Graphene exfoliating device and graphene exfoliating method using the same

Abstract

The present invention relates to a graphene exfoliation device comprising: a rotating disk; a fixed disk spaced apart and disposed on the rotating disk; an injection part connected to a reaction space between the rotating disk and the fixed disk, into which a reaction liquid containing graphite flakes is injected; and an discharge part into which a product liquid containing exfoliated graphene is discharged.

Description

Technology Field

[0001] The present invention relates to a graphene exfoliation apparatus and a graphene exfoliation method using the same. Background Technology

[0002] Graphene is a polymeric carbon allotrope in which carbon atoms are connected to each other in a hexagonal honeycomb shape to form a two-dimensional planar structure. It is a carbon material that is expected to be applied in various fields such as semiconductors and displays, as it has the advantage of exhibiting excellent electrical conductivity, thermal conductivity, and mechanical strength compared to existing carbon materials.

[0003] Generally, graphene is manufactured through oxidation / reduction methods, ultrasonic methods, chemical vapor deposition (CVD), etc.

[0004] The method for manufacturing graphene using the oxidation / reduction method involves oxidizing graphite to form graphite oxide, exfoliating it to obtain graphene oxide, and then manufacturing graphene through reduction. While this method has the advantages of enabling the mass production of graphene using low-cost graphite as a raw material and allowing for solution processing using a graphene dispersion, there is a problem in that the graphene produced has poor performance due to the presence of numerous chemical and structural defects caused by the destruction of carbon crystals during the oxidation process of graphite.

[0005] Meanwhile, the ultrasonic graphene manufacturing method produces graphene by directly exfoliating graphite in a solvent to which ultrasound is applied. Since this method does not involve oxidation / reduction processes, it has the advantage of producing graphene with fewer defects and securing excellent electrical properties; however, it has the disadvantage of a low graphene production rate due to the limited exfoliation efficiency of graphite. In addition, this method has the limitation that it is difficult to continuously mass-produce graphene due to the technical limitations of the ultrasonic equipment.

[0006] In addition, methods for synthesizing graphene at high temperatures using chemical vapor deposition (CVD) have the advantage of being able to form graphene directly on a substrate, but they have the disadvantage of incurring high costs for graphene manufacturing due to the high-temperature process.

[0007] Therefore, there is a need for research on methods to manufacture high-quality graphene relatively easily.

[0008] Korean Registered Patent No. 10-2048631, which is the technology forming the background of this application, relates to a method for exfoliating a large amount of graphene. The problem to be solved

[0009] The present invention aims to solve the problems of the aforementioned conventional technology by providing a graphene exfoliation device.

[0010] In addition, the purpose is to provide a method for exfoliating graphene using the above-described graphene exfoliation device.

[0011] However, the technical problems that the embodiments of the present invention aim to solve are not limited to the technical problems described above, and other technical problems may exist. means of solving the problem

[0012] As a technical means for achieving the above-mentioned technical problem, the first aspect of the present invention provides a graphene exfoliation device comprising: a rotating disk; a fixed disk spaced apart and disposed on the rotating disk; an injection part connected to a reaction space between the rotating disk and the fixed disk, into which a reaction liquid containing graphite flakes is injected; and an discharge part into which a product liquid containing exfoliated graphene is discharged.

[0013] According to one embodiment of the present invention, a shear force may be applied to the graphite flakes by the rotation of the rotating disk to exfoliate them into graphene, but is not limited thereto.

[0014] According to one embodiment of the present invention, the interfacial energy of the reaction solution may be controlled by controlling the type of solvent of the reaction solution, but is not limited thereto.

[0015] According to one embodiment of the present invention, the number of exfoliated graphene layers may be controlled by controlling the interfacial energy of the reaction solution, but is not limited thereto.

[0016] According to one embodiment of the present invention, the solvent may comprise, but is not limited to, a solvent selected from the group consisting of deionized water, NMP (N-Methyl-2-pyrrolidone), DMF (Dimethylformamide), DMSO (Dimethyl sulfoxide), ionic liquids, and combinations thereof.

[0017] Additionally, the second aspect of the present invention provides a graphene exfoliation method comprising: a first step of injecting a reaction solution containing graphite flakes into a graphene exfoliation device according to the first aspect of the present invention; a second step of obtaining a product solution containing exfoliated graphene by rotating a rotating disk; and a third step of reinjecting the product solution into the graphene exfoliation device, wherein the process cycle comprising the second and third steps is repeated several times to tens of times.

[0018] According to one embodiment of the present invention, the number of exfoliated graphene layers may decrease as the number of repetitions of the process cycle increases, but is not limited thereto.

[0019] According to one embodiment of the present invention, a shear force may be applied to the graphite flakes by the rotation of the rotating disk to exfoliate them into graphene, but is not limited thereto.

[0020] According to one embodiment of the present invention, the interfacial energy of the reaction solution may be controlled by controlling the type of solvent of the reaction solution, but is not limited thereto.

[0021] According to one embodiment of the present invention, the number of exfoliated graphene layers may be controlled by controlling the interfacial energy of the reaction solution, but is not limited thereto.

[0022] According to one embodiment of the present invention, the solvent may comprise, but is not limited to, a solvent selected from the group consisting of deionized water, NMP (N-Methyl-2-pyrrolidone), DMF (Dimethylformamide), DMSO (Dimethyl sulfoxide), ionic liquids, and combinations thereof.

[0023] In addition, the third aspect of the present invention provides graphene produced by the graphene exfoliation method according to the second aspect of the present invention.

[0024] According to one embodiment of the present invention, the graphene may be a single layer or a multilayer, but is not limited thereto.

[0025] The means for solving the problem described above are merely exemplary and should not be interpreted as intended to limit the present invention. In addition to the exemplary embodiments described above, additional embodiments may exist in the drawings and the detailed description of the invention. Effects of the invention

[0026] The graphene exfoliation apparatus and graphene exfoliation method according to the present invention can exfoliate graphene in a liquid phase by passing a graphite flake reaction solution between a rotating disk and a fixed disk to induce the generation of a drag force at the interface of the reaction solution, thereby inducing the generation of a shear force in the reaction solution.

[0027] In addition, the interfacial energy of the reaction solution can be controlled by adjusting the type of solvent used in the reaction solution coated on the surface of the disk, and thereby the number of exfoliated graphene layers can be controlled, allowing graphene to be manufactured to have a desired number of layers.

[0028] In addition, by controlling the number of repetitions of the process cycle, the number of graphene layers can be controlled, allowing graphene to be manufactured with a desired number of layers.

[0029] However, the effects obtainable from this invention are not limited to those described above, and other effects may exist. Brief explanation of the drawing

[0030] FIG. 1 is a schematic diagram of a graphene exfoliation apparatus according to one embodiment of the present invention. Figure 2 is an actual image of a graphene exfoliation device according to the present invention. Figure 3 is a Raman spectrum of graphene according to Examples 1 to 8 of the present invention. Figure 4 is an SEM image of graphene according to Example 1 of the present invention. Figure 5 is an SEM image of graphene according to Example 2 of the present invention. Figure 6 is an SEM image of graphene according to Example 3 of the present invention. Figure 7 is an SEM image of graphene according to Example 4 of the present invention. Figure 8 is an SEM image of graphene according to Example 5 of the present invention. FIG. 9 is an SEM image of graphene according to Examples 6 to 8 of the present invention. Specific details for implementing the invention

[0031] Embodiments of the present invention are described below with reference to the attached drawings to enable those skilled in the art to easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0032] Throughout this specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "electrically connected" with other elements interposed between them.

[0033] Throughout the entire specification, when a component is described as being located "on," "on top," "on top," "under," "on bottom," or "on bottom" of another component, this includes not only cases where the component is in contact with the other component but also cases where another component exists between the two components.

[0034] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0035] As used herein, terms of degree such as “about,” “substantially,” etc., are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the stated meaning, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which precise or absolute values ​​are mentioned to aid in understanding the invention. Furthermore, throughout this specification, “a step of” or “a step of” does not mean “a step for”.

[0036] Throughout this specification, the term “combination thereof” included in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including one or more selected from the group consisting of said components.

[0037] Throughout the entire specification, the description "A and / or B" means "A, B, or A and B".

[0038] Hereinafter, the graphene exfoliation apparatus and graphene exfoliation method of the present invention will be described in detail with reference to the embodiments, examples, and drawings. However, the present invention is not limited to these embodiments, examples, and drawings.

[0040] As a technical means for achieving the above-mentioned technical problem, the first aspect of the present invention provides a graphene exfoliation device comprising: a rotating disk; a fixed disk spaced apart and disposed on the rotating disk; an injection part connected to a reaction space between the rotating disk and the fixed disk, into which a reaction liquid containing graphite flakes is injected; and an discharge part into which a product liquid containing exfoliated graphene is discharged.

[0041] The graphene exfoliation device according to the present invention can exfoliate graphene in a liquid phase by passing a graphite flake reaction solution between a rotating disk and a fixed disk, thereby inducing a drag force at the interface of the reaction solution and inducing a shear force in the reaction solution.

[0042] In addition, the interfacial energy of the reaction solution can be controlled by adjusting the type of solvent used in the reaction solution coated on the surface of the disk, and thereby the number of exfoliated graphene layers can be controlled, allowing graphene to be manufactured to have a desired number of layers.

[0043] In addition, by controlling the number of repetitions of the process cycle, the number of graphene layers can be controlled, allowing graphene to be manufactured with a desired number of layers.

[0044] FIG. 1 is a schematic diagram of a graphene exfoliation apparatus according to one embodiment of the present invention. In this regard, FIG. 1 is illustrated as having a fixed disk positioned at the top and a rotating disk positioned at the bottom, but this is merely an exemplary description and the fixed disk may be positioned at the bottom and the rotating disk at the top.

[0045] According to one embodiment of the present invention, a shear force may be applied to the graphite flakes by the rotation of the rotating disk to exfoliate them into graphene, but is not limited thereto.

[0046] As the rotating disk rotates, a drag force is generated at the interface of the reaction solution for the graphite flakes injected between the rotating disk and the stationary disk. This causes a shear force to be applied to the reaction solution, thereby allowing graphene to be exfoliated in the liquid phase. At this time, the fluid flow can be controlled by adjusting the shape of the disk (see the enlarged section of Fig. 1), and the yield of graphene can be controlled by adjusting the shear force accordingly. Specifically, the degree of crack initiation (start of graphene exfoliation) varies depending on the magnitude of the shear force; if the shear force is strong, crack initiation occurs frequently, which can increase the yield, while if the shear force is weak, crack initiation decreases, which can decrease the yield.

[0047] Meanwhile, the fixed disk and the rotating disk may be spaced apart by a distance of 3 mm or less, and as the distance increases, the shear force decreases and the graphene exfoliation yield decreases accordingly, but is not limited thereto.

[0048] In addition, it may be preferable for the diameter of the disk to be 10 mm or more and 100 mm or less. Specifically, if the diameter of the disk exceeds 100 mm, a difference in shear force depending on the location may occur, which may result in uneven peeling, and if it is less than 10 mm, the minimum shear force is insufficient, which may lead to fewer initial cracks and a lower graphene peeling yield.

[0049] According to one embodiment of the present invention, the interfacial energy of the reaction solution may be controlled by controlling the type of solvent of the reaction solution, but is not limited thereto.

[0050] The graphene exfoliation device according to the present invention can control the interfacial energy of the reaction solution by controlling the type of solvent used in the reaction solution coated on the surface of the disk, and thereby control the number of exfoliated graphene layers, so that graphene can be manufactured to have a desired number of layers.

[0051] According to one embodiment of the present invention, the number of exfoliated graphene layers may be controlled by controlling the interfacial energy of the reaction solution, but is not limited thereto.

[0052] If the interfacial energy of the graphite flake reaction solution increases, multilayer graphene may be exfoliated, and if the interfacial energy decreases, single-layer graphene may be exfoliated. Therefore, multilayer graphene can be manufactured by using a solvent that can increase the interfacial energy of the reaction solution, and single-layer graphene can be manufactured by using a solvent that can decrease the interfacial energy of the reaction solution.

[0053] According to one embodiment of the present invention, the solvent may comprise, but is not limited to, a solvent selected from the group consisting of deionized water, NMP (N-Methyl-2-pyrrolidone), DMF (Dimethylformamide), DMSO (Dimethyl sulfoxide), ionic liquids, and combinations thereof.

[0055] Additionally, the second aspect of the present invention provides a graphene exfoliation method comprising: a first step of injecting a reaction solution containing graphite flakes into a graphene exfoliation device according to the first aspect of the present invention; a second step of obtaining a product solution containing exfoliated graphene by rotating a rotating disk; and a third step of reinjecting the product solution into the graphene exfoliation device, wherein the process cycle comprising the second and third steps is repeated several times to tens of times.

[0056] Regarding the graphene exfoliation method according to the second aspect of the present invention, detailed descriptions of parts that overlap with the first aspect of the present invention have been omitted, but even if such descriptions are omitted, the contents described in the first aspect of the present invention can be applied equally to the second aspect of the present invention.

[0057] First, a reaction solution containing graphite flakes is injected into a graphene exfoliation device. (Step 1)

[0058] According to one embodiment of the present invention, the interfacial energy of the reaction solution may be controlled by controlling the type of solvent of the reaction solution, but is not limited thereto.

[0059] According to one embodiment of the present invention, the number of exfoliated graphene layers may be controlled by controlling the interfacial energy of the reaction solution, but is not limited thereto.

[0060] According to one embodiment of the present invention, the solvent may comprise, but is not limited to, a solvent selected from the group consisting of deionized water, NMP (N-Methyl-2-pyrrolidone), DMF (Dimethylformamide), DMSO (Dimethyl sulfoxide), ionic liquids, and combinations thereof.

[0061] Next, the rotating disk is rotated to obtain a product solution containing exfoliated graphene. (Step 2)

[0062] It may be preferable for the rotational speed of the above-mentioned rotating disk to be between 500 rpm and 5000 rpm. Specifically, since a rotational speed that is too fast can increase the shear force and prevent uniform peeling, it may be preferable for the rotational speed of the disk to have the above range.

[0063] According to one embodiment of the present invention, a shear force may be applied to the graphite flakes by the rotation of the rotating disk to exfoliate them into graphene, but is not limited thereto.

[0064] Next, the generated solution is reinjected into the graphene exfoliation device. (Step 3)

[0065] According to one embodiment of the present invention, the number of exfoliated graphene layers may decrease as the number of repetitions of the process cycle increases, but is not limited thereto.

[0066] In addition to the type of coating material mentioned above, factors that may affect the number of graphene layers exfoliated include the number of process cycle repetitions, and as the number of process cycle repetitions increases, the number of graphene layers exfoliated can be reduced. For example, if the process cycle is performed more than 30 times, a single layer of graphene can be obtained, but this is not limited thereto, and the number of process cycle repetitions required to obtain a single layer of graphene may vary depending on the type of coating material.

[0067] The above-mentioned solution may contain a mixture of graphene exfoliated from graphite flakes and unexfoliated graphite flakes, and the graphite flakes may be completely exfoliated into graphene by repeating the process cycle.

[0069] In addition, the third aspect of the present invention provides graphene produced by the graphene exfoliation method according to the second aspect of the present invention.

[0070] Regarding the graphene according to the third aspect of the present invention, detailed descriptions of parts that overlap with the first and / or second aspects of the present invention have been omitted, but even if such descriptions have been omitted, the contents described in the first and / or second aspects of the present invention may be applied equally to the third aspect of the present invention.

[0071] According to one embodiment of the present invention, the graphene may be a single layer or a multilayer, but is not limited thereto.

[0072] The present invention is to be explained in more detail through the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0074] [Example 1] Grephene 0

[0075] Figure 2 is an actual image of a graphene exfoliation device according to the present invention.

[0076] First, a graphite flake reaction solution was prepared by dispersing graphite flakes in deionized water.

[0077] Next, after injecting the reaction solution through the injection port of the graphene exfoliation device, the rotation speed was set to 5000 rpm and the reaction was carried out for 2 to 3 minutes based on 20 ml of solvent.

[0078] Next, the product (exfoliated graphene in the form of a dispersion) was collected in a bottle on the output line.

[0079] [Example 2] Grephene 1

[0080] It was prepared in the same manner as in Example 1, but the product (exfoliated graphene in the form of a dispersion) was reinjected into a graphene exfoliation device and the exfoliation process was repeated once.

[0081] [Example 3] Grephene 2

[0082] The product was prepared in the same manner as in Example 1, but the product (exfoliated graphene in the form of a dispersion) was reinjected into a graphene exfoliation device and the exfoliation process was repeated twice.

[0083] [Example 4] Grephene 3

[0084] The product was prepared in the same manner as in Example 1, but the product (exfoliated graphene in the form of a dispersion) was reinjected into a graphene exfoliation device and the exfoliation process was repeated three times.

[0085] [Example 5] Grephene 4

[0086] The product was prepared in the same manner as in Example 1, but the product (exfoliated graphene in the form of a dispersion) was reinjected into a graphene exfoliation device and the exfoliation process was repeated four times.

[0087] [Example 6] Grephene 12

[0088] The product was prepared in the same manner as in Example 1, but the product (exfoliated graphene in the form of a dispersion) was reinjected into a graphene exfoliation device and the exfoliation process was repeated 12 times.

[0089] [Example 7] Grephene 15

[0090] The product was prepared in the same manner as in Example 1, but the product (exfoliated graphene in the form of a dispersion) was reinjected into a graphene exfoliation device and the exfoliation process was repeated 15 times.

[0091] [Example 8] Grephene 18

[0092] The product was prepared in the same manner as in Example 1, but the product (exfoliated graphene in the form of a dispersion) was reinjected into a graphene exfoliation device and the exfoliation process was repeated 18 times.

[0094] [Experimental Example 1] Comparison of Graphene Properties

[0095] Experiments were performed to analyze the characteristics of graphene prepared according to Examples 1 to 8. Specifically, the Raman spectra and SEM images of the graphene prepared according to Examples 1 to 8 were analyzed.

[0096] Figure 3 is a Raman spectrum of graphene according to Examples 1 to 8 of the present invention.

[0097] Referring to FIG. 3, the characteristic peak of graphene (D band 1350 cm⁻¹) in the graphene of Examples 1 to 8 of the present invention -1 , G band 1580 cm -1 , 2D band 2700 cm -1 It was confirmed that the peak intensity ratio (2D / G) represents the number of layers of the graphene samples, and the 2D / G ratio of the graphene of Examples 1 to 5 (Graphene 0 to 4) was 0.5 or less, indicating multilayer graphene, and the 2D / G ratio of the graphene of Examples 6 to 8 (Graphene 12, 15 and 18) was about 0.8, indicating a reduced number of layers compared to the graphene of Examples 1 to 5.

[0098] FIGS. 4 to 9 are SEM images of graphene according to Examples 1 to 8 of the present invention.

[0099] Referring to FIGS. 4 through 9, flake forms were observed in all embodiments, but it was confirmed that the graphene flake thickness decreased as the number of exfoliations increased. Specifically, referring to FIG. 4 (Graphene 0) and FIG. 9 (Graphene 12, 15, and 18), it was confirmed that Graphene 0 had a much thicker flake thickness, whereas Graphene samples 12, 15, and 18 were distinctly thinner.

[0101] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical concept or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0102] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 delete Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A graphene exfoliation method using a graphene exfoliation device comprising: a rotating disk; a fixed disk spaced apart and disposed on the rotating disk; an injection part connected to a reaction space between the rotating disk and the fixed disk, into which a reaction liquid containing graphite flakes is injected; and a discharge part into which a product liquid containing exfoliated graphene is discharged; wherein the method comprises: a first step of injecting a reaction liquid containing graphite flakes into the graphene exfoliation device; a second step of obtaining a product liquid containing exfoliated graphene by rotating the rotating disk; and a third step of reinjecting the product liquid into the graphene exfoliation device; wherein the process cycle including the second and third steps is repeated several times to tens of times; wherein a shear force is applied to the graphite flakes by the rotation of the rotating disk to exfoliate them into graphene; wherein the interfacial energy of the reaction liquid is controlled by adjusting the type of solvent of the reaction liquid; and wherein the number of exfoliated graphene layers is controlled by controlling the interfacial energy of the reaction liquid. Claim 7 A graphene exfoliation method according to claim 6, wherein the number of exfoliated graphene layers decreases as the number of repetitions of the process cycle increases. Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 A graphene exfoliation method according to claim 6, wherein the solvent comprises a solvent selected from the group consisting of deionized water, NMP (N-Methyl-2-pyrrolidone), DMF (Dimethylformamide), DMSO (Dimethyl sulfoxide), ionic liquids, and combinations thereof. Claim 12 Graphene produced by the graphene exfoliation method according to claim 6. Claim 13 In claim 12, the graphene is a single layer or a multilayer graphene.

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