Negative electrode active material for lithium secondary battery and negative electrode for lithium secondary battery including the same

1. A negative electrode active material for a lithium secondary battery, the negative electrode active material comprising:

(A) first artificial graphite having an average particle diameter (D50) of 15 μm to 20 μm; and

(B) second artificial graphite having an average particle diameter (D50) of 3 μm to 5 μm,

wherein the first artificial graphite (A) comprises a secondary artificial graphite particle, in which at least one primary artificial graphite particle is agglomerated, and a carbon coating layer formed on a surface of the secondary artificial graphite particle, and

a weight ratio of the first artificial graphite to the second artificial graphite is in a range of 85:15 to 95:5.

2. The negative electrode active material for a lithium secondary battery of claim 1 , wherein an average particle diameter of the primary artificial graphite particle included in the first artificial graphite (A) is in a range of 8 μm to 10 μm.

3. The negative electrode active material for a lithium secondary battery of claim 1 , wherein an average particle diameter (D50) of the secondary artificial graphite particle included in the first artificial graphite (A) is in a range of 14 μm to 20 μm.

4. The negative electrode active material for a lithium secondary battery of claim 1 , wherein the secondary artificial graphite particle has a porosity of 1% to 20%.

5. The negative electrode active material for a lithium secondary battery of claim 1 , wherein the secondary artificial graphite particle has a Brunauer-Emmett-Teller (BET) specific surface area of 2 m 2 /g to 10 m 2 /g.

6. The negative electrode active material for a lithium secondary battery of claim 1 , wherein a weight ratio of the secondary artificial graphite particle to the carbon coating layer included in the first artificial graphite (A) is in a range of 70:30 to 95:5.

7. The negative electrode active material for a lithium secondary battery of claim 1 , wherein the first artificial graphite (A) has a porosity of 5% to 15%.

8. The negative electrode active material for a lithium secondary battery of claim 1 , wherein the first artificial graphite (A) has a BET specific surface area of 2 m 2 /g to 30 m 2 /g.

9. The negative electrode active material for a lithium secondary battery of claim 1 , wherein the negative electrode active material has a porosity of 5% to 20%.

10. The negative electrode active material for a lithium secondary battery of claim 1 , wherein the negative electrode active material has a BET specific surface area of 2 m 2 /g to 30 m 2 /g.

11. The negative electrode active material for a lithium secondary battery of claim 1 , wherein the negative electrode active material has an average particle diameter of 12 μm to 20 μm.

12. A negative electrode for a lithium secondary battery, the negative electrode comprising:

a current collector; and

a negative electrode material mixture layer coated on the current collector,

wherein the negative electrode material mixture layer comprises the negative electrode active material of claim 1 .

13. The negative electrode for a lithium secondary battery of claim 12 , wherein a porosity in the negative electrode material mixture layer is in a range of 20% to 40%.

14. A lithium secondary battery comprising:

a negative electrode;

a positive electrode;

a separator disposed between the negative electrode and the positive electrode; and

an electrolyte,

wherein the negative electrode comprises the negative electrode of claim 12 .