IP Library Granted Patent US 12,113,220
Granted Patent B2
US 12,113,220 · App. 17/850,570 · Granted Oct 8, 2024

Multi-layer negative electrode comprising natural graphite and artificial graphite and lithium secondary battery comprising the same

Inventors: Taek Soo Lee (Daejeon, KR); Chang Wan Koo (Daejeon, KR); Sang Hoon Choi (Daejeon, KR); Jung Min Yang (Cheongju-si, KR); Il Jae Moon (Incheon, KR)
Assignee: LG ENERGY SOLUTION, LTD.
H01M4/587H01M4/133H01M4/364H01M4/366H01M4/621H01M4/624H01M10/0525H01M2004/027
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Quick Facts
Patent No.
US 12,113,220
App. No.
17/850,570
Granted
Oct 8, 2024
Kind
B2
Abstract

The present disclosure relates to a multilayer negative electrode comprising a negative electrode current collector configured to transfer electrons between an outer lead and a negative electrode active material, a first negative electrode mixture layer formed on one surface or both surfaces of the current collector and containing natural graphite as a negative electrode active material and a second negative electrode mixture layer formed on the first negative electrode mixture layer and containing artificial graphite as a negative electrode active material, and a lithium secondary battery including the same.

Claims (31)

1. A multilayer negative electrode comprising:

a negative electrode current collector configured to transfer electrons between an outer lead and a negative electrode active material;

a first negative electrode mixture layer formed on one surface or both surfaces of the current collector and comprising natural graphite and artificial graphite as a negative electrode active material; and

a second negative electrode mixture layer formed on the first negative electrode mixture layer and comprising a negative electrode active material consisting of artificial graphite,

wherein an amount of the natural graphite present in the first negative electrode mixture layer is from 15% by weight to 75% by weight based on a total weight of the first negative electrode mixture layer,

wherein a weight ratio of the first negative electrode mixture layer to the second negative electrode mixture layer is 1:9 to 5:5, and

wherein an amount of the artificial graphite is greater than an amount of the natural graphite based on a total amount of the first negative electrode mixture layer and second negative electrode mixture layer.

2. The multilayer negative electrode of claim 1 , wherein the natural graphite has a specific surface area (BET) of 2 m 2 /g to 8 m 2 /g.

3. The multilayer negative electrode of claim 2 , wherein the weight ratio of the first negative electrode mixture layer to the total weight of the first negative electrode mixture layer and the second negative electrode mixture layer is decreased as the content of the natural graphite of the first negative electrode mixture layer is increased.

4. The multilayer negative electrode of claim 1 , wherein the natural graphite is flake graphite, vein graphite, or amorphous graphite.

5. The multilayer negative electrode of claim 1 , wherein the natural graphite has a tap density of 0.9 g/cc to 1.3 g/cc.

6. The multilayer negative electrode of claim 1 , wherein a ratio of I 110 to I 003 of particles of the natural graphite at XRD diffraction is 20 to 40.

7. The multilayer negative electrode of claim 1 , wherein the natural graphite has an average particle diameter (D50) of 5 μm to 30 μm.

8. The multilayer negative electrode of claim 1 , wherein the artificial graphite is 0.5 m 2 /g to 5 m 2 /g in a range in which a specific surface area (BET) of the artificial graphite is smaller than that of the natural graphite.

9. The multilayer negative electrode of claim 1 , wherein the artificial graphite is in a form of a powder, a flake, a block, a plate, or a rod.

10. The multilayer negative electrode of claim 1 , wherein a ratio of I 110 to I 003 of particles of the artificial graphite at XRD diffraction is 5 to 20.

11. The multilayer negative electrode of claim 1 , wherein at least one of the natural graphite and the artificial graphite is pitch-coated.

12. The multilayer negative electrode of claim 1 , wherein some of solid contents of the first negative electrode mixture layer and the second negative electrode mixture layer is mixed therebetween so as not to form a boundary surface.

13. A lithium secondary battery comprising the multilayer negative electrode of claim 1 .

14. The multilayer negative electrode of claim 1 , wherein a weight ratio of natural graphite to artificial graphite in the first negative electrode mixture layer is from 4:6 to less than 1:1.

15. The multilayer negative electrode of claim 1 , wherein a loading amount of the first negative electrode mixture layer ranges from 6 mg/cm 2 to 8 mg/cm 2 .

16. The multilayer negative electrode of claim 1 , wherein a loading amount of the second negative electrode mixture layer ranges from 8 mg/cm 2 to 10 mg/cm 2 .

17. The multilayer negative electrode of claim 1 , wherein the second negative electrode mixture layer is applied on the first negative electrode mixture layer before drying the first negative electrode mixture layer.

18. A multilayer negative electrode comprising:

a negative electrode current collector configured to transfer electrons between an outer lead and a negative electrode active material;

a first negative electrode mixture layer formed on one surface or both surfaces of the current collector and comprising natural graphite and artificial graphite as a negative electrode active material; and

a second negative electrode mixture layer formed on the first negative electrode mixture layer and comprising natural graphite and artificial graphite as a negative electrode active material,

wherein an amount of the natural graphite present in the first negative electrode mixture layer is from 15% by weight to 75% by weight based on a total weight of the first negative electrode mixture layer,

wherein an amount of the natural graphite present in the second negative electrode mixture layer is from 0.1% by weight to 10% by weight based on a total weight of the second negative electrode mixture layer,

wherein a weight ratio of the first negative electrode mixture layer to the second negative electrode mixture layer is 1:9 to 5:5,

wherein an amount of the artificial graphite is greater than an amount of the natural graphite based on a total amount of the first negative electrode mixture layer and second negative electrode mixture layer.