Carbon-silicon composite, and lithium secondary battery anode and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-2015270538-A1
Application number	US-201514661292-A
Country	US
Kind code	A1
Filing date	Mar 18, 2015
Priority date	Mar 19, 2014
Publication date	Sep 24, 2015
Grant date	—

Abstract

The present disclosure provides a carbon-silicon composite including: a first carbon matrix; and carbonized Si-block copolymer core-shell particles dispersed uniformly in the first carbon matrix. The present disclosure also provides a lithium secondary battery anode and a lithium secondary battery, which include the carbon-silicon composite.

First claim

What is claimed is:

1 . A carbon-silicon composite comprising: a first carbon matrix; and carbonized Si-block copolymer core-shell particles incorporated and dispersed in the first carbon matrix.

2 . The carbon-silicon composite of claim 1 , wherein the carbonized Si-block copolymer core-shell particles are distributed throughout an internal of the carbon-silicon composite.

3 . The carbon-silicon composite of claim 1 , which comprises agglomerates of the carbonized Si-block copolymer core-shell particles, and in which agglomerates of the carbonized Si-block copolymer core-shell particles in the first carbon matrix have a diameter of 20 μm or less.

4 . The carbon-silicon composite of claim 1 , which has a silicon-to-carbon mass ratio of 0.5:99.5 to 30:70.

5 . The carbon-silicon composite of claim 1 , wherein the first carbon matrix comprises crystalline carbon, amorphous carbon, or a combination thereof.

6 . The carbon-silicon composite of claim 1 , wherein the first carbon matrix comprises at least one selected from the group consisting of natural graphite, artificial graphite, soft carbon, hard carbon, pitch carbide, calcined coke, graphene, carbon nanotubes, and combinations thereof.

7 . The carbon-silicon composite of claim 1 , wherein the carbonized Si-block copolymer core-shell particles is formed by carbonization of Si-block copolymer core-shell particles comprising: a Si core; and a block copolymer shell which comprises a block having relatively high affinity for Si and a block having relatively low affinity for Si and forms a spherical micelle structure around the Si core.

8 . The carbon-silicon composite of claim 7 , wherein the block having relatively high affinity for Si is polyacrylic acid, polyacrylate, polymethacrylic acid, polymethylmethacrylate, polyacrylamide, carboxymethyl cellulose, polyvinyl acetate, or polymaleic acid.

9 . The carbon-silicon composite of claim 7 , wherein the block having relatively low affinity for Si is polystyrene, polyacrylonitrile, polyphenol, polyethylene glycol, poly lauryl methacrylate, poly lauryl acrylate, or polyvinyl difluoride.

10 . The carbon-silicon composite of claim 7 , wherein the particle diameter distribution of the Si-block copolymer core-shell particles in a slurry solution satisfies the following condition:
2 nm< D 50<120 nm wherein D50 is the 50% cumulative mass-particle size distribution diameter of the Si-block copolymer core-shell particles.

11 . The carbon-silicon composite of claim 7 , wherein the particle diameter distribution of the Si-block copolymer core-shell particles in a slurry solution satisfies the following condition:
1≦ D 90/ D 50≦1.4
wherein D90 is the 90% cumulative mass-particle size distribution diameter of the Si-block copolymer core-shell particles, and D50 is the 50% cumulative mass-particle size distribution diameter of the Si-block copolymer core-shell particles.

12 . The carbon-silicon composite of claim 1 , wherein the carbonized block copolymer shell particles have a higher porosity than the first carbon matrix.

13 . The carbon-silicon composite of claim 1 , wherein the carbonized block copolymer shell particles have a carbonization yield of 5-30%.

14 . The carbon-silicon composite of claim 1 , wherein the first carbon matrix has a carbonization yield of 40-80%.

15 . The carbon-silicon composite of claim 1 , further comprising second carbon particles.

16 . The carbon-silicon composite of claim 15 , wherein the second carbon particles are spheronized together with the carbon-silicon composite.

17 . The carbon-silicon composite of claim 15 , further comprising amorphous carbon coating layer as an outermost layer.

18 . A method for preparing a carbon-silicon composite, comprising the steps of:
preparing a slurry solution containing Si-block copolymer core-shell particles; mixing the slurry solution with a carbon precursor to prepare a mixture solution; and subjecting the mixture solution to a carbonization process.

19 . The method of claim 18 , wherein the carbon precursor includes a first carbon precursor and a second carbon precursor.

20 . An anode for a lithium secondary battery, which comprises an anode current collector coated with an anode slurry, the anode slurry comprising: a carbon-silicon composite according to claim 1 ; a binder; and a thickener.

Assignees

• Oci Co Ltd

Inventors

• Kim Yo-Seop
• Jeong Eun-Hye
• Jung Sung-Ho
• Ha Jeong-Hyun

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/133 Primary

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

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title