(19)
(11)EP 2 687 626 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
09.09.2020 Bulletin 2020/37

(21)Application number: 12757510.8

(22)Date of filing:  09.03.2012
(51)International Patent Classification (IPC): 
D01F 9/12(2006.01)
D01F 1/09(2006.01)
C08J 5/00(2006.01)
D01D 1/02(2006.01)
D01D 5/06(2006.01)
B82Y 30/00(2011.01)
D01D 5/247(2006.01)
(86)International application number:
PCT/KR2012/001718
(87)International publication number:
WO 2012/124934 (20.09.2012 Gazette  2012/38)

(54)

GRAPHENE FIBER AND METHOD FOR MANUFACTURING SAME

GRAPHENFASER UND HERSTELLUNGSVERFAHREN DAFÜR

FIBRE DE GRAPHÈNE ET SON PROCÉDÉ DE FABRICATION


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 15.03.2011 KR 20110022832

(43)Date of publication of application:
22.01.2014 Bulletin 2014/04

(73)Proprietor: IUCF-HYU (Industry-University Cooperation Foundation Hanyang University)
Seoul 133-791 (KR)

(72)Inventors:
  • KIM, Seon Jeong
    Seoul 133-071 (KR)
  • SHIN, Min Kyoon
    Seoul 133-071 (KR)
  • KIM, Shi Hyeong
    Seoul 133-071 (KR)

(74)Representative: Dr. Gassner & Partner mbB 
Wetterkreuz 3
91058 Erlangen
91058 Erlangen (DE)


(56)References cited: : 
WO-A1-2010/096665
KR-A- 20100 099 586
US-A1- 2007 131 915
US-A1- 2009 092 747
KR-A- 20060 060 707
KR-A- 20110 093 666
US-A1- 2007 158 618
  
  • ZHEN XU ET AL: "Aqueous Liquid Crystals of Graphene Oxide", ACS NANO, vol. 5, no. 4, 4 March 2011 (2011-03-04), pages 2908-2915, XP055134904, ISSN: 1936-0851, DOI: 10.1021/nn200069w
  • XIN ZHAO ET AL: "Enhanced Mechanical Properties of Graphene-Based Poly(vinyl alcohol) Composites", MACROMOLECULES, vol. 43, no. 5, 9 March 2010 (2010-03-09), pages 2357-2363, XP055135340, ISSN: 0024-9297, DOI: 10.1021/ma902862u
  • GOTO T ET AL: "FABRICATION OF MULTI-FILAMENTARY Y123 SUPERCONDUCTOR", JOURNAL OF MATERIALS SCIENCE, KLUWER ACADEMIC PUBLISHERS, DORDRECHT, vol. 35, no. 7, 1 April 2000 (2000-04-01), pages 1603-1606, XP001039051, ISSN: 0022-2461, DOI: 10.1023/A:1004783225364
  • ZHEN XU ET AL: "Graphene chiral liquid crystals and macroscopic assembled fi bres", NATURE COMMUNICATIONS, 6 December 2011 (2011-12-06), XP055134887, DOI: 10.1038/ncomms1583
  • TARIQ BASHIR ET AL: "Electrical resistance measurement methods and electrical characterization of poly(3,4-ethylenedioxythiophene)-coated conductive fibers", JOURNAL OF APPLIED POLYMER SCIENCE, vol. 124, no. 4, 15 May 2012 (2012-05-15), pages 2954-2961, XP055463548, ISSN: 0021-8995, DOI: 10.1002/app.35323
 
Remarks:
The file contains technical information submitted after the application was filed and not included in this specification
 
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

[Technical Field]



[0001] The present invention relates to a method for producing a graphene fiber and a graphene fiber produced by the method. More specifically, the present invention relates to a porous graphene fiber including graphene whose wrinkled structure is maintained to achieve excellent mechanical and electrochemical properties, and a method for producing the graphene fiber.

[Background Art]



[0002] Graphene is a two-dimensional nanostructure of covalently bonded carbon atoms and exhibits outstanding mechanical, electrical, and thermal properties. Graphene flakes consist of single or several graphene sheets exfoliated from graphite. Graphene flakes have been reconstituted into bulky structures that have a modulus of elasticity exceeding that of flexible graphite while possessing high strength.

[0003] Fibers comprising exfoliated carbon materials selected from graphene are described in WO2010096665.

[0004] A major challenge for graphene structures with high strength and toughness is to maintain the inherent active surface of graphene by preventing restacking of graphene tending to form close-packed layer structures. Single-layer graphene or a graphene flake has a wrinkled structure due to high area-to-thickness ratio thereof, but a graphene paper or composite including a large amount of graphene usually has a dense layer structure similar to graphite. The dense layered structure of graphene is an obstacle in achieving maximum mechanical properties owing to the short length of graphene that reduces the van der Waals force and tensile strength between graphene layers (by 1% or less).

[0005] There are some reports on complexes including less than 1% of graphene whose wrinkled structure is maintained. However, there is no report regarding the development of composite fibers including graphene alone or at a considerable concentration while maintaining the wrinkled structure of graphene.

[0006] The dense layered structure of graphene composites limits application thereof to energy and hydrogen storage media. For these reasons, there is a need to improve the porosity, mechanical properties and electrochemical properties of graphene structures.

[Disclosure]


[Technical Problem]



[0007] It is an object of the present invention to provide a porous graphene fiber that is flexible and has excellent mechanical and electrochemical properties, and a method for producing the graphene fiber.

[Technical Solution]



[0008] According to an aspect of the present invention, there is provided a method for producing a graphene fiber, including a) dispersing graphene and a surfactant in a solvent to prepare a dispersion, b) performing wet spinning by incorporating the dispersion into a polymer solution, followed by drying to produce a composite fiber, and c) annealing the composite fiber or treating the composite fiber with a strong acid to remove the polymer, as in appended claims. The graphene is chemically reduced graphene or graphene oxide, more preferably reduced graphene with acid functional groups.

[0009] In one embodiment of the present invention, the chemically reduced graphene may be prepared by reducing an aqueous dispersion of graphene with hydrazine at 90 to 100 °C for 1 to 24 hours.

[0010] In one embodiment of the present invention, the annealing is preferably performed at a temperature of 300 to 1000 °C.

[0011] In one embodiment of the present invention, the strong acid used to remove the polymer may be hydrochloric acid, sulfuric acid, a piranha solution consisting of a mixture of sulfuric acid and hydrogen peroxide, or a superacid consisting of a mixture of sulfuric acid and oleum. The strong acid is preferably 30 to 40 wt% hydrochloric acid.

[0012] In one embodiment of the present invention, the surfactant used to disperse the graphene is preferably selected from sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfonate (SDS), Triton X-100, and cetyltrimethylammonium bromide (CTAB). The surfactant is more preferably sodium dodecyl benzene sulfonate (SDBS).

[0013] The polymer used in the method of the present invention is polyvinyl alcohol (PVA), or its mixture with poly(methyl methacrylate) (PMMA).

[0014] In one embodiment of the present invention, the contents of the graphene and the polymer in the graphene composite fiber are from 20 to 90% by weight and from 10 to 80% by weight, respectively. Within these ranges, the wrinkled structure of the graphene can be maintained.

[0015] The present invention also provides a porous graphene fiber including graphene whose wrinkled structure is maintained even when a polymer is removed from a graphene composite fiber. The porous graphene fiber of the present invention has an electrical conductivity of 10 to 100 S/cm, an electrochemical capacitance of 100 to 300 F/g, and a porosity of 1000 to 2000 m2/g. The length of the graphene is preferably from 100 to 1000 nm, the diameter of the graphene composite fiber is typically from 30 to 100 µm, which may be controlled by the diameter of a syringe tip used during wet spinning, and the diameter of the porous graphene fiber after the polymer removal is typically from 15 to 50 µm.

[0016] The porous graphene fiber of the present invention may be formed into knot and spring structures due to flexibility thereof, and several strands thereof may also be woven into a fabric.

[0017] The porous graphene fiber of the present invention can be utilized in a supercapacitor or an energy or hydrogen storage medium due to excellent electrical and mechanical properties and high porosity thereof.

[Advantageous Effects]



[0018] The graphene fiber of the present invention, which includes graphene whose wrinkled structure is maintained, exhibits far superior mechanical and electrochemical properties to conventional graphene papers, graphene composite films, and flexible graphite.

[0019] For effective current collection, graphene electrodes for supercapacitors, fuel cells, and batteries as conventional energy storage media have been used in combination with highly electrically conductive metals. In contrast, high electrical conductivity of the porous graphene fiber according to the present invention eliminates the need for a separate metal electrode.

[0020] In addition, the graphene fiber of the present invention can be formed into knot or spring structures due to flexibility thereof and can also be woven into a fabric. Therefore, the graphene fiber of the present invention is applicable to a wide variety of fields. The wrinkled structure of graphene makes the graphene fiber of the present invention porous. This enables utilization of the graphene fiber of the present invention in energy and hydrogen storage media, etc.

[0021] Furthermore, the porous graphene fiber of the present invention can be mass-produced in a simple and economical manner and its length can be extended to tens of meters in a continuous process. Therefore, the porous graphene fiber of the present invention is ideally suited to industrial applications.

[Description of Drawings]



[0022] 

FIG. 1 is a conceptual diagram showing the procedure for producing a fiber composed of graphene flakes having directivity and wrinkles according to the present invention.

FIG. 2 shows SEM images of the surface and cross-sectional morphologies of a graphene fiber having a wrinkled structure according to the present invention.

FIG. 3 is a SEM image showing the cross section of a graphene fiber from which PVA was removed by annealing a graphene/PVA fiber at 600 °C.

FIG. 4 shows cyclic voltammograms of a graphene fiber of the present invention at different scan rates.


[Mode for Invention]



[0023] The present invention will now be described in more detail with reference to exemplary embodiments thereof.

[0024] FIG. 1 is a conceptual diagram showing the procedure for producing a fiber composed of graphene flakes having directivity and wrinkles according to the present invention. According to the method of the present invention, graphene can be prevented from restacking in the individual steps of producing a fiber from a graphene solution in order to maintain a wrinkled structure.

[0025] First, chemically converted graphene flakes (RCCGFs) with functional groups such as COOH groups are dispersed in dimethylformamide (DMF). An electrostatic repulsive force induced by the functional groups allows stable maintenance of the dispersion state of the graphene for at least 3 months without serious aggregation of the graphene. In this case, the following relationship is satisfied:

where FR, FG, and FV.D.W. represent the electrostatic repulsive force, the force of gravity, and the van der Waals force between the graphene flakes, respectively. The relations of forces in the graphene solution during the overall fiber production procedure are as follows.
  1. 1. The chemically converted graphene is well dispersed in DMF under the following condition:

  2. 2. For a wet spinning solution, when DMF is exchanged with distilled water by centrifugation:

  3. 3. The step of sufficiently dispersing graphene in distilled water with the help of SDBS as a surfactant:


    This condition may be varied with increasing time when a large amount of graphene is loaded, and as a result, the graphene may aggregate.
  4. 4. During wet spinning, PVA chains replace SDBS and the wrinkled graphene surrounded by the PVA chains is aligned in a graphene fiber by a shear force induced by a shear flow.
  5. 5. After wet spinning, a graphene gel in the solution undergoes a hydrostatic force. The hydrostatic force does not greatly affect restacking of the graphene.
  6. 6. Drying


[0026] Gravimetric force is applied during drying, but stacking occurs only in the axial direction, thus maintaining the wrinkled structure of the graphene.

[0027] Since hydrophobic interaction between graphene flakes is necessary for fiber production during wet spinning, the degree of reduction of the chemically converted graphene flakes is of importance. In other words, hydrophilicity of graphene flakes or somewhat less reduced graphene flakes impedes sufficient hydrophobic interaction between the graphene flakes, making the formation of a gel-fiber difficult.

[0028] Accordingly, appropriate reduction of graphene is essential for the preparation of a stable dispersion and the production of an assembly by wet spinning. The atomic fractions of carbon and oxygen in the reduced graphene flakes (RCCGF) determined from XPS data are 88.05% and 9.75%, respectively.

[0029] According to the method of the present invention, a graphene fiber is produced by the following procedure. First, a graphene/DMF solution is prepared. The DMF is exchanged with distilled water by sonication and centrifugation, and the graphene is well dispersed in distilled water with the help of a surfactant to prepare a graphene solution. The graphene solution is incorporated into a coagulation bath containing polyvinyl alcohol (PVA). The graphene solution incorporated into the polymer is changed to a graphene gel-fiber by an assembly process through hydrophobic interaction between the graphene flakes surrounded by the PVA chains replacing the surfactant bonded to the graphene flakes. The graphene gel-fiber is washed with distilled water to remove excess PVA.

[0030] Although hydrostatic forces are applied to the graphene gel-fiber in the PVA solution and distilled water, the wrinkled structure of the graphene flakes can be maintained because the magnitudes of the hydrostatic forces in the x, y, and z directions are equal. Then, the graphene gel-fiber is suspended vertically and dried in air. As a result, a graphene-based composite fiber having a wrinkled structure is formed.

[0031] Finally, the polymer is removed from the composite fiber, leaving a porous fiber composed of graphene alone. Specifically, the composite fiber is annealed at 300 to 1000 °C to volatilize the polymer or is treated with an acidic solution to remove the polymer.

[0032] The present invention will be explained in detail with reference to the following examples and accompanying drawings. However, these examples are provided to assist in further understanding of the invention and are not to be construed as limiting the scope of the invention.

Example 1: Preparation of solution of graphene (RCCG) chemically converted by reduction



[0033] In accordance with the method illustrated in FIG. 1, RCCG was dispersed in dimethylformamide (DMF) in the presence of an appropriate amount of triethylamine to obtain a stable graphene dispersion. Several grams of RCCG was obtained by reducing an aqueous dispersion of CCG with excess hydrazine at 95 °C over 2 h in accordance with previously reported methods (Li, D., Muller, M. B., Gilje, S., Kaner, R. B. & Wallace, G. G. Processable aqueous dispersions of graphene nanosheets. Nature Nanotech. 3, 101 (2008)). As a result of the reduction reaction, the graphene aggregated in the aqueous solution. The graphene aggregates were acidified with dilute sulfuric acid under vigorous stirring to a pH of 2 or less, and transferred to a sintered funnel. The aggregates were washed with a large amount of Milli-Q water on the funnel until the pH reached about 7. The filtered material was dried under vacuum at 70 °C for 48 h to obtain RCCG as a solid. The dried RCCG powder was dissolved in DMF to prepare a 0.47-0.5 mg/mL RCCG/DMF solution. The length of the graphene flakes was about 400 nm, as measured using a Zetasizer. The particle size and zeta potential remained stable for several months. The dispersion was filtered under vacuum to obtain a paper having a resistance of 30-40 Ω/sq.

Example 2: Production of graphene fiber



[0034] The solvent (DMF) of the graphene flake dispersion was exchanged with distilled water by centrifugation. The G/F aqueous solution was mixed with sodium dodecyl benzene sulfonate (SDBS) by ultrasonication.

[0035] The graphene dispersion was slowly injected into a coagulation bath containing PVA (molecular weight = 89,000-124,000, degree of hydrolysis = ∼99%) through a syringe (26 gauge) and wet spun to continuously produce a uniform graphene/PVA fiber.

[0036] The graphene/PVA was annealed at 600 °C to remove the PVA, leaving behind a porous fiber composed of graphene alone. The diameter of the graphene fiber was 28 µm.

Experimental Example: Characterization of the graphene fiber



[0037] The graphene fiber was sufficiently flexible and thus could be wound on a glass tube having a small diameter of 6.5 mm without mechanical damage, unlike graphene papers tending to be brittle (FIG. 1B). Complete knots of the graphene fiber were difficult to form, but the formation of sufficiently strong, flexible, small diameter knots of the graphene fiber was possible (FIG. 1C). Difficulty in the formation of complete knots was due to the small length of the graphene flakes and the frictional force of the rough surface of the graphene fiber composed of the graphene flakes (FIG. 2B). Several strands of the graphene fiber can also be woven into a fabric.

[0038] FIG. 2 shows SEM images of the surface and cross-sectional morphologies of the graphene fiber obtained by removing the PVA from the graphene/PVA composite fiber. After annealing at 600 °C for 1 h or treatment with 37% hydrochloric acid for 24 h, the graphene fiber had a rough surface because of the wrinkled graphene flakes. (FIG 2B) The wrinkled graphene flakes were aligned along the axis of the fiber (FIG. 2C) and were formed into highly porous petals (FIG. 2D).

[0039] The cross section of the graphene fiber can be specifically seen in FIG. 3, too. This image demonstrates the formation of graphene flakes without serious restacking.

[0040] FIG. 4 shows cyclic voltammograms of the graphene fiber at different scan rates (solution: 1 M H2SO4, reference electrode: Ag/AgCl). The electrical conductivity and electrochemical capacitance of the graphene fiber were 10-100 S/cm and 100-200 F/g, respectively. Accordingly, the graphene fiber is expected to find application in supercapacitors.

[industrial Applicability]



[0041] As is apparent from the foregoing, the graphene fiber of the present invention has outstanding mechanical and electrochemical properties and high electrical conductivity. The graphene fiber of the present invention is highly porous due to wrinkled structure thereof. Therefore, the graphene fiber of the present invention can be used as an electrode for a supercapacitor, a fuel cell, or a battery as an energy storage medium. The graphene fiber of the present invention can also be used to develop a hydrogen storage medium. In addition, the graphene fiber of the present invention can be formed into knot and spring structures due to flexibility thereof and can also be woven into a fabric. The porous graphene fiber of the present invention can be mass-produced in a simple and economical manner and its length can be extended to tens of meters in a continuous process.


Claims

1. A method for producing a graphene fiber, comprising

a) dispersing chemically reduced graphene or graphene oxide and a surfactant in a solvent to prepare a dispersion,

b) incorporating the dispersion into a coagulation bath containing polyvinyl alcohol to form a graphene-gel fiber, followed by drying the graphene-gel fiber to produce a composite fiber, and

c) annealing the composite fiber or treating the composite fiber with a strong acid to remove the polymer.


 
2. The method according to claim 1, wherein the chemically reduced graphene is prepared by reducing an aqueous dispersion of graphene with hydrazine at 90 to 100 °C for 1 to 24 hours.
 
3. The method according to claim 1, wherein the annealing is performed at a temperature of 300 to 1000 °C.
 
4. The method according to claim 1, wherein the strong acid is selected from hydrochloric acid, sulfuric acid, a piranha solution consisting of a mixture of sulfuric acid and hydrogen peroxide, a mixture of sulfuric acid and oleum, and mixtures thereof.
 
5. The method according to claim 1, wherein the graphene is 100 to 1000 nm in length.
 
6. The method according to claim 1, wherein the surfactant is selected from sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfonate (SDS), octylphenol ethoxylate with average ethoxylation number of 9.5, and cetyltrimethylammonium bromide (CTAB).
 
7. The method according to claim 1, wherein the coagulation bath contains polyvinyl alcohol (PVA) or its mixtures with poly(methyl methacrylate) (PMMA).
 
8. The method according to claim 1, wherein the contents of the graphene and the polymer in the graphene composite fiber are from 20 to 90% by weight and from 10 to 80% by weight, respectively.
 
9. A porous graphene fiber manufactured according to any of claims 1 to 8, comprising graphene whose wrinkled structure is maintained, wherein the contents of the graphene and the polymer in the graphene composite fiber are from 20 to 90% by weight and from 10 to 80% by weight, respectively.
 
10. The graphene fiber according to claim 9, wherein the graphene fiber is flexible.
 
11. The graphene fiber according to claim 9, wherein the porous graphene fiber is capable of being formed into knot and spring structures and being woven into a fabric.
 
12. A supercapacitor comprising the graphene fiber according to claim 9.
 
13. An energy or hydrogen storage medium comprising the graphene fiber according to claim 9.
 


Ansprüche

1. Verfahren zur Herstellung einer Graphenfaser, umfassend

a) Dispergieren von chemisch reduziertem Graphen oder Graphenoxid und einem grenzflächenaktiven Stoff in einem Lösungsmittel zur Herstellung einer Dispersion,

b) Einbringen der Dispersion in ein Koagulationsbad, das Polyvinylalkohol enthält, um eine Graphen-Gel-Faser zu bilden, gefolgt vom Trocknen der Graphen-Gel-Faser, um eine Verbundfaser herzustellen, und

c) Tempern der Verbundfaser oder Behandlung der Verbundfaser mit einer starken Säure, um das Polymer zu entfernen.


 
2. Verfahren nach Anspruch 1, wobei das chemisch reduzierte Graphen durch Reduktion einer wässrigen Dispersion von Graphen mit Hydrazin bei 90 bis 100 °C für 1 bis 24 Stunden hergestellt wird.
 
3. Verfahren nach Anspruch 1, wobei das Tempern bei einer Temperatur von 300 bis 1000 °C durchgeführt wird.
 
4. Verfahren nach Anspruch 1, wobei die starke Säure ausgewählt ist aus Salzsäure, Schwefelsäure, einer Piranha-Lösung, bestehend aus einem Gemisch aus Schwefelsäure und Wasserstoffperoxid, einem Gemisch aus Schwefelsäure und Oleum und Gemischen davon.
 
5. Verfahren nach Anspruch 1, wobei das Graphen eine Länge von 100 bis 1000 nm hat.
 
6. Verfahren nach Anspruch 1, wobei der grenzflächenaktive Stoff ausgewählt ist aus Natriumdodecylbenzolsulfonat (SDBS), Natriumdodecylsulfonat (SDS), Octylphenolethoxylat mit einer durchschnittlichen Ethoxylierungszahl von 9,5 und Cetyltrimethylammoniumbromid (CTAB).
 
7. Verfahren nach Anspruch 1, wobei das Polymer ausgewählt ist aus Polyvinylalkohol (PVA) und Poly(methylmethacrylat) (PMMA).
 
8. Verfahren nach Anspruch 1, wobei der Anteil des Graphens und des Polymers in der Graphenverbundfaser 20 bis 90 Gew.-% bzw. 10 bis 80 Gew.-% beträgt.
 
9. Poröse Graphenfaser, hergestellt nach einem der Ansprüche 1 bis 8, umfassend Graphen, dessen gekräuselte Struktur erhalten bleibt, wobei der Anteil des Graphens und des Polymers in der Graphenverbundfaser 20 bis 90 Gew.-% bzw. 10 bis 80 Gew.-% beträgt.
 
10. Graphenfaser nach Anspruch 9, wobei die Graphenfaser flexibel ist.
 
11. Graphenfaser nach Anspruch 9, wobei die poröse Graphenfaser zu Knoten- und Federstrukturen geformt und zu einem Gewebe gewebt werden kann.
 
12. Superkondensator, der die Graphenfaser nach Anspruch 9 umfasst.
 
13. Energie- oder Wasserstoffspeichermedium, das die Graphenfaser nach Anspruch 9 umfasst.
 


Revendications

1. Procédé de production d'une fibre de graphène, comprenant

a) la dispersion du graphène chimiquement réduit ou de l'oxyde de graphène et d'un tensioactif dans un solvant pour préparer une dispersion,

b) l'incorporation de la dispersion dans un bain de coagulation contenant de l'alcool polyvinylique afin de former une fibre à l'état de gel graphène, suivie du séchage de la fibre à l'état de gel graphène pour produire une fibre composite, et

c) le recuit de la fibre composite ou le traitement de la fibre composite avec un acide fort pour éliminer le polymère.


 
2. Procédé selon la revendication 1, en ce que le graphène chimiquement réduit est préparé en réduisant une dispersion aqueuse de graphène avec de l'hydrazine entre 90 et 100 °C pendant 1 à 24 heures.
 
3. Procédé selon la revendication 1, en ce que le recuit est effectué à une température comprise entre 300 et 1000 °C.
 
4. Procédé selon la revendication 1, en ce que l'acide fort est sélectionné parmi l'acide hydrochlorique, l'acide sulfurique, un mélange piranha consistant en un mélange d'acide sulfurique et de peroxyde d'hydrogène, un mélange d'acide sulfurique et d'oléum, et des mélanges associés.
 
5. Procédé selon la revendication 1, en ce que le graphène a une longueur de 100 à 1000 nm.
 
6. Procédé selon la revendication 1, en ce que le tensioactif est sélectionné parmi le dodécylbenzènesulfonate de sodium (SDBS), le dodécylsulfate de sodium (SDS), l'éthoxylate d'octylphénol ayant un nombre d'éthoxylation moyen de 9,5, et le bromure d'hexadécyltriméthylammonium (CTAB).
 
7. Procédé selon la revendication 1, en ce que le bain de coagulation contient de l'alcool polyvinylique (PVA) ou de ses mélanges avec du poly(méthacrylate de méthyle) (PMMA).
 
8. Procédé selon la revendication 1, en ce que les teneurs du graphène et du polymère dans la fibre composite de graphène sont respectivement de 20 à 90% en poids et de 10 à 80% en poids.
 
9. Fibre de graphène poreuse fabriquée selon l'une des revendications 1 à 8, comprenant du graphène dont la structure ridée est maintenue, en ce que les teneurs du graphène et du polymère dans la fibre composite de graphène sont respectivement de 20 à 90% en poids et de 10 à 80% en poids.
 
10. Fibre de graphène selon la revendication 9, en ce que la fibre de graphène est flexible.
 
11. Fibre de graphène selon la revendication 9, en ce que la fibre de graphène poreuse peut être formée en structures de nœuds et de ressorts et être tissée en un tissu.
 
12. Supercondensateur comprenant la fibre de graphène selon la revendication 9.
 
13. Milieu de stockage d'énergie ou d'hydrogène comprenant la fibre de graphène selon la revendication 9.
 




Drawing

















Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description




Non-patent literature cited in the description