Anode active material for lithium secondary battery, method of preparing the same, and lithium secondary battery containing the same
Provided are an anode active material for a lithium secondary battery, a method of preparing the same, and a lithium secondary battery containing the same. The present invention provides an anode active material for a lithium secondary battery including: a carbon based particle; a first carbon coating layer positioned on the carbon based particle and including pores; a silicon coating layer positioned on the pores and/or a pore-free surface of the first carbon coating layer; and second carbon coating layer positioned on the silicon coating layer, a method of preparing the same, and a lithium secondary battery containing the same.
1. An anode active material for a lithium secondary battery, the anode active material comprising:
a carbon/silicon composite comprising:
a carbon based particle;
a first carbon coating layer positioned on and in contact with the carbon based particle the first carbon coating layer including pores;
a silicon coating layer positioned on and in contact with the first carbon coating layer; and
wherein the anode active material further comprises a second carbon coating layer positioned on the carbon/silicon composite, and
wherein the first carbon coating layer is formed from a carbon precursor which is different from the carbon based particle.
2. The anode active material of claim 1 , wherein the silicon coating layer is positioned on the pores or a pore-free surface of the first carbon coating layer.
3. The anode active material of claim 1 , wherein the first carbon coating layer includes the pores in an interior and a surface thereof.
4. The anode active material of claim 1 , wherein an average pore size of the pores of the first carbon coating layer is 30 nm or more to 900 nm or less.
5. The anode active material of claim 1 , wherein the anode active material satisfies the following Equation 1:
0.005≤ D a /D b ≤0.02 [Equation 1]
in Equation 1, Da is an average pore size of the pores of the first carbon coating layer, and Db is an average particle size of the carbon based particle.
6. The anode active material of claim 1 , wherein the carbon based particle is relatively nonporous compared to the first carbon coating layer and wherein a specific surface area when the first carbon coating layer is formed on the carbon based particle is increased by over 43% as compared to a specific surface area of only the carbon based particle due to the pores of the first carbon coating layer.
7. The anode active material of claim 1 , wherein a thickness of the silicon coating layer is 10 nm or more to 100 nm or less.
8. The anode active material of claim 1 , wherein the silicon coating layer is formed by a chemical vapor deposition (CVD) method.
9. The anode active material of claim 1 , wherein the anode active material contains 30 wt % or more to 80 wt % or less of the carbon based particle, 5 wt % or more to 30 wt % or less of the first carbon coating layer, 5 wt % or more to 40 wt % or less of the silicon coating layer, and 5 wt % or more to 30 wt % or less of the second carbon coating layer based on a total weight of the anode active material.
10. A lithium secondary battery comprising the anode active material of claim 1 .
11. The anode active material of claim 1 , wherein a thickness of the first carbon coating layer is 0.01 μm or more to 10 μm or less.
12. The anode active material of claim 1 , wherein a thickness of the silicon coating layer is 10 nm or more to 80 nm or less.