High-toughness graphene fiber and method for preparing the same

Abstract

The application discloses a high-toughness graphene fiber and a preparation method thereof. In the prior art, the graphene oxide liquid crystal wet spinning is prone to causing irregular fiber cross-section shape (such as flatness and strip shape) due to uneven coagulation process, and seriously restricts the improvement of mechanical properties. By introducing a certain amount of monovalent metal ions (such as K + , Na + , NH4 + ) into the graphene oxide dispersion liquid to control the ion strength of the dispersion liquid, the balance between the electrostatic repulsion and the van der Waals force of the graphene oxide molecules is adjusted, and the large-size liquid crystal crystalline region is broken into micro-crystalline regions with uniform size. The modified spinning liquid is extruded into a coagulation bath through a wet spinning technology. Due to the uniform shrinkage characteristics of the micro-crystalline regions, the shrinkage behavior of the fiber during the coagulation and drying processes becomes highly uniform and symmetrical, and finally the graphene fiber with regular cross-section shape and compact structure is obtained.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation, specifically relating to a high-strength and tough graphene fiber and its preparation method. Background Technology

[0002] Currently, high-performance graphene fibers are mainly prepared through wet spinning and subsequent reduction of graphene oxide (GO) liquid crystals. This method typically relies on large-size nematic liquid crystal regions formed in a high-concentration GO dispersion, which align under shear flow, giving the fibers a certain ordered structure. However, this large-crystal structure leads to significant uneven shrinkage during solidification and drying: due to the strong capillary forces between GO sheets and the uneven distribution of internal stress during solvent evaporation, stress concentration easily occurs at the boundaries of the large-crystal regions, causing the fiber cross-section to twist, collapse, or form irregular irregular structures. This structural irregularity introduces stress defects, becoming fracture initiation points under load, severely restricting further improvement of the mechanical properties (such as strength and toughness) of graphene fibers. Therefore, how to effectively control the microstructure of GO liquid crystals and overcome the uneven drying shrinkage caused by large-crystal regions is a key scientific problem and technical challenge in obtaining structurally regular, high-performance graphene fibers. Summary of the Invention

[0003] To address the problem of uneven drying shrinkage caused by large crystalline regions that is difficult to overcome in existing technologies, this invention proposes a high-strength and tough graphene fiber and its preparation method.

[0004] This invention introduces specific types and concentrations of monovalent metal ions (such as K+) into an aqueous dispersion of graphene oxide (GO). + Na + NH4 + By precisely controlling the ionic strength of the system, the electrostatic repulsion and van der Waals attraction between GO sheets are effectively balanced, thereby breaking down and refining the large-sized liquid crystal regions in the traditional spinning solution into uniformly sized microcrystalline regions. These uniformly distributed microcrystalline structures achieve highly uniform and symmetrical shrinkage during subsequent spinning, coagulation, and drying stages, fundamentally suppressing fiber deformation and structural loosening caused by uneven stress distribution. This ultimately yields high-performance graphene fibers with regular cross-sectional morphology (nearly circular) and a dense internal structure. This structure significantly improves the mechanical properties of the fiber, particularly enhancing tensile strength and toughness.

[0005] One of the technical solutions of this invention is to provide a method for preparing high-strength and tough graphene fibers, comprising the following steps:

[0006] (1) The aqueous dispersion of graphene oxide is mixed evenly with an aqueous solution of a monovalent cation salt to obtain an ion-modified graphene oxide spinning solution; the monovalent cation in the aqueous solution of the monovalent cation salt is K.+ Na + or NH4 + One of them; the concentration of monovalent cations in the ion-modified graphene oxide spinning solution is 0.02 mol / L-0.04 mol / L, and the concentration of graphene oxide in the ion-modified graphene oxide spinning solution is 2 mg / ml to 18 mg / ml; unlike polyvalent metal cations, monovalent cations do not cause cross-linking of graphene oxide sheets because they only carry one charge, and the microstructure of the spinning solution is mainly controlled by changing the ionic strength of the system.

[0007] (2) After the ion-modified graphene oxide spinning solution is filtered through a 1000-10000 mesh filter, it is extruded through the spinning head and then put into a coagulation bath for coagulation and molding to obtain graphene oxide nascent fibers. Then it is drawn onto a roll for collection and naturally dried under infrared lamp irradiation to obtain graphene oxide fibers.

[0008] 3) Reduce graphene oxide fibers to obtain high-strength and high-toughness graphene fibers.

[0009] Furthermore, the concentration of the graphene oxide aqueous dispersion described in step 1 is 4-20 mg / ml.

[0010] Furthermore, the concentration of the monovalent cation salt aqueous solution in step 1 is 0.04-0.2 mol / L.

[0011] Furthermore, in step 2, the coagulation bath is a mixed solution of calcium chloride in ethanol and water, wherein the volume ratio of ethanol to water is 1:2 to 8:1, and the concentration of calcium chloride is 4-6 wt.%.

[0012] Furthermore, in step 2, the diameter of the spinning head is 100-200 μm, the coagulation bath temperature is 20-60 ℃, and the infrared lamp heating temperature is 60-80 ℃.

[0013] Furthermore, the reduction described in step 3 is a reduction bath or thermal reduction, wherein the reduction bath is one or more of hydrazine hydrate, hydrogen iodide, and vitamin C.

[0014] The addition of metal salts increases the ionic strength of the system. According to the DLVO theory of colloid science, the stability of a colloidal system is determined by the relative magnitudes of the van der Waals attraction energy and the electric double-layer repulsion energy between particles. The increased ionic strength effectively compresses the electric double layer around the GO sheets, lowering its electrostatic repulsion barrier, thereby disrupting the mechanical equilibrium of the original dispersed system. This causes the original large-area ordered liquid crystal regions to be unable to be maintained, and under the action of shear force, they are reconstructed into small and uniform microcrystalline regions.

[0015] The monovalent cation salt can be selected from one or more of potassium chloride, sodium chloride, ammonium chloride, potassium sulfate, sodium sulfate, ammonium sulfate, and potassium nitrate. As the concentration of the monovalent cation increases, the size of the liquid crystal region continuously decreases to be comparable to the size of a single sheet of graphene oxide.

[0016] As a conventional method for dispersing and removing impurities, the present invention prepares a graphene oxide (GO) dispersion by first dissolving the graphene oxide raw material in a solvent, then ultrasonically dispersing it to prepare a dilute graphene oxide solution, and then centrifuging the dilute graphene oxide solution at high speed to concentrate and remove impurities, thereby obtaining the graphene oxide dispersion.

[0017] As a conventional method for thoroughly mixing composite spinning solutions, this invention involves magnetically stirring at room temperature for a certain period of time at a rate of 100–700 rpm when mixing the graphene oxide dispersion and the monovalent cation salt aqueous solution.

[0018] The second technical solution of the present invention is to provide a high-strength and high-toughness graphene fiber prepared as described above. The diameter of the graphene fiber is 5-30 μm.

[0019] The advantages of this invention are: by employing an "ion-induced liquid crystal refinement" strategy, it solves the problem of uneven drying shrinkage caused by large crystal regions, which leads to irregular GO fiber structures. The prepared fibers have a more regular cross-sectional shape and a highly dense internal structure, effectively reducing stress defects. The fiber tensile strength can reach 800 MPa, and the toughness can reach 20 MJ / m. 3 . Attached Figure Description

[0020] Figure 1 The image shows a polarized light microscope image of the fragmented liquid crystals in the spinning solution of Example 1 and Comparative Example 1.

[0021] Figure 2 The images show cross-sectional views of graphene fibers from Example 1 and Comparative Example 1.

[0022] Figure 3 The graphene fiber mechanical curves for Example 1 and Comparative Example 1 are shown. Detailed Implementation

[0023] The following examples are provided to further illustrate the present invention and are intended to explain the invention, not to limit its scope. Unless otherwise specified, all figures are expressed in parts by weight and weight percentages.

[0024] Unless otherwise specified, the raw materials used in this invention are all conventional commercially available products; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0025] The embodiments of the present invention will be further described below with reference to several examples.

[0026] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0027] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0028] Example 1

[0029] (1) Prepare a 10 mg / ml aqueous dispersion of graphene oxide;

[0030] (2) Prepare a 0.2 mol / L potassium chloride aqueous solution;

[0031] (3) The graphene oxide dispersion obtained in step 1 and the potassium chloride aqueous solution obtained in step 2 were mixed at a volume ratio of 4:1 to obtain an ion-modified spinning solution. The concentration of graphene oxide in the spinning solution was 2 mg / ml, and the concentration of potassium chloride was 0.04 mol / L. The average size of the liquid crystal crystal region in the ion-modified spinning solution was 15 μm;

[0032] (4) The spinning solution obtained in step 3 is filtered through a 5000-mesh filter and then extruded through a 100μm spinning head into a coagulation bath. It is coagulated into a calcium chloride ethanol / water mixed solution at 20℃, with a volume ratio of ethanol to water of 1:2 and a calcium chloride concentration of 4wt.%. The coagulated nascent fibers are drawn onto a roll for collection and then naturally dried at 60℃ under infrared lamp irradiation.

[0033] (5) Reduce the graphene oxide fibers in a reducing atmosphere at 95°C for 10 hours to obtain reduced graphene oxide fibers. The reducing atmosphere is hydrazine hydrate vapor;

[0034] (6) The reduced graphene oxide fibers obtained in step 5 were repeatedly soaked and washed with anhydrous ethanol and deionized water. They were then dried in an oven at 60°C to obtain high-strength and high-toughness graphene fibers.

[0035] (7) The mechanical testing of graphene fibers was conducted on a Keysight nano-stretcher, which is highly accurate and can accurately test the mechanical properties of nanoscale fibers. The stretching rate was 2 mm / min, and the sample gauge length was 5 mm. First, a 5×5 mm paper frame was cut, and then the fiber was fixed to the paper frame with epoxy resin. After the epoxy resin cured, the paper frame was fixed to the fixture of the Keysight nano-stretcher, and the paper was carefully cut with scissors. At this time, the software was started to perform the mechanical test. The cross-sectional area of ​​the fiber was calculated by taking pictures of the morphology of the fiber fracture with a scanning electron microscope and using software.

[0036] (8) A fiber with a diameter of 5 μm, a tensile strength of 807 MPa, an elongation at break of 4.96%, and a toughness of 20.0 MJ / m was obtained. 3 .

[0037] Example 2

[0038] (1) Prepare a 10 mg / ml aqueous dispersion of graphene oxide;

[0039] (2) Prepare a 0.2 mol / L sodium sulfate aqueous solution;

[0040] (3) The graphene oxide dispersion obtained in step (1) and the sodium sulfate aqueous solution obtained in step 2 are mixed at a volume ratio of 4:1 to obtain the ion-modified spinning solution. The concentration of graphene oxide in the spinning solution is 2 mg / ml and the concentration of sodium sulfate is 0.04 mol / L.

[0041] (4) The spinning solution obtained in step 3 is filtered through a 5000-mesh filter and then extruded through a 200μm spinning head into a coagulation bath. It is coagulated into a calcium chloride ethanol / water mixed solution at 40℃, with a volume ratio of ethanol to water of 1:2 and a calcium chloride concentration of 4wt.%. The coagulated nascent fibers are drawn onto a roll for collection and then naturally dried at 80℃ under infrared lamp irradiation.

[0042] (5) Reduce the graphene oxide fibers in a reducing atmosphere at 95°C for 10 hours to obtain reduced graphene oxide fibers. The reducing atmosphere is hydrazine hydrate vapor.

[0043] (6) The reduced graphene oxide fibers obtained in step (5) are repeatedly soaked and washed with anhydrous ethanol and deionized water. They are then dried in an oven at 60°C to obtain high-strength and high-toughness graphene fibers.

[0044] (7) The mechanical testing of graphene fibers was conducted on a Keysight nano-stretcher, which is highly accurate and can accurately test the mechanical properties of nanoscale fibers. The stretching rate was 2 mm / min, and the sample gauge length was 5 mm. First, a 5×5 mm paper frame was cut, and then the fiber was fixed to the paper frame with epoxy resin. After the epoxy resin cured, the paper frame was fixed to the fixture of the Keysight nano-stretcher, and the paper was carefully cut with scissors. At this time, the software was started to perform the mechanical test. The cross-sectional area of ​​the fiber was calculated by taking pictures of the morphology of the fiber fracture with a scanning electron microscope and using software.

[0045] The difference from Example 1 is that the monovalent cationic salt was replaced with sodium sulfate, resulting in fibers with a diameter of 30 μm, a tensile strength of 713 MPa, an elongation at break of 4.52%, and a toughness of 16.1 MJ / m. 3 .

[0046] Example 3

[0047] (1) Prepare an aqueous dispersion of graphene oxide with a concentration of 4 mg / ml;

[0048] (2) Prepare a 0.04 mol / L potassium chloride aqueous solution;

[0049] (3) The graphene oxide dispersion obtained in step (1) and the potassium chloride aqueous solution obtained in step 2 are mixed to obtain the ion-modified spinning solution. The concentration of graphene oxide in the spinning solution is 2 mg / ml, and the concentration of potassium chloride is 0.02 mol / L. The average size of the liquid crystal region in the ion-modified spinning solution is 50 μm;

[0050] (4) The spinning solution obtained in step 3 is filtered through a 5000-mesh filter and then extruded through a 200μm spinning head into a coagulation bath. It is coagulated into a calcium chloride ethanol / water mixed solution at 40℃, with a volume ratio of ethanol to water of 1:2 and a calcium chloride concentration of 4wt.%. The coagulated nascent fibers are drawn onto a roll for collection and then naturally dried at 80℃ under infrared lamp irradiation.

[0051] (5) Reduce the graphene oxide fibers in a reducing atmosphere at 95°C for 10 hours to obtain reduced graphene oxide fibers. The reducing atmosphere is hydrazine hydrate vapor;

[0052] (6) The reduced graphene oxide fibers obtained in step (5) are repeatedly soaked and washed with anhydrous ethanol and deionized water. They are then dried in an oven at 60°C to obtain high-strength and high-toughness graphene fibers.

[0053] (7) The mechanical testing of graphene fibers was conducted on a Keysight nano-stretcher, which is highly accurate and can accurately test the mechanical properties of nanoscale fibers. The stretching rate was 2 mm / min, and the sample gauge length was 5 mm. First, a 5×5 mm paper frame was cut, and then the fiber was fixed to the paper frame with epoxy resin. After the epoxy resin cured, the paper frame was fixed to the fixture of the Keysight nano-stretcher, and the paper was carefully cut with scissors. At this time, the software was started to perform the mechanical test. The cross-sectional area of ​​the fiber was calculated by taking pictures of the morphology of the fiber fracture with a scanning electron microscope and using software.

[0054] The difference from Example 1 is that only the concentration of the monovalent cation salt in the spinning solution was reduced to 0.02 mol / L, and the average size of the liquid crystal crystal region in the ion-modified spinning solution was increased to 50 μm. The resulting fiber had a tensile strength of 684 MPa, an elongation at break of 4.4%, and a toughness of 15.1 MJ / m. 3 .

[0055] Example 4

[0056] (1) Preparation of an aqueous dispersion of graphene oxide;

[0057] (2) Prepare an aqueous solution of potassium chloride;

[0058] (3) The graphene oxide dispersion obtained in step (1) and the potassium chloride aqueous solution obtained in step 2 are mixed to obtain the ion-modified spinning solution. The concentration of graphene oxide in the spinning solution is 18 mg / ml and the concentration of potassium chloride is 0.04 mol / L.

[0059] (4) The spinning solution obtained in step 3 is filtered through a 5000-mesh filter and then extruded through a 200μm spinning head into a coagulation bath. It is coagulated into a calcium chloride ethanol / water mixed solution at 40℃, with a volume ratio of ethanol to water of 1:2 and a calcium chloride concentration of 4wt.%. The coagulated nascent fibers are drawn onto a roll for collection and then naturally dried at 80℃ under infrared lamp irradiation.

[0060] (5) Reduce the graphene oxide fibers in a reducing atmosphere at 95°C for 10 hours to obtain reduced graphene oxide fibers. The reducing atmosphere is hydrazine hydrate vapor;

[0061] (6) The reduced graphene oxide fibers obtained in step (5) are repeatedly soaked and washed with anhydrous ethanol and deionized water. They are then dried in an oven at 60°C to obtain high-strength and high-toughness graphene fibers.

[0062] (7) The mechanical testing of graphene fibers was conducted on a Keysight nano-stretcher, which is highly accurate and can accurately test the mechanical properties of nanoscale fibers. The stretching rate was 2 mm / min, and the sample gauge length was 5 mm. First, a 5×5 mm paper frame was cut, and then the fiber was fixed to the paper frame with epoxy resin. After the epoxy resin cured, the paper frame was fixed to the fixture of the Keysight nano-stretcher, and the paper was carefully cut with scissors. At this time, the software was started to perform the mechanical test. The cross-sectional area of ​​the fiber was calculated by taking pictures of the morphology of the fiber fracture with a scanning electron microscope and using software.

[0063] The difference from Example 1 is that only the concentration of graphene oxide in the spinning solution was increased to 18 mg / ml, resulting in fibers with a tensile strength of 731 MPa, an elongation at break of 4.72%, and a toughness of 17.3 MJ / m. 3 .

[0064] Example 5

[0065] (1) Prepare a 10 mg / ml aqueous dispersion of graphene oxide;

[0066] (2) Prepare a 0.2 mol / L potassium chloride aqueous solution;

[0067] (3) The graphene oxide dispersion obtained in step (1) and the potassium chloride aqueous solution obtained in step 2 are mixed at a volume ratio of 4:1 to obtain the ion-modified spinning solution. The concentration of graphene oxide in the spinning solution is 2 mg / ml and the concentration of potassium chloride is 0.04 mol / L.

[0068] (4) The spinning solution obtained in step 3 is filtered through a 5000-mesh filter and then extruded through a 200μm spinning head into a coagulation bath. It is coagulated into a calcium chloride ethanol / water mixed solution at 60℃, with a volume ratio of ethanol to water of 8:1 and a calcium chloride concentration of 6wt.%. The coagulated nascent fibers are drawn onto a roll for collection and then naturally dried at 80℃ under infrared lamp irradiation.

[0069] (5) Reduce the graphene oxide fibers in a reducing atmosphere at 95°C for 10 hours to obtain reduced graphene oxide fibers. The reducing atmosphere is hydrazine hydrate vapor;

[0070] (6) The reduced graphene oxide fibers obtained in step (5) are repeatedly soaked and washed with anhydrous ethanol and deionized water. They are then dried in an oven at 60°C to obtain high-strength and high-toughness graphene fibers.

[0071] (7) The mechanical testing of graphene fibers was conducted on a Keysight nano-stretcher, which is highly accurate and can accurately test the mechanical properties of nanoscale fibers. The stretching rate was 2 mm / min, and the sample gauge length was 5 mm. First, a 5×5 mm paper frame was cut, and then the fiber was fixed to the paper frame with epoxy resin. After the epoxy resin cured, the paper frame was fixed to the fixture of the Keysight nano-stretcher, and the paper was carefully cut with scissors. At this time, the software was started to perform the mechanical test. The cross-sectional area of ​​the fiber was calculated by taking pictures of the morphology of the fiber fracture with a scanning electron microscope and using software.

[0072] The difference from Example 1 is that the volume ratio of ethanol to water in the coagulation bath was changed to 8:1, and the calcium chloride concentration was changed to 6 wt.%, resulting in a fiber with a tensile strength of 692 MPa, an elongation at break of 4.48%, and a toughness of 16.6 MJ / m. 3 .

[0073] Comparative Example 1

[0074] Graphene oxide was spun directly using an 8 mg / ml aqueous dispersion under the same spinning conditions as in Example 1. The size of the graphene oxide liquid crystal regions was 150-250 μm, resulting in fibers with a tensile strength of 284 MPa, an elongation at break of 2.96%, and a toughness of 4.2 MJ / m. 3 .

[0075] Comparative Example 2

[0076] (1) Preparation of an aqueous dispersion of graphene oxide;

[0077] (2) Prepare an aqueous solution of potassium chloride;

[0078] (3) The graphene oxide dispersion obtained in step (1) and the potassium chloride aqueous solution obtained in step 2 are mixed to obtain the ion-modified spinning solution. The concentration of graphene oxide in the spinning solution is 2 mg / ml and the concentration of potassium chloride is 0.06 mol / L.

[0079] (4) The spinning solution obtained in step 3 is filtered through a 5000-mesh filter and then extruded through a 200μm spinning head into a coagulation bath. It is coagulated into a calcium chloride ethanol / water mixed solution at 40℃, with a volume ratio of ethanol to water of 1:2 and a calcium chloride concentration of 4wt.%. The coagulated nascent fibers are drawn onto a roll for collection and then naturally dried at 80℃ under infrared lamp irradiation.

[0080] At this point, the electrostatic repulsion between the graphene oxide sheets is too weak to maintain the stability of the system, and the graphene oxide in the spinning solution obviously aggregates into many small pieces, which cannot be formed into fibers.

[0081] Comparative Example 3

[0082] (1) Preparation of an aqueous dispersion of graphene oxide;

[0083] (2) Prepare an aqueous solution of potassium chloride;

[0084] (3) The graphene oxide dispersion obtained in step 1 and the potassium chloride aqueous solution obtained in step 2 are mixed to obtain the ion-modified spinning solution. The concentration of graphene oxide in the spinning solution is 2 mg / ml and the concentration of potassium chloride is 0.005 mol / L.

[0085] (4) The spinning solution obtained in step 3 is filtered through a 5000-mesh filter and then extruded through a 200μm spinning head into a coagulation bath. It is coagulated into a calcium chloride ethanol / water mixed solution at 40℃, with a volume ratio of ethanol to water of 1:2 and a calcium chloride concentration of 4wt.%. The coagulated nascent fibers are drawn onto a roll for collection and then naturally dried at 80℃ under infrared lamp irradiation.

[0086] (5) Reduce the graphene oxide fibers in a reducing atmosphere at 95°C for 10 hours to obtain reduced graphene oxide fibers. The reducing atmosphere is hydrazine hydrate vapor;

[0087] (6) The reduced graphene oxide fibers obtained in step (5) are repeatedly soaked and washed with anhydrous ethanol and deionized water. They are then dried in an oven at 60°C to obtain graphene fibers.

[0088] (7) The mechanical testing of graphene fibers was conducted on a Keysight nano-stretcher, which is highly accurate and can accurately test the mechanical properties of nanoscale fibers. The stretching rate was 2 mm / min, and the sample gauge length was 5 mm. First, a 5×5 mm paper frame was cut, and then the fiber was fixed to the paper frame with epoxy resin. After the epoxy resin cured, the paper frame was fixed to the fixture of the Keysight nano-stretcher, and the paper was carefully cut with scissors. At this time, the software was started to perform the mechanical test. The cross-sectional area of ​​the fiber was calculated by taking pictures of the morphology of the fiber fracture with a scanning electron microscope and using software.

[0089] At this point, the electrostatic repulsion between the graphene oxide sheets was still relatively strong, and the liquid crystal in the graphene oxide showed no significant change. Consequently, the mechanical properties of the resulting fiber remained largely unchanged, with a tensile strength of 304 MPa, an elongation at break of 3.04%, and a toughness of 6.1 MJ / m. 3 .

[0090] The above embodiments detail the structure, features, and effects of the present invention. The above descriptions are merely preferred embodiments of the present invention. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent variations, shall still fall within the scope of protection of the present invention if they do not exceed the scope covered by the specification.

Claims

1. A method of producing a high tenacity graphene fiber, characterized by, The method comprises the following steps: (1) uniformly mixing the graphene oxide aqueous dispersion solution with a monovalent cation salt aqueous solution to obtain ion-modified graphene oxide spinning solution; the monovalent cation in the monovalent cation salt aqueous solution is one of K + , Na + or NH4 + ; the concentration of monovalent cations in the ion-modified graphene oxide spinning solution is 0.02 mol / L-0.04 mol / L, and the concentration of graphene oxide in the ion-modified graphene oxide spinning solution is 2 mg / ml to 18 mg / ml; (2) The ion-modified graphene oxide spinning solution is filtered through a 1000-10000 mesh filter screen, then extruded through a spinning head, and enters a coagulation bath for coagulation molding to obtain graphene oxide nascent fibers, which are then drawn to a reel for collection, and naturally dried under infrared lamp irradiation to obtain graphene oxide fibers; (3) The graphene oxide fibers are reduced to obtain high-strength graphene fibers.

2. The method of claim 1, wherein, The concentration of the graphene oxide aqueous dispersion in step (1) is 4-20 mg / ml.

3. The method of claim 1, wherein, The concentration of the monovalent cation salt aqueous solution in step (1) is 0.04-0.2 mol / L.

4. The method of claim 1, wherein, The coagulation bath in step (2) is a mixed solution of calcium chloride in ethanol and water, wherein the volume ratio of ethanol to water is 1:2 to 8:1, and the concentration of calcium chloride is 4-6 wt.%.

5. The method of claim 1, wherein, The spinning head in step (2) has a diameter of 100-200 μm, the coagulation bath has a temperature of 20-60 ℃, and the infrared lamp heating temperature is 60-80 ℃.

6. The method of claim 1, wherein, The reduction method in step (3) is reduction bath or thermal reduction, and the reduction bath is one or more of hydrazine hydrate, hydrogen iodide, and vitamin C.

7. A high-strength graphene fiber prepared by the method of claim 1.

8. The high tenacity graphene fiber of claim 7, wherein, The diameter of the graphene fiber is 5-30 μm.

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