Process for producing highly oriented graphene films

Patent metadata

Field	Value
Publication number	US-2015218003-A1
Application number	US-201413999282-A
Country	US
Kind code	A1
Filing date	Feb 6, 2014
Priority date	Feb 6, 2014
Publication date	Aug 6, 2015
Grant date	—

Abstract

A process for producing a highly oriented graphene film (HOGF), comprising: (a) preparing a graphene oxide (GO) dispersion having GO sheets dispersed in a fluid medium; (b) dispensing and depositing the dispersion onto a surface of a supporting substrate to form a layer of GO, wherein the dispensing and depositing procedure includes subjecting the dispersion to an orientation-inducing stress; (c) removing the fluid medium to form a dried layer of GO having an inter-plane spacing d 002 of 0.4 nm to 1.2 nm; (d) slicing the dried layer of GO into multiple pieces of dried GO and stacking at least two pieces of dried GO to form a mass of multiple pieces of GO; and (f) heat treating the mass under an optional first compressive stress to produce the HOGF at a first heat treatment temperature higher than 100° C. to an extent that an inter-plane spacing d 002 is decreased to a value less than 0.4 nm.

First claim

We claim:

1 . A process for producing a highly oriented graphene film (HOGF) with a thickness no greater than 0.1 mm, said process comprising:
(a) preparing either a graphene oxide dispersion having graphene oxide sheets dispersed in a fluid medium or a graphene oxide gel having graphene oxide molecules dissolved in a fluid medium, wherein said graphene oxide sheets or graphene oxide molecules contain an oxygen content higher than 5% by weight; (b) dispensing and depositing said graphene oxide dispersion or graphene oxide gel onto a surface of a supporting substrate to form a first layer of graphene oxide, wherein said dispensing and depositing procedure includes subjecting said graphene oxide dispersion or graphene oxide gel to an orientation-inducing stress; (c) partially or completely removing said fluid medium from the first layer of graphene oxide to form a first dried layer of graphene oxide having a layer thickness less than 200 μm and having an inter-plane spacing d 002 of 0.4 nm to 1.2 nm as determined by X-ray diffraction and an oxygen content no less than 5% by weight; (d) preparing at least a second dried layer of graphene oxide by repeating steps (b) and (c) at least one time or preparing multiple sheets of dried graphene oxide by slicing said first dried layer of graphene oxide; (e) stacking either said first dried layer of graphene oxide with said at least the second dried layer of graphene oxide or said multiple sheets of dried graphene oxide under an optional first compressive stress to form a mass of multiple layers of graphene oxide; and (f) heat treating the mass of multiple layers of graphene oxide under an optional second compressive stress to produce said highly oriented graphene film at a first heat treatment temperature higher than 100° C. to an extent that an inter-plane spacing d 002 is decreased to a value less than 0.4 nm and the oxygen content is decreased to less than 5% by weight, wherein said step (f) occurs before, during, or after said step (e).

2 . A process for producing a highly oriented graphene film (HOOF) with a thickness no greater than 0.1 mm, said process comprising:
(a) preparing either a graphene oxide dispersion having graphene oxide sheets dispersed in a fluid medium or a graphene oxide gel having graphene oxide molecules dissolved in a fluid medium, wherein said graphene oxide sheets or graphene oxide molecules contain an oxygen content higher than 5% by weight; (b) dispensing and depositing said graphene oxide dispersion or graphene oxide gel onto a surface of a supporting substrate to form a first layer of graphene oxide, wherein said dispensing and depositing procedure includes subjecting said graphene oxide dispersion or graphene oxide gel to an orientation-inducing stress; (c) partially or completely removing said fluid medium from the first layer of graphene oxide to form a first dried layer of graphene oxide having a layer thickness no greater than 200 μm and having an inter-plane spacing d 002 of 0.4 nm to 1.2 nm as determined by X-ray diffraction and an oxygen content no less than 5% by weight; (d) preparing at least a second dried layer of graphene oxide by repeating steps (b) and (c) at least one time or preparing multiple sheets of dried graphene oxide by slicing said first dried layer of graphene oxide; (e) heat treating said first dried layer of graphene oxide and said at least second dried layer of graphene oxide or said multiple sheets of dried graphene oxide at a first heat treatment temperature higher than 100° C. under an optional first compressive stress to an extent that an inter-plane spacing d 002 in said first dried layer, second dried layer, or multiple sheets of dried graphene oxide is decreased to a value less than 0.4 nm and the oxygen content is decreased to less than 5% by weight; and (f) stacking said first with said at least the second dried layer of graphene oxide or stacking said multiple sheets of dried graphene oxide under a second compressive stress to form said highly oriented graphene film, wherein said step (f) occurs before, during, or after said step (e).

3 . A process for producing a highly oriented graphene film with a thickness no greater than 0.1 mm, said process comprising:
(a) preparing a pristine graphene dispersion having oxygen-free pristine graphene sheets dispersed in a fluid medium; (b) dispensing and depositing said pristine graphene dispersion onto a surface of a supporting substrate to form a layer of pristine graphene, wherein said dispensing and depositing procedure includes subjecting said pristine graphene dispersion to an orientation-inducing stress; (c) partially or completely removing said fluid medium from said layer of pristine graphene to form a dried layer of pristine graphene; (d) slicing said dried layer of pristine graphene into multiple pieces of dried pristine graphene or repeating steps (b) and (c) to produce multiple layers of dried pristine graphene, and stacking at least two pieces or two layers of dried pristine graphene under an optional first compressive stress to form a mass of multiple pieces of pristine graphene; and (e) heat-treating the mass of multiple pieces or layers of dried pristine graphene at a first heat treatment temperature higher than 2,000° C. under a second compressive stress for a sufficient period of time to produce said highly oriented graphene film.

4 . The process of claim 1 , wherein said fluid medium further contains pristine graphene sheets and a pristine graphene to graphene oxide ratio is from 1/100 to 100/1.

5 . The process of claim 2 , wherein said fluid medium further contains pristine graphene sheets and a pristine graphene to graphene oxide ratio is from 1/100 to 100/1.

6 . The process of claim 1 , wherein said step (f) further includes heat-treating the graphene oxide mass at a second heat treatment temperature higher than 280° C. for a length of time sufficient for decreasing an inter-plane spacing d 002 to a value of from 0.3354 nm to 0.36 nm and decreasing the oxygen content to less than 2% by weight.

7 . The process of claim 2 , further comprising heat-treating said highly oriented graphene film at a second heat treatment temperature higher than 280° C. for a length of time sufficient for decreasing an inter-plane spacing d 002 to a value of from 0.3354 nm to 0.36 nm and decreasing the oxygen content to less than 2% by weight.

8 . The process of claim 1 , wherein said fluid medium consists of water and/or an alcohol.

9 . The process of claim 6 , wherein said second heat treatment temperature includes at least a temperature selected from (A) 300-1,500° C., (B) 1,500-2,100° C., and/or (C) higher than 2,100° C.

10 . The process of claim 7 , wherein said second heat treatment temperature includes at least a temperature selected from (A) 300-1,500° C., (B) 1,500-2,100° C., and/or (C) higher than 2,100° C.

11 . The process of claim 6 , wherein said second heat treatment temperature includes a temperature in the range of 300-1,500° C. for at least 1 hour and then a temperature in the range of 1,500-3,200° C. for at least 1 hour.

12 . The process of claim 7 , wherein said second heat treatment temperature includes a temperature in the range of 300-1,500° C. for at least 1 hour and then a temperature in the range of 1,500-3,200° C. for at least 1 hour.

13 . The process of claim 6 , further comprising a compression step, after said step (f), to reduce a thickness of said highly oriented graphene film.

14 . The process of claim 7 , further comprising a compression step, after said step (f), to reduce a thickness of said highly oriented graphene f

Assignees

• Zhamu Aruna
• Jang Bor Z
• Wang Yanbo
• Fu Lucy

Inventors

• Zhamu Aruna
• Jang Bor Z
• Wang Yanbo
• Fu Lucy

Classifications

• C01B32/192 Primary

  starting from graphitic oxides · CPC title

• C01B31/0476 Primary

  Chemistry & Metallurgy · mapped topic

• B29C39/38

  Heating or cooling · CPC title

• B29K2105/0061

  Gel or sol · CPC title

• B29C43/003

  characterised by the choice of material · CPC title