Method for preparing graphene

Patent metadata

Field	Value
Publication number	US-9428395-B2
Application number	US-201214364970-A
Country	US
Kind code	B2
Filing date	Dec 11, 2012
Priority date	Dec 12, 2011
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

The present invention relates to a method for preparing graphene substantially free of contamination by metallic, magnetic, organic and inorganic impurities, and also to the use of the resulting graphene for the production of transparent electrodes, batteries, electron-acceptor or electron-donor materials, in particular in photovoltaic systems, photovoltaic panels, transistor channels, in particular in electronics, nonlinear emitters or absorbers of infrared photons, current-conducting electrodes, anti-static coatings, chemical detectors, vias and interconnections in electronics, current-conducting cables, and solar cells.

First claim

The invention claimed is:

1. A process for preparing graphene whose degree of contamination with metallic, magnetic, organic and mineral impurities is not more than 0.01% by mass, relative to the total mass of the graphene, the process comprising
a) reacting a dispersion of graphene oxide (GO) in at least one solvent selected from the group consisting of a solvent having a nonzero dipole moment a mineral acid, and an organic acid, with at least one tin compound and at least one acidic compound, wherein a pH of the dispersion is less than 7, to obtain graphene, and
b) performing at least one acidic washing at a pH <5 on the graphene obtained in a), to obtain graphene whose degree of contamination with metallic, magnetic, organic and mineral impurities is not more than 0.01% by mass, relative to the total mass of the graphene.

2. The process of claim 1 , wherein:
the solvent having a nonzero dipole moment is selected from the group consisting of water, pyrrolidinone, a C 1 -C 12 alkylpyrrolidinone, octylpyrrolidinone, dimethylformamide (DMF), dimethylacetamide, dimethyl sulfoxide (DMSO), acetonitrile, tetrahydrofuran (THF), and hexamethylphosphoramide (HMPA);
the mineral acid is selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, and perchloric acid; and
the organic acid is selected from the group consisting of formic acid, lactic acid, benzoic acid, methanesulfonic acid, para-toluenesulfonic acid (PTSA), trifluoroacetic acid, trichloroacetic acid, α-naphthol, and picric acid.

3. The process of claim 1 , wherein the solvent in a) is water.

4. The process of claim 1 , wherein a graphene oxide (GO) concentration in the dispersion is between 1×10 −4 and 1×10 3 g/L, limits inclusive.

5. The process of claim 1 , wherein the tin compound is at least one member selected from the group consisting of:
tin metal; and
a tin(II) salt selected from the group consisting of tin chloride, tin sulfate, tin nitrate, tin perchlorate, tin tetraphenylborate, tin phosphate, tin acetate, and tin oxalate.

6. The process of claim 1 , wherein an amount of tin compound is from 0.1 to 5 equivalents, limits inclusive, relative to an amount of oxygen to be removed from the graphene oxide.

7. The process of claim 1 , wherein the acidic compound is at least one member selected from the group consisting of:
a mineral acid selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, and phosphoric acid; and
an organic acid selected from the group consisting of formic acid, lactic acid, benzoic acid, methanesulfonic acid, para-toluenesulfonic acid (PTSA), trifluoroacetic acid, trichloroacetic acid, α-naphthol, and picric acid.

8. The process of claim 1 , wherein the acidic compound is used pure or diluted as an aqueous solution to a concentration of at least 0.1 mol·L −1 .

9. The process of claim 1 , wherein the pH of the dispersion in a) is less than 5.

10. The process of claim 1 , wherein the washing in b) is performed at a pH <3.

11. The process of claim 1 , wherein in a), the reaction occurs at a temperature between 0° C. and a reflux temperature of the solvent.

12. The process of claim 1 , wherein a reaction time in a) is from 1 minute to 72 hours, limits inclusive.

13. The process of claim 1 , wherein the reacting in a) is performed chemically or electrochemically.

14. The process of claim 1 , wherein the acidic washing in b) is performed with a mineral acid selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, and phosphoric acid.

15. The process of claim 1 , wherein the degree of contamination of the graphene with metallic, magnetic, organic and mineral impurities is not more than 0.001% by mass, relative to the total mass of the graphene.

16. The process of claim 1 , wherein the degree of contamination of the graphene with metallic, magnetic, organic and mineral impurities is not more than 0.0001% by mass, relative to the total mass of the graphene.

17. The process of claim 1 , wherein the graphene obtained by the process is in the form of a powder having a density <100 mg·mL −1 .

18. The process of claim 15 , wherein the graphene obtained by the process is in the form of a powder having a density <100 mg·mL −1 .

Assignees

• Commissariat A L'Energie Atomique Et Aux Ene Alt
• Commissariat Energie Atomique

Inventors

• Dubois Lionel
• Gambarelli Serge
• Nanjundan Ashok

Classifications

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C01B31/0476

  Chemistry & Metallurgy · mapped topic

• C25B1/00 Primary

  Electrolytic production of inorganic compounds or non-metals · CPC title

• C01B31/0446

  Chemistry & Metallurgy · mapped topic

• B82Y30/00 Primary

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title