Composite anode active material and anode and lithium secondary battery including the same

A composite anode active material, comprising:

• a silicon-carbon composite;
• a first graphite having an average particle diameter D50 of about 19 μm to about 22 um;
• a second graphite having an average particle diameter D50 of 33.8 μm to about 44 μm;
• and
• flake graphite,
• wherein:
• the silicon-carbon composite has an average particle diameter D50 of about 8 μm to about 12 μm,
• an average particle diameter D50 of the flake graphite is smaller than or equal to that of the silicon-carbon composite,
• the average particle diameter D50 of the silicon-carbon composite is smaller than or equal to that of the first graphite,
• the average particle diameter D50 of the first graphite is smaller than or equal to that of the second graphite,
• the first graphite is artificial graphite, and the second graphite is natural graphite,
• the flake graphite is included in an amount of about 5% by weight or less, based on a total weight of the composite anode active material,
• the first graphite has a pellet density in a range of about 1.69 g/cc to about 1.73 g/cc,
• the second graphite has a pellet density in a range of about 2.0 g/cc to about 2.13 g/cc, and
• the pellet density is the density of the pellet which is obtained by adding 1 g of the first graphite or the second graphite to a circular mold having a diameter of 1 centimeter (cm), and then applying a pressure of 1,000 kgf/cm2.