Negative electrode for secondary battery and manufacturing method of the same

Patent metadata

Field	Value
Publication number	US-2017040602-A1
Application number	US-201615229999-A
Country	US
Kind code	A1
Filing date	Aug 5, 2016
Priority date	Aug 7, 2015
Publication date	Feb 9, 2017
Grant date	—

Abstract

The present invention relates to a negative electrode for a secondary battery and a method for manufacturing the negative electrode, and more particularly, to a negative electrode for a secondary battery which exhibits excellent charge/discharge characteristics and lifespan characteristics by including a carbon-silicon composite and graphite at a predetermined particle size ratio.

First claim

What is claimed is:

1 . A negative electrode for a secondary battery, the negative electrode comprising a negative electrode active material that comprises:
a carbon-silicon composite having a Si-block copolymer core-shell particle in a carbonaceous material; and graphite, wherein the negative electrode comprises a plurality of pores therein, and when a 50% accumulated weight particle size distribution diameter in particle distribution in the negative electrode is D50, D50 of the carbon-silicon composite is D Si—C , and D50 of graphite is D G , D Si—C and D G satisfy 1.0≦D G /D Si—C ≦1.8.

2 . The negative electrode of claim 1 , wherein D Si—C satisfies 3 μm≦D Si—C ≦12 μm.

3 . The negative electrode of claim 1 , wherein D G satisfies 8 μm≦D G ≦20 μm.

4 . The negative electrode of claim 1 , wherein an electrode porosity of the negative electrode is in a range of about 25% to about 45%.

5 . The negative electrode of claim 1 , wherein when pores having a particle diameter less than 100 nm among the pores are referred to as fine pores, a porosity of the fine pores is in a range of about 30% to about 50%.

6 . The negative electrode of claim 1 , wherein a tap density (D T ) of the negative electrode active material is in a range of about 1.0 g/cc to about 1.2 g/cc.

7 . The negative electrode of claim 1 , wherein an electrode density (D R ) of the negative electrode is in a range of about 1.35 g/cc to about 1.85 g/cc.

8 . The negative electrode of claim 1 , wherein a weight ratio of the carbon-silicon composite and the graphite in the negative electrode is in a range of about 50:50 to about 1:99.

9 . The negative electrode of claim 1 , wherein the carbon-silicon composite and the graphite have a spherical shape.

10 . A method for manufacturing a negative electrode for a secondary battery, the method comprising:
(a) mixing a slurry solution including Si-block copolymer core-shall particles and a carbonaceous raw material to prepare a mixture; (b) performing heat-treatment on the mixture; (c) carbonizing and pulverizing the heat-treated mixture to prepare a carbon-silicon composite; (d) mixing the carbon-silicon composite and graphite to prepare a negative electrode active material; and (e) coating a current collector with a mixture of the negative electrode active material, a conducting agent, a binder, and a thickener, wherein the (c) carbonizing and pulverizing are repeated at least twice, and when a 50% accumulated weight particle size distribution diameter in particle distribution in the negative electrode is D50, D50 of the carbon-silicon composite is D Si—C , and D50 of graphite is D G , D Si—C and D G satisfy 1.0≦D G /D Si—C ≦1.8.

11 . The method for claim 10 , wherein D Si—C satisfies 3 μm≦D Si—C ≦12 μm.

12 . The method for claim 10 , wherein D G satisfies 8 μm≦D G ≦20 μm.

13 . The method for claim 10 , wherein (b) the performing heat-treatment on the mixture is performed at a temperature in a range of about 100° C. to about 200° C.

14 . The method for claim 10 , wherein (c) the mixing the carbon-silicon composite and graphite is repeated at least twice at temperatures different from each other.

15 . The method for claim 14 , wherein (c) the mixing the carbon-silicon composite and graphite comprises a primary carbonization process which comprises heat-treating the mixture at a temperature in a range of about 400° C. to about 600° C. for about 1 hour to about 24 hours and then pulverizing the mixture; and a secondary carbonization process which comprises heat-treating the resultant of the primary carbonization process at a temperature in a range of about 700° C. to about 1400° C. for about 1 hour to about 24 hours and then pulverizing the resultant.

16 . The method for claim 15 , wherein the pulverizing of the primary carbonization process or the secondary carbonization process is performed at a pressure of 13 bar or lower.

17 . The method for claim 10 , wherein a weight ratio of the carbon-silicon composite and graphite in (d) the mixing the carbon-silicon composite and graphite is in a range of about 50:50 to about 1:99.

Assignees

• Oci Co Ltd

Inventors

• Ha Jeong-Hyun
• Kim Yo-Seop
• Jeong Eun-Hye
• LEE Jun-Eun

Classifications

• H01M4/602

  Polymers · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M10/0525

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

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/366 Primary

  as layered products · CPC title