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

Patent metadata

Field	Value
Publication number	US-2018026257-A1
Application number	US-201715655258-A
Country	US
Kind code	A1
Filing date	Jul 20, 2017
Priority date	Jul 21, 2016
Publication date	Jan 25, 2018
Grant date	—

Abstract

A negative active material for a rechargeable lithium battery includes a silicon-carbon composite including a core including a crystalline carbon material, a silicon oxide, and a silicon particle and an amorphous carbon-containing coating layer on the surface of the core. An intensity ratio (Si/SiO 2 ) of a Si peak relative to a SiO 2 peak ranges from about 2.0 to about 3.0 as measured using an X-ray photoelectron spectroscopy for the negative active material.

First claim

What is claimed is:

1 . A negative active material for a rechargeable lithium battery, the negative active material comprising:
a silicon-carbon composite including a core including a crystalline carbon material, a silicon oxide, and a silicon particle, and an amorphous carbon-containing coating layer on the surface of the core, wherein an intensity ratio (Si/SiO 2 ) of a Si peak relative to a SiO 2 peak ranges from about 2.0 to about 3.0 as measured using an X-ray photoelectron spectroscopy for the negative active material.

2 . The negative active material as claimed in claim 1 , wherein the negative active material includes about 70 atom % to about 80 atom % of silicon and about 30 atom % to about 20 atom % of oxygen as measured using energy dispersive spectroscopy.

3 . The negative active material as claimed in claim 1 , wherein a content of the silicon oxide ranges from about 8 wt % to about 13 wt % based on 100 wt % of the silicon-carbon composite.

4 . The negative active material as claimed in claim 1 , wherein a maximum particle diameter of the silicon particle is less than or equal to about 250 nm.

5 . The negative active material as claimed in claim 1 , wherein a maximum particle diameter of the silicon particle is about 30 nm to about 250 nm.

6 . A method of preparing a negative active material for a rechargeable lithium battery, the method comprising:
mixing silicon and the antioxidant in a mixing ratio of about 9 wt % to about 11 wt % of an antioxidant relative to 100 wt % of silicon in a solvent to prepare a mixture; ball milling the mixture to prepare a silicon mixture of a silicon oxide and a silicon particle coated with the antioxidant; mixing the silicon mixture with a crystalline carbon-based material to prepare a silicon-crystalline carbon-based material mixture; adding an amorphous carbon precursor to the silicon-crystalline carbon-based material mixture, and heat-treating the resultant.

7 . The method as claimed in claim 6 , wherein the antioxidant is stearic acid, polyvinylpyrrolidone, or a combination thereof.

8 . The method as claimed in claim 6 , wherein the solvent is an alcohol.

9 . The method as claimed in claim 6 , wherein a maximum particle diameter of the silicon particle is less than or equal to about 250 nm.

10 . The method as claimed in claim 6 , wherein a maximum particle diameter of the silicon particle is about 30 nm to about 250 nm.

11 . A rechargeable lithium battery, comprising:
a negative electrode including the negative active material according as claimed in claim 1 ; a positive electrode including a positive active material; and an electrolyte.

Assignees

• Samsung Sdi Co Ltd

Inventors

• OH Doori
• Youm Chul

Classifications

• G01N23/2273

  Measuring photoelectron spectrum, e.g. electron spectroscopy for chemical analysis [ESCA] or X-ray photoelectron spectroscopy [XPS] · CPC title

• H01M4/133 Primary

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M2004/027

  Negative electrodes · CPC title