Negative electrode for rechargeable lithium battery, method of manufacturing same, and rechargeable lithium battery including same

Patent metadata

Field	Value
Publication number	US-9806329-B2
Application number	US-201615065302-A
Country	US
Kind code	B2
Filing date	Mar 9, 2016
Priority date	Mar 13, 2015
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

Disclosed are a negative electrode for a rechargeable lithium battery that includes a plurality of non-sheet-shaped graphite particles, at least one silicon-based particle in a void formed by assembling the non-sheet-shaped graphite particles, and a sheet-shaped graphite powder between the non-sheet-shaped graphite particles, the void, or both thereof, wherein a size of the silicon particle is smaller than a length of the longest axis of the sheet-shaped graphite powder.

First claim

What is claimed is:

1. A negative electrode for a rechargeable lithium battery, comprising
an assembly of non-sheet-shaped graphite particles, at least one silicon-based particle in a region formed between the non-sheet-shaped graphite particles and at least one sheet-shaped graphite powder particle between the non-sheet-shaped graphite particles contacting at least one non-sheet-shaped graphite particle and at least one silicon-based particle,
wherein a size of the at least one silicon particle is smaller than a length of the longest axis of the at least one sheet-shaped graphite powder particle.

2. The negative electrode for a rechargeable lithium battery of claim 1 , wherein the at least one non-sheet-shaped graphite particle comprises spherical graphite, pseudo-spherical graphite, or a mixture thereof.

3. The negative electrode for a rechargeable lithium battery of claim 1 , wherein the at least one non-sheet-shaped graphite particle comprises about 10 wt % to about 40 wt % of natural graphite and about 60 wt % to about 90 wt % of artificial graphite.

4. The negative electrode for a rechargeable lithium battery of claim 1 , wherein the at least one silicon-based particle is selected from Si, SiOx (0<x<2), a Si-M alloy (wherein, M is an alkali metal, an alkaline-earth metal, a Group 13 element, a Group 14 element, a Group 15 element, a Group 16 element, a transition metal, a rare earth element, or a combination thereof, and not Si), a composite of Si and carbon, and a combination thereof.

5. The negative electrode for a rechargeable lithium battery of claim 1 , wherein the at least one non-sheet-shaped graphite particle has a particle size (D50) of about 10 μm to about 35 μm.

6. The negative electrode for a rechargeable lithium battery of claim 1 , wherein the at least one silicon-based particle has a particle size (D50) of about 1 μm to about 5 μm.

7. The negative electrode for a rechargeable lithium battery of claim 1 , wherein a ratio (A/B) of the length (A) of the longest axis of the sheet-shaped graphite powder and a particle size (B) of the at least one silicon-based particle is greater than about 1 and less than or equal to about 4.

8. The negative electrode for a rechargeable lithium battery of claim 1 , wherein the sheet-shaped graphite powder has an average length of the longest axis of about 3 μm to about 7 μm.

9. The negative electrode for a rechargeable lithium battery of claim 1 , wherein a thickness of the sheet-shaped graphite powder is greater than about 100 nm and less than or equal to about 900 nm.

10. The negative electrode for a rechargeable lithium battery of claim 1 , wherein a ratio of (L/D) of a length (L) and a thickness (D) of the longest axis of the sheet-shaped graphite powder is about 4 to about 70.

11. The negative electrode for a rechargeable lithium battery of claim 1 , wherein an amount of the at least one non-sheet-shaped graphite particle is about 50 wt % to about 90 wt % based on the total weight, 100 wt % of the negative active material layer.

12. The negative electrode for a rechargeable lithium battery of claim 1 , wherein an amount of the at least one silicon-based particle may be about 5 wt % to about 50 wt % based on the total weight, 100 wt % of the negative active material layer.

13. The negative electrode for a rechargeable lithium battery of claim 1 , wherein an amount of the sheet-shaped graphite powder is about 2 wt % to about 15 wt % based on the total weight, 100 wt % of the negative active material layer.

14. The negative electrode for a rechargeable lithium battery of claim 1 , wherein the negative electrode further comprises an aqueous binder.

15. The negative electrode for a rechargeable lithium battery of claim 14 , wherein the aqueous binder is a styrene-butadiene rubber (SBR), carboxylmethyl cellulose (CMC), an acrylonitrile-butadiene rubber, an acryl-based resin, a hydroxyethyl cellulose, or a combination thereof.

16. A rechargeable lithium battery comprising the negative electrode of claim 1 , a positive electrode, and an electrolyte solution.

17. The rechargeable lithium battery of claim 16 , wherein the at least one non-sheet-shaped graphite particle has a particle size (D50) of about 10 μm to about 35 μm.

18. The rechargeable lithium battery of claim 16 , wherein the at least one silicon-based particle has a particle size (D50) of about 1 μm to about 5 μm.

19. The negative electrode for a rechargeable lithium battery of claim 16 , wherein a ratio (A/B) of the length (A) of the longest axis of the sheet-shaped graphite powder and a particle size (B) of the at least one silicon-based particle is greater than about 1 and less than or equal to about 4.

20. A method of manufacturing a negative electrode for a rechargeable lithium battery, comprising
adding at least one non-sheet-shaped graphite particle, at least one silicon-based particle, and a sheet-shaped graphite powder to an aqueous binder solution to prepare a composition, wherein a size of the at least one silicon particle is smaller than the length of the longest axis of the sheet-shaped graphite powder, and
applying the composition on a current collector followed by drying and compressing the the composition applied on the current collector to manufacture a negative electrode.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Choi Young-Jin
• You Yong-Chan
• Ahn Sang-Hyuck
• Lee Su-Kyung
• Kim Deok-Hyun
• Meng Xianhui
• Kim Sang-Pil

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/364

  as mixtures · CPC title

• H01M4/621

  Binders · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title