WO2024053831A1

WO2024053831A1 - Graphene synthesis device and graphene synthesis method

Info

Publication number: WO2024053831A1
Application number: PCT/KR2023/009090
Authority: WO
Inventors: 남우석; 오은석
Original assignee: 주식회사 이녹스에코엠
Priority date: 2022-09-06
Filing date: 2023-06-29
Publication date: 2024-03-14
Also published as: KR20240033995A

Abstract

According to the present invention, provided is a graphene synthesis device comprising a graphene synthesis reaction tank, and an electrode part arranged inside the reaction tank, wherein the electrode part includes n metal electrode parts and n+1 working electrode parts arranged alternately with the metal electrode parts, a predetermined concentration of an electrolyte solution is contained in the graphene synthesis reaction tank, the metal electrode parts are electrochemically connected so as to act as an anode, the working electrode parts are electrochemically connected so as to act as a cathode, the metal electrode parts include a metal electrodes arranged with predetermined intervals therebetween, the working electrode parts include b working electrodes arranged alternately with the metal electrodes with predetermined intervals therebetween, and n, a and b are an integer of 1 or greater.

Description

Graphene synthesis device and graphene synthesis method

The present invention relates to a graphene synthesis device and a graphene synthesis method, and more specifically, to a device capable of continuously synthesizing high-quality low-oxidized graphene and a graphene synthesis method using the same.

Graphene is one of the allotropes of carbon, and is a two-dimensional planar structure with a single atomic layer thickness in which carbon atoms are each connected by SP ² hybrid structure bonds, and has a hexagonal structure in which benzene-type carbon rings are connected to form a honeycomb or network. It has a crystal form.

Individual graphene units exist in the form of graphite due to Van der Waals forces, and for industrial use, a process of exfoliating graphene from graphite is essential.

Conventional methods for synthesizing graphene include a method of mechanically exfoliating graphene from graphite, a method of directly producing graphene by chemical vapor deposition (CVD), and an oxidation-reduction method of graphite. In particular, , the oxidation-reduction method of graphite has been most commonly used in that it is suitable for mass production.

The oxidation-reduction method of graphite is a method that facilitates exfoliation between graphene layers by reducing the van der Waals attraction by reducing the pi electron density between the graphene layers that make up graphite by inducing oxygen-based functional groups. A recent research paper 『"Nature and Strength of Interlayer Binding in Graphite", Spanu, L.; Sorella, S.; Galli, G. Phys. Rev. Lett. 2009, 103, 196401196404』 and 『"Application of van der Waals Density Functional to an Extended System: Adsorption of Benzene and Naphthalene on Graphite", Chakarova-Kack, S. D.; Schroder, E.; Lundqvist, B. I.; Langreth, D. C. Phys. Rev. Lett. According to 2006, 96, 146107-146110, etc., it has been revealed that when the interlayer spacing of graphene in graphite becomes 5Å or more, the interlayer van der Waals attraction of graphene completely disappears.

However, since the oxidation process in the graphite oxidation-reduction method is oxidized under extreme conditions combining a strong acid and a strong oxidizing agent, not only is the original graphene structure not restored even after reduction, but oxygen remains after the reduction process. Therefore, it is easy to mass-produce graphene, but it has the disadvantage that high-quality graphene cannot be produced because the defect rate and oxidation degree increase.

More specifically, in the oxidation between graphene layers, hydroxyl groups and epoxy groups are created as an initial reaction, and as the oxidation reaction continues, ethers are formed, and finally carboxyl groups are formed. group) is created, and in this process, the carbon-carbon bonds that make up graphene are broken, causing defects, and there is a problem in that these defects are not completely restored even after reduction.

Recently, a method of producing multilayer graphene from graphite using an electrochemical process (hereinafter referred to as 'electrochemical method') has been developed. When using an electrochemical process, multilayer graphene with a size of several micrometers or more is obtained from graphite through a single process. It has the advantage of being able to manufacture pins with high yield. However, because the electrochemical method uses a sulfuric acid electrolyte, a chemical reaction occurs between radicals generated by sulfuric acid and graphite, which has the disadvantage of increasing the defect rate of the finally produced multilayer graphene.

In order to finally manufacture the multilayer graphene synthesized by the electrochemical method as described above into single-layer graphene, a method of inserting an alkali metal between graphene layers to exfoliate the graphene is used. However, since the relative size of the inserted metal ion is small, peeling does not occur easily or the efficiency is not high, so an additional peeling process is essential. Another exfoliation method is a method of exfoliating graphene by electrochemically inserting ammonium-based single molecules, and more than 90% of the produced graphene has a thickness of 10 layers or more, so it is not called graphene in the conventional sense. There is a limitation that it is closer to thinner exfoliated graphite.

As such, the method of producing multilayer graphene using a conventional electrochemical method has the disadvantages that the produced multilayer graphene has a high defect rate, requires additional processes, is limited in size, or is thick.

Therefore, for effective industrial use of graphene, the quality of the final manufactured graphene can be improved by increasing the size of graphene and thinning the thickness, while at the same time reducing the defect rate of graphene as much as possible. There is a demand for the development of a graphene synthesis device and method to improve mass productivity by continuously synthesizing graphene.

The purpose of the present invention is to solve the limitations and problems of the conventional graphene synthesis process as described above, thereby increasing the size of graphene and making it thinner, while at the same time producing excellent quality graphene that reduces the defect rate of graphene as much as possible. The goal is to provide a graphene synthesis device and a graphene synthesis method that can efficiently and continuously mass produce pins.

The object of the present invention is not limited to the object mentioned above, and other objects and advantages of the present invention that are not mentioned can be understood through the following description and will be more clearly understood by the examples of the present invention. In addition, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof indicated in the patent claims.

According to one aspect of the present invention, a graphene synthesis reaction tank; and an electrode portion disposed inside the reaction tank, wherein the electrode portion includes n metal electrode portions and n+1 working electrode portions alternately disposed with the metal electrode portion, and the graphene synthesis reaction tank. The inside of contains an electrolyte solution of a certain concentration, the metal electrode portion is electrochemically connected and operates as a cathode, the working electrode portion is electrochemically connected and operates as an anode, and the metal electrode portion is spaced at a predetermined interval. A graphene synthesis device comprising a number of metal electrodes arranged, wherein the working electrode unit includes b number of working electrodes arranged alternately with the metal electrodes at a predetermined interval, wherein n, a, and b are integers of 1 or more. can be provided.

The metal electrode portion and the working electrode portion may each be a plate-shaped electrode portion, and the metal electrode and the working electrode may be a metal electrode and a working electrode respectively applied in the form of a rod.

When the diameters of the metal electrode and the working electrode are each D (cm), the distance between the metal electrode and the working electrode may be arranged at 2D (cm).

The metal electrode may be a stainless steel electrode, and the working electrode may be a graphite electrode.

The electrolyte solution may include one or more selected from the group consisting of sulfate, nitrate, phosphate, potassium salt, metal halide, and ionic liquid. According to a preferred embodiment, the electrolyte solution includes ammonium sulfate and sulfuric acid. It may contain one or more types of potassium.

The graphene synthesis device may further include an electrolyte solution supply device for continuously supplying an electrolyte solution, and the electrolyte solution supply device may include an electrolyte solution concentration measuring/controlling unit; and an electrolyte solution supply unit.

A drive motor that can operate up and down opposite to the graphene synthesis reaction tank may be connected to the electrode unit.

It may further include a spare working electrode unit including a spare working electrode that is replaced when the working electrode is consumed by graphene synthesis, and the spare working electrode unit may be connected to the driving motor.

The graphene synthesis device may further include a filter system that separates the graphene synthesized from the graphene synthesis device and the electrolyte solution, and the filter system may include a graphene recovery unit that recovers the synthesized graphene. And, the filter system may be installed separately from the graphene synthesis reaction tank.

The graphene synthesis apparatus may further include a heat exchanger that controls the temperature of the electrolyte solution in the graphene synthesis reaction tank.

A constant current regulator may be connected to the electrode unit.

According to another aspect of the present invention, adding an electrolyte solution into a graphene synthesis reaction tank; Arranging an electrode unit including n metal electrode units and n+1 working electrode units alternately disposed with the metal electrode units, inside the reaction tank; electrochemically connecting the metal electrode portion to a cathode and electrochemically connecting the working electrode portion to an anode; and synthesizing graphene by applying a voltage to the metal electrode portion and the working electrode portion, wherein the metal electrode portion may include a number of metal electrodes arranged at predetermined intervals, and The working electrode unit may include b working electrodes alternately arranged with the metal electrode at a predetermined interval, and n, a, and b are integers of 1 or more.

The metal electrode may be a stainless steel electrode in the form of a rod, and the working electrode may be a graphite electrode in the form of a rod.

The electrolyte solution may include one or more selected from the group consisting of sulfate, nitrate, phosphate, metal halide, and ionic liquid.

In order to maintain the concentration and volume of the electrolyte solution, the electrolyte solution may be continuously supplied. At this time, the initial concentration of the electrolyte solution may be preferably 0.1 to 0.5 M, and more preferably 0.3 to 035 M. As the graphene synthesis reaction progresses, the concentration may increase due to moisture evaporating into water vapor during the reaction, so the electrolyte solution can be continuously supplied to maintain the initial concentration, and for this purpose, a buffer containing the electrolyte solution is provided. A buffer solution tank can be used. The capacity of the buffer solution tank may vary depending on design conditions, etc., and may be, for example, 20 to 50 L, for example, 30 to 40 L, but is not limited thereto.

The temperature of the electrolyte solution can be controlled to remain constant. Since the temperature of the system continues to rise due to the graphene synthesis reaction, the reaction heat generated thereby activates moisture evaporation in the electrolyte solution, so it is desirable to cool the reaction heat to maintain room temperature (approximately 25°C). One way to implement this is, for example, using a chiller.

The graphene synthesis method may further include the step of replacing the working electrode with a spare working electrode when it is consumed by graphene synthesis.

The graphene synthesis method may further include the step of separating and recovering the synthesized graphene.

The graphene synthesis device of the present invention consists of a multi-electrode system in which a plurality of metal electrodes are arranged around a plurality of working electrodes, so that a large amount of metal electrodes surround each working electrode, resulting in the production of a large amount in a short time. Graphene can be synthesized.

In the graphene synthesis device of the present invention, the distance between electrodes is constant and a metal electrode surrounds the working electrode, so the peeling effect due to chemical reaction in an electric field can be maximized, and the yield of graphene synthesis is high while Since the variation in synthesis yield is small, it has the advantage of being advantageous for mass production and management of graphene.

The graphene synthesis apparatus of the present invention may further include a spare working electrode unit including a spare working electrode that is replaced when the working electrode is consumed by graphene synthesis, so that graphene can be continuously mass-produced.

The graphene synthesis device of the present invention can continuously supply an electrolyte solution and stably discharge an electrolyte containing synthesized graphene, thereby enabling continuous mass production of graphene.

1 is a schematic diagram of a graphene synthesis device according to an aspect of the present invention.

2 to 4 are cross-sectional schematic diagrams of electrode portions of a graphene synthesis device according to an aspect of the present invention.

Figure 5 is a photograph of the electrode portion of the graphene synthesis device according to one aspect of the present invention.

Figure 6 is a photograph of a graphene synthesis device according to an aspect of the present invention.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and identical or similar components are given the same reference numerals throughout the specification.

In describing the present specification, if it is determined that a detailed description of related known technology may unnecessarily obscure the gist of the present specification, the detailed description will be omitted.

In this specification, when 'includes', 'has', 'consists of', 'arranges', etc. are used for constituent elements, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

In interpreting the components in this specification, they are interpreted to include the margin of error even if there is no separate explicit description.

In this specification, the “top (or bottom)” of a component or the arrangement of any component on the “top (or bottom)” of a component means that any component is disposed in contact with the top (or bottom) of the component. In addition, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

According to one aspect of the present invention, a graphene synthesis device can be provided. Figure 1 is a simplified illustration of a graphene synthesis device, and Figures 2 to 4 are a simplified cross-sectional view of an electrode portion of the graphene synthesis device.

Referring to Figures 1 and 2, the graphene synthesis apparatus 1 includes a graphene synthesis reaction tank 10; and an electrode unit 20 disposed inside the reaction tank 10, wherein the electrode unit 20 is alternately arranged with n metal electrode units 20A and the metal electrode units 20A. It includes n+1 working electrode units 20B, and the inside of the graphene synthesis reaction tank 10 contains an electrolyte solution of a certain concentration, and the metal electrode unit 20A is electrochemically connected to the cathode. The working electrode unit 20B is electrochemically connected and operates as an anode, and the metal electrode unit 20A includes a number of metal electrodes (20a in FIG. 2) arranged at predetermined intervals. , the working electrode unit 20B includes b working electrodes (20b in FIG. 2) arranged alternately with the metal electrodes (20a in FIG. 2) at a predetermined interval, where n, a, and b are 1. It can be an integer above.

The operating voltage applied from the graphene synthesis device 1 may be 5V to 20V, and for example, it may be desirable to maintain the voltage at a level of 10 ± 0.1V. Additionally, the applied operating current may be 15A to 30A, and for example, it may be desirable for the current to be supplied maintained at a level of 23±0.3A.

By connecting a constant current regulator 50 to the electrode unit 10, the constant current applied for the graphene synthesis reaction can be controlled.

As can be seen with reference to FIG. 3, the metal electrode portion 20A and the working electrode portion 20B may each be plate-shaped electrode portions. Each electrode may be arranged at predetermined intervals in the plate-shaped electrode portion.

As can be seen with reference to FIG. 3, when the diameters of the metal electrode 20a and the working electrode 20b are D (cm), the distance between the metal electrode 20a and the working electrode 20b is It may be arranged in 2D (cm), but is not necessarily limited thereto.

The metal electrode 20a may be a stainless steel electrode, and the working electrode 20b may be a graphite electrode.

For example, a stainless steel electrode, which is a metal electrode 20a, may be fixed and installed as a cathode on the upper part of the graphene synthesis reaction tank 10 in which an electrolyte solution is prepared, and working electrodes 20b may be alternately arranged between them. The phosphorus graphite electrode operates as an anode and can be continuously placed and exchanged between the cathodes of the graphene synthesis reaction tank 10.

There are various types of stainless steel, but among them, ferritic stainless steel or martensitic stainless steel contains relatively less nickel (Ni) than austenitic stainless steel, so it is prone to crevice corrosion. Therefore, from the viewpoint of mass production of graphene, austenitic stainless steel may be preferable for use as a working electrode.

More specifically, among the types of austenitic stainless steel, the 316/316L or 317L series are relatively superior to the 304/304L series, but preferably, the 310S electrode, which has a relatively high nickel content among austenitic stainless steels, is used. It may be more desirable to do so.

When an electrolyte solution is supplied to the inside of the graphene synthesis reaction tank 10 and a constant direct current is supplied to each electrode (20a, 20b), the ammonium sulfate electrolyte solution and SO ₄ contained between the graphite electrodes (operating electrodes) are ^2- Ions and water molecules are oxidized to generate SO ₂ and O ₂ gas, and as the graphite layer is exfoliated through the gasification reaction, low-oxidation exfoliated graphene with almost no defects can be continuously produced.

The graphene synthesis apparatus 1 may supply an electrolyte solution to the graphene synthesis reaction tank 10 through an electrolyte solution supply passage 60.

The electrolyte solution may include one or more selected from the group consisting of sulfate, nitrate, phosphate, metal halide, and ionic liquid. Preferably, the electrolyte solution of the present invention may contain ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), but in order to produce graphene with a thinner layer, ammonium, which has the effect of increasing the thickness of the graphene layer, is used. An electrolytic solution containing metal ions, which are more advantageous for producing thinner graphene than ions (NH ₄ ⁺ ), can also be used.

For example, an electrolyte solution in which the amount of ammonium ions is reduced and the concentration of ammonium ions is set to 70 wt% to 90 wt% in consideration of mass productivity, and the amount of other metal ions mixed is mixed at a ratio of 10 wt% to 30 wt%. can be used.

Specifically, the concentration of metal ions in the electrolyte solution varies depending on the thickness conditions of graphene required in the final manufactured product. For example, the composition of the electrolytic solution for producing thick graphene of about 5 to 10 layers is preferably composed of 100 wt% ammonium ions and no other metal ions.

For example, in order to mass-produce multilayer graphene with a thickness of about 3 to 6 layers, it is preferable to contain 85 wt% to 90 wt% of ammonium ions, and more preferably to contain 87 wt% to 90 wt% of ammonium ions. It is preferable and can be used as an electrolytic solution by mixing with other metal ions. Candidate materials for the other metal ions include potassium ions (K ⁺ ), sodium ions (Na ⁺ ), preferably 10 wt% to 15 wt% potassium ions, more preferably 13 wt% to 15 wt% potassium ions, and A mixed electrolyte solution can be used.

The electrolytic solution can be prepared as an aqueous solution in which metal ions at a concentration of 0.3 mol to 0.5 mol are dissolved. For example, in order to manufacture thick graphene with 5 to 10 layers, it is desirable to use an ammonium sulfate electrolyte solution with a concentration of about 0.3 mol. For example, in order to manufacture thin graphene of 3 to 6 layers, it is desirable to use a mixed electrolyte solution of ammonium sulfate and potassium sulfate with a mixing concentration of about 0.35 mol. For example, the mixing ratio (by weight) of ammonium sulfate:potassium sulfate is preferably 70:30 to 95:5, more preferably 80:20 to 90:10, and 85:15 to 90:10. It is more desirable.

In addition, the graphene synthesis device 1 further includes an electrolyte solution additional supply device 80 to continuously supply the electrolyte solution, and the electrolyte solution additional supply device 80 is an electrolyte solution concentration measurement and control unit. (80a); and an electrolyte solution supply unit (80b).

A drive motor 30 that can operate up and down opposite to the graphene synthesis reaction tank 10 may be connected to the electrode unit 20.

The working electrode 20a of the working electrode unit 20A can be supplied in a vertical up and down direction by being connected to the driving motor 30 against the electrolyte solution of the graphene synthesis reaction tank 10. At this time, the optimal conditions for driving the drive motor 30 may vary depending on the conditions of the applied voltage and current.

For example, the drive motor 30 is preferably driven at a feed rate of 0.10 cm/min to 0.50 cm/min, and more preferably driven at a feed rate of 0.2 cm/min to 0.35 cm/min.

In addition, because the working electrode 20a is ultimately shortened to a length where it cannot be lowered due to the phenomenon of graphite exfoliation, the graphene synthesis device 1 is used when the working electrode 20a is consumed by graphene synthesis. , It may further include a spare working electrode unit 40 including a spare working electrode 40a that is replaced with the used working electrode 20a. As a result, the spent working electrode 20a is recovered and replaced with a spare working electrode 40a that can continuously participate in the graphene synthesis reaction, thereby allowing the synthesis of graphene to proceed continuously.

Since the preliminary operating electrode unit 40 is connected to the driving motor 30, exchange of the operating electrode 20a and the preliminary operating electrode 40a is automatically performed by the driving motor 30, thereby producing graphene. It has the advantage of being able to be mass-produced continuously.

The graphene synthesis device 1 is installed separately from the graphene synthesis reaction tank 10, and may further include a filter system 70 for separating the synthesized graphene and the electrolyte solution, The filter system 70 may include a graphene recovery unit 70a that recovers synthesized graphene.

The filter system 70, which separates the synthesized graphene, blocks the flow of the electrolyte solution when a certain amount of graphene accumulates, thereby reducing the amount of electrolyte solution refluxed into the graphene synthesis reaction tank 10. This prevents this and continues. If a pressure difference exceeds a certain pressure occurs so that a negative reaction can occur, it can be replaced with another filter.

The separated graphene can be washed three times using ultrapure water to remove as much residual electrolyte solution as possible, and then commercialized while dispersed in water containing an organic solvent or surfactant.

In order to return the electrolyte solution from which the graphene has been removed to the graphene synthesis reaction tank 10, the graphene synthesis apparatus may further include an electrolyte solution reflux pump 90.

At this time, an electrolyte solution supply device 100 may be further included to continuously supply the electrolyte solution so as to check the electrolyte concentration and replenish and reflux the insufficient electrolyte.

In addition, in order to control the total amount of the electrolyte solution and supply it so that the electrolyte solution can always be present in the graphene reaction synthesis tank 10 in a constant quantity from the electrolyte solution preliminary tank 110 (not shown), the electrolyte solution supplier 100 ) is the electrolyte solution concentration measurement/control unit (100a); and an electrolyte solution supply unit 100b.

However, since the temperature of the refluxed electrolyte solution increases through a large amount of electrochemical reaction, the graphene synthesis device 1 may further include a heat exchanger 100 to maintain it at room temperature. The heat exchanger 100 can maintain the temperature of the electrolyte solution that passes through the filter system 70 and then is refluxed and returned to the graphene reaction synthesis tank 10 at room temperature.

According to another aspect of the present invention, a graphene synthesis method capable of continuously mass producing high quality graphene can be provided, and in this case, the graphene mass production apparatus according to an aspect of the present invention can be used.

The graphene synthesis method of the present invention includes the steps of disposing an electrode unit including n metal electrode units and n+1 working electrode units alternately arranged with the metal electrode units, inside the reaction tank; electrochemically connecting the metal electrode portion to a cathode and electrochemically connecting the working electrode portion to an anode; and synthesizing graphene by applying voltage to the metal electrode portion and the working electrode portion.

The metal electrode unit 10 may include a number of metal electrodes arranged at a predetermined interval, and the working electrode part 20 may include b number of operating electrodes arranged alternately with the metal electrodes at a predetermined interval. It may include an electrode, and n, a, and b may be integers of 1 or more.

The electrolyte solution may contain one or more selected from the group consisting of sulfate, nitrate, phosphate, metal halide, and ionic liquid, and the electrolyte solution and electrical energy conditions may vary depending on the thickness of the graphene to be manufactured. You can.

In order to maintain the concentration and volume of the electrolyte solution, the electrolyte solution can be continuously supplied, and the temperature of the electrolyte solution can be controlled to be constant.

When the working electrode is consumed by graphene synthesis, it may further include replacing it with a spare working electrode.

In addition, the step of separating and recovering the synthesized graphene may be further included.

Hereinafter, embodiments of the present invention will be described. However, the following example is only an example of the present invention and is not limited thereto.

실시예 1Example 1

Using 6 graphite electrodes as working electrodes and 13 stainless steel electrodes as metal electrodes, the working electrodes were placed in a cylindrical reactor between two rows of metal electrodes, and the electrolyte solution was a 0.35M ammonium sulfate and potassium sulfate mixed electrolyte. was used mixed in a ratio of 87:13.

The metal electrode was immersed in the electrolyte solution to a depth of 35 cm, and while the distance between each electrode was maintained at 1.0 cm, the working electrode was immersed to a depth of about 1.5 cm from the top of the electrolyte solution to prepare for reaction.

Start the reaction by applying a constant voltage constant current of 10V, 23A to the graphite electrode for 1 hour. When low-oxidized graphene is peeled off, the working electrode gradually peels off and becomes shorter, so slowly move the working electrode vertically downward at a speed of 0.283 cm per minute. supplied.

As a result, 80.05 g of low-oxidized graphene could be obtained through a reaction of 1 hour.

실시예 2Example 2

Six graphite electrodes were used as the working electrodes and 13 stainless steel electrodes were used as the metal electrodes. The working electrodes were placed in a cylindrical reactor between two rows of metal electrodes, and then a 0.30M ammonium sulfate electrolyte solution was used as the electrolyte solution.

The metal electrode was immersed in the electrolyte solution to a depth of 35 cm, and while the distance between each electrode was maintained at 1.0 cm, the working electrode was immersed to a depth of about 1.5 cm above the electrolyte solution to prepare for reaction.

A constant voltage constant current of 10V, 20A was applied to the graphite electrode for 1 hour to start the reaction, and the working electrode, which gradually became shorter as it peeled off, was slowly supplied vertically downward at a rate of 0.30 cm per minute.

As a result, 82.65 g of low-oxidized graphene could be obtained through a reaction of 1 hour.

실시예 3Example 3

Using 35 natural graphite electrodes as the working electrodes and 54 stainless steel electrodes as the metal electrodes, the metal electrodes were arranged to surround the working electrodes with the counter electrodes positioned at 90-degree intervals at the corners around the working electrodes, and a square electrode was used. After being placed in the reaction tank, 40 L of 0.3 M ammonium sulfate and potassium sulfate mixed electrolyte solution was prepared and used in a ratio of 87:13.

The metal electrode was immersed in the electrolyte solution to a depth of 15 cm, and the distance between electrodes was maintained at 2.0 cm diagonally from the center point of the electrodes, and the working electrode was immersed about 0.5 cm above the electrolyte solution to prepare for reaction.

An electrolyte absorption time of 1 hour was allowed to allow the electrolyte solution to be sufficiently absorbed into the graphite electrode and for the sulfate group to penetrate between the graphite layers. With the electrolyte absorbed, a constant voltage constant current of 10V, 15A is applied to the graphite electrode for 1 hour to start the reaction. When the low-oxidized graphene is peeled off, the working electrode gradually peels off and becomes shorter, so it operates at a speed of 0.25 cm per minute. The electrode was slowly fed vertically downward.

As a result, 92.32 g of low-oxidized graphene could be obtained through a reaction of 1 hour.

실시예 4Example 4

The electrolyte solution was absorbed for 2 hours so that the electrolyte solution could be sufficiently absorbed into the graphite electrode and the sulfate group could penetrate between the graphite layers. When the electrolyte solution is absorbed, a constant voltage constant current of 10V, 25A is applied to the graphite electrode for 1 hour to start the reaction. When the low-oxidized graphene is peeled off, the working electrode gradually peels off and becomes shorter, so it operates at a speed of 0.25 cm per minute. The electrode was slowly fed vertically downward.

As a result, 90.78 g of low-oxidized graphene could be obtained through a reaction of 1 hour.

비교예 1Comparative Example 1

Six graphite electrodes were used as the working electrodes and two stainless steel electrodes were used as the metal electrodes. Six working electrodes were placed between the two metal electrodes, and 0.3M ammonium sulfate was used as the electrolyte.

Each electrode was immersed in the electrolyte solution to a depth of 7 cm, and the distance between each electrode was maintained at 1.0 cm, and a current of 10V and 20A was applied to the graphite electrode for 1 hour to exfoliate the graphite.

As a result, a total of 7.3 g of graphene was obtained.

비교예 2Comparative Example 2

Six graphite electrodes were used as the working electrodes and eight stainless steel electrodes were used as the metal electrodes. One working electrode was placed between the metal electrodes, and 0.3M ammonium sulfate was used as the electrolyte.

Each electrode was immersed in the electrolyte solution to a depth of 7 cm, and the distance between electrodes was maintained at 1.0 cm, and a current of 10V and 20A was applied to the graphite electrode for 1 hour to exfoliate the graphite.

The reaction that existed between the graphite electrode, which is the working electrode, and the stainless steel electrode, which was the metal electrode, showed a fast reaction rate, and almost all of the immersed working electrodes were peeled off.

As a result, a total of 39.81 g of graphene was obtained.

Although the embodiments of the present specification have been described in more detail with reference to the accompanying drawings, the present specification is not necessarily limited to these embodiments, and various modifications may be made without departing from the technical spirit of the present specification. . Accordingly, the embodiments disclosed in this specification are not intended to limit the technical idea of the present specification, but rather to explain it, and the scope of the technical idea of the present specification is not limited by these embodiments. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of protection of this specification should be interpreted in accordance with the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of this specification.

[부호의 설명][Explanation of symbols]

1: Graphene synthesis device

10: Graphene synthesis reaction tank

20: electrode part, 20A: metal electrode part, 20B: working electrode part, 20a: metal electrode, 20b: working electrode

30: drive motor

40: preliminary operation electrode part, 40a: preliminary operation electrode

50: constant current regulator

60: Electrolyte solution supply passage

70: filter system, 70a: graphene recovery unit

80: Electrolyte reflux pump

90: heat exchanger

100: electrolyte solution additional supply unit, 100a: electrolyte solution concentration measurement/control unit, 100b: electrolyte solution supply unit

110: Electrolyte reserve tank (not shown)

Claims

Graphene synthesis reaction bath; and

It includes an electrode portion disposed inside the reaction tank,

The electrode portion includes n metal electrode portions and n+1 working electrode portions alternately arranged with the metal electrode portions,

The interior of the graphene synthesis reaction tank contains an electrolyte solution of a certain concentration,

The metal electrode portion is electrochemically connected and operates as a cathode,

The working electrode portion is electrochemically connected and operates as an anode,

The metal electrode unit includes a number of metal electrodes arranged at predetermined intervals,

The working electrode unit includes b working electrodes arranged alternately with the metal electrode at a predetermined interval,

where n, a and b are integers of 1 or more,

Graphene synthesis device.
According to paragraph 1,

The metal electrode portion and the working electrode portion are each plate-shaped electrode portion,

The metal electrode and the working electrode are a metal electrode and a working electrode, respectively,

Graphene synthesis device.
According to paragraph 2,

When the diameters of the metal electrode and the working electrode are each D (cm), the distance between the metal electrode and the working electrode is arranged at 2D (cm),

Graphene synthesis device.
According to paragraph 2,

The metal electrode is a stainless steel electrode,

Graphene synthesis device.
According to paragraph 2,

The operating electrode is a graphite electrode,

Graphene synthesis device.
According to paragraph 1,

The electrolyte solution contains at least one member selected from the group consisting of sulfate, nitrate, phosphate, potassium salt, metal halide, and ionic liquid.

Graphene synthesis device.
According to paragraph 1,

The electrolyte solution contains at least one of ammonium sulfate and potassium sulfate,

Graphene synthesis device.
According to paragraph 1,

It further includes an electrolyte solution supplier for continuously supplying the electrolyte solution,

The electrolyte solution supply unit includes an electrolyte solution concentration measuring/controlling unit; And an electrolyte solution supply unit;

Graphene synthesis device.
According to paragraph 1,

A drive motor that can operate up and down opposite the graphene synthesis reaction tank is connected to the electrode part,

Graphene synthesis device.
According to clause 9,

Further comprising a spare working electrode unit that is replaced when the working electrode is consumed by graphene synthesis,

The preliminary operating electrode unit is connected to the driving motor,

Graphene synthesis device.
According to paragraph 1,

It further includes a filter system that separates the graphene synthesized from the graphene synthesis device and the electrolyte solution,

The filter system includes a graphene recovery unit that recovers synthesized graphene,

The filter system is installed spaced apart from the graphene synthesis reaction tank,

Graphene synthesis device.
According to paragraph 1,

Further comprising a heat exchanger that controls the temperature of the electrolyte solution in the graphene synthesis reaction tank,

Graphene synthesis device.
According to paragraph 1,

A constant current regulator is connected to the electrode part,

Graphene synthesis device.
Injecting an electrolyte solution into a graphene synthesis reaction tank;

Arranging an electrode unit including n metal electrode units and n+1 working electrode units alternately disposed with the metal electrode units inside the reaction tank;

Electrochemically connecting the metal electrode portion to a cathode and electrochemically connecting the working electrode portion to an anode; and

Comprising: synthesizing graphene by applying voltage to the metal electrode portion and the working electrode portion,

The metal electrode unit includes a number of metal electrodes arranged at predetermined intervals,

The working electrode unit includes b working electrodes arranged alternately with the metal electrode at a predetermined interval,

where n, a and b are integers of 1 or more,

Graphene synthesis method.
According to clause 14,

The metal electrode is a stainless steel electrode, and the working electrode is a graphite electrode,

Graphene synthesis method.
According to clause 14,

The electrolyte solution contains at least one member selected from the group consisting of sulfate, nitrate, phosphate, metal halide, and ionic liquid.

Graphene synthesis method.
According to clause 14,

The electrolyte solution is continuously supplied to maintain the concentration and volume of the electrolyte solution.

Graphene synthesis method.
According to clause 14,

Controlled so that the temperature of the electrolyte solution is maintained constant,

Graphene synthesis method.
According to clause 14,

Further comprising the step of exchanging the working electrode for a spare working electrode when the working electrode is consumed by graphene synthesis.

Graphene synthesis method.
According to clause 14,

Further comprising the step of separating and recovering the synthesized graphene,

Graphene synthesis method.