Method for producing graphene

Abstract

The present invention relates to a method for producing graphene by an electrochemical non-oxidative exfoliation method. The method for producing graphene is performed by using an electrolyte solution comprising: a first electrolyte including sodium chloride (NaCl); and a second electrolyte including a chlorate compound, a quaternary ammonium salt compound, or a combination thereof, and is excellent in terms of yield, carbon / oxygen content ratio, defectivity, and degree of graphitization.

Description

Method for manufacturing graphene

[0001] The present invention relates to a method for producing graphene that is environmentally friendly, has a high yield, and is excellent in terms of carbon / oxygen content ratio, defect degree, and graphitization degree by controlling the electrolyte components in the electrolyte, and to graphene produced thereby.

[0002]

[0003] Graphene is one of the new materials currently in the spotlight. Graphene is a carbon allotrope in which carbon atoms are connected to each other in a hexagonal honeycomb pattern, forming a two-dimensional planar structure. While a single layer of graphene has a planar structure, the graphene actually used exists in the form of many layers stacked one on top of the other.

[0004] graphene's sp 2 Hybrid orbitals are the sp of three neighboring atoms 2 The p orbitals remaining after forming sigma bonds with the orbitals form pi bonds with the p orbitals of neighboring atoms. Since pi bonds are possible in three directions, the pi bonds form a resonance structure; in this case, the pi bonds become delocalized and spread across multiple carbon atoms. Consequently, the p orbitals are spread throughout the graphene, allowing graphene to conduct electricity like graphite even though it is not a metal.

[0005] Methods for manufacturing such graphene include mechanical exfoliation, chemical exfoliation, exfoliation-reinsertion-expansion, chemical vapor deposition (CVD), and electrochemical exfoliation.

[0006] Among these, Korean Registered Patent Publication No. 10-1633503 discloses a "method for manufacturing graphene using a quaternary ammonium salt," which relates to a method for manufacturing graphene in a liquid phase process at a relatively low temperature through a reduction process of graphene oxide using a quaternary ammonium salt.

[0007] However, the method of oxidizing graphite to produce graphite oxide, exfoliating it under a solvent, mixing it with a reducing agent, and heating it to reduce it to graphene has limitations in that carbon bonds are irregularly broken or it is difficult to completely reduce the oxidized graphene because the graphite is treated with a strong acid and the chemical reaction is carried out under high temperature and high pressure conditions.

[0008] Accordingly, the method of manufacturing graphene by electrochemical exfoliation is gaining attention. The electrochemical exfoliation method involves immersing a graphite electrode and a metal electrode in an electrolyte and then applying a voltage to exfoliate them. It has the advantages of a relatively short exfoliation time, a simple process, and a large surface area and few defects in the obtained graphene.

[0009] In order to obtain eco-friendly graphene with a higher yield and superior carbon / oxygen content ratio, defects, and graphitization, various approaches are being taken regarding the composition of the electrolyte, but no method has yet been found that makes a significant difference.

[0010] [Prior Art Literature]

[0011] [Patent Literature]

[0012] (Patent Document 1) Korean Registered Patent Publication No. 10-1633503

[0013]

[0014] To solve the above-mentioned problems, the present invention aims to provide a method for producing graphene that is environmentally friendly, has a high yield, and is excellent in terms of carbon / oxygen content ratio, defect degree, and graphitization degree, by applying a voltage to a working electrode and a counter electrode disposed in an electrolyte, wherein the electrolyte comprises a first electrolyte containing sodium chloride (NaCl); and a second electrolyte containing a chlorate compound, a quaternary ammonium salt compound, or a combination thereof.

[0015] Furthermore, the purpose is also to provide a method for manufacturing graphene that enables simultaneous production of graphene at high yield by using graphite electrodes (graphite electrodes) for both the working electrode and the counter electrode while applying an alternating voltage (alternating current), thereby making it possible to produce graphene at both electrodes at the same time.

[0016]

[0017] According to one embodiment of the present invention, a method for producing graphene by an electrochemical non-oxidative exfoliation method is provided, wherein the electrochemical non-oxidative exfoliation method is performed by applying a voltage to a working electrode and a counter electrode disposed in an electrolyte, and the electrolyte comprises a solvent and an electrolyte, wherein the electrolyte comprises a first electrolyte comprising sodium chloride (NaCl); and a second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof.

[0018] In addition, according to one embodiment of the present invention, graphene is provided that is excellent in terms of carbon / oxygen content ratio, defect degree, and degree of graphitization obtained by the above manufacturing method.

[0019]

[0020] According to the manufacturing method of the present invention, graphene with a high yield and excellent carbon / oxygen content ratio, defects, and graphitization can be produced.

[0021]

[0022] FIG. 1 is an exemplary diagram showing that graphene is obtained by applying a DC voltage, wherein the working electrode is a metal electrode and the counter electrode is a graphite electrode, according to one embodiment of the present invention.

[0023] FIG. 2 is an exemplary diagram showing that graphene is obtained by applying an alternating voltage, wherein both the working electrode and the counter electrode are graphite electrodes according to one embodiment of the present invention.

[0024] Figure 3 is an XPS spectrum graph for graphene of Examples 1-1 to 1-3 and Comparative Examples 1-1 and 1-2.

[0025] Figure 4 is an XPS spectrum graph for graphene of Examples 1-4 to 1-9.

[0026] Figure 5 is a Raman spectrum graph for graphene of Examples 1-1 to 1-3 and Comparative Examples 1-1 and 1-2.

[0027] Figure 6 is a Raman spectrum graph for the graphene of Examples 1-4 to 1-9.

[0028]

[0029] In the following description of the present invention, if it is determined that a detailed description of related known configurations or functions may obscure the essence of the embodiments, such detailed description is omitted.

[0030] In this specification, terms referring to each component are used to distinguish them from other components and are not intended to limit the embodiments. Additionally, in this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0031] In this specification, the use of the term "comprising" is intended to specify characteristics, regions, steps, processes, elements, and components, and unless specifically stated otherwise, it does not exclude the existence or addition of other characteristics, regions, steps, processes, elements, or components.

[0032] In numerical ranges defining the size, physical properties, etc., of components described in this specification, if a numerical range in which only the upper limit is defined and a numerical range in which only the lower limit is defined are separately exemplified, it should be understood that a numerical range combining these upper and lower limits is also included in the exemplary range.

[0033]

[0034] Method for manufacturing graphene

[0035] A method for manufacturing graphene according to an embodiment of the present invention is a method for manufacturing graphene by an electrochemical non-oxidative exfoliation method, wherein the electrochemical non-oxidative exfoliation method is performed by applying a voltage to a working electrode and a counter electrode disposed in an electrolyte, and the electrolyte comprises a solvent and an electrolyte, wherein the electrolyte comprises a first electrolyte comprising sodium chloride (NaCl); and a second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof.

[0036] The term "graphene" as used in the present invention refers to isolated graphene and may include single-layer graphene, or multilayer or multilayer graphene having an intermediate layer of 2 to 10 hexagonal carbon atoms or graphene planes. More preferably, it may include multilayer or multilayer graphene with 5 layers or fewer, or 3 layers or fewer.

[0037]

[0038] The method for producing graphene by the electrochemical non-oxidative exfoliation method according to the present invention can be carried out in a reaction chamber having a predetermined volume capable of accommodating an electrolyte, in which a working electrode and a counter electrode are disposed inside.

[0039] The working electrode and the counter electrode disposed inside the reaction chamber may each be spaced apart by a predetermined interval, and one or more working electrodes and one or more counter electrodes may be used. When multiple working electrodes and multiple counter electrodes are used, the working electrodes and the counter electrodes may be spaced apart from each other by a predetermined interval and arranged in an alternating manner, or multiple working electrodes may be spaced apart from the counter electrodes by a predetermined interval. Furthermore, the electrochemical non-oxidative exfoliation method according to the present invention can be applied regardless of the specific arrangement structure of the working electrodes and the counter electrodes, provided that the multiple working electrodes and the multiple counter electrodes are electrochemically connected.

[0040] The working electrode used in the method for manufacturing graphene according to the present invention may be a graphite electrode, and specifically, the graphite used as the working electrode may include one or more selected from the group consisting of artificial graphite, natural graphite, graphitized carbon fiber, graphitized mesocarbon microbeads, hard carbon, soft carbon, petroleum coke, resin calcined body, carbon fiber, and pyrolytic carbon.

[0041] The counter electrode used in the method for manufacturing graphene according to the present invention may be a metal electrode or a graphite electrode. The metal electrode that can be used as the counter electrode may include a stainless steel electrode or a nickel electrode, and other metal electrodes may also be used. The graphite used as the counter electrode likewise may include one or more selected from the group consisting of artificial graphite, natural graphite, graphitized carbon fiber, graphitized mesocarbon microbeads, hard carbon, soft carbon, petroleum coke, resin calcined body, carbon fiber, and pyrolytic carbon.

[0042] According to one embodiment of the present invention, when a metal electrode is used as the counter electrode, the applied voltage may be a direct current (DC) voltage, and graphene may be generated at the working electrode. According to another embodiment of the present invention, both the counter electrode and the working electrode may be graphite electrodes. In this case, electrochemical exfoliation of graphene may occur simultaneously at the counter electrode as well as at the working electrode, thereby significantly improving the yield of the final graphene obtained. In this case, the applied voltage may be an alternating current (AC) voltage, and it is preferable that the voltage be an alternating current voltage so that graphene is generated at a similar exfoliation rate at both electrodes. In summary, the method for manufacturing graphene according to the present invention, in which both the working electrode and the counter electrode are graphite electrodes and the applied voltage is an alternating current voltage, allows for the simultaneous acquisition of graphene at both the working electrode and the counter electrode, thereby further improving the yield of graphene.

[0043] Referring to FIG. 1, a method for manufacturing graphene according to one embodiment of the present invention can be performed by applying a DC voltage to a counter electrode, such as a stainless steel electrode or a nickel electrode, and a working electrode, such as a graphite electrode. In this case, exfoliation of graphene is performed at the working electrode, and high-quality graphene can be obtained.

[0044] Referring to FIG. 2, a method for manufacturing graphene according to another embodiment of the present invention can be performed by using graphite electrodes for both the working electrode and the counter electrode and applying an alternating voltage. In this case, as the anode and cathode are periodically switched, exfoliation of graphene can be performed on both graphite electrodes, and graphene can be obtained with a relatively higher yield.

[0045] The shapes of the counter electrode and the working electrode may vary depending on the shape of the reaction chamber, reaction conditions, etc. Specifically, the counter electrode and the working electrode may each independently take the form of a sheet, foil, plate, or rod, but are not limited thereto. However, since a larger surface area of ​​the graphite electrode in contact with the electrolyte is advantageous in terms of graphene production, a sheet, foil, or plate shape with a large surface area per unit volume is preferred.

[0046]

[0047] electrolyte

[0048] The electrolyte used in the electrochemical non-oxidative exfoliation method according to the present invention comprises a solvent and an electrolyte.

[0049] Meanwhile, the molar concentration of the electrolyte contained in the above electrolyte may be 0.05 M to 1.0 M, and specifically, 0.05 M to 1.0 M, 0.05 M to 0.9 M, 0.1 M to 0.8 M, 0.3 M to 0.8 M, 0.3 M to 0.7 M, 0.3 M to 0.6 M, 0.3 M to 0.5 M, 0.3 M to 0.4 M, 0.4 M to 0.8 M, 0.4 M to 0.7 M, 0.4 M to 0.6 M, 0.4 M to 0.5 M, 0.5 M to 0.8 M, 0.5 M to 0.7 M, 0.5 M to 0.6 M, 0.6 M to 0.8 M, 0.6 M to 0.7 M, 0.5 M to 0.6 M, 0.6 M to 0.8 M, 0.6 M to 0.7 M, or 0.7 M to It can be 0.8 M. When the molar concentration of the electrolyte contained in the above electrolyte is within the corresponding range, graphene can be produced with a high yield and excellent in terms of carbon / oxygen content ratio, defect degree, and graphitization degree.

[0050] The pH of the above electrolyte may be 5.0 to 9.5, 6.0 to 8.0, 6.1 to 7.9, 6.2 to 7.8, 6.3 to 7.7, 6.4 to 7.6, 6.5 to 7.5, 6.6 to 7.9, 6.7 to 7.0, or 6.8 to 7.0.

[0051]

[0052] electrolytes

[0053] In particular, the method for manufacturing graphene according to the present invention is characterized by comprising a first electrolyte comprising sodium chloride (NaCl) as the electrolyte; and a second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof.

[0054]

[0055] First electrolyte

[0056] The first electrolyte may include sodium chloride (NaCl). Sodium chloride (NaCl) is a compound of chlorine and sodium, is the main component of salt, and is the substance that accounts for the largest proportion of salts in seawater. Therefore, it has the advantages of being easy to obtain, inexpensive, and environmentally friendly compared to other salt compounds.

[0057] The method for manufacturing graphene according to the present invention may have a molar concentration of sodium chloride (NaCl) contained in the electrolyte of 0.05 M to 2.5 M. Specifically, the sodium chloride contained in the electrolyte has a molar concentration of 0.05 M to 2.5 M, 0.05 M to 1 M, 0.05 M to 0.5 M, 0.05 M to 0.29 M, 0.05 M to 0.28 M, 0.05 M to 0.27 M, 0.05 M to 0.26 M, 0.05 M to 0.25 M, 0.05 M to 0.23 M, 0.05 M to 0.21 M, 0.05 M to 0.2 M, 0.05 M to 0.15 M, 0.05 M to 0.1 M, 0.05 M to 0.08 M, 0.75 M to 0.3 M, 0.75 M to 0.25 M, 0.75 M to 0.23 M, 0.75 M to 0.21 M, 0.75 M to 0.2 M, 0.75 M to 0.15 M, 0.75 M to 0.1 M, 0.75 M to 0.08 M, 0.1 M to 0.3 M, 0.1 M to 0.25 M, 0.1 M to 0.23 M, 0.1 M to 0.21 M, 0.1 M to 0.2 M, 0.1 M to 0.15 M, 0.15 M to 0.3 M, 0.15 M to 0.25 M, 0.15 M to 0.23 M, 0.15 M to 0.21 M, 0.15 M to 0.2 M, 0.2 M to 0.3 M, 0.2 M to 0.25 M, 0.2 M to It may be 0.23 M, 0.2 M to 0.21 M, 0.22 M to 0.3 M, 0.22 M to 0.25 M, 0.22 M to 0.23 M, 0.24 M to 0.3 M, 0.24 M to 0.25 M, or 0.05 M to 0.3 M. When the molar concentration of sodium chloride is within the appropriate range, the exfoliation of graphene proceeds smoothly, and the desired amount of graphene can be obtained.

[0058] In addition, the sodium chloride (NaCl) is, based on the total molar amount of electrolyte contained in the electrolyte, 0.1 mol% to 99.9 mol%, 0.1 mol% to 99.8 mol%, 0.1 mol% to 99 mol%, 0.1 mol% to 80 mol%, 0.1 mol% to 75 mol%, 0.1 mol% to 70 mol%, 0.1 mol% to 67 mol%, 0.1 mol% to 51 mol%, 0.1 mol% to 38 mol%, 0.1 mol% to 36 mol%, 0.1 mol% to 34 mol%, 0.1 mol% to 31 mol%, 0.1 mol% to 26 mol%, 0.1 mol% to 21 mol%, 0.1 mol% to 17 mol%, 10 mol% to 99.9 mol%, 10 mol% to 99.8 mol%, 10 mol% to 99 mol%, 10 mol% to 80 mol%, 10 mol% to 75 mol%, 10 mol% to 70 mol%, 10 mol% to 67 mol%, 10 mol% to 51 mol%, 10 mol% to 38 mol%, 10 mol% to 36 mol%, 10 mol% to 34 mol%, 10 mol% to 31 mol%, 10 mol% to 26 mol%, 10 mol% to 21 mol%, 10 mol% to 17 mol%, 16 mol% to 99.9 mol%, 16 mol% to 99.8 mol%, 16 mol% to 99 mol%, 16 mol% to 80 mol%, 16 mol% to 75 mol%, 16 mol% to 70 mol%, 16 mol% to 67 mol%, 16 mol% to 51 mol%, 16 mol% to 38 mol%, 16 mol% to 36 mol%, 16 mol% to 34 mol%, 16 mol% to 31 mol%, 16 mol% to 26 mol%, 16 mol% to 21 mol%, 16 mol% to 17 mol%, 19 mol% to 99.9 mol%, 19 mol% to 99.8 mol%, 19 mol% to 99 mol%, 19 mol% to 80 mol%, 19 mol% to 75 mol%, 19 mol% to 70 mol%, 19 mol% to 67 mol%, 19 mol% to 51 mol%, 19 mol% to 38 mol%, 19 mol% to 36 mol%, 19 mol% to 34 mol%, 19 mol% to 31 mol%, 19 mol% to 26 mol%, 19 mol% to 21 mol%, 24 mol% to 99.9 mol%, 24 mol% to 99.8 mol%, 24 mol% to 99 mol%, 24 mol% to 80 mol%, 24 mol% to 75 mol%, 24 mol% to 70 mol%, 24 mol% to 67 mol%, 24 mol% to 51 mol%, 24 mol% to 38 mol%, 24 mol% to 36 mol%, 24 mol% to 34 mol%, 24 mol% to 31 mol%, 24 mol% to 26 mol%, 29 mol% to 99.9 mol%, 29 mol% to 99.8 mol%, 29 mol% to 99 mol%, 29 mol% to 80 mol%, 29 mol% to 75 mol%, 29 mol% to 70 mol%, 29 mol% to 67 mol%, 29 mol% to 51 mol%, 29 mol% to 38 mol%, 29 mol% to 36 mol%, 29 mol% to 34 mol%, 29 mol% to 31 mol%, 35 mol% to 99.9 mol%, 35 mol% to 99.8 mol%, 35 mol% to 99 mol%, 35 mol% to 80 mol%, 35 mol% to 75 mol%, 35 mol% to 70 mol%, 35 mol% to 67 mol%, 35 mol% to 51 mol%, 35 mol% to 38 mol%, 35 mol% to 36 mol%, 37 mol% to 99.9 mol%, 37 mol% to 99.8 mol%, 37 mol% to 99 mol%, 37 mol% to 80 mol%, 37 mol% to 75 mol%, 37 mol% to 70 mol%, 37 mol% to 67 mol%, 37 mol% to 51 mol%, 37 mol% to 38 mol%, 49 mol% to 99.9 mol%, 49 mol% to 99.It may be used as 8 mol%, 49 mol% to 99 mol%, 49 mol% to 80 mol%, 49 mol% to 75 mol%, 49 mol% to 70 mol%, 49 mol% to 67 mol%, 49 mol% to 51 mol%, 66 mol% to 99.9 mol%, 66 mol% to 99.8 mol%, 66 mol% to 99 mol%, 66 mol% to 80 mol%, 66 mol% to 75 mol%, 66 mol% to 70 mol%, 66 mol% to 67 mol%, 74 mol% to 99.9 mol%, 74 mol% to 99.8 mol%, 74 mol% to 99 mol%, 74 mol% to 80 mol%, 74 mol% to 75 mol%, or 15 mol% to 75 mol%. When the content of the above sodium chloride (NaCl) is within the corresponding range, graphene can be produced with a high yield and excellent performance in terms of carbon / oxygen content ratio, defects, and graphitization.

[0059]

[0060] Second electrolyte

[0061] The second electrolyte may include a chlorate compound, a quaternary ammonium salt compound, or a combination thereof.

[0062] In the present invention, the chlorate compound is used in a comprehensive sense to include chlorate compounds, perchlorate compounds, hypochlorite compounds, and hypochlorite compounds; specifically, chlorate ions (ClO3 - ), perchlorate ion (ClO4 - ), hypochlorite ion (ClO2 - ) or hypochlorite ions (ClO - It can be defined as a compound that includes ) and forms a salt by combining with the above ions.

[0063] Specifically, the chlorate compounds include lithium chlorate (LiClO3), sodium chlorate (NaClO3), potassium chlorate (KClO3), calcium chlorate (Ca(ClO3)2), ammonium chlorate (NH4ClO3), lithium perchlorate (LiClO4), sodium perchlorate (NaClO4), potassium perchlorate (KClO4), magnesium perchlorate (Mg(ClO4)2), calcium perchlorate (Ca(ClO4)2), barium perchlorate (Ba(ClO4)2), ammonium perchlorate (NH4ClO4), sodium hypochlorite (NaClO2), potassium hypochlorite (KClO2), calcium hypochlorite (Ca(ClO2)2), magnesium hypochlorite (Mg(ClO2)2), ammonium hypochlorite (NH4ClO2), and lithium hypochlorite (LiClO). It may include one or more selected from the group consisting of sodium hypochlorite (NaClO), potassium hypochlorite (KClO), calcium hypochlorite (Ca(ClO)2) and ammonium hypochlorite (NH4ClO).

[0064] The method for manufacturing graphene according to the present invention comprises a molar concentration of the chlorate compound included in the electrolyte of 0 M to 2.5 M, 0 M to 1 M, 0 M to 0.5 M, 0 M to 0.41 M, 0 M to 0.36 M, 0 M to 0.35 M, 0 M to 0.31 M, 0 M to 0.3 M, 0 M to 0.26 M, 0 M to 0.21 M, 0 M to 0.16 M, 0 M to 0.15 M, 0 M to 0.11 M, 0 M to 0.1 M, 0 M to 0.06 M, 0 M to 0.05 M, 0.01 M to 0.41 M, 0.01 M to 0.4 M, 0.01 M to 0.36 M, 0.01 M to 0.35 M, 0.01 M to 0.31 M, 0.01 M to 0.3 M, 0.01 M to 0.26 M, 0.01 M to 0.21 M, 0.01 M to 0.16 M, 0.01 M to 0.15 M, 0.01 M to 0.11 M, 0.01 M to 0.1 M, 0.01 M to 0.06 M, 0.01 M to 0.05 M, 0.04 M to 0.41 M, 0.04 M to 0.4 M, 0.04 M to 0.36 M, 0.04 M to 0.35 M, 0.04 M to 0.31 M, 0.04 M to 0.3 M, 0.04 M to 0.26 M, 0.04 M to 0.21 M, 0.04 M to 0.16 M, 0.04 M to 0.15 M, 0.04 M to 0.11 M, 0.04 M to 0.1 M, 0.04 M to 0.06 M, 0.04 M to 0.05 M, 0.09 M to 0.41 M, 0.09 M to 0.4 M, 0.09 M to 0.36 M, 0.09 M to 0.35 M, 0.09 M to 0.31 M, 0.09 M to 0.3 M, 0.09 M to 0.26 M, 0.09 M to 0.21 M, 0.09 M to 0.16 M, 0.09 M to 0.15 M, 0.09 M to 0.11 M, 0.14 M to 0.41 M, 0.14 M to 0.4 M, 0.14 M to 0.36 M, 0.14 M to 0.35 M, 0.14 M to 0.31 M, 0.14 M to 0.3 M, 0.14 M to 0.26 M, 0.14 M to 0.21 M, 0.14 M to 0.16 M, 0.19 M to 0.41 M, 0.19 M to 0.4 M, 0.19 M to 0.36 M, 0.19 M to 0.35 M, 0.19 M to 0.31 M, 0.19 M to 0.3 M, 0.19 M to 0.26 M, 0.19 M to 0.21 M, 0.24 M to 0.41 M, 0.24 M to 0.4 M, It may be 0.24 M to 0.36 M, 0.24 M to 0.35 M, 0.24 M to 0.31 M, 0.24 M to 0.3 M, 0.24 M to 0.26 M, 0.29 M to 0.41 M, 0.29 M to 0.4 M, 0.29 M to 0.36 M, 0.29 M to 0.35 M, 0.29 M to 0.31 M, 0.34 M to 0.41 M, 0.34 M to 0.4 M, 0.34 M to 0.36 M, 0.39 M to 0.41 M, or 0 M to 0.4 M. When the molar concentration of the chlorate compound is within the appropriate range, the exfoliation of graphene proceeds smoothly, and the desired amount of graphene can be obtained.

[0065] In addition, the above chlorate compound, based on the total molar amount of electrolyte contained in the electrolyte, is 0 mol% to 99.9 mol%, 0 mol% to 90 mol%, 0 mol% to 80 mol%, 0 mol% to 70 mol%, 0 mol% to 67 mol%, 0 mol% to 51 mol%, 0 mol% to 41 mol%, 0 mol% to 34 mol%, 0.1 mol% to 99.9 mol%, 0.1 mol% to 90 mol%, 0.1 mol% to 80 mol%, 0.1 mol% to 70 mol%, 0.1 mol% to 67 mol%, 0.1 mol% to 51 mol%, 0.1 mol% to 41 mol%, 0.1 mol% to 34 mol%, 1 mol% to 99.9 mol%, 1 mol% to 90 mol%, 1 mol% to 80 mol%, 1 mol% to 70 mol%, 1 mol% to 67 mol%, 1 mol% to 51 mol%, 1 mol% to 41 mol%, 1 mol% to 34 mol%, 10 mol% to 99.9 mol%, 10 mol% to 90 mol%, 10 mol% to 80 mol%, 10 mol% to 70 mol%, 10 mol% to 67 mol%, 10 mol% to 51 mol%, 10 mol% to 41 mol%, 10 mol% to 34 mol%, 20 mol% to 99.9 mol%, 20 mol% to 90 mol%, 20 mol% to 80 mol%, 20 mol% to 70 mol%, 20 mol% to 67 mol%, 20 mol% to 51 mol%, 20 mol% to 41 mol%, 20 mol% to 34 mol%, 33 mol% to 99.9 mol%, 33 mol% to 90 mol%, 33 mol% to 80 mol%, 33 mol% to 70 mol%, 33 mol% to 67 mol%, 33 mol% to 51 mol%, 33 mol% to 41 mol%, 33 mol% to 34 mol%, 39 mol% to 99.9 mol%, 39 mol% to 90 mol%, 39 mol% to 80 mol%, 39 mol% to 70 mol%, 39 mol% to 67 mol%, 39 mol% to 51 mol%, 39 mol% to 41 mol%, 49 mol% to 99.It can be used in an amount of 9 mol%, 49 mol% to 90 mol%, 49 mol% to 80 mol%, 49 mol% to 70 mol%, 49 mol% to 67 mol%, 49 mol% to 51 mol%, 66 mol% to 99.9 mol%, 66 mol% to 90 mol%, 66 mol% to 80 mol%, 66 mol% to 70 mol%, 66 mol% to 67 mol%, or 0 mol% to 67 mol%. When the content of the chlorate compound is within the corresponding range, graphene can be produced with a high yield and excellent characteristics in terms of carbon / oxygen content ratio, defects, and graphitization.

[0066] The above quaternary ammonium salt compounds are tetramethylammonium hydroxide (TMAOH), tetramethylammonium chloride (TMACl), tetramethylammonium bromide (TMABr), tetramethylammonium iodide (TMAI), tetraethylammonium chloride (TEACl), tetraethylammonium bromide (TEABr), tetraethylammonium iodide (TEAI), tetrapropylammonium chloride (TPACl), tetrabutylammonium chloride (TBACl), and tetrabutylammonium bromide (TBABr). It may include one or more selected from the group consisting of tetrabutylammonium hydrogen sulfate (TBAH2SO4) and benzyltrimethylammonium chloride (BTMACl).

[0067] Referring to FIG. 2, the quaternary ammonium salt compound enables even exfoliation of graphene at both the working electrode and the counter electrode when both are used as graphite electrodes. This is due to anions (Cl) contained in the electrolyte. - ) graphene exfoliation at the anode by ) along with cations (R4N) formed by the quaternary ammonium salt compound + This is because graphene exfoliation at the cathode proceeds simultaneously due to ).

[0068] The method for manufacturing graphene according to the present invention comprises a molar concentration of the quaternary ammonium salt compound included in the electrolyte of 0 M to 2.5 M, 0 M to 1 M, 0 M to 0.5 M,

[0069] 0 M to 0.31 M, 0 M to 0.26 M, 0 M to 0.25 M, 0 M to 0.23 M, 0 M to 0.21 M, 0 M to 0.2 M, 0 M to 0.16 M, 0 M to 0.15 M, 0 M to 0.11 M, 0 M to 0.1 M, 0 M to 0.08 M, 0.01 M to 0.31 M, 0.01 M to 0.26 M, 0.01 M to 0.25 M, 0.01 M to 0.23 M, 0.01 M to 0.21 M, 0.01 M to 0.2 M, 0.01 M to 0.16 M, 0.01 M to 0.15 M, 0.01 M to 0.11 M, 0.01 M to 0.1 M, 0.01 M to 0.08 M, 0.09 M to 0.31 M, 0.09 M to 0.26 M, 0.09 M to 0.25 M, 0.09 M to 0.23 M, 0.09 M to 0.21 M, 0.09 M to 0.2 M, 0.09 M to 0.16 M, 0.09 M to 0.15 M, 0.09 M to 0.11 M, 0.14 M to 0.31 M, 0.14 M to 0.26 M, 0.14 M to 0.25 M, 0.14 M to 0.23 M, 0.14 M to 0.21 M, 0.14 M to 0.2 M, 0.14 M to It may be 0.16 M, 0.19 M to 0.31 M, 0.19 M to 0.26 M, 0.19 M to 0.25 M, 0.19 M to 0.23 M, 0.19 M to 0.21 M, 0.22 M to 0.31 M, 0.22 M to 0.26 M, 0.22 M to 0.25 M, 0.22 M to 0.23 M, 0.24 M to 0.31 M, 0.24 M to 0.26 M, or 0.29 M to 0.31 M. When the molar concentration of the quaternary ammonium salt compound is within the appropriate range, the exfoliation of graphene proceeds smoothly, and the desired amount of graphene can be obtained.

[0070] In addition, the above-mentioned quaternary ammonium salt compound is, based on the total molar amount of electrolyte contained in the electrolyte, 0 mol% to 99.9 mol%, 0 mol% to 90 mol%, 0 mol% to 80 mol%, 0 mol% to 76 mol%, 0 mol% to 70 mol%, 0 mol% to 67 mol%, 0 mol% to 60 mol%, 0 mol% to 51 mol%, 0 mol% to 40 mol%, 0 mol% to 34 mol%, 0 mol% to 26 mol%, 0 mol% to 17 mol%, 0 mol% to 15 mol%, 0 mol% to 13 mol%, 0.1 mol% to 99.9 mol%, 0.1 mol% to 90 mol%, 0.1 mol% to 80 mol%, 0.1 mol% to 76 mol%, 0.1 mol% to 70 mol%, 0.1 mol% to 67 mol%, 0.1 mol% to 60 mol%, 0.1 mol% to 51 mol%, 0.1 mol% to 40 mol%, 0.1 mol% to 34 mol%, 0.1 mol% to 26 mol%, 0.1 mol% to 17 mol%, 0.1 mol% to 15 mol%, 0.1 mol% to 13 mol%, 0.1 mol% to 99.9 mol%, 0.1 mol% to 90 mol%, 0.1 mol% to 80 mol%, 0.1 mol% to 76 mol%, 0.1 mol% to 70 mol%, 0.1 mol% to 67 mol%, 0.1 mol% to 60 mol%, 0.1 mol% to 51 mol%, 0.1 mol% to 40 mol%, 0.1 mol% to 34 mol%, 0.1 mol% to 26 mol%, 0.1 mol% to 17 mol%, 0.1 mol% to 15 mol%, 0.1 mol% to 13 mol%, 12 mol% to 99.9 mol%, 12 mol% to 90 mol%, 12 mol% to 80 mol%, 12 mol% to 76 mol%, 12 mol% to 70 mol%, 12 mol% to 67 mol%, 12 mol% to 60 mol%, 12 mol% to 51 mol%, 12 mol% to 40 mol%, 12 mol% to 34 mol%, 12 mol% to 26 mol%, 12 mol% to 17 mol%, 12 mol% to 15 mol%, 12 mol% to 13 mol%, 14 mol% to 99.9 mol%, 14 mol% to 90 mol%, 14 mol% to 80 mol%, 14 mol% to 76 mol%, 14 mol% to 70 mol%, 14 mol% to 67 mol%, 14 mol% to 60 mol%, 14 mol% to 51 mol%, 14 mol% to 40 mol%, 14 mol% to 34 mol%, 14 mol% to 26 mol%, 14 mol% to 17 mol%, 14 mol% to 15 mol%, 15 mol% to 99.9 mol%, 15 mol% to 90 mol%, 15 mol% to 80 mol%, 15 mol% to 76 mol%, 15 mol% to 70 mol%, 15 mol% to 67 mol%, 15 mol% to 60 mol%, 15 mol% to 51 mol%, 15 mol% to 40 mol%, 15 mol% to 34 mol%, 15 mol% to 26 mol%, 15 mol% to 17 mol%, 24 mol% to 99.9 mol%, 24 mol% to 90 mol%, 24 mol% to 80 mol%, 24 mol% to 76 mol%, 24 mol% to 70 mol%, 24 mol% to 67 mol%, 24 mol% to 60 mol%, 24 mol% to 51 mol%, 24 mol% to 40 mol%, 24 mol% to 34 mol%, 24 mol% to 26 mol%, 33 mol% to 99.9 mol%, 33 mol% to 90 mol%, 33 mol% to 80 mol%, 33 mol% to 76 mol%, 33 mol% to 70 mol%, 33 mol% to 67 mol%, 33 mol% to 60 mol%, 33 mol% to 51 mol%, 33 mol% to 40 mol%, 33 mol% to 34 mol%, 49 mol% to 99.9 mol%, 49 mol% to 90 mol%, 49 mol% to 80 mol%, 49 mol% to 76 mol%, 49 mol% to 70 mol%, 49 mol% to 67 mol%, 49 mol% to 60 mol%, 49 mol% to 51 mol%, 66 mol% to 99.9 mol%, 66 mol% to 90 mol%, 66 mol% to 80 mol%, 66 mol% to 76 mol%, 66 mol% to 70 mol%, 66 mol% to 67 mol%, 74 mol% to 99.It can be used in an amount of 9 mol%, 74 mol% to 90 mol%, 74 mol% to 80 mol%, 74 mol% to 76 mol%, or 0 mol% to 75 mol%. When the content of the quaternary ammonium salt compound is within the corresponding range, graphene can be produced with a high yield and excellent characteristics in terms of carbon / oxygen content ratio, defects, and graphitization.

[0071]

[0072] Combination of the first electrolyte and the second electrolyte

[0073] The above electrolyte may include various combinations of the first electrolyte and the second electrolyte.

[0074] The above electrolyte may include a first electrolyte containing the sodium chloride (NaCl) and a second electrolyte containing the chlorate compound. At this time, the electrolyte may contain the sodium chloride (NaCl) and the chlorate compound in a molar ratio of 0.5 to 3 : 0.5 to 3, and specifically, a molar ratio of 0.5 to 3 : 0.5 to 3, a molar ratio of 1 to 2.5 : 0.5 to 2.5, a molar ratio of 1.5 to 2.5 : 0.5 to 2, a molar ratio of 1.5 to 2.5 : 0.5 to 1.5, a molar ratio of 1.9 to 2.1 : 0.9 to 1.1, a molar ratio of 0.5 to 2.5 : 1 to 2.5, a molar ratio of 0.5 to 2 : 1.5 to 2.5, a molar ratio of 0.5 to 1.5 : 1.5 to 2.5, a molar ratio of 0.9 to 1.1 : 1.9 to 2.1, and 0.5 to It may be included in a molar ratio of 2.5 : 0.5 ~ 2.5, a molar ratio of 0.5 ~ 2 : 0.5 ~ 2, a molar ratio of 0.5 ~ 1.5 : 0.5 ~ 1.5, a molar ratio of 0.9 ~ 1.1 : 0.9 ~ 1.1, or a molar ratio of 1 ~ 2 : 2 ~ 1. When the molar ratio of the sodium chloride (NaCl) and the chlorate compound included in the electrolyte is within the corresponding range, graphene can be produced with a high yield and excellent carbon / oxygen content ratio, defect degree, and graphitization degree.

[0075] Alternatively, the electrolyte may include a first electrolyte containing the sodium chloride (NaCl) and a second electrolyte containing the quaternary ammonium salt compound. At this time, the electrolyte may contain the sodium chloride (NaCl) and the quaternary ammonium salt compound in a molar ratio of 0.5 to 4 : 0.5 to 4, and specifically, a molar ratio of 0.5 to 4 : 0.5 to 4, a molar ratio of 1 to 3.5 : 0.5 to 3.5, a molar ratio of 1.5 to 3.5 : 0.5 to 3, a molar ratio of 2 to 3.5 : 0.5 to 2.5, a molar ratio of 2.5 to 3.5 : 0.5 to 2, a molar ratio of 2.5 to 3.5 : 0.5 to 1.5, a molar ratio of 2.9 to 3.1 : 0.9 to 1.1, a molar ratio of 1.5 to 2.5 : 0.5 to 1.5, a molar ratio of 1.9 to 2.1 : 0.9 to 1.1. It may include a molar ratio of 0.5 to 3.5: 1 to 3.5, a molar ratio of 0.5 to 3: 1.5 to 3.5, a molar ratio of 0.5 to 2.5: 2 to 3.5, a molar ratio of 0.5 to 2: 2.5 to 3.5, a molar ratio of 0.5 to 1.5: 2.5 to 3.5, a molar ratio of 0.9 to 1.1: 2.9 to 3.1, a molar ratio of 0.5 to 1.5: 1.5 to 2.5, a molar ratio of 0.9 to 1.1: 1.9 to 2.1, a molar ratio of 0.5 to 1.5: 0.5 to 1.5, a molar ratio of 0.9 to 1.1: 1.9 to 2.1, or a molar ratio of 1 to 3: 1 to 3. When the molar ratio of the sodium chloride (NaCl) and the quaternary ammonium salt included in the electrolyte is within the corresponding range, graphene can be produced with a high yield and excellent in terms of carbon / oxygen content ratio, defects, and graphitization.

[0076] Alternatively, the electrolyte may include a first electrolyte comprising the sodium chloride (NaCl) and a second electrolyte comprising the chlorate compound and the quaternary ammonium salt compound. When the electrolyte comprises the sodium chloride (NaCl), the chlorate compound, and the quaternary ammonium salt compound, the sodium chloride (NaCl), the chlorate compound, and the quaternary ammonium salt compound may be included in a molar ratio of 0.1 to 4 : 0.1 to 5 : 0.1 to 4. Specifically, the electrolyte comprises the sodium chloride (NaCl), the chlorate compound, and the quaternary ammonium salt compound in a molar ratio of 0.1–4 : 0.1–5 : 0.1–4, a molar ratio of 0.5–3 : 0.5–4 : 0.5–3, a molar ratio of 0.5–1.5 : 1.5–2.5 : 0.5–1.5, a molar ratio of 0.9–1.1 : 1.9–2.1 : 0.9–1.1, a molar ratio of 0.5–1 : 1–2 : 0.5–1.5, a molar ratio of 0.4–0.6 : 1.4–1.6 : 0.9–1.1, a molar ratio of 1–2 : 2–3 : 0.5–1.5, and 1.4–1.6 : 2.4 ~ 2.6 : molar ratio of 0.9 ~ 1.1, 1.5 ~ 2.5 : 2.5 ~ 3.5 : molar ratio of 0.5 ~ 1.5, 1.9 ~ 2.1 : 2.9 ~ 3.1 : molar ratio of 0.9 ~ 1.1, 2 ~ 3 : 3 ~ 4 : molar ratio of 0.5 ~ 1.5, 2.4 ~ 2.6 : 3.4 ~ 3.6 : molar ratio of 0.9 ~ 1.1, 2.5 ~ 3 : 3.5 ~ 4 : molar ratio of 0.5 ~ 1.5, 2.9 ~ 3.1 : 3.9 ~ 4.1 : molar ratio of 0.9 ~ 1.1, 0.5 ~ 1.5 : 1.5 ~ 2.5 : molar ratio of 1.5 ~ 2.5, 0.9 ~ 1.1 : 1.9 ~ 2.1 : 1.9 ~ 2.1 molar ratio, 0.5 ~ 1.5 : 1.5 ~ 2.5 : 2.5 ~ 3, 0.9 ~ 1.1 : 1.9 ~ 2.1 : 2.9 ~ 3.1 molar ratio or 0.5 ~ 3 : 1.It can be included in a molar ratio of 5 to 4:1 to 3. When the molar ratio of sodium chloride (NaCl), chlorate compounds, and quaternary ammonium salt compounds included in the electrolyte is within the corresponding range, graphene can be produced with a high yield and excellent in terms of carbon / oxygen content ratio, defects, and graphitization.

[0077]

[0078] Other alkali compounds

[0079] Meanwhile, the electrolyte may additionally include other alkali compounds. For example, the electrolyte may include a first electrolyte comprising sodium chloride (NaCl); a second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof; and other alkali compounds.

[0080] The above other alkali compounds may include sodium fluoroborate (NaBF), lithium bromite (LiBr), sodium bromide (NaBr), potassium bromide (KBr), sodium iodide (NaI), potassium iodide (KI), lithium oxide (Li2O), sodium oxide (Na2O), potassium oxide (K2O), lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), potassium carbonate (K2CO3), potassium bicarbonate (KHCO3), sodium nitrate (NaNO3), potassium nitrate (KNO3), sodium sulfate (Na2SO4), potassium sulfate (K2SO4), sodium aluminate (NaAlO2), sodium silicate (Na2SiO3), n-butyllithium (n-BuLi), methyllithium (MeLi), phenyl sodium (PhNa), etc.

[0081] Where the above electrolyte comprises a first electrolyte comprising sodium chloride (NaCl); a second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof; and other alkali compounds, the first electrolyte comprising sodium chloride (NaCl); the second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof; and other alkali compounds may be included in a molar ratio of 0.5 to 3: 0.5 to 3: 0.5 to 4. Specifically, the electrolyte comprises the first electrolyte comprising sodium chloride (NaCl); and the second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof; and other alkali compounds in molar ratios of 0.5–3 : 0.5–3 : 0.5–4, molar ratios of 0.5–1.5 : 0.5–1.5 : 1.5–2.5, molar ratios of 0.5–1 : 0.5–1.5 : 1–2, molar ratios of 1–2 : 0.5–1.5 : 2–3, molar ratios of 1.5–2.5 : 0.5–1.5 : 2.5–3.5, molar ratios of 2–3 : 0.5–1.5 : 3–4, molar ratios of 2.5–3 : 0.5–1.5 : 3.5–4, molar ratios of 0.5–1.5 : 1.5–2.5 : 1.5–2.5, molar ratios of 0.5–1.5 It may be included in a molar ratio of 2.5 to 3: 1.5 to 2.5, a molar ratio of 1.9 to 2.1: 0.9 to 1.1: 0.9 to 1.1, a molar ratio of 0.9 to 1.1: 1.9 to 2.1: 0.9 to 1.1, or a molar ratio of 0.9 to 1.1: 0.9 to 1.1: 1.9 to 2.1. When the molar ratio of the first electrolyte containing sodium chloride (NaCl) included in the electrolyte; the second electrolyte containing a chlorate compound, a quaternary ammonium salt compound, or a combination thereof; and other alkali compounds is within the corresponding range, graphene can be produced with a high yield and excellent in terms of carbon / oxygen content ratio, defect degree, and degree of graphitization.

[0082]

[0083] menstruum

[0084] The solvent used in the method for manufacturing graphene according to the present invention may include water. The water may be distilled water or deionized water, may be naturally obtained water such as groundwater, mineral water, or precipitation, and may be drinking water such as industrial water or tap water. Specifically, the electrolyte used in the method for manufacturing graphene according to the present invention may include water as a solvent and may include a combination of a first electrolyte comprising sodium chloride (NaCl) and a second electrolyte comprising a chlorate compound; a combination of a first electrolyte comprising sodium chloride (NaCl) and a second electrolyte comprising a quaternary ammonium salt compound; a combination of a first electrolyte comprising sodium chloride (NaCl) and a second electrolyte comprising a chlorate compound and a quaternary ammonium salt compound; or a combination of a first electrolyte comprising sodium chloride (NaCl); a second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof; and other alkali compounds.

[0085]

[0086] Specific steps of the graphene manufacturing method

[0087] A method for manufacturing graphene according to one embodiment of the present invention may include: (1) a step of exfoliating graphite by applying a voltage to a working electrode and a counter electrode disposed in an electrolyte; (2) a step of filtering and washing the exfoliated graphite; and (3) a step of ultrasonically treating.

[0088] Step (1) above is a step of applying voltage to a working electrode and a counter electrode placed in the electrolyte to peel off graphite. In Step (1), the distance between the working electrode and the counter electrode placed in the electrolyte may be 0.5 cm or more, 1 cm or more, or 2 cm or more, and may be 20 cm or less, 15 cm or less, or 10 cm or less. The working electrode and the counter electrode must maintain an appropriate distance so that the peeling of graphite occurs effectively, and the size of the reaction chamber and the amount of electrolyte used can be maintained within an appropriate range, which is advantageous in terms of economy.

[0089] Before applying voltage in step (1) above, the working electrode and the counter electrode may be immersed in the electrolyte for a predetermined period of time. The immersion may be performed for 1 minute or more, 2 minutes or more, 3 minutes or more, or 5 minutes or more. The electrodes must be immersed for a predetermined period of time or longer so that the electrodes are sufficiently wetted, allowing for smooth peeling when voltage is applied and shortening the peeling time.

[0090] The voltage applied in step (1) above may be 1 V to 200 V, specifically, a voltage of 1 V to 150 V, 1 V to 100 V, 1 V to 50 V, 5 V to 25 V, or 5 V to 20 V may be applied. Meanwhile, the applied voltage may be an alternating current voltage. In particular, when both the working electrode and the counter electrode are used as graphite electrodes, graphene can be generated simultaneously at the anode when an alternating current voltage is applied.

[0091] Step (2) above is a step of filtering and washing the exfoliated graphite. The filtration of the exfoliated graphite can be performed using a vacuum filtration device. Specifically, the filtration of the exfoliated graphite can be performed using a vacuum filtration device, and the filtration and washing processes can be performed simultaneously using a paper filter and a washing solution. At this time, the washing solution may include water or ethanol. Specifically, when the quaternary ammonium salt compound is used together as an electrolyte, an additional washing step using ethanol may be included.

[0092] Step (3) above is a step of ultrasonically treating the filtered exfoliated graphite. The filtered exfoliated graphite is placed in distilled water to perform ultrasonical treatment. The ultrasonical treatment can be performed at room temperature for 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 1 hour or more, 2 hours or more, or 3 hours or more, and can be performed at a frequency of 5 kHz or more, 7 kHz or more, or 8 kHz or more.

[0093] After step (3) above, the exfoliated graphene can be dried to obtain graphene powder. The drying can be performed for 1 hour or more, 2 hours or more, 3 hours or more, 5 hours or more, 7 hours or more, or 10 hours or more under temperature conditions of 70°C or more, 80°C or more, 90°C or more, or 100°C or more.

[0094] Furthermore, in the method for manufacturing graphene according to one embodiment of the present invention, the residual electrolyte after filtering the graphite exfoliated in step (2) can be reused by reintroducing it into the electrolyte of step (1). Since the electrolyte used in the present invention is not only environmentally friendly but can also be reused multiple times, process costs can be reduced more effectively.

[0095]

[0096] graphene

[0097] High-quality graphene can be obtained through the method for manufacturing graphene according to one embodiment of the present invention.

[0098] Graphene produced through the method for producing graphene of the present invention has a defect degree (D peak intensity (I D ) / G peak intensity(I G )) may be 0.7 or less. More specifically, the graphene produced through the method for producing graphene of the present invention may have a defect degree of 0.7 or less, and specifically, may be 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, 0.19 or less, or 0.18 or less. In addition, the graphene produced through the method for producing graphene of the present invention has a degree of graphitization (intensity of the 2D peak (I 2D ) / G peak intensity(I G )) may be 0.3 or higher, specifically 0.35 or higher, 0.4 or higher, 0.45 or higher, 0.48 or higher, 0.49 or higher, or 0.5 or higher. In addition, the graphene has a ratio of defect degree to degree of graphitization (defect density / degree of graphitization; i.e., intensity of the D peak (I D ) / 2D peak intensity(I 2D )) may be 1 or less, specifically 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, or 0.554 or less. Here, the G peak, D peak, and 2D peak are peaks appearing in the spectrum analyzed by measuring graphene powder by Raman spectroscopy, ranging from 1500 to 1700 cm⁻¹. -1 The G peak measured in the wavelength range is a key characteristic peak of graphene, and this is sp 2 It is a peak attributed to in-plane vibrations of hybrid carbon atoms, and 1250 to 1450 cm⁻¹ -1 The D peak measured in the wavelength range is the disordered vibration peak of graphene, and is between 2600 and 2800 cm⁻¹ -1 The 2D peak measured in the wavelength range represents the 2-phonon resonance second-order Raman peak.

[0099] In addition, the graphene produced by the method for producing graphene according to the present invention may have a carbon content ratio (atomic ratio) of 80% or more, specifically 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, 86% or more, or 87% or more. Furthermore, the graphene may have an oxygen content ratio (atomic ratio) of less than 20%, specifically less than 17%, less than 16%, less than 15%, less than 14%, or less than 13%. The graphene may have an atomic ratio of carbon to oxygen (C / O ratio) of 1 or more, specifically 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, or 8 or more. Moreover, the graphene produced by the method for producing graphene according to the present invention may not contain C=O functional groups. Accordingly, the graphene produced through the method of producing graphene of the present invention has a very low oxygen content and possesses superior quality.

[0100] The above contents will be explained in more detail by the following examples. However, the following examples are merely for illustrating the present invention, and the scope of the examples is not limited to these.

[0101]

[0102] <Example 1-1>

[0103] 35.064 g of sodium chloride (NaCl) and 36.732 g of sodium perchlorate (NaClO4) were mixed (molar ratio of 2:1) and mixed with 3 L of distilled water to prepare an electrolyte solution with a concentration of 0.3 M. A graphite electrode (110 mm Y 100 mm, thickness 0.5 mm) was used as the working electrode and a stainless steel electrode as the counter electrode. One working electrode was placed in a reaction vessel at a distance of 2.5 cm between two counter electrodes. Subsequently, the electrolyte solution was introduced so that the working electrode and the counter electrode were immersed. Afterward, a constant voltage of 10 V was applied to the electrodes for 60 minutes to exfoliate the graphite. Subsequently, the exfoliated graphite was washed using a vacuum filtration device with 20 L of distilled water while vacuum filtering. Next, the filtered and washed exfoliated graphite was mixed with distilled water and subjected to ultrasonic treatment for 3 hours. Afterwards, the solvent was evaporated in an oven and vacuum dried at 100°C for 12 hours to obtain graphene powder.

[0104]

[0105] <Example 1-2>

[0106] Graphene was obtained through the same process as in Example 1-1, except that 26.298 g of sodium chloride (NaCl) and 55.098 g of sodium perchlorate (NaClO4) were mixed (1:1 molar ratio) and an electrolyte solution mixed to a concentration of 0.3 M in 3 L of distilled water was applied.

[0107]

[0108] <Examples 1-3>

[0109] Graphene was obtained through the same process as in Example 1-1, except that 17.532 g of sodium chloride (NaCl) and 73.464 g of sodium perchlorate (NaClO4) were mixed (molar ratio of 1:2) and an electrolyte solution mixed to a concentration of 0.3 M in 3 L of distilled water was applied.

[0110]

[0111] <Examples 1-4>

[0112] Graphene was obtained through the same process as in Example 1-1, except that 8.766 g of sodium chloride (NaCl) and 18.366 g of sodium perchlorate (NaClO4) were mixed (1:1 molar ratio) and an electrolyte solution mixed to a concentration of 0.1 M in 3 L of distilled water was applied.

[0113]

[0114] <Examples 1-5>

[0115] Graphene was obtained through the same process as in Example 1-1, except that 17.533 g of sodium chloride (NaCl) and 36.732 g of sodium perchlorate (NaClO4) were mixed (1:1 molar ratio) and an electrolyte solution mixed to a concentration of 0.2 M in 3 L of distilled water was applied.

[0116]

[0117] <Examples 1-6>

[0118] Graphene was obtained through the same process as in Example 1-1, except that 35.065 g of sodium chloride (NaCl) and 73.464 g of sodium perchlorate (NaClO4) were mixed (1:1 molar ratio) and an electrolyte solution mixed to a concentration of 0.4 M in 3 L of distilled water was applied.

[0119]

[0120] <Examples 1-7>

[0121] Graphene was obtained through the same process as in Example 1-1, except that 26.299 g of sodium chloride (NaCl) and 47.898 g of sodium chlorate (NaClO3) were mixed (1:1 molar ratio) and an electrolyte solution mixed to a concentration of 0.3 M in 3 L of distilled water was applied.

[0122]

[0123] <Examples 1-8>

[0124] Graphene was obtained through the same process as in Example 1-1, except that 26.299 g of sodium chloride (NaCl) and 62.347 g of potassium perchlorate (KClO4) were mixed (1:1 molar ratio) and an electrolyte solution mixed to a concentration of 0.3 M in 3 L of distilled water was applied.

[0125]

[0126] <Examples 1-9>

[0127] Graphene was obtained through the same process as in Example 1-1, except that 26.299 g of sodium chloride (NaCl) and 55.148 g of potassium chlorate (KClO3) were mixed (1:1 molar ratio) and an electrolyte solution mixed to a concentration of 0.3 M in 3 L of distilled water was applied.

[0128]

[0129] <Example 3-1>

[0130] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 2.19 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Two graphite electrodes (area 20 mm, Υ60 mm, thickness 0.254 mm) were placed in a reaction vessel with a spacing of 2 cm. Subsequently, the electrolyte solution was introduced so that the two graphite electrodes were immersed. Then, using both graphite electrodes as electrodes, a constant voltage of 10 V was applied for 60 minutes to exfoliate the graphite. Afterward, graphene was obtained through the same process as in Example 1-1.

[0131]

[0132] <Example 3-2>

[0133] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 1.82 g of tetramethylammonium hydroxide (TMAOH) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Example 3-1.

[0134]

[0135] <Example 3-3>

[0136] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 3.08 g of tetramethylammonium bromide (TMABr) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Example 3-1.

[0137]

[0138] <Examples 3-4>

[0139] Graphene was obtained through the same process as in Example 3-1, except that both graphite electrodes were used as electrodes, and the applied voltage was set to a square wave alternating current, and the graphite was exfoliated by applying a maximum voltage of 10 V and 50 Hz for 60 minutes.

[0140]

[0141] <Comparative Example 1-1>

[0142] Graphene was obtained through the same process as in Example 1-1, except that an electrolyte solution was applied in which 52.596 g of sodium chloride (NaCl) was mixed with 3 L of distilled water at a concentration of 0.3 M.

[0143]

[0144] <Comparative Example 1-2>

[0145] Graphene was obtained through the same process as in Example 1-1, except that an electrolyte solution was applied in which 110.196 g of sodium perchlorate (NaClO4) was mixed with 3 L of distilled water at a concentration of 0.3 M.

[0146]

[0147] <Comparative Example 1-3>

[0148] Graphene was obtained through the same process as in Example 1-1, except that an electrolyte solution of ammonium sulfate ((NH4)2SO4) mixed in 3 L of distilled water at a concentration of 0.3 M was applied.

[0149]

[0150] <Test Example>

[0151] 1) Graphene yield

[0152] The graphene yield was calculated based on the mass of the input graphite and the mass of the obtained graphene. The graphene yield was calculated using the following formula.

[0153]

[0154]

[0155] Classification Electrolyte Electrolyte Molar Ratio Concentration (M) Graphene Yield (%) Electrolyte 1 Electrolyte 2 Comparative Example 1-1 NaCl - 0.3 7.0 Comparative Example 1-2 NaClO4 - 0.3 29.0 Comparative Example 1-3 (NH4)2SO4 - 0.3 65.3 Example 1-1 NaClNaClO42 : 10.3 19.3 Example 1-2 NaClNaClO41 : 10.3 17.2 Example 1-3 NaClNaClO41 : 20.3 21.0 Example 1-4 NaClNaClO41 : 10.1 4.24 Example 1-5 NaClNaClO41 : 10.2 9.43 Example 1-6 NaClNaClO41 : 10.4 20.59 Example 1-7 NaClNaClO31 : 10.312.73 Example 1-8 NaClKClO41 : 10.312.70 Example 1-9 NaClKClO31 : 10.311.95 Example 3-1 NaClNaClO4, TMACl1 : 2 : 10.443.7 Example 3-2 NaClNaClO4, TMAOH 1 : 2 : 10.437.0 Example 3-3 NaClNaClO4, TMABr 1 : 2 : 10.438.6 Example 3-4 NaClNaClO 4, TMACl1 : 2 : 10.460.4

[0156] According to the manufacturing method of the embodiment, a relatively excellent yield was exhibited, and the manufacturing method according to the present invention is economical as it can effectively produce graphene. In particular, in the case of Comparative Example 1-1, which used only NaCl as the electrolyte, there is a problem that the yield is too low. Although the yield tends to increase as the content of the chlorate compound used increases, as shown in Tables 2 and 3 below, there is a problem that the defect rate increases as the oxygen content increases. Furthermore, when using the conventionally used ammonium sulfate ((NH4)2SO4), although the yield is high, there is a problem that it is difficult to economically produce high-quality graphene because it is not environmentally friendly and has a high defect rate. On the other hand, when a quaternary ammonium salt compound is used together with a chlorate compound as the electrolyte, the yield can be significantly improved, and furthermore, graphene can be produced more economically when an AC voltage is applied.

[0157]

[0158] 2) Carbon / Oxygen Content Ratio

[0159] X-ray photoelectron spectroscopy (XPS) analysis of the graphene powder prepared in the above examples and comparative examples was performed using an X-ray photoelectron spectrometer (ThermoFisher K-ALPHA), and the oxidation degree of the prepared graphene powder was evaluated based on this.

[0160] The oxygen (O) content ratio of graphene material can be confirmed through the C 1s peak and O 1s peak measured by X-ray photoelectron spectroscopy. Generally, when graphene is manufactured using electrochemical exfoliation, the processability and quality of the produced graphene deteriorate as the likelihood of electro-oxidation increases due to the prolonged electrochemical reaction. Therefore, the lower the oxygen content in the graphene, the higher the quality of the graphene can be evaluated.

[0161] The XPS spectrum graphs for the graphene of Examples 1-1 to 1-3 and Comparative Examples 1-1 and 1-2 are as shown in FIG. 3, and the XPS spectrum graphs for the graphene of Examples 1-4 to 1-9 are as shown in FIG. 4. In addition, the carbon / oxygen content ratios of Examples 1-1 to 1-9, 3-1 to 1-4, and Comparative Examples 1-1 to 1-3 are as shown in Table 2 below.

[0162]

[0163] C(%) O(%) C / O ratio Comparative Example 1-19 45.6 316.7 Comparative Example 1-28 4.48 14.45 5.85 Comparative Example 1-38 711.55 7.54 Example 1-19 4.39 5.1 118.47 Example 1-295.9 43.89 24.66 Example 1-38 7.59 12.19 7.18 Example 1-49 4.2 35.5 117.1 Example 1-59 5.6 24.23 22.6 Example 1-69 2.9 36.86 13.5 Example 1-79 5.39 4.34 22 Example 1-89 2.4 27.31 12.6 Example 1-994.774.620.6 Example 3-192.447.0213.17 Example 3-291.408.2411.09 Example 3-390.358.3910.77 Example 3-493.546.2315.01

[0164] The graphene produced in the examples had a carbon / oxygen content ratio of 7.18 to 24.66, exhibiting an overall superior carbon / oxygen content ratio compared to the graphene in the comparative examples. In particular, it was confirmed that when the content of the chlorate compound increases, the oxygen content in the resulting graphene becomes relatively higher, leading to an increase in defects. Additionally, it was confirmed that the oxygen content is relatively high even when using the conventionally used ammonium sulfate ((NH4)2SO4).

[0165]

[0166] 3) Defectiveness and Graphitization

[0167] The graphene powder prepared in the above examples and comparative examples was tested using an inVia Raman spectrometer (514 nm, Ar) from Renishaw (UK). + Analysis was performed using an ion laser, and the defect rate and graphitization rate of the graphene powder produced using this were evaluated.

[0168] Raman spectroscopy of graphene powder is a widely used analytical method for the analysis of carbon materials, and the Raman spectrum of graphene can consist primarily of several peaks, namely G, D, and G'. The G peak is the main characteristic peak of graphene; it is attributed to the in-plane vibrations of sp2 hybridized carbon atoms and can effectively reflect the number of graphene layers in a graphene sample. The D peak is generally considered to be a disordered vibration peak of graphene used to characterize structural defects in graphene samples, and the 2D peak is a second-order Raman peak representing 2-phonon resonance. The 2D peak can be used to characterize the interlayer stacking modes of carbon atoms in graphene samples. In the Raman spectrum of graphene powder, the peak height is I D Phosphorus 1250 to 1450 cm -1 A D peak is measured in the wavelength range of, and the peak height is I G Phosphorus 1500 to 1700 cm -1 A G peak is measured in the wavelength range of, and the peak height is I 2DPhosphorus 2600 to 2800 cm -1 A 2D peak is measured in the wavelength range. Raman spectroscopy has advantages in characterizing defects in graphene materials. Generally, defect density is the intensity of the "D peak (I D ) / G peak intensity(I G It is thought to be proportional to )", and I D / I G A low value means there are fewer defects. Also, "the intensity of the 2D peak (I 2D ) / G peak intensity(I G )" serves as a measure of the degree of graphitization.

[0169] The Raman spectrum graphs for the graphene of Examples 1-1 to 1-3 and Comparative Examples 1-1 and 1-2 are as shown in FIG. 5, and the Raman spectrum graphs for the graphene of Examples 1-4 to 1-9 are as shown in FIG. 6. In addition, the defect degree and graphitization degree for the graphene of Examples 1-1 to 1-9, 3-1 to 3-4, and Comparative Examples 1-1 to 1-3 are as shown in Table 3 below.

[0170]

[0171] Classification I D / I G (Defect level) I 2D / I G (Degree of Graphitization) Comparative Example 1-10.07 0.53 Comparative Example 1-20.86 0.28 Comparative Example 1-30.77 0.47 Example 1-10.13 0.52 Example 1-20.17 0.55 Example 1-30.18 0.5 Example 1-40.15 0.51 Example 1-50.14 0.51 Example 1-60.19 0.46 Example 1-70.07 0.54 Example 1-80.04 0.6 Example 1-90.05 0.53 Example 3-10.17 0.49 Example 3-20.18 0.47 Example 3-30.19 0.48 Example 3-40.18 0.50

[0172] Referring to Table 3, the graphene prepared in the examples is I D / I GThe (defect degree) was 0.13 to 0.19, showing lower defects compared to the comparative example, and at the same time I 2D / I G Since the degree of graphitization is 0.46 to 0.6, which is higher than that of the comparative example, it was confirmed that the manufacturing method of the present invention can economically produce graphene of excellent quality.

[0173]

[0174] <Example 2-1>

[0175] An electrolyte was prepared by mixing 26.298 g of sodium chloride (NaCl) and 49.32 g of tetramethylammonium chloride (TMACl) (molar ratio of 1:1) and mixing it with 3 L of distilled water to a concentration of 0.3 M. A graphite electrode (110 mm x 100 mm, thickness 0.5 mm) was used as the working electrode and a stainless steel electrode as the counter electrode, and one working electrode was placed in a reaction vessel at a 2.5 cm interval between two counter electrodes. Subsequently, the electrolyte was introduced so that the working electrode and the counter electrode were immersed. Afterward, a constant voltage of 10 V was applied to the electrodes for 60 minutes to exfoliate the graphite. Subsequently, the exfoliated graphite was washed using a vacuum filtration device with 20 L of distilled water while vacuum filtering. Next, the filtered and washed exfoliated graphite was mixed with distilled water and subjected to ultrasonic treatment for 3 hours. Next, the filtered and washed exfoliated graphite was mixed with distilled water and subjected to ultrasonic treatment for 3 hours. Afterward, the solvent was evaporated in an oven and vacuum dried at 100°C for 12 hours to obtain graphene powder.

[0176]

[0177] <Example 2-2>

[0178] 26.298 g of sodium chloride (NaCl) and 69.32 g of tetramethylammonium bromide (TMABr) were mixed (1:1 molar ratio), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Example 2-1.

[0179]

[0180] <Example 2-3>

[0181] 26.298 g of sodium chloride (NaCl) and 74.57 g of tetraethylammonium chloride (TEACl) were mixed (1:1 molar ratio), and an electrolyte solution was prepared by mixing it with 3 L of distilled water at a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Example 2-1.

[0182]

[0183] <Example 2-4>

[0184] 26.298 g of sodium chloride (NaCl) and 145.06 g of tetrabutylammonium bromide (TBABr) were mixed (1:1 molar ratio), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Example 2-1.

[0185]

[0186] <Example 2-5>

[0187] 26.298 g of sodium chloride (NaCl) and 152.78 g of tetrabutylammonium hydrogen sulfate (TBAH2SO4) were mixed (1:1 molar ratio), and an electrolyte was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Example 2-1.

[0188]

[0189] <Example 2-6>

[0190] An electrolyte was prepared by mixing 26.298 g of sodium chloride (NaCl) and 49.32 g of tetramethylammonium chloride (TMACl) (molar ratio of 1:1) and mixing it with 3 L of distilled water to a concentration of 0.3 M. Two graphite electrodes (area 20 mm x 60 mm, thickness 0.254 mm) were placed in a reaction vessel with a 2 cm gap between them. Subsequently, the electrolyte was introduced so that the two graphite electrodes were immersed. Then, using both graphite electrodes as electrodes, the graphite was exfoliated by applying a square wave alternating current voltage of 10 V and 50 Hz for 60 minutes. Next, the filtered and washed exfoliated graphite was mixed with distilled water and subjected to ultrasonic treatment for 3 hours. Afterward, the solvent was evaporated in an oven, and vacuum drying was performed at 100 °C for 12 hours to obtain graphene powder.

[0191]

[0192] <Example 2-7>

[0193] 26.298 g of sodium chloride (NaCl) and 69.32 g of tetramethylammonium bromide (TMABr) were mixed (1:1 molar ratio), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0194]

[0195] <Example 2-8>

[0196] 26.298 g of sodium chloride (NaCl) and 74.57 g of tetraethylammonium chloride (TEACl) were mixed (1:1 molar ratio), and an electrolyte was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0197]

[0198] <Example 2-9>

[0199] 26.298 g of sodium chloride (NaCl) and 145.06 g of tetrabutylammonium bromide (TBABr) were mixed (1:1 molar ratio), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0200]

[0201] <Example 2-10>

[0202] 26.298 g of sodium chloride (NaCl) and 152.78 g of tetrabutylammonium hydrogen sulfate (TBAH2SO4) were mixed (1:1 molar ratio), and an electrolyte was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0203]

[0204] <Example 2-11>

[0205] 17.53 g of sodium chloride (NaCl) and 193.42 g of tetrabutylammonium bromide (TBABr) were mixed (molar ratio of 1:2), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0206]

[0207] <Example 2-12>

[0208] 13.15 g of sodium chloride (NaCl) and 217.59 g of tetrabutylammonium bromide (TBABr) were mixed (molar ratio of 1:3), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0209]

[0210] <Example 2-13>

[0211] 35.06 g of sodium chloride (NaCl) and 96.71 g of tetrabutylammonium bromide (TBABr) were mixed (molar ratio of 2:1), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0212]

[0213] <Example 2-14>

[0214] 39.45 g of sodium chloride (NaCl) and 72.53 g of tetrabutylammonium bromide (TBABr) were mixed (molar ratio of 3:1), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0215]

[0216] <Example 2-15>

[0217] 35.06 g of sodium chloride (NaCl) and 203.72 g of tetrabutylammonium hydrogen sulfate (TBAH2SO4) were mixed (1:1 molar ratio), and an electrolyte was prepared by mixing it with 3 L of distilled water to a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0218]

[0219] <Example 2-16>

[0220] 43.83 g of sodium chloride (NaCl) and 254.64 g of tetrabutylammonium hydrogen sulfate (TBAH2SO4) were mixed (1:1 molar ratio), and an electrolyte was prepared by mixing it with 3 L of distilled water to a concentration of 0.5 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0221]

[0222] <Examples 3-5>

[0223] 1.17 g of sodium chloride (NaCl), 4.26 g of sodium chlorate (NaClO3), and 1.82 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0224]

[0225] <Examples 3-6>

[0226] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium fluoroborate (NaBF), and 1.82 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0227]

[0228] <Example 3-7>

[0229] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 3.08 g of tetramethylammonium bromide (TMABr) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0230]

[0231] <Example 3-8>

[0232] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 3.31 g of tetraethylammonium chloride (TEACl) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0233]

[0234] <Example 3-9>

[0235] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 6.45 g of tetrabutylammonium bromide (TBABr) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0236]

[0237] <Example 3-10>

[0238] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 6.79 g of tetrabutylammonium hydrogen sulfate (TBAH2SO4) were mixed (molar ratio of 1:2:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.4 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0239]

[0240] <Example 3-11>

[0241] 0.58 g of sodium chloride (NaCl), 3.67 g of sodium perchlorate (NaClO4), and 2.19 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 0.5:1.5:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0242]

[0243] <Example 3-12>

[0244] 1.75 g of sodium chloride (NaCl), 6.12 g of sodium perchlorate (NaClO4), and 2.19 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 1.5:2.5:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.5 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0245]

[0246] <Example 3-13>

[0247] 2.34 g of sodium chloride (NaCl), 7.35 g of sodium perchlorate (NaClO4), and 2.19 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 2:3:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.6 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0248]

[0249] <Example 3-14>

[0250] 2.92 g of sodium chloride (NaCl), 8.57 g of sodium perchlorate (NaClO4), and 2.19 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 2.5:3.5:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.7 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0251]

[0252] <Example 3-15>

[0253] 3.51 g of sodium chloride (NaCl), 9.80 g of sodium perchlorate (NaClO4), and 2.19 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 3:4:1) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.8 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0254]

[0255] <Example 3-16>

[0256] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 4.38 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 1:2:2) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.5 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0257]

[0258] <Example 3-17>

[0259] 1.17 g of sodium chloride (NaCl), 4.89 g of sodium perchlorate (NaClO4), and 6.58 g of tetramethylammonium chloride (TMACl) were mixed (molar ratio of 1:2:3) and mixed with 200 mL of distilled water to prepare an electrolyte solution with a concentration of 0.6 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0260]

[0261]

[0262]

[0263] <Comparative Example 2-1>

[0264] 26.298 g of sodium chloride (NaCl) and 55.098 g of sodium perchlorate (NaClO4) were mixed (1:1 molar ratio), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0265]

[0266] <Comparative Example 2-2>

[0267] 26.298 g of sodium chloride (NaCl) and 55.098 g of sodium perchlorate (NaClO4) were mixed (1:1 molar ratio), and an electrolyte solution was prepared by mixing it with 3 L of distilled water to a concentration of 0.3 M. Subsequently, graphene was obtained through the same process as in Examples 2-6.

[0268]

[0269] <Test Example>

[0270] 1) Graphene yield

[0271] The graphene yield was calculated based on the mass of the input graphite and the mass of the obtained graphene. The graphene yield was calculated using the following formula.

[0272]

[0273]

[0274] Classification Voltage Solvent Electrolyte Addition Electrolyte Molar Ratio Concentration Yield (%) Addition 1 Addition 2 Example 2-1 DC Water NaCl TMACl1 : 10.3 M 5.1 Example 2-2 DC Water NaCl TMABr1 : 10.3 M 7.1 Example 2-3 DC Water NaCl TEACl1 : 10.3 M 2.7 Example 2-4 DC Water NaCl TBABr1 : 10.3 M 5.3 Example 2-5 DC Water NaCl TBAH2SO41 : 10.3 M 4.3 Example 2-6 AC Water NaCl TMACl1 : 10.3 M 10.5 Example 2-7 AC Water NaCl TMABr1 : 10.3 M 13.8 Example 2-8 AC Water NaCl TEACl1 : 10.3 M 4.5 Example 2-9 AC Water NaCl TBABr1 : 10.3 M 90 Example 2-10 AC Water NaCl TBAH2SO41 : 10.3 M 2.3 Example 2-11 AC Water NaCl TBABr1 : 20.3 M 15.5 Example 2-12 AC Water NaCl TBABr1 : 30.3 M 15.1 Example 2-13 AC Water NaCl TBABr2 : 10.3 M 9.6 Example 2-14 AC Water NaCl TBABr3 : 10.3 M 7.7 Example 2-15 AC Water NaCl TBAH2SO41 : 10.4 M 4.8 Example 2-16 AC Water NaCl TBAH2SO41 : 10.5 M 6.5 Example 3-5 AC Water NaCl NaCl O3 TBACl1 : 2 : 10.4 M 16.5 Example 3-6 AC Water NaCl NaBF 4TMACl 1 : 2 : 10.4 M 7.1 Example 3-7 AC Water NaCl NaCl O 4TMABr 1 : 2 : 10.4 M 6.0 Example 3-8 AC Water NaCl NaCl O 4TEACl 1 : 2 : 10.4 M 22.8 Example 3-9 AC Water NaCl NaCl O 4TBABr 1 : 2 : 10.4 M 48.8 Example 3-10 AC Water NaCl NaCl O 4TBAH 2SO 4 1 : 2 : 10.4 M 8.3 Example 3-11 AC Water NaCl NaCl O 4TMACl 0.5 : 1.5 : 10.3 M 11.2 Example 3-12 AC Water NaCl NaCl O 4TMACl 1.5 : 2.5 : 10.5 M 34.2 Example 3-13AC Water NaCl NaCl O 4TMACl 2 : 3 : 10.6 M27.8 Example 3-14AC Water NaCl NaCl O 4TMACl 2 5 : 3.5 : 10.7 M3 3.1 Example 3-15 AC Water NaCl NaCl O 4 TMACl 3 : 4 : 10.8 M 4 3.1 Example 3-16 AC Water NaCl NaCl O 4 TMACl 1 : 2 : 20.5 M 17.6 Example 3-17 AC Water NaCl NaCl O 4 TMACl 1 : 2 : 30.6 M 18.3 Comparative Example 1-1 DC Water NaCl --- 0.3 M 7.0 Comparative Example 1-2 DC Water NaCl O 4 --- 0.3 M 29.0 Comparative Example 1-3 DC Water (NH4)2SO 4 --- 0.3 M 6 5.3 Comparative Example 2-1 AC Water TMACl --- 0.3 M 10.3 Comparative Example 2-2 AC Water TMABr --- 0.3 M 12.4.

[0275] According to the manufacturing method of the example, a relatively excellent yield was observed, and the manufacturing method according to the present invention is economical as it can effectively produce graphene. In particular, Comparative Example 1-1, which used only sodium chloride (NaCl) as the electrolyte, has a problem of low yield, and Comparative Example 1-2, which used only sodium perchlorate (NaClO4), shows a somewhat high yield, but as shown in Tables 5 and 6 below, there is a problem that the defect rate increases as the oxygen content increases. In addition, Comparative Example 1-3, which uses the conventionally used ammonium sulfate ((NH4)2SO4), has a high yield, but there is a problem that it is difficult to economically produce high-quality graphene because it is not environmentally friendly and has a high defect rate. In addition, Comparative Examples 2-1 and 2-2, in which only tetramethylammonium chloride (TMACl) or tetramethylammonium bromide (TMABr) was used as the electrolyte, have a problem of low yield compared to Examples 2-6 and 2-7, in which they were used together with sodium chloride (NaCl). On the other hand, when a quaternary ammonium salt compound is used together with sodium chloride (NaCl) as the electrolyte, the yield can be significantly improved, and furthermore, graphene can be produced more economically when an alternating voltage is applied.

[0276]

[0277] 2) Carbon / Oxygen Content Ratio

[0278] X-ray photoelectron spectroscopy (XPS) analysis of the graphene powder prepared in the above examples and comparative examples was performed using an X-ray photoelectron spectrometer (ThermoFisher K-ALPHA), and the oxidation degree of the prepared graphene powder was evaluated based on this.

[0279] The oxygen (O) content ratio of graphene material can be confirmed through the C 1s peak and O 1s peak measured by X-ray photoelectron spectroscopy. Generally, when graphene is manufactured using electrochemical exfoliation, the processability and quality of the produced graphene deteriorate as the likelihood of electro-oxidation increases due to the prolonged electrochemical reaction. Therefore, the lower the oxygen content in the graphene, the higher the quality of the graphene can be evaluated.

[0280]

[0281] Classification C / O ratio Example 2-120.00 Example 2-233.59 Example 2-314.11 Example 2-431.45 Example 2-511.67 Example 2-619.21 Example 2-732.34 Example 2-815.79 Example 2-947.39 Example 2-1018.30 Example 2-1126.45 Example 2-1225.87 Example 2-1329.15 Example 2-1428.55 Example 2-1512.37 Example 2-1610.60 Example 3-516.21 Example 3-613.88 Example 3-724.68 3-8 25.59 Example 3-9 27.37 Example 3-108.69 Example 3-11 21.91 Example 3-12 21.02 Example 3-13 20.04 Example 3-14 18.11 Example 3-15 18.56 Example 3-16 27.88 Example 3-17 25.95 Comparative Example 1-116.7 Comparative Example 1-25.85 Comparative Example 1-37.54 Comparative Example 2-136.67 Comparative Example 2-233.28

[0282] The graphene produced in the examples exhibited an overall superior carbon-to-oxygen ratio compared to the graphene in the comparative examples. In particular, it was confirmed that as the content of the chlorate compound increased, the oxygen content in the resulting graphene became relatively higher, leading to an increase in defects. Furthermore, it was confirmed that the oxygen content was also relatively high when using the conventionally used ammonium sulfate ((NH4)2SO4).

[0283]

[0284] 3) Defectiveness and Graphitization

[0285] The graphene powder prepared in the above examples and comparative examples was tested using an inVia Raman spectrometer (514 nm, Ar) from Renishaw (UK). + Analysis was performed using an ion laser, and the defect degree, graphitization degree, and the ratio of defect degree to graphitization degree of the graphene powder prepared using this method were evaluated.

[0286] Raman spectroscopy of graphene powder is a widely used analytical method for the analysis of carbon materials, and the Raman spectrum of graphene can consist mainly of several peaks of G, D, and G'. The G peak is the main characteristic peak of graphene, and this is sp 2 It is attributed to the in-plane vibrations of hybridized carbon atoms and can effectively reflect the number of graphene layers in a graphene sample. The D peak is generally considered to be a disordered vibration peak of graphene used to characterize structural defects in graphene samples, and the 2D peak is a second-order Raman peak of 2-phonon resonance. The 2D peak can be used to characterize the interlayer stacking modes of carbon atoms in graphene samples. In the Raman spectrum of graphene powder, the peak height is I D Phosphorus 1250 to 1450 cm -1 A D peak is measured in the wavelength range of, and the peak height is I G Phosphorus 1500 to 1700 cm -1 A G peak is measured in the wavelength range of, and the peak height is I 2DPhosphorus 2600 to 2800 cm -1 A 2D peak is measured in the wavelength range. Raman spectroscopy has advantages in characterizing defects in graphene materials. Generally, defect density is the intensity of the "D peak (I D ) / G peak intensity(I G It is thought to be proportional to )", and I D / I G A low value means there are fewer defects. Also, "the intensity of the 2D peak (I 2D ) / G peak intensity(I G )" serves as a measure of the degree of graphitization.

[0287]

[0288] Classification I D / I 2d (Ratio of defect degree to graphitization degree) Example 2-10.176 Example 2-20.243 Example 2-30.188 Example 2-40.177 Example 2-50.554 Example 2-60.029 Example 2-70.089 Example 2-80.033 Example 2-90.031 Example 2-100.178 Example 2-110.099 Example 2-120.125 Example 2-130.088 Example 2-140.084 Example 2-150.244 Example 2-160.279 Example 3-50.119 Example 3-60.099 Example 3-70.084 Example 3-80.09 Example 3-90.044 Example 3-100.3 Example 3-110.53 Example 3-120.043 Example 3-130.065 Example 3-140.060 Example 3-150.066 Example 3-160.095 Example 3-170.15 Comparative Example 1-11.321 Comparative Example 1-23.071 Comparative Example 1-31.638 Comparative Example 2-10.055 Comparative Example 2-20.072

[0289] The graphene prepared in the example has a ratio of defect degree to graphitization (defect density / graphitization degree; i.e., intensity of the D peak (I D ) / 2D peak intensity(I 2DAs )) was found to be low at 1.0 or less, it was confirmed that the manufacturing method of the present invention can economically produce high-quality graphene.

Claims

1. A method for manufacturing graphene by electrochemical non-oxidative exfoliation, The above electrochemical non-oxidative stripping method is performed by applying voltage to a working electrode and a counter electrode placed in an electrolyte, and The above electrolyte comprises a solvent and an electrolyte, and A method for producing graphene, wherein the electrolyte comprises a first electrolyte comprising sodium chloride (NaCl); and a second electrolyte comprising a chlorate compound, a quaternary ammonium salt compound, or a combination thereof.

2. In Paragraph 1, A method for manufacturing graphene in which the molar concentration of the electrolyte contained in the above electrolyte is 0.05 M to 1.0 M.

3. In Paragraph 1, A method for manufacturing graphene, wherein the above solvent includes water.

4. In Paragraph 1, The above electrolyte includes sodium chloride (NaCl) and chlorate compounds, and A method for producing graphene comprising the sodium chloride (NaCl) and the chlorate compound in a molar ratio of 2.5 : 0.5 to 0.5 : 2.

5.

5. In Paragraph 1, The above electrolyte includes sodium chloride (NaCl) and chlorate compounds, and The above chlorate compounds are lithium chlorate (LiClO3), sodium chlorate (NaClO3), potassium chlorate (KClO3), calcium chlorate (Ca(ClO3)2), ammonium chlorate (NH4ClO3), lithium perchlorate (LiClO4), sodium perchlorate (NaClO4), potassium perchlorate (KClO4), magnesium perchlorate (Mg(ClO4)2), calcium perchlorate (Ca(ClO4)2), barium perchlorate (Ba(ClO4)2), ammonium perchlorate (NH4ClO4), sodium hypochlorite (NaClO2), potassium hypochlorite (KClO2), calcium hypochlorite (Ca(ClO2)2), magnesium hypochlorite (Mg(ClO2)2), ammonium hypochlorite (NH4ClO2), lithium hypochlorite (LiClO), A method for producing graphene comprising one or more selected from the group consisting of sodium hypochlorite (NaClO), potassium hypochlorite (KClO), calcium hypochlorite (Ca(ClO)2), and ammonium hypochlorite (NH4ClO).

6. In Paragraph 5, A method for producing graphene, wherein the chlorate compound comprises one or more selected from the group consisting of sodium chlorate (NaClO3), potassium chlorate (KClO3), sodium perchlorate (NaClO4), and potassium perchlorate (KClO4).

7. In Paragraph 1, The above electrolyte comprises sodium chloride (NaCl) and a quaternary ammonium salt compound, and A method for manufacturing graphene comprising the sodium chloride and the quaternary ammonium salt compound in a molar ratio of 0.5 to 3 : 0.5 to 3.

8. In Paragraph 1, The above electrolyte comprises sodium chloride (NaCl) and a quaternary ammonium salt compound, and The above quaternary ammonium salt compounds are tetramethylammonium hydroxide (TMAOH), tetramethylammonium chloride (TMACl), tetramethylammonium bromide (TMABr), tetramethylammonium iodide (TMAI), tetraethylammonium chloride (TEACl), tetraethylammonium bromide (TEABr), tetraethylammonium iodide (TEAI), tetrapropylammonium chloride (TPACl), tetrabutylammonium chloride (TBACl), and tetrabutylammonium bromide (TBABr). A method for producing graphene comprising one or more selected from the group consisting of tetrabutylammonium hydrogen sulfate (TBAH2SO4) and benzyltrimethylammonium chloride (BTMACl).

9. In Paragraph 1, The above electrolyte comprises sodium chloride, a chlorate compound, and a quaternary ammonium salt compound, and A method for manufacturing graphene comprising the sodium chloride, the chlorate compound, and the quaternary ammonium salt compound in a molar ratio of 0.5 to 3 : 0.5 to 4 : 0.5 to 3.

10. In Paragraph 1, The above working electrode and the above counter electrode are both graphite electrodes, and A method for manufacturing graphene, wherein the applied voltage is an alternating current voltage.

11. In Paragraph 1, (1) A step of exfoliating graphite by applying voltage to a working electrode and a counter electrode placed in an electrolyte; (2) A step of filtering and washing the exfoliated graphite; and (3) Ultrasonic treatment step A method for manufacturing graphene comprising 12. In Paragraph 11, A method for manufacturing graphene, wherein the above washing solution comprises water or ethanol.

13. In Paragraph 11, A method for manufacturing graphene, further comprising a drying process.

14. Graphene prepared according to the method of claim 1.

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