Graphene-based films

Patent metadata

Field	Value
Publication number	US-2016016804-A1
Application number	US-201414773527-A
Country	US
Kind code	A1
Filing date	Mar 3, 2014
Priority date	Mar 8, 2013
Publication date	Jan 21, 2016
Grant date	—

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

1 . 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.

2 . The method according to claim 1 , wherein at least 70 vol % of the liquid medium is exchanged with the packing density adjustment medium.

3 . The method according to claim 1 , wherein the packing density adjustment medium comprises no more than about 70 vol % of the more volatile component relative to the combined volume of the less and more volatile components.

4 . The method according to claim 1 , wherein the packing density adjustment medium comprises one or more of water, water soluble polymer, sulfuric acid and ionic liquid.

5 . The method according to claim 1 , wherein the packing density adjustment medium comprises water and sulphuric acid, 1-ethyl-3-methylimidazolium tetrafluoroborate and acetonitrile, 1-ethyl-3-methylimidazolium tetrafluoroborate and water, or water, sulphuric acid and polyvinyl alcohol.

6 . The method according to claim 1 , wherein removal of at least some of the more volatile component of the exchanged packing density adjustment medium from the first graphene-based film provides for a graphene-based film having a packing density (ρ) of the graphene-based sheets ranging from 0.5-1.40 g/cm 3 .

7 . The method according to claim 6 , wherein removal of at least some of the more volatile component of the exchanged packing density adjustment medium from the first graphene-based film provides for a graphene-based film having a packing density (ρ) of the graphene-based sheets ranging from 1-1.40 g/cm 3 .

8 . The method according to claim 1 , wherein removal of at least some of the more volatile component of the exchanged packing density adjustment medium from the first graphene-based film provides for a graphene-based film 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.

9 . The method according to claim 1 , wherein removal of at least some of the more volatile component of the exchanged packing density adjustment medium from the first graphene-based film provides for a graphene-based film a having specific gravimetric capacitance (C wt-c ) of at least 100 F/g at an operation rate of 0.1 A/g and using 1.0 M H 2 SO 4 as electrolyte, or a specific gravimetric capacitance (C wt-c ) of at least 50 F/g at an operation rate of 50 A/g and using 1.0 M H 2 SO 4 as electrolyte.

10 . The method according to claim 1 , wherein removal of at least some of the more volatile component of the exchanged packing density adjustment medium from the first graphene-based film provides for a graphene-based film 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 τ 0 is the minimum time needed to discharge all energy from the capacitor cell with an efficiency of at least 50%.

11 . 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, wherein the film exhibits a packing density (ρ) of the graphene-based sheets ranging from 0.1-1.40 g/cm 3 .

12 . The graphene-based film according to claim 10 , wherein the packing density (ρ) of the graphene-based sheets ranges from 0.5-1.40 g/cm 3 .

13 . The graphene-based film according to claim 11 , wherein the packing density (ρ) of the graphene-based sheets ranges from 1-1.40 g/cm 3 .

14 . The graphene-based film according to claim 1 , wherein the liquid medium comprises one or more of water, water soluble polymer, sulfuric acid and an ionic liquid.

15 . The graphene-based film according to claim 11 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.

16 . The graphene-based film according to claim 11 having specific gravimetric capacitance (C wt-c ) of at least 100 F/g at an operation rate of 0.1 A/g and using 1.0 M H 2 SO 4 as electrolyte, or a specific gravimetric capacitance (C wt-c ) of at least 50 F/g at an operation rate of 50 A/g and using 1.0 M H 2 SO 4 as electrolyte.

17 . The graphene-based film according claim 11 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 τ 0 is the minimum time needed to discharge all energy from the capacitor cell with an efficiency of at least 50%.

18 . A device comprising at least one graphene-based film according to claim 11 .

19 . A supercapacitor comprising at least one graphene-based film according to claim 11 , as an electrode.

Assignees

• Univ Monash

Inventors

• Li Dan
• Yang Xiaowei

Classifications

• C01B32/22

  Intercalation · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C01B2204/22

  Electronic properties · CPC title

• C01B32/23

  Oxidation · CPC title

• H01G11/36

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