Negative electrode and rechargeable lithium battery including same

Patent metadata

Field	Value
Publication number	US-9496549-B2
Application number	US-201414538476-A
Country	US
Kind code	B2
Filing date	Nov 11, 2014
Priority date	Jan 9, 2014
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A negative electrode for a rechargeable lithium battery includes: a current collector; and a negative active material layer on the current collector. The negative active material layer includes a negative active material including a graphite-silicon composite including a graphite particle, a silicon (Si) particle on a surface of the graphite particle, and a carbon coating layer surrounding the graphite particle on the surface of the silicon (Si) particle. A rechargeable lithium battery includes the negative electrode.

First claim

What is claimed is:

1. A negative electrode for a rechargeable lithium battery comprising:
a current collector; and
a negative active material layer on the current collector,
wherein the negative active material layer comprises a negative active material comprising a graphite-silicon composite comprising a graphite particle, a silicon (Si) particle on a surface of the graphite particle, and a carbon coating layer surrounding the Si particle on the surface of the graphite particle, wherein the graphite particle is present in the graphite-silicon composite in an amount of about 72 wt % to about 83 wt % based on the total amount of the graphite-silicon composite.

2. The negative electrode of claim 1 , wherein the silicon (Si) particle is present in the graphite-silicon composite in an amount of about 0.5 wt % to about 3.5 wt % based on the total amount of the graphite-silicon composite.

3. The negative electrode of claim 1 , wherein the silicon (Si) particle is present in the graphite-silicon composite in an amount of about 1.0 wt % to about 2.5 wt % based on the total amount of the graphite-silicon composite.

4. The negative electrode of claim 1 , wherein the silicon (Si) particle has an average particle diameter of about 50 nm to about 300 nm.

5. The negative electrode of claim 1 , wherein the graphite particle has an average particle diameter of about 5 μm to about 20 μm.

6. The negative electrode of claim 1 , wherein the carbon coating layer is present in the graphite-silicon composite in an amount of about 15 wt % to about 25 wt % based on the total amount of the graphite-silicon composite.

7. The negative electrode of claim 1 , wherein the carbon coating layer has a thickness of about 0.5 μm to about 2.0 μm.

8. The negative electrode of claim 1 , wherein the negative active material layer further comprises a binder and a conductive material, and
the silicon (Si) particle is present in the graphite-silicon composite in an amount of about 1.0 wt % to about 7.5 wt % based on the total amount of the negative active material layer.

9. A rechargeable lithium battery comprising:
the negative electrode of claim 1 ;
a positive electrode facing the negative electrode; and
an electrolyte.

10. The rechargeable lithium battery of claim 9 , wherein the electrolyte comprises an electrolyte solution comprising a lithium salt, a non-aqueous organic solvent, and about 2 wt % to about 5 wt % fluoroethylene carbonate based on the total amount of the non-aqueous organic solvent.

11. The rechargeable lithium battery of claim 10 , wherein the non-aqueous organic solvent comprises dimethyl carbonate (DMC).

12. The rechargeable lithium battery of claim 11 , wherein the dimethyl carbonate (DMC) is present in the non-aqueous organic solvent in an amount of about 50 volume % to about 70 volume % based on the total amount of the non-aqueous organic solvent.

13. The rechargeable lithium battery of claim 10 , wherein the non-aqueous organic solvent has a viscosity of about 0.3 cP to about 5.0 cP.

14. The rechargeable lithium battery of claim 10 , wherein the rechargeable lithium battery is configured to be operated at a rate of about 5 C to about 10 C.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Youm Chul

Classifications

• H01M2300/0028

  characterised by the solvent · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M10/0567

  characterised by the additives · CPC title