Anode plate for lithium secondary battery, and lithium secondary battery comprising the same
The present disclosure is to provide a negative electrode for a lithium secondary battery having high negative electrode efficiency and excellent capacity retention, and a lithium secondary battery including the negative electrode. In one aspect, there is provided a negative electrode for a lithium secondary battery, wherein the electrode contains 3 to 9% by weight of a silicon-based negative-electrode active material having a following composition formula (1); and 87.5 to 95.5% by weight of a graphite-based negative-electrode active material: Si x Ti y Fe z Al u (1) where x, y, z and u are atomic %, x: 1−(y+z+u), y: 0.09 to 0.14, z: 0.09 to 0.14, u: 0.01 exclusive to 0.2 exclusive.
1. A negative electrode for a lithium secondary battery, wherein the electrode contains:
3 to 9% by weight of a silicon-based negative-electrode active material having a following composition formula (1);
87.5 to 95.5% by weight of a graphite-based negative-electrode active material; and
0.05 to 0.2% by weight of carbon nanotubes (CNT),
wherein the silicon-based negative-electrode active material having the composition formula (1) has amorphization in a matrix-phase microcrystalline region, wherein the amorphization is in a range of 25% or more and the composition formula (1) is expressed as:
Si x Ti y Fe z Al u (1)
where x, y, z and u are atomic %, x: 1−(y+z+u), y: 0.09 to 0.14, z: 0.09 to 0.14, u: 0.01 exclusive to 0.2 exclusive.
2. The negative electrode of claim 1 , further containing 0.5 to 1.5 wt % of a thickener and 1 to 2 wt % of a binder.
3. The negative electrode of claim 1 , wherein the negative electrode has a capacity retention equal to or greater than 90% after 50 charge/discharge cycles.
4. The negative electrode of claim 1 , wherein the negative electrode containing the carbon nanotubes (CNT) has a capacity retention equal to or greater than 95% after 50 charge/discharge cycles.
5. The negative electrode of claim 1 , wherein the silicon-based negative-electrode active material has an expansion of 70 to 150% after 50 charge/discharge cycles.
6. The negative electrode of claim 5 , wherein u is in a range of 0.05 to 0.19.
7. The negative electrode of claim 6 , wherein u is in a range of 0.10 to 0.19.
8. The negative electrode of claim 5 , wherein y is in a range of 0.09 to 0.125, and z is in a range of 0.09 to 0.125.
9. The negative electrode of claim 2 , wherein the thickener is CMC (carboxymethyl cellulose)-based thickener.
10. The negative electrode of claim 2 , wherein the binder is SBR (styrene-butadiene rubber)-based binder.
11. A lithium secondary battery comprising:
a negative electrode, wherein the negative electrode contains:
3 to 9% by weight of a silicon-based negative-electrode active material having a following composition formula (1);
87.5 to 95.5% by weight of a graphite-based negative-electrode active material;
0.5 to 1.5 wt % of a thickener;
1 to 2 wt % of a binder; and
0.05 to 0.2% by weight of carbon nanotubes (CNT),
wherein the silicon-based negative-electrode active material having the composition formula (1) has amorphization in a matrix-phase microcrystalline region, wherein the amorphization is in a range of 25% or more and the composition formula (1) is expressed as:
Si x Ti y Fe z Al u (1)
where x, y, z and u are atomic %, x: 1−(y+z+u), y: 0.09 to 0.14, z: 0.09 to 0.14, u: 0.01 exclusive to 0.2 exclusive.
12. The battery of claim 11 , wherein the negative electrode has a capacity retention equal to or greater than 90% after 50 charge/discharge cycles.
13. The battery of claim 11 , wherein the negative electrode containing the carbon nanotubes (CNT) has a capacity retention equal to or greater than 95% after 50 charge/discharge cycles.