Negative active material for rechargeable lithium battery, method of preparing the same and rechargeable lithium battery including the same

Patent metadata

Field	Value
Publication number	US-11830972-B2
Application number	US-202117164800-A
Country	US
Kind code	B2
Filing date	Feb 1, 2021
Priority date	Sep 21, 2011
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

A negative active material for a rechargeable lithium battery includes a core including a SiO 2 matrix and a Si grain, and a coating layer continuously or discontinuously coated on the core. The coating layer includes SiC and C, and the peak area ratio of the SiC (111) plane to the Si (111) plane as measured by X-ray diffraction analysis (XRD) using a CuKα ray ranges from about 0.01 to about 0.5.

First claim

What is claimed is:

1. A negative active material for a rechargeable lithium battery, comprising:
a core comprising a Si grain in a SiO 2 matrix; and
a coating layer on at least a portion of the core, the coating layer comprising carbon, and the coating layer having a thickness of about 0.01 μm to about 1 μm,
wherein the negative active material has an average particle size of about 0.5 μm to about 50 μm, and
wherein in the core of the manufactured negative active material, amounts of the SiO 2 matrix and the Si grain are sufficient to yield an oxygen and silicon content represented by SiOx in which 1≤x≤1.2.

2. The negative active material according to claim 1 , wherein a weight ratio of the core to the coating layer is about 99.9:0.1 to about 90:10.

3. The negative active material according to claim 1 , wherein the carbon comprises crystalline carbon, amorphous carbon, or a combination thereof.

4. The negative active material according to claim 3 , wherein the amorphous carbon comprises soft carbon, hard carbon, mesophase pitch carbonized products, fired coke, or a combination thereof.

5. A rechargeable lithium battery comprising:
a positive electrode comprising a positive electrode active material;
an electrolyte comprising a non-aqueous organic solvent, the non-aqueous organic solvent comprising a cyclic carbonate and a linear carbonate;
a separator; and
a negative electrode comprising a negative active material comprising:
a core comprising a Si grain in a SiO 2 matrix; and
a coating layer on at least a portion of the core, the coating layer comprising carbon, and the coating layer having a thickness of about 0.01 μm to about 1 μm,

wherein the negative active material has an average particle size of about 0.5 μm to about 50 μm, and
wherein in the core of the manufactured negative active material, amounts of the SiO 2 matrix and the Si grain are sufficient to yield an oxygen and silicon content represented by SiOx in which 1≤x≤1.2.

6. The rechargeable lithium battery according to claim 5 , wherein a weight ratio of the core to the coating layer is about 99.9:0.1 to about 90:10.

7. The rechargeable lithium battery according to claim 5 , wherein the positive electrode active material comprises at least two of Ni, Mn, and Al.

8. The rechargeable lithium battery according to claim 5 , wherein the carbon comprises crystalline carbon, amorphous carbon, or a combination thereof.

9. The rechargeable lithium battery according to claim 8 , wherein the amorphous carbon comprises soft carbon, hard carbon, mesophase pitch carbonized products, fired coke, or a combination thereof.

10. The rechargeable lithium battery according to claim 5 , wherein the non-aqueous organic solvent further comprises vinylene carbonate, an ethylene carbonate-based compound represented by the following Chemical Formula 2, or a combination thereof:

wherein in Chemical Formula 2, each of R 7 and R 8 is independently selected from hydrogen, halogens, cyano groups (CN), nitro groups (NO 2 ), and C1 to C5 fluoroalkyl groups, provided that at least one of R 7 and R 8 is selected from halogens, cyano groups (CN), nitro groups (NO 2 ), or C1 to C5 fluoroalkyl groups.

11. The rechargeable lithium battery according to claim 10 , wherein the ethylene carbonate-based compound represented by Chemical Formula 2 comprises difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, fluoroethylene carbonate, or a combination thereof.

12. The rechargeable lithium battery according to claim 5 , wherein the separator comprises polyethylene.

13. The rechargeable lithium battery according to claim 5 , wherein the separator comprises a ceramic component.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Park Sang-Eun
• Kim Young-Ugk

Classifications

• H01M10/052 Primary

  Li-accumulators · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title

• H01M4/366

  as layered products · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title