Preparation of graphene by mechanically thinning graphite materials

Patent metadata

Field	Value
Publication number	US-9309122-B2
Application number	US-201013505815-A
Country	US
Kind code	B2
Filing date	Nov 3, 2010
Priority date	Nov 3, 2009
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

The preparation of graphene, mono-, bi- and multi-layers from graphite-based precursor materials, for example, pencil lead or graphite, by a method of mechanical thinning on the surface of a planar substrate with controlled roughness, followed by sonication in order to collect the graphene deposited on the substrate in a liquid medium. The bearing force during thinning by mechanical friction enables the number of graphene sheets deposited on the surface of the substrate to be controlled.

First claim

What is claimed is:

1. A method for producing a dispersion of one of graphene particles and graphene sheets in a liquid medium, the method comprising:
providing a graphite-based material including at least 10% by mass of graphite;
rubbing the surface of said graphite-based material on the surface of a substrate so as to create a trace of friction of said graphite-based material on said surface of said substrate; and then
soaking said substrate in a liquid medium and subjecting said liquid medium to ultrasound in order to detach said trace from said surface of said substrate to obtain a dispersion of the one of graphene particles and graphene sheets in said liquid medium after rubbing the surface of said graphite-based material.

2. The method of claim 1 , wherein said graphite-based material is chosen from pencil leads, natural graphite and synthetic graphite.

3. The method of claim 1 , wherein the liquid medium comprises a reducing agent selected from the group consisting of: NaBH 4 , hydrazine and ammonia.

4. The method of claim 3 , further comprising
separating any organic material or inorganic material present in said dispersion, by sedimentation or centrifugation, or by chemical dissolution.

5. The method of claim 4 , further comprising
reducing said dispersion of graphite particles and/or graphene sheets that may be present in said dispersion including a thickness that exceeds a predetermined value, by sedimentation or by centrifugation.

6. The method of claim 5 , further comprising
collecting the graphene sheets from said suspension, and re-dispersing said graphene sheets in a liquid phase.

7. The method of claim 1 , wherein said surface of said substrate has a roughness of between 0.01 μm and 10 μm.

8. The method of claim 7 , wherein the thickness of the one of said graphene particles and graphene sheets is between 1 and 50 nm, and/or the number of parallel graphene sheets is between 1 and 15.

9. The method of claim 1 , wherein the speed of friction between said graphite-based material and said surface of said substrate is between 0.001 m.s −1 and 0.1 m.s −1 .

10. The method of claim 1 , wherein said substrate is selected from polymers, flexible polymers, transparent polymers, glasses, ceramics and silicon.

11. The method of claim 1 , wherein said surface of said substrate and said graphite-based material are in relative movement to cause a lateral offset between two adjacent segments of traces of said graphite-based material on said surface of said substrate.

12. The method of claim 11 , wherein:
said substrate is a disk configured to rotate about its axis; and
the trace of friction of said graphite-based material on said surface of said substrate is one of continuously and periodically offset by lateral displacement means so as to obtain a continuous trace in the form of a spiral.

13. The method of claim 1 , wherein at least some of said dispersion is collected one of periodically and continuously.

14. The method of claim 1 , further comprising subjecting said dispersion to a second ultrasound treatment for a duration of time which is greater than that of the first ultrasound treatment.

15. The method of claim 14 , further comprising subjecting said dispersion to a microwave heating treatment after the second ultrasound treatment.

16. The method of claim 1 , further comprising collecting the one of said graphene particles and said graphene sheets from said suspension.

17. The method of claim 1 , wherein the graphite-based material includes at least 50% by mass of graphite.

18. The method of claim 1 , wherein the graphite-based material includes a geometric shape of a block or a rod.

19. A device for producing a dispersion of one of graphene particles and graphene sheets in a liquid medium, the device comprising:
means for holding a graphite-based material including at least 10% by mass of graphite;
a substrate equipped with a surface configured for contact with said graphite-based material;
means for enabling a relative displacement between said graphite-based material and said substrate;
means for one of regulating, controlling and measuring a pressure force between said graphite-based material and said surface of said substrate;
a liquid container for receiving a liquid and configured to permit at least a partial immersion of said surface of said substrate in said liquid; and
an ultrasound generator configured to subject said liquid to ultrasound waves.

20. The device of claim 19 , further comprising means for one of a continuous and a periodic drainage of liquid from said liquid.

Assignees

• Janowska Izabela
• Begin Dominique
• Chizari Kambiz
• Ersen Ovidiu
• Bernhardt Pierre
• Romero Thierry
• Ledoux Marc
• Pham-Huu Cuong
• Centre Nat Rech Scient
• Univ Strasbourg

Inventors

• Janowska Izabela
• Begin Dominique
• Chizari Kambiz
• Ersen Ovidiu
• Bernhardt Pierre
• Romero Thierry
• Ledoux Marc
• Pham-Huu Cuong

Classifications

• C01B31/0206 Primary

  Chemistry & Metallurgy · mapped topic

• C01B2204/32

  Size or surface area · CPC title

• C01B2204/28

  Solid content in solvents · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C01B31/0469

  Chemistry & Metallurgy · mapped topic