Rechargeable lithium battery

Patent metadata

Field	Value
Publication number	US-9385369-B2
Application number	US-201414571109-A
Country	US
Kind code	B2
Filing date	Dec 15, 2014
Priority date	Jan 9, 2014
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

A rechargeable lithium battery includes a negative electrode including a negative active material, a positive electrode including a positive active material, and an electrolyte including a lithium salt, a non-aqueous organic solvent, and an additive. The negative active material includes a graphite-silicon composite and graphite. The graphite-silicon composite includes a graphite particle, a silicon (Si) particle on the surface of the graphite particle, and a carbon coating layer surrounding the silicon particle on the surface of the graphite particle. The additive includes fluoroethylene carbonate in an amount of about 2 to about 5 wt % based on the total amount of the non-aqueous organic solvent.

First claim

What is claimed is:

1. A rechargeable lithium battery comprising:
a negative electrode comprising a negative active material comprising a graphite-silicon composite and graphite, the 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 silicon particle on the surface of the graphite particle;
a positive electrode comprising a positive active material; and
an electrolyte comprising a lithium salt, a non-aqueous organic solvent, and an additive comprising fluoroethylene carbonate in an amount of about 2 wt % to about 5 wt % based on the total amount of the non-aqueous organic solvent.

2. The rechargeable lithium battery of claim 1 , wherein the graphite-silicon composite is present in an amount of about 5 wt % to about 15 wt % based on the total amount of the negative active material.

3. The rechargeable lithium battery of claim 1 , wherein the silicon particle is present in an amount of about 1.0 wt % to about 7.5 wt % based on the total amount of the negative active material.

4. The rechargeable lithium battery of claim 1 , wherein the silicon particle is present in an amount of about 15 wt % to about 25 wt % based on the total amount of the graphite-silicon composite.

5. The rechargeable lithium battery of claim 1 , wherein the graphite particle is present in an amount of about 55 wt % to about 65 wt % based on the total amount of the graphite-silicon composite.

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

7. The rechargeable lithium battery of claim 1 , wherein the silicon particle has an average particle diameter of about 50 nm to about 300 nm.

8. The rechargeable lithium battery of claim 1 , wherein the carbon coating layer has a thickness of about 0.5 μm to about 1.0 μm.

9. The rechargeable lithium battery of claim 1 , wherein the non-aqueous organic solvent comprises dimethyl carbonate (DMC).

10. The rechargeable lithium battery of claim 9 , wherein the dimethyl carbonate is present in an amount of about 50 volume % to about 70 volume % based on the total amount of the non-aqueous organic solvent.

11. The rechargeable lithium battery of claim 1 , wherein the non-aqueous organic solvent has a viscosity of about 0.3 cP to about 5.0 cP.

12. The rechargeable lithium battery of claim 1 , wherein the rechargeable lithium battery is configured to operate at a rate of about 5 C to about 10 C.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Youm Chul

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/052

  Li-accumulators · CPC title

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M2004/027

  Negative electrodes · CPC title