Negative electrode for lithium secondary battery and lithium secondary battery including the same
Provided are a negative electrode for a lithium secondary negative electrode battery including: a current collector; a first negative electrode active material layer disposed on the current collector and including a silicon-based active material, a first graphite-based active material, and a linear conductive material; and a second negative electrode active material layer disposed on the first negative electrode active material layer and including a second graphite-based active material. The first graphite-based active material has a carbon coating layer on at least a part of a surface. Also provided is a lithium secondary battery including the negative electrode.
1. A negative electrode for a lithium secondary battery comprising:
a current collector;
a first negative electrode active material layer disposed on the current collector and including a silicon-based active material, a first graphite-based active material, and a linear conductive material; and
a second negative electrode active material layer disposed on the first negative electrode active material layer and including a second graphite-based active material,
wherein the first graphite-based active material comprises artificial graphite with a carbon coating layer on at least a part of a surface,
wherein the second graphite-based active material is artificial graphite, and
wherein the linear conductive material is carbon nanotubes.
2. The negative electrode for a lithium secondary battery of claim 1 , wherein the first graphite-based active material is artificial graphite or a mixture of artificial graphite and natural graphite.
3. The negative electrode for a lithium secondary battery of claim 1 , wherein the silicon-based active material and the first graphite-based active material are included at a weight ratio of 1:9 to 4:6.
4. The negative electrode for a lithium secondary battery of claim 1 , wherein the carbon coating layer included on the first graphite-based active material is formed from hard carbon, soft carbon, heavy oil, or pitch.
5. The negative electrode for a lithium secondary battery of claim 1 , wherein the linear conductive material is included at 0.1 to 1 wt % with respect to a total weight of the first negative electrode active material layer.
6. The negative electrode for a lithium secondary battery of claim 1 , wherein the first negative electrode active material layer satisfies the following Relation 1:
0.2< A 1 /A 2 (%)<1.7 [Relation 1]
wherein A 1 is a content (part by weight) of the linear conductive material, A 2 is a content (part by weight) of the silicon-based active material, and A 1 /A 2 is a percentage (%) of the content of the linear conductive material to the content of the silicon-based active material.
7. The negative electrode for a lithium secondary battery of claim 1 , wherein the second negative electrode active material layer does not include a silicon-based active material, and the second graphite-based active material does not have a carbon coating layer.
8. The negative electrode for a lithium secondary battery of claim 1 , wherein the second negative electrode active material layer does not include the linear conductive material.
9. A lithium secondary battery comprising: the negative electrode of claim 1 ; a positive electrode; a separator; and an electrolyte.