )
• -
• 1
• -
• (
• pore
• ⁢
• volume
• ⁢
• measured
• ⁢
• by
• ⁢
• the
• ⁢
• BJH
• ⁢
• method
• )
• .
• [
• Equation
• ⁢
• 1
• ]