Graphene product with electrothermal performance and preparation method

Abstract

The application provides a graphene product with electrothermal performance and a preparation method, and the method comprises the following steps: performing laser irradiation treatment on the surface of a diamond substrate to form a high-orientation graphite layer on the surface of the diamond substrate; performing mechanical cleavage treatment on the outer layer of the high-orientation graphite layer to obtain a graphene layer formed by a plurality of graphene sheets, and the angle between the graphene sheets and the surface of the diamond substrate in the graphene layer is 30-40 degrees; and performing electrochemical exfoliation on the graphene layer, the pH of the electrolyte used in the electrochemical exfoliation is 9, the angle between the graphene sheets and the surface of the diamond substrate in the graphene layer is 80-90 degrees, a micro-nano scale nearly vertical graphene layer is formed, and the graphene product with electrothermal performance is obtained. The application also provides the product prepared by the above method. Compared with the prior art, the application can directly generate electrothermal graphene on the surface of the diamond in situ, and not only omits complex process steps such as reduction, but also has a service life far longer than that of ordinary graphene film electrothermal elements and excellent electrothermal performance.

Description

Technical Field

[0001] This invention belongs to the field of surface engineering technology, and particularly relates to the field of graphene electrothermal technology, specifically to a graphene component with electrothermal properties and its preparation method. Background Technology

[0002] Graphene is a single-atom-layer two-dimensional carbon nanomaterial, with carbon atoms based on sp. 2 Hybridized bonding is the thinnest and stiffest material currently available, while also possessing a huge specific surface area and excellent thermal properties. Its thermal conductivity ranges from 4840 to 5300 W / (m·K), making it the carbon material with the highest thermal conductivity to date.

[0003] However, graphene still faces many unavoidable key challenges in its widespread application. For example, most common graphene preparations use graphene oxide as a raw material, and obtaining graphene with better electrical and thermal conductivity requires extremely complex processes to reduce it and restore the carbon atom structure. Furthermore, graphene films coated on insulating substrates tend to have weak adhesion to the substrate and short lifespans. Finding ideal substrates for graphene is difficult, and the thermal conductivity at the interface between graphene and silicon or metals is often limited, making it challenging to fabricate graphene components with good electrothermal properties.

[0004] Based on the above, this invention proposes a graphene component with electrothermal properties and its preparation method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a graphene component with electrothermal properties and its preparation method. The method employs an in-situ generation of electrothermal graphene on the surface of diamond, which omits complex processes such as reduction compared to traditional graphene preparation methods, and the resulting component has a lifespan far exceeding that of ordinary graphene film electrothermal elements.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] (I) This invention provides a method for preparing a graphene part with electrothermal properties, comprising the following steps: laser irradiation treatment of the surface of a diamond substrate to form a highly oriented graphite layer on the surface of the diamond substrate; mechanical cleavage treatment of the outer layer of the highly oriented graphite layer to obtain a graphene layer formed by multiple graphene sheets, wherein the angle between the graphene sheets in the graphene layer and the surface of the diamond substrate is 30-40°; electrochemical exfoliation of the graphene layer, wherein the pH of the electrolyte used for electrochemical exfoliation is 8-10, so that the angle between the graphene sheets in the graphene layer and the surface of the diamond substrate is 80-90°, forming a near-vertical graphene layer at the micro-nano scale, thereby obtaining a graphene part with electrothermal properties.

[0008] Furthermore, the laser irradiation treatment uses a pulsed laser; the laser irradiation operation is carried out in an air atmosphere, with a pulse frequency of 30 kHz, a spot diameter of 20 μm, a laser power of 8–10 W, and a scanning interval of 1 μm; considering heat dissipation of the diamond substrate during laser irradiation treatment, the angle between the laser incident direction of the pulsed laser and the surface of the diamond substrate to be processed is 80–85°. This invention, by utilizing the precision of lasers, can ensure the accuracy of the electrothermal graphene generation region, enabling the generation of electrothermal graphene in a defined shape and location. Preferably, this invention performs laser irradiation treatment under the above conditions to obtain a layered graphite layer of suitable thickness.

[0009] Furthermore, the equipment used for the mechanical cleaving includes a flywheel made of stainless steel with an outer diameter of 120 mm and a thickness of 8 mm; during the mechanical cleaving process, the flywheel feed control accuracy is 1 μm and the flywheel speed is 2000 r / min.

[0010] Furthermore, in the electrochemical stripping operation, the electrolyte is a mixed solution of (NH4)2SO4 and NaOH, and the pH of the electrolyte is 9.

[0011] Furthermore, the electrochemical stripping operation is carried out in a classic dual-part immersion electrode system, specifically: a graphene part with an angle of 30-40° to the diamond substrate surface is used as the working anode, and a platinum sheet is used as the working cathode for electrochemical stripping. The applied voltage is 10V and the stripping time is 30min.

[0012] Furthermore, the platinum sheet has dimensions of 10×15×0.1mm. 3 Purity > 99.9%; the anode and cathode are placed parallel to each other with a distance of 3 cm between them.

[0013] Furthermore, the diamond substrate is a diamond-coated part or a diamond thick film part, wherein the diamond-coated part is prepared by depositing a diamond coating on the substrate using a CVD deposition method.

[0014] Furthermore, the highly oriented graphite layer formed after laser irradiation treatment has a thickness of 100–300 nm; the micro-nano scale near-vertical graphene layer with high-efficiency electrothermal properties obtained after electrochemical exfoliation has a thickness of 700–900 nm.

[0015] (II) The present invention also provides a graphene component with electrothermal properties, which is prepared by the method described above. The graphene component includes a diamond matrix connected by carbon-carbon covalent bonds, a highly oriented graphite layer and a graphene layer with high-efficiency electrothermal properties. The angle between the graphene sheet of the graphene layer and the surface of the diamond matrix is ​​80-90°.

[0016] Furthermore, in the graphene component, the mass fraction of graphene with high-efficiency electrothermal properties is 50-70%, the mass fraction of highly oriented graphite layer is 20-30%, and the mass fraction of amorphous carbon is 10%.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) The present invention treats the surface of a diamond substrate by laser irradiation to form a highly oriented graphite layer on its surface, and mechanically cleaves the graphite layer to obtain a graphene layer. The angle between the graphene sheets in the graphene layer and the surface of the diamond substrate is 30-40°. Finally, the angle between the graphene sheets in the graphene layer and the surface of the diamond substrate is changed from 30-40° to 80-90° by electrochemical exfoliation. The nearly vertical graphene sheets overlap each other to form a good conductive grid, thus obtaining better electrothermal performance.

[0019] (2) Compared with the traditional graphene with electrothermal properties prepared by deposition method, the method provided by the present invention can directly generate electrothermal graphene on the diamond surface in situ. It not only omits complex process steps such as reduction, but also has a lifespan far exceeding that of ordinary graphene film electrothermal elements and has superior electrothermal performance compared to ordinary graphene electrothermal elements.

[0020] (3) By leveraging the precision of lasers, this invention can ensure the accuracy of the electrothermal graphene generation area, enabling the generation of electrothermal graphene in a defined shape and location. It offers high flexibility, low operational difficulty, and strong applicability. Attached image description:

[0021] Figure 1 These are scanning electron microscope (SEM) images of the electrothermal graphene fabrication prepared in Example 1 at different magnifications. Figure 1 Image a is a scanning electron microscope image of the electrothermal graphene fabrication at 15000 magnification. Figure 1 b is a scanning electron microscope image of the electrothermal graphene fabrication at 20,000 magnification. Figure 1 c is a scanning electron microscope image of the electrothermal graphene component at 35000 magnification;

[0022] Figure 2 The images shown are scanning electron microscope (SEM) images of the part from Example 1 after mechanical cleavage and chemical peeling treatments. Figure 2 a is an electron microscope image of the graphene layer after mechanical cleavage treatment in step two of Example 1. Figure 2 b is an electron microscope image of the graphene layer after electrochemical exfoliation in step three of Example 1;

[0023] Figure 3 A dual-part immersion electrode system for use during electrochemical stripping;

[0024] Figure 4Temperature rise curves of the electrothermal graphene component prepared in Example 1 under different heat flux densities;

[0025] Figure 5 The temperature rise curves of the graphene prepared in Example 1 and Comparative Examples 1-2 at the same heat flux density are shown. Detailed implementation method:

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention provides a method for preparing a graphene component with electrothermal properties, comprising the following steps:

[0028] A diamond substrate is laser-irradiated to form a highly oriented graphite layer, resulting in a graphite-containing part. The outer layer of this highly oriented graphite layer is then mechanically cleaved to obtain a graphene layer composed of multiple graphene sheets, with the angle between the graphene sheets and the diamond substrate surface being 30–40°. The graphene layer is then electrochemically exfoliated using an electrolyte with a pH of 8–10, resulting in an angle of 80–90° between the graphene sheets and the diamond substrate surface, forming a near-vertical graphene layer at the micro-nano scale, thus obtaining a graphene part with electrothermal properties.

[0029] For the diamond substrate, natural diamond or synthetic diamond can be selected, more preferably diamond-coated parts, diamond thick-film parts, or CVD diamond. This invention does not limit the type, shape, or size of the diamond; selection is based on need. Before laser irradiation, the diamond substrate needs to be planarized, cleaned, and dried to facilitate uniform laser absorption. The planarization, cleaning, and drying methods are conventional techniques in the field, and this invention does not limit their application.

[0030] For laser irradiation, a pulsed laser is used. Preferred operating parameters in this embodiment are: pulse frequency of 30 kHz, spot diameter of 20 μm, laser power of 8–10 W, and scanning spacing of 1 μm. Through laser irradiation, the diamond on the diamond substrate surface transforms into graphite, forming a graphite layer of a certain thickness. This invention leverages the precision of lasers to ensure the accuracy of the electrothermal graphene generation region, enabling the generation of electrothermal graphene in a defined shape and location. Furthermore, considering heat dissipation from the diamond substrate during laser irradiation, the angle between the incident laser direction of the pulsed laser and the surface of the diamond substrate to be processed is 80–85°.

[0031] After obtaining the graphite-containing part, the present invention performs mechanical cleaving on the part, causing the outer layer of the graphite layer to be cleaved into a graphene layer formed by multiple graphene sheets, wherein the angle between the graphene sheets and the diamond substrate surface in the graphene layer is 30-40°. The equipment used for mechanical cleaving includes a flywheel made of stainless steel, with an outer diameter of 120 mm and a thickness of 8 mm; the operating conditions for mechanical cleaving include: flywheel feed control accuracy of 1 μm and flywheel speed of 2000 r / min.

[0032] After obtaining the graphene layer component, the present invention performs electrochemical exfoliation on the graphene layer component. The electrochemical exfoliation is carried out in a classic two-part immersion electrode system, with the graphene layer component as the working anode and a platinum sheet (purity >99.9%) as the working cathode. The anode and cathode are placed in parallel. The electrolyte is a mixed solution of (NH4)2SO4 and NaOH with a pH value of 8-10, preferably pH value of 9. The voltage applied during exfoliation is 10V and the duration is 30min.

[0033] Compared to traditional graphene with electrothermal properties prepared by deposition, this invention generates a near-vertical graphene layer at the Wiener scale on the diamond surface in situ. The graphene is uniformly distributed on the diamond surface, and the graphene sheets overlap to form a well-conductive grid, thus achieving excellent electrothermal performance. This eliminates complex process steps such as reduction, and the electrothermal performance is superior to that of ordinary graphene heating elements.

[0034] Example 1

[0035] This invention provides a graphene component with electrothermal properties, the preparation method of which includes the following steps:

[0036] Step 1: Take a CVD diamond sheet with dimensions of 10mm × 10mm × 0.4mm, and after polishing, acetone washing, and drying, irradiate the surface of the CVD diamond sheet in an air atmosphere using a laser (pulsed laser, IPG Photonics, model YLP-1 / 100 / 20). Considering heat dissipation from the diamond substrate during laser irradiation, the angle between the laser incident direction and the diamond substrate surface to be processed is 85°. After laser irradiation, a highly oriented graphite layer is formed on the surface of the CVD diamond sheet (the fluffy graphite can be observed through a CCD lens). Specifically, the laser irradiation process involves a full-surface laser-filled scan starting from the edge of the CVD diamond sheet. The operating parameters include: pulse frequency of 30kHz, spot diameter of 20μm, laser power of 8W, and scanning interval of 1μm. The final thickness of the highly oriented graphite layer is 100nm.

[0037] Step 2: The outer layer of the highly oriented graphite layer prepared in Step 1 is mechanically cleaved using a flywheel. The flywheel is a stainless steel flywheel with a brushed and polished surface, and its outer circumference is flat. The outer diameter of the stainless steel flywheel is 120 mm, and its thickness is 8 mm. The operating conditions for mechanical cleaving include: flywheel feed control accuracy of 1 μm and flywheel speed of 2000 r / min. After mechanical cleaving, a graphene layer (700 nm thick) is obtained, consisting of multiple graphene sheets, with the angle between the graphene sheets and the diamond substrate surface being 30–40°.

[0038] Step 3: Electrochemically exfoliate the graphene layer prepared in Step 2 using a classic dual-part immersion electrode system. Specifically, a graphene sample with an angle of 30–40° to the diamond substrate surface is used as the working anode, and a platinum sheet is used as the working cathode. The anode and cathode are placed parallel to each other with a spacing of 3 cm. Electrochemical exfoliation is performed at a voltage of 10V for 30 minutes. The platinum sheet has dimensions of 10 × 15 × 0.1 mm. 3 The purity is >99.9%. In the electrochemical stripping operation, the electrolyte is a mixed solution of (NH4)2SO4, NaOH and water, wherein the pH of the electrolyte is 9.

[0039] After electrochemical exfoliation, the angle between the graphene sheets in the graphene layer and the diamond substrate surface is 80-90°, forming a near-vertical graphene layer at the micro-nano scale, thus obtaining a graphene component with electrothermal properties.

[0040] The graphene component with electrothermal properties prepared in this embodiment includes a diamond substrate connected by carbon-carbon covalent bonds, a highly oriented graphite layer, and a graphene layer with high-efficiency electrothermal properties. The angle between the graphene sheet in the graphene layer and the surface of the diamond substrate is 80-90°. The graphene with high-efficiency electrothermal properties comprises 70% by mass, the highly oriented graphite layer comprises 20% by mass, and the amorphous carbon comprises 10% by mass.

[0041] Example 2

[0042] Graphene parts with electrothermal properties were prepared according to the method of Example 1, except that the laser power was 9W during laser irradiation treatment.

[0043] In this embodiment, after laser irradiation treatment on the surface of a CVD diamond wafer, a highly oriented graphite layer with a thickness of 100 nm was obtained. Following mechanical cleavage and electrochemical exfoliation, a near-vertical graphene layer with a thickness of 800 nm was formed at the micro-nano scale. The final graphene component with electrothermal properties comprises 60% graphene by mass, 25% highly oriented graphite by mass, and 15% amorphous carbon by mass.

[0044] Example 3

[0045] Graphene parts with electrothermal properties were prepared according to the method of Example 1, except that the laser power was 10W during laser irradiation treatment.

[0046] In this embodiment, after laser irradiation treatment on the surface of a CVD diamond wafer, a highly oriented graphite layer with a thickness of 300 nm was obtained. Following mechanical cleavage and electrochemical exfoliation, a near-vertical graphene layer with a thickness of 900 nm was formed at the micro-nano scale. The final graphene component with electrothermal properties comprises 50% graphene by mass, 30% highly oriented graphite by mass, and 20% amorphous carbon by mass.

[0047] Comparative Example 1

[0048] The diamond-graphene component prepared in Example 1 of the invention patent application number 202011472104.4 includes diamond and a graphene film generated in situ on the surface of the diamond.

[0049] Comparative Example 2

[0050] The diamond component with a mixed-dimensional carbon covalent stacked structure surface layer prepared in Example 1 of the invention patent application number 2022103707517 includes a diamond substrate and a mixed-dimensional carbon covalent stacked structure surface layer. The mixed-dimensional carbon covalent stacked structure surface layer comprises, from the inside out, a micro / nano-scale near-vertical graphite layer and a graphene layer connected by carbon-carbon covalent bonds. The angle between the graphite sheets in the micro / nano-scale near-vertical graphite layer and the surface of the diamond substrate is 70–80°. The graphene layer is formed by multiple graphene sheets, and the angle between the graphene sheets in the graphene layer and the surface of the diamond substrate is independently 0–90°, and the angle between the graphene sheets in the graphene layer and the surface of the diamond substrate is not simultaneously 0°.

[0051] Characterization and performance testing:

[0052] Figure 1 The images shown are scanning electron microscope (SEM) images of the electrothermal graphene fabrication prepared in Example 1 at different magnifications. Figure 1 Image a is a scanning electron microscope image of the electrothermal graphene fabrication at 15000 magnification. Figure 1 b is a scanning electron microscope image of the electrothermal graphene fabrication at 20,000 magnification. Figure 1 c is a scanning electron microscope image of the electrothermal graphene fabrication at 35000 magnification.

[0053] Figure 2 a is an electron microscope image of the graphene layer after mechanical cleavage treatment in step two of Example 1. Figure 2 b is an electron microscope image of the graphene layer after electrochemical exfoliation in step three of Example 1.

[0054] The electrothermal graphene fabrication prepared in Example 1 was used to bond copper foil electrodes to both ends with conductive silver paste, and different heat flux densities (0.3 W / cm²) were applied at both ends. 2 0.6w / cm 2 and 0.9w / cm 2 ),like Figure 4 As shown, with the increase of heat flux density, the heating rate and the maximum steady-state temperature of the electrothermal graphene component also increase.

[0055] The electrothermal graphene fabrications prepared in Example 1 and Comparative Examples 1-2 were fitted with copper foil electrodes bonded to both ends using conductive silver paste, and the same heat flux density was applied to both ends. The heating rate and the highest steady-state temperature of Example 1 and Comparative Examples 1-2 were measured. The test results are shown in […]. Figure 5 ,Depend on Figure 5 It can be seen that, compared with comparative examples 1 and 2, the electrothermal graphene components prepared by the present invention have higher electrothermal conversion efficiency and stronger electrothermal performance.

[0056] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a graphene component with electrothermal properties, characterized in that, Includes the following steps: Laser irradiation is applied to the surface of a diamond matrix to form a highly oriented graphite layer on the diamond matrix surface; The outer layer of the highly oriented graphite layer is mechanically cleaved to obtain a graphene layer formed by multiple graphene sheets, wherein the angle between the graphene sheets and the diamond substrate surface in the graphene layer is 30~40°. The graphene layer is electrochemically exfoliated. The electrolyte used for electrochemical exfoliation has a pH of 8-10, so that the angle between the graphene sheet in the graphene layer and the surface of the diamond substrate is 80-90°, forming a near-vertical graphene layer at the micro-nano scale, thus obtaining a graphene part with electrothermal properties. The laser irradiation process uses a pulsed laser; during the laser irradiation operation, the pulse frequency is 30kHz, the spot diameter is 20μm, the laser power is 8~10W, and the scanning interval is 1μm; the angle between the laser incident direction of the pulsed laser and the surface of the diamond substrate is 85°.

2. The method for preparing a graphene part with electrothermal properties according to claim 1, characterized in that, The mechanical cleaving device includes a flywheel with an outer diameter of 120 mm and a thickness of 8 mm. During the mechanical cleavage process, the flywheel feed control accuracy is 1μm, and the flywheel speed is 2000r / min.

3. The method for preparing the graphene part with electrothermal properties according to claim 1, characterized in that, In the electrochemical stripping operation, the electrolyte is a mixed solution of (NH4)2SO4 and NaOH, and the pH of the electrolyte is 9.

4. The method for preparing the graphene part with electrothermal properties according to claim 1, characterized in that, The electrochemical stripping operation specifically involves: A graphene part with an angle of 30~40° to the diamond substrate surface was used as the working anode, and a platinum sheet was used as the working cathode for electrochemical stripping. The applied voltage was 10V and the stripping time was 30min.

5. The method for preparing the graphene part with electrothermal properties according to claim 4, characterized in that, The platinum sheet measures 10×15×0.1mm. 3 Purity > 99.9%; the anode and cathode are placed parallel to each other with a distance of 3 cm between them.

6. The method for preparing a graphene part with electrothermal properties according to claim 1, characterized in that, The diamond substrate is a diamond-coated component or a diamond thick-film component.

7. The method for preparing a graphene part with electrothermal properties according to claim 1, characterized in that, The thickness of the highly oriented graphite layer formed after laser irradiation treatment is 100~300nm; The thickness of the near-vertical graphene layer at the micro-nano scale obtained after electrochemical exfoliation is 700~900 nm.

8. A graphene component with electrothermal properties, prepared by the method according to any one of claims 1 to 7, characterized in that, The graphene component comprises a diamond substrate, a highly oriented graphite layer, and a graphene layer connected by carbon-carbon covalent bonds, wherein the angle between the graphene sheet of the graphene layer and the surface of the diamond substrate is 80-90°.

9. The graphene component with electrothermal properties as described in claim 8, characterized in that, In the graphene component, the mass fraction of graphene is 50-70%, the mass fraction of highly oriented graphite layer is 20-30%, and the mass fraction of amorphous carbon is 10%, with the sum of their mass fractions being 100%.

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