TWI788770B - Graphene formation device - Google Patents

Abstract

The present invention discloses a graphene formation device, which comprises a reaction tank, a graphite electrode and a counter electrode, a fixed member and a power supply unit. The reaction tank contains an electrolyte. The graphite electrode and the counter electrode are disposed in the reaction tank at intervals. The fixed member is disposed in the reaction tank. The graphite electrode is disposed in the reaction tank through the fixed member, and the fixed member exposes partial of the graphite electrode to the electrolyte. The power supply unit is electrically connected with the graphite electrode and the counter electrode.

Description

Graphene generating device

The present invention relates to a generating device, in particular to a graphene generating device that utilizes an electrochemical exfoliation method to generate graphene.

Graphene is a single-layer atom-thick carbon material, each carbon atom is mixed with sp ² to form a bond with three adjacent atoms, and extends into a honeycomb two-dimensional structure. Graphene is known for its good carrier mobility. Because of its excellent electrical properties, chemical stability, good thermal conductivity and high penetration rate, it has been widely used in semiconductors, mobile phones, tablets, A popular material in areas such as touch panels or solar cells.

Generally, graphene can be produced by mechanical exfoliation, epitaxial growth, chemical vapor deposition (CVD) and chemical exfoliation. Among them, although the mechanical exfoliation method and the epitaxial growth method can produce graphene with better quality, neither of these two methods can synthesize graphene in large quantities. However, the operating temperature of the chemical vapor deposition method is a high temperature of nearly 1,000 degrees and an expensive metal substrate, and the preparation process takes several hours to complete. The deficiencies of the above-mentioned methods limit the production and subsequent application of graphene. The chemical exfoliation method is to generate graphene by redoxing graphite under the conditions of strong acid and strong oxidation. Although this method is suitable for mass production, the surface structure and size of the graphene produced are not ideal.

In addition to the above-mentioned production methods, graphene can also be produced by electrochemical exfoliation. The main principle is that the surface layer of graphite material is oxidized and exfoliated through the interaction between the electrolyte and the graphite surface. Compared with the other methods mentioned above, the electrochemical exfoliation method can rapidly and economically produce graphene at room temperature. In other words, if the production efficiency of the chemical exfoliation method can be improved, the electrochemical exfoliation method will be able to become an economical and large-scale production method of graphene.

The object of the present invention is to provide a graphene generating device that utilizes an electrochemical exfoliation method to generate graphene, which can rapidly and economically manufacture graphene at room temperature.

The invention provides a graphene generating device, which includes a reaction tank, a graphite electrode, a pair of counter electrodes, a fixing piece and a power supply unit. The reaction tank accommodates an electrolyte; the graphite electrode and the counter electrode are arranged in the reaction tank at intervals; the fixing member is arranged in the reaction tank, the graphite electrode is arranged in the reaction tank through the fixing member, and the fixing member exposes part of the graphite electrode to the electrolyte ; The power supply unit is electrically connected with the graphite electrode and the counter electrode.

In one embodiment, viewed from the side of the reaction tank, the width of the upper side of the reaction tank is greater than the width of the lower side.

In one embodiment, two opposite side walls of the reaction tank have a plurality of guide rails, and the opposite electrode and the fixing member are arranged in the reaction tank through the guide rails.

In one embodiment, the area of the counter electrode is larger than that of the graphite electrode.

In one embodiment, the area ratio of the counter electrode to the graphite electrode is greater than or equal to 2 and less than or equal to 8.

In one embodiment, the material of the counter electrode or the fixing member is inert metal or graphite, or a combination thereof.

In one embodiment, the fixing member includes at least one opening, and the opening of the fixing member exposes a part of the graphite electrode to the electrolyte.

In one embodiment, the number of openings of the fixing member is plural.

In one embodiment, the fixing part includes two sub-fixing parts, and the graphite electrode is located between the two sub-fixing parts.

In one embodiment, the power supply unit forms a voltage difference between the graphite electrode and the counter electrode, and the voltage difference is less than or equal to 15 volts.

In one embodiment, the graphene generating device further includes a handle, which is connected to the fixing member or the opposite electrode.

In one embodiment, the graphite electrodes and the counter electrodes are plural in number, and the graphite electrodes and the counter electrodes are alternately arranged in the reaction tank.

In one embodiment, the graphene generating device further includes a stirring unit for stirring the electrolyte.

In one embodiment, the graphene generating device further includes at least one collection tank connected to the bottom of the reaction tank.

As mentioned above, in the graphene generating device of the present invention, the electrolyte is accommodated by the reaction tank; the graphite electrode and the counter electrode are arranged in the reaction tank at intervals; the fixing member is arranged in the reaction tank, and the graphite electrode is arranged on the reaction tank, and the fixture exposes part of the graphite electrode to the electrolyte; and the design of the electrical connection between the power supply unit and the graphite electrode and the counter electrode makes the graphene generating device that utilizes the electrochemical exfoliation method to generate graphene in the present invention capable of The purpose of rapidly and economically producing graphene under normal temperature environment is achieved.

A graphene generating device according to a preferred embodiment of the present invention will be described below with reference to related drawings, wherein the same elements will be described with the same reference symbols. The dimensions and ratios of elements or units appearing in the drawings of the following embodiments are only to illustrate the relationship between units and elements, and have nothing to do with the dimensions and ratios of real units or elements.

The graphene generating device in the following examples uses the electrochemical exfoliation method to generate graphene. The main principle is to oxidize and peel off the surface layer of the graphite material into graphene flakes through the interaction between the electrolyte and the surface of the graphite material at room temperature. or powder, and finally the graphene flakes or powders that are peeled off and left in the electrolyte are vacuum-dried to obtain the product.

FIG. 1A and FIG. 1B are respectively an assembled schematic view and an exploded schematic view of a graphene generating device according to an embodiment of the present invention, and FIG. 1C is a cross-sectional schematic view of the graphene generating device shown in FIG. 1A . Here, the power unit 15 is only shown in FIG. 1A , and the electrolyte S is only shown in FIG. 1C .

As shown in FIG. 1A to FIG. 1C , the graphene generating device 1 includes a reaction tank 11 , a graphite electrode 12 , a pair of counter electrodes 13 , a fixing member 14 and a power supply unit 15 . In addition, the graphene generating device 1 of this embodiment may further include at least one collection tank 17 .

The reaction tank 11 is a containing tank for containing the electrolyte S ( FIG. 1C ). As shown in FIG. 1C , in this embodiment, there is an electrolyte S in the reaction tank 11 , and the graphite electrode 12 , the counter electrode 13 and the fixing member 14 are soaked in the electrolyte S. Wherein, viewed from the side of the reaction tank 11 , the width of the upper side of the reaction tank 11 is larger than the width of the lower side (wider at the top and narrower at the bottom, similar to an inverted cone shape), so that it is easy to collect the electrolyte S at the bottom of the reaction tank 11 . The electrolyte S of this embodiment can include water, sulfuric acid, sulfates (such as ammonium sulfate, sodium sulfate), nitrates (such as potassium nitrate), potassium hydroxide, sodium chloride, lithium chloride, lithium perchlorate , perchloric acid, phosphoric acid, oxalic acid, or dimethylsulfoxide, or combinations thereof.

The graphite electrode 12 is disposed opposite to the counter electrode 13 , and the graphite electrode 12 and the counter electrode 13 are spaced apart in the reaction tank 11 . Here, the graphite electrodes 12 and the counter electrodes 13 are spaced apart and connected to the side walls 112 of the reaction tank 11 respectively. In addition, the fixing member 14 is disposed on the reaction tank 11 . Wherein, the fixing member 14 can fix the graphite electrode 12 , so that the graphite electrode 12 can be disposed in the reaction tank 11 through the fixing member 14 , and the fixing member 14 can expose part of the graphite electrode 12 to the electrolyte S.

Specifically, the two opposite side walls 112 of the reaction tank 11 in this embodiment have a plurality of guide rails 111 (four guide rails 111 are shown in FIG. The guide rails 111 are arranged correspondingly, so that the counter electrode 13 and the fixing member 14 can be installed on the side wall 112 of the reaction tank 11 through the guide rails 111, so that the graphite electrode 12 and the counter electrode 13 are arranged at intervals in the reaction tank 11, thereby Electrolyte S is used for electrochemical reaction.

In addition, in order to make the electrolyte S in the reaction tank 11 contact the graphite electrode 12, and then generate an electrochemical reaction with the graphite electrode 12, the fixing member 14 of this embodiment may include at least one opening O1, and the opening O1 of the fixing member 14 will be Part of the graphite electrode 12 is exposed to the electrolyte solution S, so that the electrolyte solution S in the reaction tank 11 can contact the graphite electrode 12 through the opening O1. In detail, as shown in FIG. 1B, the fixture 14 of this embodiment includes two sub-fixtures 14a, 14b, and the graphite electrode 12 is located between the sub-fixtures 14a, 14b, so that the graphite electrode 12 can be covered by the sub-fixtures 14a. , 14b clamped and fixed, and then the graphite electrode 12 is set in the reaction tank 11 through the sub-fixtures 14a, 14b and the guide rail 111 . In different embodiments, the fixing part 14 can also be of other types (for example, only a single plate body), or the graphite electrode 12 can also be connected with the fixing part 14 in other ways (such as locking, fitting), as long as the The fixing member 14 fixes the graphite electrode 12 and arranges it in the reaction tank 11 so that at least part of the graphite electrode 12 can be exposed to the electrolyte S, which is not limited in the present invention.

The number of openings O1 of the fixing member 14 in this embodiment is plural. Here, each sub-fixer 14a, 14b has a corresponding opening O1 with the same size (or different size), so as to expose a part of the graphite electrode 12 to the electrolyte S. In order to expose and contact the electrolyte S with a larger area of the graphite electrode 12 to accelerate the reaction speed, the larger the opening O1 exposing the graphite electrode 12 can be, the better. In addition, the electrolyte S in the reaction tank 11 can be made uniform and in contact with the graphite electrode 12. In some embodiments, the graphene generating device can further include a stirring unit (not shown). The stirring unit is, for example but not limited to, A pump or a stirrer is used to stir the electrolyte S in the reaction tank 11. In addition, in order to make the electrolyte S in the reaction tank 11 mix more evenly when stirring, the fixing parts 14 (sub-fixing parts 14a, 14b) of this embodiment also have corresponding openings O2 and O3 with the same size. Therefore, the stirring reaction When the electrolytic solution S in the tank 11 is used, the electrolytic solution S can pass through the openings O2 and O3 of the fixing member 14 to be more uniform.

Referring to FIG. 1C again, the area of the counter electrode 13 in this embodiment is larger than that of the graphite electrode 12 , and the area of the counter electrode 13 is also larger than that of the fixing member 14 . Here, the area ratio of the counter electrode 13 and the graphite electrode 12 may be greater than or equal to 2 and less than or equal to 8. In some embodiments, the area ratio of the counter electrode 13 to the graphite electrode 12 is greater than or equal to 4 and less than or equal to 6, for example. Wherein, the size of the area ratio of the counter electrode 13 and the graphite electrode 12 is to control a fixed current density. When the area ratio of the counter electrode 13 and the graphite electrode 12 changes, the current value must be adjusted to maintain a certain current density to optimize the efficiency of electrolysis, thereby controlling the optimization of product yield.

As the name implies, the graphite electrode 12 is an electrode made of graphite material (such as a graphite plate), and the graphite material can be artificial graphite or natural graphite, without limitation. In addition, the material of the counter electrode 13 or the fixing member 14 can be an inert metal or graphite material, or a combination thereof. The inert metal is, for example but not limited to, titanium, gold, silver, or platinum, or a combination thereof, and the graphite material can be artificial Graphite or natural graphite, as long as it does not chemically interact with the electrolyte S and has good electrical conductivity. In this embodiment, the materials of the counter electrode 13 and the fixing member 14 are respectively titanium metal as an example.

The power unit 15 is electrically connected to the graphite electrode 12 and the counter electrode 13 . The power supply unit 15 can form a voltage difference between the graphite electrode 12 and the counter electrode 13, the voltage difference can be less than or equal to 15 volts, and can be direct current or alternating current, which is not limited by the present invention. As shown in Figure 1A, the graphite electrode 12 of this embodiment is connected to the positive pole of the power supply unit 15 through the fixing piece 14, and the opposite electrode 13 is connected to the negative pole of the power supply unit 15, but it is not limited to this, in different In an embodiment, the connection relationship between the two can be reversed.

In addition, in order to easily install the fixture 14 (graphite electrode 12) and the counter electrode 13 in the reaction tank 11, or take out the fixture 14 (graphite electrode 12) and the counter electrode 13 from the reaction tank 11, the graphite electrode 13 of this embodiment The ene generating device 1 may further include at least one handle 16 , and the handle 16 is connected to the fixing member 14 or the counter electrode 13 . In this embodiment, a fixed handle 16 is installed on the top of the fixing member 14 and the counter electrode 13 to facilitate extraction or placement. Of course, in different embodiments, the carrying handle 16 can also be of a movable type, which can be installed only when the fixing part 14 or the opposite electrode 13 is to be extracted.

In addition, the graphene generating device 1 of this embodiment may further include at least one collection tank 17 , and the collection tank 17 is connected to the bottom of the reaction tank 11 . In this embodiment, a collecting tank 17 is connected to the bottom of the reaction tank 11 through a connecting pipeline 18 . Wherein, a valve 181 is provided on the connecting pipeline 18 , through the control of the valve 181 , the electrolyte S can be replenished from the connecting pipeline 18 , or the electrolyte S can be discharged to the collection tank 17 . Here, the electrolytic solution S is easily discharged from the bottom of the reaction tank 11 to the collection tank 17 by virtue of the reaction tank 11 having a wide top and a narrow bottom.

In actual operation, the electrolyte S in the reaction tank 11 of this embodiment can contact the graphite electrode 12 through the opening O1 of the fixture 14, and the power supply unit 15 can provide an electromotive force to be applied to the graphite electrode 12 and the counter electrode 13, so that the graphite A voltage difference is formed between the electrode 12 and the counter electrode 13 , and the electrolytic solution S is used to generate an electrochemical reaction. During the electrochemical reaction, the voltage difference will electrolyze the electrolyte S and generate gases (such as hydrogen and oxygen) and ions (such as ammonium ions or sulfate ions). The graphite monolayer or multilayer on the surface of the graphite electrode 12 contacted by the liquid S expands and peels off to form graphene flakes or powders mixed in the electrolytic solution S.

After performing the electrochemical reaction for a period of time (the operating temperature can range from room temperature to, for example, 40°C), the electrolyte S with graphene flakes or powders is discharged to the collection tank 17 through the connecting pipeline 18, filtered and vacuum-dried Graphene products can be obtained. In an application example of actually generating graphene, under the condition that the voltage difference is 5 volts and the current is 2 amperes, the graphene generating device 1 of this embodiment is used to react for one hour, and after filtration and vacuum drying, about 1 gram of graphene powder.

It is supplemented that the stripping speed, properties and yield of graphene can be changed by adjusting the concentration of the electrolyte S, the type of electrolyte, the type of solvent and the voltage difference. Furthermore, the graphene generating device of this embodiment may also include a filtering and product separation module in other implementations. In order to realize the purpose of the continuous process, the exfoliated products of the graphene generating device of the present embodiment can filter the unexfoliated coarse-grained graphite particles through the micropore screen of the module for filtering and separating the products, and obtain suitable graphite particles through screening. After the size of the product (generally thin-layer graphene below 10nm), a large amount of deionized water is used to remove the residual electrolyte, or other ionic solutions that can dissolve and replace residual ions.

In addition, please refer to FIG. 2 and FIG. 3 , which are schematic diagrams of graphene generating devices according to different embodiments of the present invention.

As shown in FIG. 2 , the graphene generating device 1a of this embodiment is substantially the same as the graphene generating device 1 of the previous embodiment in terms of component composition and connection relationship of each component. The difference is that, in the graphene generating device 1a of this embodiment, the number of graphite electrodes 12 (fixers 14) and counter electrodes 13 are three respectively, and the graphite electrodes 12 (and the fixers 14) and the The counter electrodes 13 are arranged in the reaction tank 11 alternately. Wherein, the graphite electrodes 12 (and the fixing member 14 ) and the counter electrodes 13 can be equidistantly or unequally disposed on the sidewall 112 of the reaction tank 11 staggeredly, without limitation. In addition, the graphite electrodes 12 of this embodiment can be connected to the positive pole of a power supply unit (not shown), and the counter electrodes 13 are connected to the negative pole of the power supply unit; of course, the connection relationship can also be reversed.

In addition, as shown in FIG. 3 , the graphene generating device 1b of this embodiment is substantially the same as the graphene generating device 1 or 1a of the previous embodiment in terms of component composition and connection relationship of each component. The difference is that the graphene generating device 1b in this embodiment includes two collection tanks 17a, 17b, and the collection tanks 17a, 17b can be connected to the bottom of the reaction tank 11 through a connecting pipeline 18 respectively. The electrolyte S with different concentrations in the reaction tank 11 can be collected by the two collection tanks 17a, 17b. For example, the electrolyte S with graphene flakes or powders is first discharged to the collection tank 17a through the connection pipeline 18, and then the electrolyte S is discharged to the collection tank 17b through another connection pipeline 18, then the collection tanks 17a, 17b The concentration of the graphene flakes or powders of the electrolytic solution S is different, the concentration of the collection tank 17a will be greater than the concentration of the collection tank 17b, and the weight of the graphene obtained after filtration and vacuum drying is different.

Compared with the conventional electrochemical stripping process, the graphene generating device of the present invention has at least the following advantages: the voltage used in the present invention is lower, the operating temperature is normal temperature, and the thickness of the product will be concentrated in the standard and device required by the industry. The structure is simple and the operation is easy, therefore, the graphene generating device of the present invention can be applied to generate graphene and meet the requirements of mass production.

In summary, in the graphene generating device of the present invention, the electrolyte is accommodated by the reaction tank; the graphite electrode and the counter electrode are arranged in the reaction tank at intervals; the fixing member is arranged in the reaction tank, and the graphite electrode is arranged on the The reaction tank, and the fixing part exposes part of the graphite electrode to the electrolyte; the design of the electrical connection between the power supply unit and the graphite electrode and the counter electrode enables the graphene generation device of the present invention to generate graphene by the electrochemical exfoliation method to achieve The purpose of producing graphene quickly and economically at room temperature.

The above descriptions are illustrative only, not restrictive. Any equivalent modification or change made without departing from the spirit and scope of the present invention shall be included in the scope of the appended patent application.

1,1a,1b: Graphene generating device 11: Reaction tank 111: guide rail 112: side wall 12: Graphite electrode 13: Counter electrode 14:Fixer 14a, 14b: sub-fixtures 15: Power supply unit 16: Handle 17,17a,17b: collection tank 18: Connect the pipeline 181: valve O1, O2, O3: opening S: Electrolyte

FIG. 1A and FIG. 1B are respectively an assembled schematic diagram and an exploded schematic diagram of a graphene generating device according to an embodiment of the present invention. FIG. 1C is a schematic cross-sectional view of the graphene generating device shown in FIG. 1A . FIG. 2 and FIG. 3 are schematic diagrams of graphene generating devices according to different embodiments of the present invention.

1: Graphene generating device

11: Reaction tank

111: guide rail

112: side wall

12: Graphite electrode

13: Counter electrode

14:Fixer

16: Handle

17: Collection tank

18: Connect the pipeline

181: valve

O1, O2, O3: opening

S: Electrolyte

Claims (13)

A graphene generation device, comprising: a reaction tank, containing an electrolyte; a graphite electrode and a pair of electrodes, arranged in the reaction tank at intervals; a fixing piece, arranged in the reaction tank, the graphite electrode passes through the fixing A part is arranged in the reaction tank, and the fixing part exposes part of the graphite electrode to the electrolyte; at least one collecting tank is connected to the bottom of the reaction tank; and a power supply unit is connected to the graphite electrode and the opposite The electrodes are electrically connected. The graphene generating device according to claim 1, wherein viewed from the side of the reaction tank, the width of the upper side of the reaction tank is greater than the width of the lower side. The graphene generating device according to claim 1, wherein two opposite side walls of the reaction tank have a plurality of guide rails, and the opposite electrode and the fixing member are disposed in the reaction tank through the guide rails. The graphene generating device as claimed in claim 1, wherein the area of the counter electrode is larger than the area of the graphite electrode. The graphene generating device according to claim 1, wherein the area ratio of the counter electrode to the graphite electrode is greater than or equal to 2 and less than or equal to 8. The graphene generating device according to claim 1, wherein the material of the counter electrode or the fixing member is an inert metal or graphite material, or a combination thereof. The graphene generating device as claimed in claim 1, wherein the fixing member includes at least one opening, and the opening of the fixing member exposes part of the graphite electrode to the electrolyte. The graphene generating device as claimed in claim 7, wherein the number of the openings of the fixing member is plural. The graphene generating device as claimed in item 7, wherein the fixing member includes two sub-fixing members, and the graphite electrode is located between the two sub-fixing members. The graphene generating device as claimed in claim 1, wherein the power supply unit forms a voltage difference between the graphite electrode and the counter electrode, and the voltage difference is less than or equal to 15 volts. The graphene generating device according to claim 1, further comprising: a handle connected to the fixing member or the counter electrode. The graphene generating device as claimed in claim 1, wherein the number of the graphite electrodes and the counter electrodes are plural, and the graphite electrodes and the counter electrodes are arranged alternately in the reaction tank. The graphene generating device as claimed in claim 1, further comprising: a stirring unit for stirring the electrolyte.

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