Method and device for stripping graphene and obtained graphene

Abstract

The invention belongs to the field of graphene materials. The invention provides a method and device for stripping graphene and obtained graphene. According to the method, hydrogen is converted into proton flow, the obtained proton flow is used for bombarding a graphite material, stripping of the graphene is achieved, and the graphene is obtained. The preparation method can be used for batch production of graphene, does not need strong acid and strong alkali treatment, is green and environment-friendly, simple and convenient to operate and high in efficiency, and is a method which can be used for rapid mass production of high-quality graphene and is stable in product quality.

Description

Technical Field

[0001] The present invention belongs to the field of graphene materials, and relates to a method and apparatus for exfoliating graphene and the obtained graphene. Background Art

[0002] Graphene is known as the "king of new materials" and combines excellent material properties such as mechanics, electricity, heat conduction, and barrier properties. It can replace traditional materials and enable numerous technological revolutions, having inestimable application prospects.

[0003] Currently, traditional graphene preparation methods mainly include mechanical exfoliation method, liquid-phase exfoliation method, oxidation-reduction method, chemical vapor deposition method, and epitaxial growth method.

[0004] The mechanical exfoliation method, including the method for first successfully preparing graphene, i.e., the Scotch-tape method, which exfoliates graphite flakes into thinner layers using tape until single-layer graphene. The advantages of the mechanical exfoliation method are simple preparation process and easy implementation, but the disadvantages are low yield, difficulty in achieving high-efficiency large-scale production, and difficulty in controlling the size and quality of graphene.

[0005] The liquid-phase exfoliation method is a method of dispersing graphite materials in a suitable solvent and using ultrasonic or vigorous stirring to prepare graphene. Its operation is simple, the cost is low, and large-scale production can be achieved. However, the size of the graphene flakes prepared by this method is limited, and it may cause defects in the graphene structure and residual solvents.

[0006] The oxidation-reduction method is to oxidize graphite by a wet chemical method to prepare graphene oxide, and then obtain graphene through a reduction treatment. Its cost is relatively low and the operation is relatively simple. However, due to involving chemical reactions, a large amount of strong acid substances need to be used, the preparation process is prone to generating toxic gases, and chemical residues and structural and surface defects may be generated, affecting the performance of graphene.

[0007] The cost of preparing graphene by the epitaxial growth method is high; while the chemical vapor deposition method can achieve large-scale production of graphene, but the process is complex and the cost is high.

[0008] The chemical vapor deposition method, i.e., the CVD method, is a method for preparing graphene by controlling the deposition of carbon atoms in a gas phase environment. At high temperatures, a carbon source gas (such as methane) decomposes, and the generated carbon atoms are deposited on the catalyst surface to form a graphene film. The graphene prepared by the CVD method has good structural quality and a large single crystal domain. However, the disadvantages of this method are the need for a high-temperature, high-purity gas environment and expensive equipment, resulting in a relatively high preparation cost.

[0009] The epitaxial growth method mainly involves heating the surface of single-crystal SiC at high temperatures to vaporize Si atoms, and the remaining C atoms are reconstructed through self-assembly to form graphene. The graphene obtained by this method has a large area and high quality. However, the growth conditions are harsh, and it needs to be carried out at high temperatures, which consumes a lot of energy, and the temperature range is narrow and difficult to control. In addition, the obtained graphene is not easy to transfer to other substrates for use, and has poor flexibility.

[0010] From the above, it can be seen that the preparation methods of the existing technology have their own advantages and disadvantages, but overall it is still impossible to better realize large-scale and high-quality industrial production of graphene in a simple and low-cost manner. Therefore, the preparation method of graphene remains to be explored. Summary of the invention

[0011] In view of the problems existing in the prior art, the object of the present invention is to provide a method and device for exfoliating graphene and the obtained graphene, wherein the method converts hydrogen into a proton flow, uses the obtained proton flow to bombard a graphite material, and realizes the exfoliation of graphene to obtain graphene. The preparation method can mass-produce graphene without the need for strong acid or strong alkali treatment, is green and environmentally friendly, easy to operate and highly efficient, and is a method that can quickly mass-produce high-quality graphene and maintain stable product quality.

[0012] To achieve this object, the present invention adopts the following technical solutions:

[0013] In a first aspect, the present invention provides a method for exfoliating graphene, the method comprising:

[0014] The hydrogen gas is converted into a proton flow, and the resulting proton flow is used to bombard a graphite material to obtain graphene.

[0015] The method described in the present invention is different from the traditional preparation method of direct mechanical exfoliation or deposition growth. The principle and idea of preparing graphene in the present invention starts from manufacturing defects in the graphite raw material, and then utilizes the defects to perform exfoliation preparation from the defects. However, since the honeycomb hexagonal lattice formed by carbon atoms in the graphite material hinders the penetration of various molecular atoms, there is no scheme in the prior art that can realize graphene exfoliation based on this principle. The present invention finds that electrons can penetrate between graphite molecular layers, and protons can also directly pass through the hexagonal lattice of graphite, which means that protons and electrons can be sent between graphite lattice sheets, so that protons and electrons combine to form hydrogen molecules. Since hydrogen molecules are difficult to pass through the lattice, an effect similar to explosion will be formed between the layers, resulting in interlayer expansion and enlargement of the interlayer spacing, and then it is very easy to exfoliate a single layer or several layers of graphene. The present invention is based on this principle and idea to explore and form the method of exfoliating graphene.

[0016] The following are the preferred technical solutions of the present invention, but not the limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0017] As a preferred technical solution of the present invention, the method for converting hydrogen into a proton stream includes introducing hydrogen into a reactor, where the reactor includes at least one of a laser ionization reactor, a plasma reactor, or a strong electric field reactor, and then obtaining a proton stream through magnetic field separation;

[0018] Preferably, the flow rate of the hydrogen introduced into the reactor is 0.1 m 3 / min to 10 m 3 / min, for example, it can be 0.1 m 3 / min, 0.5 m 3 / min, 0.8 m 3 / min, 1 m 3 / min, 1.5 m 3 / min, 2 m 3 / min, 2.5 m 3 / min, 3 m 3 / min, 3.5 m 3 / min, 4 m 3 / min, 4.5 m 3 / min, 5 m 3 / min, 5.5 m 3 / min, 6 m 3 / min, 6.5 m 3 / min, 7 m 3 / min, 7.5 m 3 / min, 8 m 3 / min, 8.5 m 3 / min, 9 m 3 / min, 9.5 m 3 / min or 10 m 3 / min, etc., but not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0019] To ensure the effect of proton stream bombarding the graphite material, the flow rate of hydrogen should not be too small, otherwise the reaction caused by the bombardment will be too slow.

[0020] As a preferred technical solution of the present invention, the method for exfoliating graphene further includes using an external electric field to control the proton stream to bombard the graphite material.

[0021] Preferably, the external electric field is formed by an electrode pair connected to an AC power supply.

[0022] Preferably, the frequency of the alternating current power supply for forming the external electric field is 10 Hz to 50 kHz. For example, it can be 10 Hz, 30 Hz, 50 Hz, 80 Hz, 100 Hz, 150 Hz, 200 Hz, 250 Hz, 300 Hz, 350 Hz, 400 Hz, 450 Hz, 500 Hz, 1 kHz, 5 kHz, 8 kHz, 10 kHz, 20 kHz, 30 kHz, 40 kHz or 50 kHz, etc. The voltage is 100 V to 200 kV. For example, it can be 100 V, 300 V, 500 V, 800 V, 1000 V, 2 kV, 5 kV, 8 kV, 10 kV, 30 kV, 50 kV, 80 kV, 100 kV, 120 kV, 140 kV, 160 kV, 180 kV or 200 kV, etc. However, it is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0023] Preferably, the bombardment time is 10 to 120 min. For example, it can be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, etc. However, it is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0024] The parameters of the alternating current power supply in the present invention will affect the speed of bombarding and stripping by controlling the proton flow with the external electric field. Therefore, the bombardment time should be reasonably adjusted according to the bombarding and stripping effect of the external electric field.

[0025] As a preferred technical solution of the present invention, the graphite material is disposed on the electrodes of the electrode pair and is in the formed external electric field, or the electrode pair is formed by the graphite material.

[0026] As a preferred technical solution of the present invention, the graphite material includes flake graphite blocks and / or blocks made of flake graphite powder.

[0027] The present invention preferably uses the graphite material as a block to facilitate fixing on the electrode pair or directly as the electrode pair. The specific fixing form is not limited, as long as it is ensured that the graphite material can conduct electricity. For example, the graphite material, such as graphite powder, can also be laid on the lower electrode plate of the upper and lower opposite electrode pairs to perform the method. However, in this case, the bombarding and stripping effect may be affected, resulting in a mixture of graphene and graphite powder in the finally prepared product.

[0028] As a preferred technical solution of the present invention, the method for stripping graphene includes:

[0029] Fix a block of flake graphite and / or a block made of flake graphite powder as the graphite material to opposite parallel electrode pairs, connect the electrode pairs to an AC power supply to form an applied electric field, the frequency of the AC power supply is 10 Hz to 50 kHz, and the voltage is 100 V to 200 kV, so that the graphite material is in the formed applied electric field;

[0030] Introduce hydrogen into the reactor, control the flow rate of hydrogen to be 0.1 m 3 / min to 10 m 3 / min, the reactor includes at least one of a laser ionization reactor, a plasma reactor or a strong electric field reactor, and obtain a proton stream;

[0031] Introduce the proton stream into the region of the applied electric field, use the applied electric field to control the proton stream to bombard the graphite material, bombard for 10 to 120 minutes, and collect the falling graphene.

[0032] In a second aspect, the present invention provides a kind of graphene, and the graphene is obtained by using the method described in the first aspect.

[0033] In a third aspect, the present invention provides a device for exfoliating graphene, the device realizes the method described in the first aspect, and the device includes:

[0034] A reaction chamber, having a reaction inner cavity, and the graphite material is arranged in the reaction inner cavity;

[0035] A reactor, communicated with the reaction inner cavity, for converting hydrogen into a proton stream.

[0036] As a preferred technical solution of the present invention, the device further includes:

[0037] An electrode pair, arranged in the reaction inner cavity, and the graphite material is arranged on the electrode;

[0038] An AC power supply, connected to the electrode pair, so that an applied electric field is formed between the electrode pairs, and the graphite material is in the region of the applied electric field.

[0039] Furthermore, the electrode pair can also be completely composed of graphite material.

[0040] As a preferred technical solution of the present invention, the device further includes:

[0041] A collection unit, for collecting the graphene generated in the reaction chamber.

[0042] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0043] The method of the present invention converts hydrogen into a proton stream, bombards a graphite material with the obtained proton stream to achieve the exfoliation of graphene, and obtains graphene. The preparation method can mass-produce graphene, does not require treatment with strong acids or strong bases, is environmentally friendly, simple to operate and highly efficient, and is a method that can quickly mass-produce high-quality graphene with stable product quality. Description of the Drawings

[0044] Figure 1 It is a schematic diagram of the device for exfoliating graphene of the present invention;

[0045] In the figure: 1 - reaction chamber, 2 - reactor, 3 - electrode pair, 4 - AC power supply, 5 - collection unit;

[0046] Figure 2 It is the SEM test chart of the product obtained in Example 2;

[0047] Figure 3 It is the SEM test chart of the product obtained in Comparative Example 1. Detailed Embodiments

[0048] The technical solution of the present invention will be further described below through specific embodiments.

[0049] Those skilled in the art should understand that the embodiments are only helpful for understanding the present invention and should not be regarded as specific limitations on the present invention.

[0050] The following examples and comparative examples are all carried out in the following device for exfoliating graphene, as Figure 1 shown, the device includes:

[0051] A reaction chamber 1 having a reaction inner cavity, and a graphite material is arranged in the reaction inner cavity;

[0052] A reactor 2 communicated with the reaction inner cavity for converting hydrogen into a proton stream;

[0053] An electrode pair 3 arranged in the reaction inner cavity, and the graphite material is arranged on the electrode;

[0054] An AC power supply 4 connected to the electrode pair 3 to form an external electric field between the electrode pair 3, and the graphite material is in the region of the external electric field;

[0055] A collection unit 5 for collecting the graphene generated in the reaction chamber 1.

[0056] Example 1

[0057] This example provides a method for exfoliating graphene, and the method includes:

[0058] Fix a flake graphite block as the graphite material on opposite parallel electrode pairs. The electrode pairs are connected to an AC power supply to form an external electric field. The frequency of the AC power supply is 50 kHz and the voltage is 100 V, so that the graphite material is in the formed external electric field;

[0059] Introduce hydrogen gas into the reactor and control the flow rate of hydrogen gas to be 10 m 3 / min. The reactor is a laser ionization reactor to obtain a proton beam;

[0060] Introduce the proton beam into the region of the external electric field, and use the external electric field to control the proton beam to bombard the graphite material for 120 min, and collect the fallen graphene.

[0061] Example 2

[0062] This example provides a method for exfoliating graphene, and the method includes:

[0063] Fix a flake graphite block as the graphite material on opposite parallel electrode pairs. The electrode pairs are connected to an AC power supply to form an external electric field. The frequency of the AC power supply is 200 Hz and the voltage is 10 kV, so that the graphite material is in the formed external electric field;

[0064] Introduce hydrogen gas into the reactor and control the flow rate of hydrogen gas to be 5.5 m 3 / min. The reactor is a laser ionization reactor to obtain a proton beam;

[0065] Introduce the proton beam into the region of the external electric field, and use the external electric field to control the proton beam to bombard the graphite material for 60 min, and collect the fallen graphene.

[0066] Example 3

[0067] This example provides a method for exfoliating graphene, and the method includes:

[0068] Use a flake graphite block as the graphite material and directly as opposite parallel electrode pairs. The electrode pairs are connected to an AC power supply to form an external electric field. The frequency of the AC power supply is 10 Hz and the voltage is 200 kV, so that the graphite material is in the formed external electric field;

[0069] Introduce hydrogen gas into the reactor and control the flow rate of hydrogen gas to be 0.1 m 3 / min. The reactor is a laser ionization reactor to obtain a proton beam;

[0070] Introduce the proton beam into the region of the external electric field, and use the external electric field to control the proton beam to bombard the graphite material for 10 min, and collect the fallen graphene.

[0071] Comparative Example 1

[0072] This comparative example provides a method for preparing graphene. In this method, argon is used to replace hydrogen, and argon plasma is formed and introduced into the reactor. Except for the above, other conditions are exactly the same as those in Example 2.

[0073] SEM characterization tests were carried out on the products obtained in Example 2 and Comparative Example 1, as shown respectively in Figure 2 and 3 As can be seen from the figures, for proton-exfoliated graphene, the graphene has a thin thickness and relatively uniform size, which is suitable for subsequent applications. While the sample produced by argon plasma is severely damaged, has a thick thickness, and uneven size.

[0074] In summary, in the present invention, hydrogen is converted into a proton stream, and the obtained proton stream is used to bombard graphite materials to achieve the exfoliation of graphene and obtain graphene. The preparation method can mass-produce graphene, without the need for strong acid or strong base treatment, is green and environmentally friendly, simple to operate and highly efficient, and is a method capable of quickly mass-producing high-quality graphene with stable product quality.

[0075] The present invention uses the above-mentioned examples to illustrate the detailed process equipment and process flow of the present invention. However, the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0076] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0077] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0078] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for exfoliating graphene, characterized in that, The method includes: Converting hydrogen into a proton stream, bombarding a graphite material with the obtained proton stream to obtain graphene.

2. The method for exfoliating graphene according to claim 1, wherein The method for converting hydrogen into a proton stream includes introducing hydrogen into a reactor, where the reactor includes at least one of a laser ionization reactor, a plasma reactor, or a strong electric field reactor, and then obtaining a proton stream through magnetic field separation; Preferably, the flow rate of the hydrogen gas introduced into the reactor is 0.1 m 3 / min to 10 m 3 / min.

3. The method for exfoliating graphene according to claim 1 or 2, characterized in that, The method for exfoliating graphene further includes using an externally applied electric field to control the proton stream to bombard the graphite material; Preferably, the externally applied electric field is formed by an electrode pair connected to an AC power source; Preferably, the frequency of the AC power source for forming the externally applied electric field is 10 Hz to 50 kHz, and the voltage is 100 V to 200 kV; Preferably, the bombardment time is 10 to 120 minutes.

4. The method for exfoliating graphene according to claim 3, wherein, The graphite material is disposed on the electrodes of the electrode pair and is in the formed externally applied electric field, or the graphite material forms the electrode pair.

5. The method for exfoliating graphene according to claim 4, wherein, The graphite material includes flake graphite blocks and / or blocks made of flake graphite powder.

6. The method for exfoliating graphene according to any one of claims 1-5, characterized in that, The method for exfoliating graphene includes: Fixing flake graphite blocks and / or blocks made of flake graphite powder as the graphite material on opposite parallel electrodes, where the electrodes are connected to an AC power source to form an externally applied electric field, the frequency of the AC power source is 10 Hz to 50 kHz, and the voltage is 100 V to 200 kV, so that the graphite material is in the formed externally applied electric field; Hydrogen is introduced into the reactor, and the flow rate of hydrogen is controlled to be 0.1 m 3 / min to 10 m 3 / min. The reactor includes at least one of a laser ionization reactor, a plasma reactor, or a strong electric field reactor to obtain a proton flow; Introducing a proton stream into the region of the externally applied electric field, using the externally applied electric field to control the proton stream to bombard the graphite material, performing bombardment for 10 to 120 minutes, and collecting the fallen graphene.

7. A graphene, characterized in that, The graphene is obtained by using the method according to any one of claims 1 - 6.

8. A device for exfoliating graphene, characterized in that, The device implements the method according to any one of claims 1 - 6, and the device includes: A reaction chamber having a reaction inner cavity, where a graphite material is disposed in the reaction inner cavity; A reactor communicating with the reaction inner cavity for converting hydrogen into a proton stream.

9. The apparatus for exfoliating graphene according to claim 8, wherein The device further includes: An electrode pair disposed in the reaction inner cavity, and the graphite material is disposed on the electrodes; An AC power source connected to the electrode pair to form an externally applied electric field between the electrode pair, and the graphite material is in the region of the externally applied electric field.

10. The apparatus for exfoliating graphene according to claim 8 or 9, characterized in that, The device further includes: A collection unit for collecting the graphene generated in the reaction chamber.

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