Synthesis of three-dimensional graphene foam: use as supercapacitors

Patent metadata

Field	Value
Publication number	US-9352500-B2
Application number	US-201314396000-A
Country	US
Kind code	B2
Filing date	Jun 3, 2013
Priority date	Jun 1, 2012
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

The application discloses methods of fabricating three-dimensional (3D) graphene crystalline foam, based on mixing a carbon source with a skelet (scaffold) powder. In one embodiment heat and pressure are used to compact the carbon and a metal powder into a close packed structure. In another embodiment a 3D crystalline graphene foam is fabricated with a large surface area (550 m 2 /g) from a 3D metal foam, depositing a layer of graphene using chemical vapor deposition (CVD), depositing a polymer support and removing the metal via wet chemical etching, such that the graphene retains the configuration, and then finally removing the polymer. A method of fabricating the metal foam framework and coating the metal with graphene are also disclosed.

First claim

What is claimed is:

1. A method of fabricating a three-dimensional graphene crystalline foam, comprising:
a) mixing a carbon source and a skelet powder together to obtain a uniform mixture, wherein the carbon source is optionally coated on a group IV-B element;
b) applying pressure to the uniform mixture obtained in step (a) to obtain a closed packed structure;
c) applying temperature and pressure to the closed packed structure to form a graphene sheet layered around the skelet powder and the group IV-B element if present; and
d) removing the skelet powder from the closed packed structure using a chemical bath to dissolve the skelet powder away from the closed packed structure leaving voids, resulting in a three-dimensional crystalline foam comprising graphene and optionally a group IV-B element.

2. The method of claim 1 , wherein the carbon source is carbon black, amorphous carbon, or a combination thereof.

3. The method of claim 1 , wherein the optional group IV-B element is silicon (Si), germanium (Ge), tin (Sn), lead (Pb), or a combination thereof.

4. The method of claim 1 , wherein the carbon-coated group IV-B element is carbon-coated silicon nanoparticle.

5. The method of claim 1 , wherein the skelet powder is silicon dioxide (SiO2), aluminum oxide (A12O3), sodium chloride (NaCl), magnesium oxide (MgO), hafnium oxide (HfO2), zirconium dioxide (ZrO2), or a combination thereof.

6. The method of claim 1 , wherein the skelet powder has a particle size of between about 1 nm to 10 μm.

7. The method of claim 1 , wherein the pressure is applied in a uniform direction.

8. The method of claim 1 , wherein the chemical bath is aqueous potassium hydroxide or aqueous sodium hydroxide.

9. A method of fabricating a three-dimensional crystalline graphene foam, comprising:
a) providing a three-dimensional metal foam framework having a surface area of at least about 500 m2/g, for fabricating a three-dimensional graphene foam;
b) depositing a layer of graphene onto the metal foam of step (a) by template-directed chemical vapor deposition (CVD);
c) depositing a polymer support onto the graphene layer;
d) removing the three-dimensional metal foam framework via wet chemical etching, such that the graphene layer and the polymer support retain the three-dimensional configuration provided by the metal foam framework; and
e) removing the polymer support using a solvent to thereby obtain the three-dimensional crystalline graphene foams wherein the metal foam framework of step (a) is fabricated by:
i) mixing a metal powder and a skelet powder together to obtain a uniform mixture;
ii) applying pressure to the uniform mixture of the metal powder and the skelet powder to obtain a closed packed structure;
iii) applying temperature and pressure to the closed packed structure obtained in step (ii) to melt the metal powder around the skelet powder; and
iv) removing the skelet powder using a chemical bath to dissolve the skelet powder away from the closed packed structure leaving voids, resulting in a metal foam.

10. The method of claim 9 , wherein the metal powder is composed of nickel (Ni), cobalt (Co), copper (Cu), iron (Fe), platinum (Pt), or a combination thereof.

11. The method of claim 9 , wherein the skelet powder is silicon dioxide (SiO2), aluminum oxide (A12O3), sodium chloride (NaCl), magnesium oxide (MgO), hafnium oxide (HfO2), zirconium dioxide (ZrO2), or a combination thereof.

12. The method of claim 9 , wherein the skelet powder has a particle size of between about 1 nm to 10 gm.1.

13. The method of claim 9 , wherein the pressure is applied in a uniform direction.

Assignees

• Univ Singapore

Inventors

• Lee Jonghak
• Ozyilmaz Barbaros
• Kahya Orhan

Classifications

• H01G11/36

  Nanostructures, e.g. nanofibres, nanotubes or fullerenes · CPC title

• Y10T29/43

  Electric condenser making · CPC title

• B29K2105/04

  cellular or porous · CPC title

• H01G11/68

  characterised by their material · CPC title

• H01G11/70

  characterised by their structure · CPC title