Graphene-based films

Patent metadata

Field	Value
Publication number	US-10297396-B2
Application number	US-201414773527-A
Country	US
Kind code	B2
Filing date	Mar 3, 2014
Priority date	Mar 8, 2013
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

This present invention relates to a method of preparing graphene-based film, said method comprising: providing a first graphene-based film comprising sheets of graphene, graphene oxide, partially reduced graphene oxide, reduced graphene oxide, or a combination of two or more thereof, that are (i) arranged relative to each other in a substantially planar manner so as to form a layered structure, and (ii) at least partially separated by a liquid medium; exchanging said liquid medium with a packing density adjustment medium that comprises at least two components, wherein one of said components has a volatility greater than the other component; and removing at least some of the more volatile component from the first graphene-based film to produce a graphene-based film that has a different packing density of the graphene-based sheets relative to that of the first graphene-based film.

First claim

The invention claimed is:

1. Graphene-based film comprising sheets of graphene, graphene oxide, partially reduced graphene oxide, reduced graphene oxide, or a combination of two or more thereof, that are (i) arranged relative to each other in a substantially planar manner so as to form a layered structure, and (ii) separated by a liquid medium comprising one or more of polymer, sulfuric acid, and an ionic liquid, wherein the film exhibits (i) a packing density (ρ) of the graphene-based sheets ranging from 1-1.40 g/cm 3 and (ii) a gravimetric capacitance over 100 F/g at an operational rate of 100 A/g.

2. The graphene-based film according to claim 1 having a specific volumetric capacitance (C vol ) of at least 100 F/cm 3 at an operation rate of 0.1 A/g and using 1.0 M H 2 SO 4 as electrolyte, or a specific volumetric capacitance (C vol ) of at least 50 F/cm 3 at an operation rate of 50 A/g and using 1.0 M H 2 SO 4 as electrolyte.

3. The graphene-based film according claim 1 having a relaxation time (τ 0 ) of less than 1 second when measured from a capacitor cell based on 1.0 mg/cm 2 of the so formed graphene-based film, where to is the minimum time needed to discharge all energy from the capacitor cell with an efficiency of at least 50%.

4. A device comprising at least one graphene-based film according to claim 1 .

5. A supercapacitor comprising at least one graphene-based film according to claim 1 , as an electrode.

6. The graphene-based film according claim 1 wherein the sheets are arranged so as to form a layered structure where at least about 60% of the graphene-based sheets within the film are aligned along their major axis at less than about 45°.

Assignees

• Univ Monash

Inventors

• Li Dan
• Yang Xiaowei

Classifications

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C01B32/225

  Expansion; Exfoliation · CPC title

• H01G11/36

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

• C01B32/198

  Graphene oxide · CPC title

• C01B32/194

  After-treatment · CPC title