Graphene fiber electrothermal component and preparation method and application thereof

Abstract

The application relates to the technical field of electric heating, and discloses a graphene fiber electric heating assembly and a preparation method and application thereof. The graphene fiber electric heating assembly provided by the application comprises a base body, an electric heating functional layer conformally coated on the surface of the base body, and a resistance regulation layer conformally coated on the surface of the electric heating functional layer. The base body is a fiber or a product thereof, the electric heating functional layer is a graphene film, and the resistance regulation layer is an oxidized graphene film. The base body provides the mechanical properties required by the electric heating assembly. The graphene film is the electric heating functional layer and provides an electric conduction path. The oxidized graphene film is the resistance regulation layer, the resistance of an electric heating device can be regulated according to the different oxidation degrees of the graphene film, and the heating uniformity of the electric heating device is not changed. When irregular shapes such as trapezoidal shapes, arc shapes, polygonal shapes and the like are involved, the local oxidized graphene resistance is changed, so that the overall heating uniformity of the device is realized.

Description

Technical Field

[0001] This invention relates to the field of electrothermal technology, specifically to a graphene fiber electrothermal component, its preparation method, and its application. Background Technology

[0002] A graphene coating layer of controllable thickness was directly grown at high temperatures on the surface of traditional glass fibers, resulting in a uniform and continuous graphene glass fiber composite material. This material exhibits excellent electrothermal performance, heating from room temperature to 300°C in less than 10 seconds, with an electrothermal conversion efficiency as high as 87%, far exceeding that of conventional electrothermal materials. It also possesses lightweight and flexibility not found in ordinary electrothermal materials. Currently, graphene glass fiber materials have achieved great success in the field of aircraft de-icing and anti-icing, demonstrating irreplaceable and unique advantages.

[0003] Chinese patent document CN108545966A discloses a method for preparing graphene glass fiber. By using chemical vapor deposition to form a graphene layer on the surface of glass fiber, the graphene glass fiber exhibits excellent comprehensive performance and a wide range of applications. Moreover, the preparation method of this graphene glass fiber is simple and has good prospects for industrial application. However, since the carbon source content and heating temperature are fixed in each production, the sheet resistance of the generated graphene glass fiber fabric is uniform, making it difficult to control the sheet resistance of the material in subsequent practical applications.

[0004] Furthermore, in practical applications involving irregularly shaped structures, such as trapezoids, arcs, and polygons, the current preferentially flows from the positive electrode to the negative electrode along the shortest path because the distance between the positive and negative electrodes of the irregularly shaped structure cannot be kept consistent. This can lead to uneven heating of the graphene glass fiber electric heating device as a whole.

[0005] Therefore, developing a graphene fiber electrothermal component that can control the resistance of graphene glass fiber fabric through a simple and effective method; in addition, for irregularly shaped graphene glass fiber electrothermal devices, how to make the overall surface of the sample heat up uniformly without changing the electrode structure is an urgent problem to be solved in this field. Summary of the Invention

[0006] In view of this, the present invention provides a graphene fiber electrothermal component to solve the problems of graphene fiber resistance regulation and uneven heating of the overall surface of irregularly shaped graphene fiber electrothermal devices in the prior art.

[0007] The present invention also provides a method for preparing a graphene fiber electrothermal component.

[0008] In a first aspect, the present invention provides a graphene fiber electrothermal component, comprising a substrate, an electrothermal functional layer conformally coated on the surface of the substrate, and a resistance regulating layer conformally coated on the surface of the electrothermal functional layer.

[0009] The substrate is fiber or its product, the electrothermal functional layer is a graphene film, and the resistance regulating layer is a graphene oxide film.

[0010] In some alternative embodiments, the matrix comprises chopped fibers or fiber blankets processed therefrom, or continuous long fibers or fiber fabrics woven therefrom.

[0011] In some alternative embodiments, the fibers include quartz fibers, glass fibers, alumina fibers, ceramic fibers, silicon carbide fibers, or boron fibers.

[0012] In some optional embodiments, the sheet resistance of the graphene fiber electrothermal component is 100 Ω·sq. -1 -5000Ω·sq -1 .

[0013] In some alternative embodiments, the thickness of the electrothermal functional layer is 50nm-100nm.

[0014] In some alternative implementations, the thickness of the resistance control layer is 5nm-10nm.

[0015] In a second aspect, the present invention provides a method for preparing the graphene fiber electrothermal component described in the first aspect, comprising the following steps;

[0016] (1) A carbon source gas is introduced to deposit and grow a graphene film on the substrate surface to obtain a graphene fiber fabric.

[0017] (2) The graphene fiber fabric is oxidized at 200℃-400℃ to form a graphene oxide film, thereby obtaining a graphene fiber electrothermal component.

[0018] In some optional embodiments, the oxidation method includes:

[0019] The graphene fiber fabric is oxidized in an air atmosphere in a muffle furnace or heating table;

[0020] Alternatively, the graphene fiber fabric can be oxidized in a tube furnace under an oxygen atmosphere.

[0021] In some alternative embodiments, the oxidation time is 1-5 hours.

[0022] In some optional embodiments, the deposition step includes: increasing the temperature to 900°C-1100°C at a heating rate of 10°C / min-20°C / min, maintaining a pressure of 10Pa-100Pa, and a deposition time of 1h-3h.

[0023] Thirdly, the present invention provides an electrothermal device, comprising the graphene fiber electrothermal component described in the first aspect or the graphene fiber electrothermal component prepared by the preparation method described in the second aspect, and electrodes located on both sides of the graphene fiber electrothermal component.

[0024] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0025] 1. The graphene fiber electrothermal component provided by the present invention includes a substrate, an electrothermal functional layer conformally coated on the surface of the substrate, and a resistance regulating layer conformally coated on the surface of the electrothermal functional layer; the substrate is fiber or its product, the electrothermal functional layer is a graphene film, and the resistance regulating layer is a graphene oxide film; the substrate provides the mechanical properties required for the electrothermal component; the graphene film, as the electrothermal functional layer, provides a conductive path; the graphene oxide film, as the resistance regulating layer, can regulate the resistance of the electrothermal device according to the different oxidation degrees of the graphene film without changing its heating uniformity; when it involves irregularly shaped devices, such as trapezoidal, arc-shaped, polygonal, etc., the local graphene oxide resistance is changed, thereby achieving uniform heating of the entire device.

[0026] 2. The method for preparing a graphene fiber electrothermal component provided by the present invention includes the following steps: introducing a carbon source gas to deposit and grow a graphene layer on the substrate surface to obtain a graphene fiber fabric; oxidizing the graphene fiber fabric at 200℃-400℃ to form a graphene oxide layer, thereby obtaining a graphene fiber electrothermal component. The present invention uses chemical vapor deposition to deposit and grow a graphene layer on the substrate surface, followed by oxidation treatment at 200℃-400℃ to control the resistance of the graphene fiber without altering its heating uniformity. For irregularly shaped devices, a heating stage can be used for localized heating, selectively oxidizing certain areas to control the local resistance, thereby achieving uniform heating of the entire device and broadening the application of graphene fiber fabrics in irregularly shaped electric heating devices. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 The diagram shows the circuit analysis of graphene glass fiber fabric (a) and graphene fiber electrothermal component (b) according to the present invention.

[0029] Figure 2This is a schematic diagram of the Raman spectra of the graphene glass fiber fabric (a) and the graphene fiber electrothermal component (b) prepared in Example 7 of the present invention;

[0030] Figure 3 It is the peak intensity ratio of the Raman D peak and G peak of the graphene glass fiber fabric and graphene fiber electrothermal component prepared in Example 7 of the present invention.

[0031] Figure 4 This is a schematic diagram showing the change rate of electrode resistance of graphene fiber electrothermal components prepared at different oxidation temperatures according to embodiments of the present invention.

[0032] Figure 5 This is a photograph of the graphene fiber electrothermal component prepared in Comparative Example 2 of this invention;

[0033] Figure 6-a These are scanning electron microscope images of the graphene glass fiber fabric prepared in Example 5 of the present invention; wherein, (a-1) magnification is 100; (a-2) magnification is 800; (a-3) magnification is 8000; (a-4) magnification is 20000;

[0034] Figure 6-b These are scanning electron microscope (SEM) images of the graphene fiber electrothermal assembly prepared in Example 5 of this invention; wherein, (b-1) magnification is 100; (b-2) magnification is 800; (b-3) magnification is 8000; and (b-4) magnification is 20000.

[0035] Figure 6-c These are scanning electron microscope images of the graphene fiber electrothermal component prepared in Example 7 of the present invention; wherein, (c-1) magnification is 100; (c-2) magnification is 800; (c-3) magnification is 8000; (c-4) magnification is 20000;

[0036] Figure 7-a This is the infrared radiation pattern of the graphene glass fiber fabric prepared in Example 7 of the present invention;

[0037] Figure 7-b This is an infrared radiation diagram of the graphene fiber electrothermal component prepared in Example 7 of the present invention;

[0038] Figure 8 These are the temperatures at nine measurement points in the infrared radiation test of the graphene glass fiber fabric and graphene fiber electrothermal component prepared in Example 7 of this invention. Detailed Implementation

[0039] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0040] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0041] To address the problems existing in the aforementioned related technologies, according to a first aspect of the present invention, a graphene fiber electrothermal component is provided. The graphene fiber electrothermal component includes a substrate, an electrothermal functional layer conformally coated on the surface of the substrate, and a resistance regulating layer conformally coated on the surface of the electrothermal functional layer. The substrate is a fiber or a product thereof, the electrothermal functional layer is a graphene film, and the resistance regulating layer is a graphene oxide film. The sheet resistance of the graphene fiber electrothermal component is 100 Ω·sq. -1 -5000Ω·sq -1 The thickness of the electrothermal functional layer is 50nm-100nm; the thickness of the resistance control layer is 5nm-10nm; the substrate includes chopped fibers or fiber blankets processed from them, or continuous long fibers or fiber fabrics woven from them; the fibers include quartz fibers, glass fibers, alumina fibers, ceramic fibers, silicon carbide fibers or boron fibers.

[0042] Secondly, the present invention provides a method for preparing a graphene fiber electrothermal component, comprising the following steps:

[0043] (1) High-temperature oxidation to remove the adhesive layer on the substrate surface: Place the fiber fabric substrate in the reaction chamber, introduce oxygen into the reaction chamber, raise the temperature to 400℃-500℃ at a heating rate of 10℃ / min-20℃ / min, keep it at the temperature for 1h-4h and then take it out.

[0044] (2) Graphene deposition on substrate surface: Hydrogen, carbon source gas and protective gas are introduced into the reaction chamber of the tube furnace. The carbon source gas includes at least one of methane, ethylene, propylene, acetylene and propyne. The protective gas includes at least one of nitrogen and argon. The temperature is increased to 900℃-1100℃ at a rate of 10℃ / min-20℃ / min. The pressure in the reaction chamber is kept at 10Pa-100Pa. The deposition time is 1h-3h to obtain graphene fiber fabric.

[0045] (3) Graphene oxidation treatment: including method one, method two or method three, as detailed below:

[0046] Method 1: Take the graphene fiber fabric out of the tube furnace and put it into a muffle furnace. Heat it in the muffle furnace to 200℃-400℃ for 1-5 hours.

[0047] Method 2: After graphene deposition is completed, the tube furnace is cooled to 200℃-400℃, oxygen is introduced, and the heating time is 1h-5h.

[0048] Method 3: Remove the graphene fiber fabric from the tube furnace, place it on a heating platform, and heat it at 200℃-400℃ for 1-5 hours.

[0049] This invention employs chemical vapor deposition to deposit and grow a graphene layer on a substrate surface, followed by oxidation treatment at 200℃-400℃ to regulate the resistance of the graphene glass fiber without altering its heating uniformity. For irregularly shaped devices, the local resistance can be regulated based on the resistance change pattern of the graphene fiber at different oxidation temperatures to achieve uniform heating, thus broadening the application of graphene fiber fabrics in irregularly shaped electric heating devices.

[0050] Taking glass fiber as the matrix as an example, electrodes are added to both sides of the graphene glass fiber fabric. After an electric current is applied, a complex circuit is formed inside the material, such as... Figure 1 As shown, the two parallel contacting fibers are equivalent to two resistors connected in parallel (R). 0-1 and R 0-2 (Representing the resistance of two different graphene glass fibers) and the contact resistance R between the two fibers. c1 Series connection; multiple parallel graphene glass fibers form a warp bundle with a resistance of R. warp The weft strand is perpendicular to the warp strand, and its resistance is R. weft R warp and R weft The contact resistance R between the parallel connection and the warp and weft yarn bundles c2 Series connection; Since graphene glass fiber can be commercially produced, the samples we obtain often have a given resistance, and it is impossible to adjust the resistance of graphene glass fiber through a simple and effective method; In addition, in practical applications involving irregular shapes such as trapezoids, arcs, and polygons, only by locally changing the resistance can we ensure that the overall heating of the sample surface is uniform.

[0051] This invention involves oxidizing the surface of a sample with known resistance, transforming the graphene coating on the glass fiber into graphene oxide. Graphene oxide has a much higher resistivity than graphene, and the resistance can be controlled within a certain range depending on the degree of graphene oxidation. As the graphene glass fiber surface is oxidized, the resistance R0 increases, and the contact resistance R... c1 The resistance R increases, simultaneously forming the warp and weft strands. warpand R weft Contact resistance R c2 It is also larger than unoxidized graphene glass fiber, so the resistance can be adjusted according to actual needs, thus broadening the application of graphene glass fiber in the field of electric heating.

[0052] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0053] Example 1

[0054] This embodiment provides a method for preparing a graphene fiber electrothermal component, including the following steps:

[0055] Glass fibers were pretreated in a reaction chamber under normal pressure and an atmosphere of 200 sccm oxygen, and the temperature was increased to 500℃ at a rate of 10℃ / min, and held for 4 hours before being removed. The pretreated glass fibers were then placed in the reaction chamber of a CVD tube furnace, and a vacuum was applied to maintain a pressure of 10 Pa. The temperature was increased to 1050℃ at a rate of 10℃ / min under an atmosphere of 100 sccm argon, 25 sccm hydrogen, and 100 sccm methane, and the reaction time was 1 hour. After cooling, the fibers were removed to obtain graphene glass fiber fabric. Then, the fabric was oxidized in a muffle furnace at 200℃ for 2 hours to prepare a graphene fiber electric heating component.

[0056] Example 2

[0057] This embodiment provides a method for preparing a graphene fiber electrothermal component, which is basically the same as the steps in Embodiment 1, except that the oxidation temperature is 300℃.

[0058] Example 3

[0059] This embodiment provides a method for preparing a graphene fiber electrothermal component, which is basically the same as the steps in Embodiment 1, except that the oxidation temperature is 320℃.

[0060] Example 4

[0061] This embodiment provides a method for preparing a graphene fiber electrothermal component, which is basically the same as the steps in Embodiment 1, except that the oxidation temperature is 340℃.

[0062] Example 5

[0063] This embodiment provides a method for preparing a graphene fiber electrothermal component, which is basically the same as the steps in Embodiment 1, except that the oxidation temperature is 360℃.

[0064] Example 6

[0065] This embodiment provides a method for preparing a graphene fiber electrothermal component, which is basically the same as the steps in Embodiment 1, except that the oxidation temperature is 380℃.

[0066] Example 7

[0067] This embodiment provides a method for preparing a graphene fiber electrothermal component, which is basically the same as the steps in Embodiment 1, except that the oxidation temperature is 400℃.

[0068] Comparative Example 1

[0069] This comparative example provides a method for preparing a graphene fiber electrothermal component, which is basically the same as the steps in Example 1, except that the oxidation temperature is 150°C.

[0070] Comparative Example 2

[0071] This comparative example provides a method for preparing a graphene fiber electrothermal component, which is basically the same as the steps in Example 1, except that the oxidation temperature is 420℃.

[0072] Experimental Example 1

[0073] Raman spectroscopy was performed on the graphene glass fiber fabric and graphene fiber electrothermal assembly prepared in Example 7. The results are shown in [Figure 7]. Figure 2 As shown in the figure, the Raman spectrum of graphene consists of several peaks, mainly the G peak and the D peak; the D peak is the disorder vibration peak of graphene, and its specific peak position is 1328.4 cm⁻¹. -1 The G peak is used to characterize structural defects or edges in graphene samples; the G peak is the main characteristic peak of graphene, caused by the in-plane vibration of sp2 carbon atoms, and appears at 1580 cm⁻¹. -1 Nearby, this peak effectively reflects the number of graphene layers, but it is highly susceptible to stress. To investigate the changes in defects in graphene fiber electrothermal components, the peak intensities of the D and G peaks are compared... Figure 3 As shown in the figure, it can be seen that after oxidation at 400℃, the intensity of peak D usually increases, and the intensity ratio of peak D to peak G (I D / I G The increase in the value indicates that graphene oxide was generated on the surface after oxidation.

[0074] Experimental Example 2

[0075] The graphene glass fiber fabric and graphene fiber electrothermal assembly prepared in each embodiment were used to fabricate power supply electrodes on both sides using copper tape. Copper sheets were welded to the power supply electrodes as lead-out electrodes. After power was applied, the resistance between the two electrodes was tested using a multimeter. The results are as follows: Figure 4As shown in Table 1; where, the rate of change of polar resistance % = (resistance of graphene fiber heating element - resistance of graphene glass fiber fabric) / resistance of graphene glass fiber fabric × 100%.

[0076] Table 1. Sheet resistance and resistance test results of the fiber fabric and electrothermal assembly in each embodiment.

[0077]

[0078] From Table 1 and Figure 4 As can be seen, the rate of change of resistivity gradually increases with increasing temperature, and the change becomes more pronounced after 300℃. When the oxidation temperature reaches 420℃, the graphene is oxidized to an excessive degree, and uneven white spots appear on the device surface (see...). Figure 5 As shown in the figure, this indicates that the graphene has been completely oxidized and is non-conductive, resulting in uneven resistance and uneven heating. When the oxidation temperature is 150℃, the graphene is not oxidized, and the resistance remains unchanged.

[0079] Experimental Example 3

[0080] Scanning electron microscopy (SEM) tests were performed on the graphene glass fiber fabrics and graphene fiber electrothermal components prepared in Examples 5 and 7. The results are as follows: Figure 6-a , Figure 6-b , Figure 6-c As shown in the figure, it can be seen that when the oxidation temperature is 360℃ and 400℃, the sample surface is still intact and the microstructure is not damaged.

[0081] Experiment Example 4

[0082] The infrared radiation patterns of the graphene glass fiber fabric and graphene fiber electrothermal component prepared in Example 7 were tested at 120V AC voltage. The results are shown in [Figure Number]. Figure 7-a , Figure 7-b and Figure 8 As shown, each sample has 9 temperature measurement points; from Figure 7-a , Figure 7-b As can be seen, at an oxidation temperature of 400℃, the infrared radiation temperature decreases under the same voltage, but the heating remains very uniform. Figure 8 This further demonstrates the uniformity of heat generation.

[0083] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A graphene fibre electrothermal assembly, characterised in that, The graphene fiber electrothermal component comprises a substrate, an electrothermal functional layer conformally coated on the surface of the substrate, and a resistance control layer conformally coated on the surface of the electrothermal functional layer. The substrate is a fiber or a product thereof, the electrothermal functional layer is a graphene film, and the resistance control layer is an oxidized graphene film; the thickness of the electrothermal functional layer is 50 nm-100 nm, and the thickness of the resistance control layer is 5 nm-10 nm. The preparation method of the graphene fiber electrothermal component comprises the following steps. (1) carbon source gas is introduced to deposit and grow a graphene film on the surface of the substrate to obtain a graphene fiber fabric; (2) the graphene fiber fabric is oxidized at 200-400 ℃ to form an oxidized graphene film, thereby obtaining a graphene fiber electrothermal component.

2. A graphene fibre electrothermal assembly according to claim 1, characterised in that, The substrate comprises chopped fibers or a fiber blanket processed from the chopped fibers, or continuous long fibers or a fiber fabric woven from the continuous long fibers.

3. A graphene fibre electrothermal assembly according to claim 2, characterised in that, The fibers comprise quartz fibers, glass fibers, alumina fibers, ceramic fibers, silicon carbide fibers, or boron fibers.

4. The graphene-fiber electrothermal component according to claim 1, characterized in that, The sheet resistance of the graphene fiber electrothermal assembly is 100 Ω sq -1 - 5000 Ω sq -1 .

5. The graphene-fiber electrothermal component according to claim 1, characterized in that, The oxidation mode comprises: The graphene fiber fabric is oxidized in a muffle furnace or a heating table in an air atmosphere; or the graphene fiber fabric is oxidized in a tube furnace in an oxygen atmosphere.

6. A graphene fibric electrothermal component according to claim 5, characterised in that, The oxidation time is 1-5 h.

7. The graphene-fiber electrothermal component according to claim 1, characterized in that, The deposition step comprises: increasing the temperature to 900-1100 ℃ at a temperature increasing rate of 10-20 ℃ / min, maintaining the pressure at 10-100 Pa, and depositing for 1-3 h.

8. An electrothermal device comprising the graphene fiber electrothermal component according to any one of claims 1-7 and electrodes located on both sides of the graphene fiber electrothermal component.

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