Graphene-coated porous silicon-carbon composite and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-2017047584-A1
Application number	US-201515307627-A
Country	US
Kind code	A1
Filing date	May 8, 2015
Priority date	May 9, 2014
Publication date	Feb 16, 2017
Grant date	—

Abstract

Provided are a porous silicon-carbon composite, which includes a core including a plurality of active particles, a conductive material formed on at least a portion of surfaces of the active particles, first pores, and second pores, and a first shell layer which is coated on the core and includes graphene, wherein the active particles include a plurality of silicon particles, silicon oxide particles, or a combination thereof, the first pores are present in the core and are formed by agglomeration of the plurality of active particles, and the second pores are irregularly dispersed and present in the core, has an average particle diameter smaller than an average particle diameter of the active particles, and are spherical, a method of manufacturing the same, and a negative electrode and a lithium secondary battery including the porous silicon-carbon composite.

First claim

1 . A porous silicon-carbon composite comprising:
a core including a plurality of active particles, a conductive material formed on at least a portion of surfaces of the active particles, first pores, and second pores; and a first shell layer which is coated on the core and includes graphene, wherein the active particles comprise a plurality of silicon particles, silicon oxide particles, or a combination thereof, the first pores are present in the core and are formed by agglomeration of the plurality of active particles, and the second pores are irregularly dispersed and present in the core, has an average particle diameter smaller than an average particle diameter of the active particles, and are spherical.

2 . The porous silicon-carbon composite of claim 1 , wherein the active particle comprises a silicon-based composite expressed by SiO x (0<x≦2).

3 . The porous silicon-carbon composite of claim 1 , wherein an average particle diameter (D50) of the active particles is in a range of 3 nm to 900 nm.

4 . The porous silicon-carbon composite of claim 1 , wherein the active particles are included in an amount of 10 wt % to 95 wt % based on a total weight of the core.

5 . The porous silicon-carbon composite of claim 1 , wherein an average particle diameter (D50) of the core is in a range of 0.5 μm to 50 μm.

6 . The porous silicon-carbon composite of claim 1 , wherein a total volume of the first pores and the second pores is in a range of 50 vol % to 300 vol % based on a total volume of the active particles of the core.

7 - 8 . (canceled)

9 . The porous silicon-carbon composite of claim 1 , wherein an average particle diameter (D50) of the second pores is in a range of 50 nm to 500 nm.

10 . (canceled)

11 . The porous silicon-carbon composite of claim 1 , wherein the conductive material is at least one selected from the group consisting of carbon nanotubes (CNT), graphene, and amorphous carbon.

12 . The porous silicon-carbon composite of claim 1 , wherein the conductive material is included in an amount of 1 wt % to 30 wt % based on a total weight of the porous silicon-carbon composite.

13 . (canceled)

14 . The porous silicon-carbon composite of claim 1 , wherein the active particle further comprises a carbon coating layer.

15 . The porous silicon-carbon composite of claim 14 , wherein the carbon coating layer is formed by heat-treating a single material selected from the group consisting of glucose, sucrose, gum arabic, tannic acid, lignosulfonate, poly-aromatic oxide, saccharides, and polyphenols, or a mixture of two or more thereof, which is in a state of being combined with the active particles.

16 . The porous silicon-carbon composite of claim 1 , wherein the core further comprises a polymer material.

17 . The porous silicon-carbon composite of claim 16 , wherein the polymer material comprises a single material selected from the group consisting of a polystyrene monomer, a polystyrene oligomer, polyacrylonitrile, polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and polyhexafluoropyrene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, polysiloxane, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, a styrene-butadiene rubber, a nitrile-butadiene rubber, polyethylene, polypropylene, polybutylene, and polycarbonate, or a mixture of two or more thereof.

18 . The porous silicon-carbon composite of claim 16 , wherein the polymer material is included in an amount of 1 wt % to 30 wt % based on a total weight of the porous silicon-carbon composite.

19 . (canceled)

20 . The porous silicon-carbon composite of claim 1 , wherein an average particle diameter (D50) of the porous silicon-carbon composite is in a range of 0.5 μm to 55 μm.

21 . The porous silicon-carbon composite of claim 1 , further comprising a second shell layer coated on the first shell layer.

22 . The porous silicon-carbon composite of claim 21 , wherein the second shell layer is formed by a combination of two or more materials selected from the group consisting of carbon, rubber, and carbon nanotubes.

23 . A method of manufacturing the porous silicon-carbon composite of claim 1 , the method comprising:
preparing a first mixed solution in which silicon or silicon oxide particles, a conductive material, and a porogen are dispersed; dispersing graphene oxide in the first mixed solution to prepare a second mixed solution; spray drying the second mixed solution to prepare a composite including a core and a first shell layer; and sintering the composite to manufacture a porous silicon-carbon composite having a portion of a surface or an entire surface thereof coated with graphene.

24 . The method of claim 23 , wherein the porogen comprises a polymer bead that is partially pyrolyzed at a high temperature.

25 . The method of claim 24 , wherein the polymer bead comprises a single material selected from the group consisting of a polystyrene monomer, a polystyrene oligomer, polyacrylonitrile, polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and polyhexafluoropyrene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, polysiloxane, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, a styrene-butadiene rubber, a nitrile-butadiene rubber, polyethylene, polypropylene, polybutylene, and polycarbonate, or a mixture of two or more thereof.

26 . The method of claim 24 , wherein an average particle diameter (D50) of the polymer beads is in a range of 50 nm to 500 nm.

27 . The method of claim 23 , wherein a volume ratio of the silicon or silicon oxide particles to the porogen is in a range of 1:0.5 to 1:3.

28 - 29 . (canceled)

30 . The method of claim 23 , further comprising adding a first carbon precursor as a binder during the preparation of the first mixed solution.

31 . The method of claim 30 , wherein the first carbon precursor comprises a single material selected from the group consisting of glucose, sucrose, gum arabic, tannic acid, lignosulfonate, poly-aromatic oxide, saccharides, and polyphenols, or a mixture of two or more thereof.

32 . The method of claim 30 , wherein a weight ratio of the first carbon precursor:the silicon or silicon oxide particles is in a range of 50:50 to 5:95.

33 . The method of claim 23 , further comprising forming a composite coating layer on the surface of the sintered composite, after the sintering of the composite.

34 . The method of claim 33 , wherein the composite coating layer is formed by one selected from the group consisting of a second carbon precursor, a rubber precursor, and carbon nanotubes, or a combination of two or more materials thereof.

35 . The method of claim 34 , wherein the second carbon precursor comprises a single material selected from the group consisting of glucose, sucrose, gum arabic, tannic acid, lignosulfonate, poly-aromatic oxide, pitch, saccharides, and polyphenols, or a mixture of two or more thereof.

36 . The method of claim 34 , wherein the rubber precursor comprises a single material selected from the group consisting of styrene butadiene

Assignees

• Lg Chemical Ltd
• Lg Chemical Ltd

Inventors

• Hwang Eui Yong
• Kim In Young
• Lee Jin Yeong
• Kwon Won Jong
• Sohn Kwon Nam
• Yang Seung Bo

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M2004/021

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

• H01M4/366 Primary

  as layered products · CPC title

• H01M10/0525

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