Stable dispersions of single and multiple graphene layers in solution

Patent metadata

Field	Value
Publication number	US-9548494-B2
Application number	US-201514666692-A
Country	US
Kind code	B2
Filing date	Mar 24, 2015
Priority date	May 26, 2009
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

A method for producing colloidal graphene dispersions comprises the steps of: (i) stirring graphite oxide in an aqueous dispersion medium to form a dispersion; (ii) determining if the dispersion is optically clear in a light microscope at 1000 fold magnification after 1 to 5 hours of stirring, and, if not clear, removing any undissolved impurities in the dispersion, in order to form a colloidal graphene oxide dispersion, or a multi-graphene oxide dispersion, that is optically clear in a light microscope at 1000 fold magnification; and (iii) thermally reducing the graphene oxide, or multi-graphene oxide, in dispersion in the aqueous dispersion medium at a temperature between 120° C. and 170° C. under pressure in order to ensure that the dispersion medium is not evaporated to form a stable colloidal graphene dispersion or a stable multi-graphene dispersion. Using the method used for the preparation of the starting dispersion a graphene or a multi-graphene dispersion is obtained that can be further processed to multi-graphene with larger inter-planar distances than graphite. Such dispersions and multi-graphenes are suitable materials in the manufacturing of rechargeable lithium ion batteries.

First claim

What is claimed is:

1. A method for producing a graphene layer using a colloidal graphene or multi-graphene layers using a multi-graphene dispersion, the colloidal graphene or the multi-graphene dispersion, respectively, obtained by a first method comprising the steps of:
(i) stirring graphite oxide in an aqueous dispersion medium to form a dispersion;
(ii) determining if the dispersion is optically clear in a light microscope at 1000 fold magnification after 1 to 5 hours of stirring, and, if not clear, removing any undissolved impurities in the dispersion, in order to form a colloidal graphene oxide dispersion, or a multi-graphene oxide dispersion, that is optically clear in a light microscope at 1000 fold magnification; and
(iii) thermally reducing the graphene oxide, or multi-graphene oxide, in dispersion in the aqueous dispersion medium at a temperature between 120° C. and 170° C. under pressure in order to ensure that the dispersion medium is not evaporated to form a stable colloidal graphene dispersion or a stable multi-graphene dispersion,
wherein the method for producing the graphene layer using the colloidal graphene or multi-graphene layers using a multi-graphene dispersion, comprises, either the steps of:
(1) deposit the dispersion of step (ii) on a substrate or precipitate the dispersion of step (ii); and
(2) then perform step (iii); or
(3) deposit the dispersion of step (iii) on a substrate or precipitate the dispersion of step (iii).

Assignees

• Belenos Clean Power Holding Ag

Inventors

• Nesper Reinhard
• Kaspar Tommy

Classifications

• Y02E60/324

  Cross-Sectional Technologies · mapped topic

• B82Y30/00

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

• H01B13/32

  Filling or coating with impervious material · CPC title

• C01B2204/02

  Single layer graphene · CPC title

• H01B1/04

  mainly consisting of carbon-silicon compounds, carbon or silicon · CPC title