Heating structure based on graphene-carbon nanotube heterojunction and preparation method thereof

Abstract

The invention belongs to the technical field of electric heating, and relates to a heating structure based on graphene-carbon nanotube heterojunction and a preparation method thereof, the heating structure comprises a heterojunction heating film, and a modified polyimide layer and a glass fiber composite layer symmetrically distributed on two sides of the heterojunction heating film.

Description

Technical Field

[0001] This invention belongs to the field of electric heating technology and relates to a heating structure based on graphene-carbon nanotube heterostructure and its preparation method. Background Technology

[0002] In the aviation field, aircraft require heating and anti-icing measures for components such as wings and engines to ensure flight safety during icing operations. Existing heating films generally have limited functionality and typically require multiple auxiliary detection devices to provide surface icing parameters and control on / off states, increasing the overall system weight. Therefore, a more advanced, lightweight heating film with integrated sensing capabilities is needed. Summary of the Invention

[0003] Objective of the invention: To provide a heating structure based on graphene-carbon nanotube heterostructure and its preparation method, which has the ability to monitor ice thickness while heating and de-icing.

[0004] The technical solution of this invention: A heating structure based on graphene-carbon nanotube heterojunction includes: a heterojunction heating film and a modified polyimide layer and a glass fiber composite layer symmetrically distributed on both sides of the heterojunction heating film.

[0005] Furthermore, the heterojunction heating film is prepared as follows: Step 1: Pretreatment of glass fiber substrate (removal of impurities + activation of surface silanol groups), using continuous glass fiber yarn with a diameter of 10~45μm and a single filament strength ≥3.5GPa; Step 2: Catalytic template preparation: GO powder with a monolayer ratio ≥90%, a sheet diameter of 1-5μm, and an oxidation degree of 30% was selected as the catalytic template. A GO aqueous dispersion with a concentration of 0.5mg / mL was prepared, and 0.1% of nonionic surfactant (Tween-80) was added. The dispersion was ultrasonically dispersed for 30 minutes (power 100W) to ensure that the dispersion was uniform and free of agglomeration (particle size test D90 < 2μm). Step 3: Carbon source gas preparation: High-purity methane, argon, and hydrogen are pretreated. All gases are dehydrated by molecular sieves and purified by activated carbon before being introduced into the reactor to avoid moisture and impurities affecting the growth effect. Step 4: GO catalytic template coating (thickness controlled at 5-10nm): Immerse the pretreated glass fiber into the GO dispersion at a uniform speed (pulling speed 5mm / s) to ensure that a uniform liquid film is formed on the fiber surface; immediately after pulling, place it in a 60℃ forced-air oven to dry for 10 minutes to make the GO film thickness reach the range of 5-10nm.

[0006] Step 5: Loading and Atmosphere Replacement of CVD Furnace: Fix the glass fiber coated with GO template onto the quartz support and lay it flat in the central constant temperature zone of the CVD furnace, ensuring that the distance between the fiber and the furnace wall is ≥5cm to avoid edge temperature fluctuations; after closing the furnace door, first introduce Ar gas (flow rate 200sccm) to replace the air in the furnace for 30 minutes; then introduce H2 gas (flow rate 50sccm) and continue to replace the air for 10 minutes to ensure that the oxygen content in the furnace is <10ppm; Step Six: Heating and GO Restoration: Heating program: Increase the temperature to 700℃ at a rate of 10℃ / min, and maintain a mixed atmosphere of Ar (200 sccm) + H2 (50 sccm) throughout the process; Reduction and heat preservation: After reaching 700℃, maintain this temperature and atmosphere for 30 minutes to allow the GO film to be fully reduced to reduced graphene oxide (rGO). Step 7: Carbon nanotube growth and heterostructure formation: Carbon source introduction: After the reduction stage is completed, keep the temperature constant at 700℃ and adjust the gas flow rate to Ar (150sccm) + H2 (30sccm) + CH4 (80sccm), with methane continuously supplied as the carbon source; Growth temperature control: Maintain the gas atmosphere and temperature for 120 minutes. The defect sites on the rGO surface (such as edge carbon atoms and vacancy defects) will become the growth core of carbon nanotubes. Carbon atoms grow in a directional manner at the defect sites to form carbon nanotubes with a diameter of 5-10 nm and a length of 1-3 μm. Growth control: By real-time monitoring of furnace gas pressure (maintained at 1 atm) and gas flow stability, excessive growth of carbon nanotubes leading to agglomeration is avoided; Step 8: Cooling and Removing from the Bake Cooling procedure: After the growth stage is completed, turn off the methane gas and maintain the Ar (200 sccm) + H2 (50 sccm) atmosphere, and cool down to below 350℃ at a rate of 5℃ / min; then turn off the hydrogen gas and only introduce Ar gas (200 sccm) to continue cooling down to room temperature; Furnace removal requirements: After the furnace temperature drops to room temperature, stop the Ar gas supply, open the furnace door and remove the sample; Step Nine: Post-processing Low-temperature plasma cleaning: Place the sample into the plasma cleaner, introduce Ar gas (flow rate 50 sccm), power 50W, and clean for 10 minutes; Vacuum drying: After cleaning, place in an 80℃ vacuum oven to dry for 30 minutes to remove the moisture adsorbed on the surface.

[0007] Furthermore, the thickness of the heterojunction heating film is 0.1 mm, the thickness of the modified polyimide layer is 0.02 mm, the thickness of the glass fiber composite layer is 0.1 mm, and the minimum total thickness can reach 0.34 mm.

[0008] Furthermore, the glass fiber composite layer is made of glass fiber reinforced polyetheretherketone, with a glass fiber content of 30%.

[0009] Furthermore, the modified polyimide layer was obtained by adding 10% by mass of nano-silica to modify the polyimide.

[0010] Furthermore, positive and negative electrodes are set on both sides of the heterojunction heating film, and the heterojunction heating film is heated and de-iced when energized.

[0011] Furthermore, the ice thickness on the surface of the heating film was measured by monitoring the resistance values ​​of the positive and negative electrodes.

[0012] A method for preparing a heating film based on a graphene-carbon nanotube heterostructure, used to prepare the aforementioned heating structure, is described in the following steps: Step 1: Prepare a heterojunction heating film. Graphene-carbon nanotube heterojunctions are deposited on a piece of quartz fiber cloth using a chemical vapor deposition device. After completion, the shape is cut to obtain the heterojunction heating film. Step 2: Prepare modified polyimide film and glass fiber composite prepreg, and cut them to the required shape; Step 3: Lay the fiberglass composite prepreg, modified polyimide film, heterojunction heating film, modified polyimide film, and fiberglass composite prepreg on the mold in that order and vacuum to 0.2MPa, then set for 1 hour; Step 4: After the shaping is completed, maintain the vacuum and transfer it to an autoclave. Heat the autoclave to 120°C at a pressure of 0.2 MPa and a heating rate of 2°C / min, and hold for 2 hours for pressure curing. Step 5: After heating is complete, maintain pressure and allow the can to cool naturally to below 60°C before releasing the pressure and opening the can; Step 6: After removing the product from the can, trim the outer shape to obtain the heating structure.

[0013] Beneficial effects This invention relates to a graphene-carbon nanotube heterojunction heating film prepared by chemical vapor deposition and installed on the icing protection surface of an aircraft. It has the function of electric heating and can monitor ice thickness at the same time.

[0014] This invention utilizes chemical vapor deposition to prepare a heating film on quartz glass fiber, and symmetrically lays a protective layer on both sides of the heating film to improve environmental adaptability. The protective layer consists of two layers from the outside to the inside: a composite material layer (0.2 mm) and a modified polyimide layer (0.08 mm).

[0015] This invention can be installed on icing surfaces in the form of a thin-walled structure, featuring light weight, small thickness, and conformal curvature. It can be installed in pre-reserved grooves on the icing surface or co-cured with composite material skin. The heating film thickness is less than 0.9 mm.

[0016] This invention utilizes a graphene-carbon nanotube heterostructure heating film. Because this heterostructure possesses a defined electronic potential barrier, this barrier can be used to measure ice thickness. The ice thickness is measured by exploiting the interfacial electric field between the ice layer and the heterostructure surface to suppress electrons from crossing the heterostructure barrier; that is, by establishing a linear positive correlation between ice thickness and resistivity. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a heating film based on a graphene-carbon nanotube heterostructure according to the present invention.

[0019] Figure 2 This is a schematic diagram of a heated film for depositing heterojunctions. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0021] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0022] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0024] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0026] A heating structure based on graphene-carbon nanotube heterojunction includes: a heterojunction heating film and a modified polyimide layer and a glass fiber composite layer symmetrically distributed on both sides of the heterojunction heating film.

[0027] Furthermore, the heterojunction heating film is prepared as follows: Step 1: Pretreatment of glass fiber substrate (removal of impurities + activation of surface silanol groups): Select continuous glass fiber yarn with a diameter of 10~45μm and a single filament strength ≥3.5Gpa; A three-step cleaning and activation process is adopted to ensure that the substrate is free of oil and dust residue; 1. Alkaline cleaning: Immerse the glass fiber in a 5% sodium hydroxide aqueous solution and keep it at 60°C for 30 minutes to remove organic release agents and silane residues from the surface, while simultaneously etching the surface to form a micro-rough structure (increasing the specific surface area). 2. Acid washing and neutralization: Soak in 1% hydrochloric acid aqueous solution for 10 minutes to neutralize residual alkali and prevent hydrolysis failure during subsequent GO coating; 3. Ultrasonic cleaning + drying: Clean the surface with deionized water using ultrasonic cleaning (power 80W, frequency 40kHz) 3 times, 15 minutes each time, and finally dry it in a vacuum oven at 120℃ for 2 hours to completely remove surface moisture and activate the surface silanol (-Si-OH) activity.

[0028] Step 2: Catalytic template preparation: GO powder with a monolayer ratio ≥90%, a sheet diameter of 1-5μm, and an oxidation degree of 30% was selected as the catalytic template. A GO aqueous dispersion with a concentration of 0.5mg / mL was prepared, and 0.1% of nonionic surfactant (Tween-80) was added. The dispersion was ultrasonically dispersed for 30 minutes (power 100W) to ensure that the dispersion was uniform and free of agglomeration (particle size test D90 < 2μm). Step 3: Carbon Source Gas Preparation: High-purity methane (CH4, 99.999% purity) was selected as the carbon source, argon (Ar, 99.999% purity) as the carrier and protective gas, and hydrogen (H2, 99.999% purity) as the reducing gas (to assist in GO reduction and carbon nanotube growth); Gas Pretreatment: All gases were dehydrated by molecular sieves and purified by activated carbon before being introduced into the reactor to avoid moisture and impurities affecting the growth effect; Step 4: GO catalytic template coating (thickness controlled at 5-10nm): Immerse the pretreated glass fiber into the GO dispersion at a uniform speed (pulling speed 5mm / s) to ensure that a uniform liquid film is formed on the fiber surface; immediately after pulling, place it in a 60℃ forced-air oven to dry for 10 minutes to remove free surface moisture and form a pre-attached GO film with a thickness of 5-10nm.

[0029] Step 5: Loading and Atmosphere Replacement of CVD Furnace: Fix the glass fiber coated with GO template onto the quartz support and lay it flat in the central constant temperature zone of the CVD furnace, ensuring that the distance between the fiber and the furnace wall is ≥5cm to avoid edge temperature fluctuations; after closing the furnace door, first introduce Ar gas (flow rate 200sccm) to replace the air in the furnace for 30 minutes; then introduce H2 gas (flow rate 50sccm) and continue to replace the air for 10 minutes to ensure that the oxygen content in the furnace is <10ppm; Step Six: Heating and GO Restoration: Heating program: Increase the temperature to 700℃ at a rate of 10℃ / min, and maintain a mixed atmosphere of Ar (200 sccm) + H2 (50 sccm) throughout the process; Reduction and heat preservation: After reaching 700℃, maintain this temperature and atmosphere for 30 minutes to allow the GO film to be fully reduced to reduced graphene oxide (rGO). At this time, rGO not only serves as a "nucleation site" for subsequent carbon nanotube growth, but the hydroxyl groups (-OH) remaining on its surface will also undergo a dehydration condensation reaction with the silanol groups (-Si-OH) on the glass fiber surface to initially form CO-Si covalent bonds. Step 7: Carbon nanotube growth and heterostructure formation: Carbon source introduction: After the reduction stage is completed, keep the temperature constant at 700℃ and adjust the gas flow rate to Ar (150sccm) + H2 (30sccm) + CH4 (80sccm), with methane continuously supplied as the carbon source; Growth and temperature control: Maintaining the gas atmosphere and temperature for 120 minutes allows the defect sites on the rGO surface (such as edge carbon atoms and vacancy defects) to become the growth cores for carbon nanotubes. Carbon atoms grow directionally at the defect sites, forming carbon nanotubes with a diameter of 5-10 nm and a length of 1-3 μm. At the same time, the rGO sheets and the walls of the carbon nanotubes form a "tube-sheet" overlapping structure, forming a complete G-CNT heterojunction through van der Waals forces and some C-C covalent bonds (which combine with the edge carbon atoms of rGO during the growth of carbon nanotubes). Growth control: By real-time monitoring of furnace gas pressure (maintained at 1 atm) and gas flow stability, excessive growth of carbon nanotubes leading to agglomeration is avoided; Step 8: Cooling and Removing from the Bake Cooling procedure: After the growth stage is completed, turn off the methane gas and maintain the Ar (200 sccm) + H2 (50 sccm) atmosphere, and cool down to below 350℃ at a rate of 5℃ / min; then turn off the hydrogen gas and only introduce Ar gas (200 sccm) to continue cooling down to room temperature; Furnace exit requirements: After the furnace temperature drops to room temperature, stop the Ar gas supply, open the furnace door and take out the sample to avoid contact with air at high temperature, which may cause the heterojunction to oxidize. Step Nine: Post-processing Low-temperature plasma cleaning: The sample is placed in a plasma cleaner, Ar gas (flow rate 50 sccm), power 50W, and cleaned for 10 minutes to remove unreacted carbon fragments and residual impurities on the surface of the heterojunction without damaging the G-CNT heterojunction and interfacial covalent bonds. Vacuum drying: After cleaning, place in an 80℃ vacuum oven to dry for 30 minutes to remove the moisture adsorbed on the surface.

[0030] Furthermore, the thickness of the heterojunction heating film is 0.1 mm, the thickness of the modified polyimide layer is 0.02 mm, the thickness of the glass fiber composite layer is 0.1 mm, and the minimum total thickness can reach 0.34 mm.

[0031] Furthermore, the glass fiber composite layer is made of glass fiber reinforced polyetheretherketone, with a glass fiber content of 30%.

[0032] Furthermore, the modified polyimide layer was obtained by adding 10% by mass of nano-silica to modify the polyimide.

[0033] Furthermore, positive and negative electrodes are set on both sides of the heterojunction heating film, and the heterojunction heating film is heated and de-iced when energized.

[0034] Furthermore, the ice thickness on the surface of the heating film was measured by monitoring the resistance values ​​of the positive and negative electrodes.

[0035] A method for preparing a heating film based on a graphene-carbon nanotube heterostructure, used to prepare the aforementioned heating structure, is described in the following steps: Step 1: Prepare a heterojunction heating film. Graphene-carbon nanotube heterojunctions are deposited on a piece of quartz fiber cloth using a chemical vapor deposition device. After completion, the shape is cut to obtain the heterojunction heating film. Step 2: Prepare modified polyimide film and glass fiber composite prepreg, and cut them to the required shape; Step 3: Lay the fiberglass composite prepreg, modified polyimide film, heterojunction heating film, modified polyimide film, and fiberglass composite prepreg on the mold in that order and vacuum to 0.2MPa, then set for 1 hour; Step 4: After the shaping is completed, maintain the vacuum and transfer it to an autoclave. Heat the autoclave to 120°C at a pressure of 0.2 MPa and a heating rate of 2°C / min, and hold for 2 hours for pressure curing. Step 5: After heating is complete, maintain pressure and allow the can to cool naturally to below 60°C before releasing the pressure and opening the can; Step 6: After removing the product from the can, trim the outer shape to obtain the heating structure.

[0036] Example Figure 1 As shown, the heating film 1 comprises: a modified polyimide layer 2, a glass fiber composite layer 3, and a heterojunction heating film 4.

[0037] A glass fiber composite layer 3, a modified polyimide layer 2, a heterojunction heating film 4, a modified polyimide layer 2, and a glass fiber composite layer 3 are sequentially laid on a curved mold, and the heating film 1 is cured and formed by vacuum hot pressing.

[0038] The preferred material for the glass fiber composite layer 3 is glass fiber reinforced polyetheretherketone (GF-PEEK) with a fiber content of 30%. This material can withstand impacts from ice crystals or sand with a diameter of less than 5 mm and a speed of 30 m / s without cracking, and its surface hardness reaches Rockwell hardness R110.

[0039] The modified polyimide layer 2 is optimized with the addition of 10% nano-silica. This layer has certain plasticity and toughness, which can eliminate the difference in thermal expansion between the heterojunction heating film 4 and the glass fiber composite layer 3. At the same time, the nano-silica can improve the heat conduction efficiency, dissipate heat in time, and avoid thermal stress concentration.

[0040] The heterojunction heating film 4, with its designed deposition thickness (micrometer level), allows for adjustable resistance. After calibration, the ice thickness-resistance comparison is input into the on-board control system. When the ice thickness reaches the de-icing threshold, the on-board system powers on the heating film 1, causing it to heat up and de-ice. When the ice thickness decreases below the threshold, power is cut off, and the heating film 1 stops heating. This on-board system enables an icing-de-icing cycle, preventing energy waste and extending product lifespan.

[0041] Therefore, heating film 1 has superiority and advanced features.

[0042] Work process The manufacturing process of heating film 1 is as follows: The design confirmed that a heating film 1 with an area of ​​1m² was produced. 2 The resistance value is 74Ω; A piece of quartz fiber cloth is deposited with a graphene-carbon nanotube heterostructure in a special chemical vapor deposition equipment. After completion, the shape is cut to obtain a heterostructure heating film 4. Prepare a modified polyimide film and 30% glass fiber prepreg, and cut it to the required shape; The glass fiber prepreg, modified polyimide film, heterojunction heating film 4, modified polyimide film, and glass fiber prepreg were laid on the mold in the following order and vacuum-formed for 1 hour. After the shape is set, maintain the vacuum and transfer it to an autoclave for heating and pressure curing according to the required curing conditions for the glass fiber prepreg (150℃, 3h); After cooling and unloading from the can, the outer shape is trimmed to obtain heating film 1; A wind tunnel icing test was conducted on heating film 1. After blowing air for a period of time, the ice thickness and resistance changes were recorded. Multiple points were recorded to complete the calibration and obtain the resistance-ice thickness relationship curve of the heating film. By determining the resistance corresponding to the ice thickness when the power is switched on and off on the curve, the resistance is written into the control system logic and the de-icing test is carried out according to this logic. When the ice thickness reaches the specified value, the system will automatically begin de-icing, and will automatically cut off the power after the ice is removed. In summary, this invention provides a heating film based on a graphene-carbon nanotube heterostructure. The heating film, which has a curved, conformal shape, small thickness, and easy adhesion, is prepared by chemical vapor deposition, thereby realizing the integrated heating and ice thickness sensing functions. The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A graphene-carbon nanotube heterojunction-based heating structure, characterized by, Comprise: Heterojunction heating film and modified polyimide layer and glass fiber composite layer symmetrically distributed on both sides of the heterojunction heating film.

2. The heating structure according to claim 1, characterized in that The preparation method of the heterojunction heating film is as follows: Step one: glass fiber substrate pretreatment, remove impurities + activate surface silicon hydroxyl, select continuous glass fiber yarn with diameter of 10-45 μm, single filament strength ≥3.5GPa; Step two: catalyst template preparation: the GO catalyst template selects GO powder with single layer rate ≥90%, flake diameter 1-5 μm, and oxidation degree 30%, configures GO water dispersion liquid with concentration 0.5 mg / mL, adds 0.1% non-ionic surfactant Tween-80, ultrasonic dispersion for 30 minutes, power 100 W, ensures that the dispersion liquid is uniform without aggregation, and particle size test D90<2 μm; Step three: carbon source gas preparation: high-purity methane, argon and hydrogen are pretreated by molecular sieve dehydration and activated carbon impurity removal, and then introduced into the reaction furnace to avoid the influence of water and impurities on the growth effect; Step four: GO catalyst template coating: the pretreated glass fiber is uniformly immersed in the GO dispersion liquid to ensure that a uniform liquid film is formed on the surface of the fiber; immediately after lifting, it is placed in a 60°C air oven for drying for 10 minutes to make the GO film thickness reach 5-10 nm; Step five: CVD reaction furnace loading and atmosphere replacement: the glass fiber coated with GO template is fixed on a quartz support and laid flat in the center of the CVD reaction furnace constant temperature zone to ensure that the distance between the fiber and the furnace wall is ≥5 cm to avoid temperature fluctuation at the edge; after closing the furnace door, Ar gas is first introduced to replace the air in the furnace for 30 minutes; then H2 gas is introduced to continue to replace for 10 minutes to ensure that the oxygen content in the furnace is <10 ppm; Step six: temperature rising and GO reduction; Temperature rising program: rising to 700°C at a rate of 10°C / min, maintaining Ar gas 200 sccm+H2 gas 50 sccm mixed atmosphere throughout the process; Reduction holding: after reaching 700°C, the temperature and atmosphere are maintained for 30 minutes to fully reduce the GO film to reduced graphene oxide rGO; Step seven: carbon nanotube growth and heterojunction formation; carbon source introduction: after the reduction stage is completed, the temperature is kept at 700°C, the gas flow is adjusted to Ar gas 150 sccm+H2 gas 30 sccm+CH4 gas 80 sccm, and methane is continuously supplied as the carbon source; Growth holding: maintaining the gas atmosphere and temperature for 120 minutes, the defect sites on the surface of rGO will become the growth core of carbon nanotubes, and carbon atoms will grow directionally at the defect sites to form carbon nanotubes with diameter 5-10 nm and length 1-3 μm; Growth control: by real-time monitoring of the stability of the gas pressure and gas flow in the furnace, the aggregation caused by excessive growth of carbon nanotubes is avoided; Step eight: cooling and furnace discharge; cooling program: after the growth stage is completed, the methane gas is turned off, the Ar gas 200 sccm+H2 gas 50 sccm atmosphere is maintained, and the temperature is lowered to below 350°C at a rate of 5°C / min; then the hydrogen gas is turned off, only Ar gas is introduced, and the temperature is continuously lowered to room temperature; Furnace discharge requirement: after the temperature in the furnace is lowered to room temperature, stop introducing Ar gas, open the furnace door and take out the sample; Step nine: post-treatment process; low-temperature plasma cleaning: put the sample into the plasma cleaning machine, input Ar gas, power 50W, clean for 10 minutes; Vacuum drying: after cleaning, put it into an 80℃ vacuum oven for 30 minutes to remove the surface adsorbed moisture.

3. The heating structure of claim 1, wherein The thickness of the heterojunction heating film is 0.1mm, the thickness of the modified polyimide layer is 0.02mm, the thickness of the glass fiber composite layer is 0.1mm, and the total thickness can reach at least 0.34mm.

4. The heating structure of claim 1, wherein The glass fiber composite layer is glass fiber reinforced polyether ether ketone, and the glass fiber content is 30%.

5. The heating structure of claim 1, wherein, The modified polyimide layer is modified by adding 10% mass percentage of nano silicon dioxide to polyimide.

6. The heating structure of claim 1, wherein, The heterojunction heating film is provided with positive and negative electrodes on both sides, and the heterojunction heating film is powered to heat and deice.

7. The heating structure of claim 6, wherein, The ice thickness on the surface of the heating film is measured by monitoring the resistance value of the positive and negative electrodes.

8. A method for preparing a graphene-carbon nanotube heterojunction-based heating film for preparing the heating structure according to any one of claims 1 to 7, characterized in that, The specific process is as follows: Step one: prepare the heterojunction heating film, deposit graphene-carbon nanotube heterojunction on a piece of quartz fiber cloth using chemical vapor deposition equipment, and cut the shape after completion to obtain the heterojunction heating film; Step two: prepare the modified polyimide film and glass fiber composite prepreg, and cut to the required shape; Step three: according to the order of glass fiber composite prepreg, modified polyimide film, heterojunction heating film, modified polyimide film, and glass fiber composite prepreg, lay them on the mold and vacuumize to 0.2MPa, and shape for 1h; Step four: after shaping, keep the vacuum and transfer to the hot press tank, pressurize and solidify at a pressure of 0.2MPa, a temperature of 120℃, and a heating rate of 2℃ / min for 2h; Step five: after heating, keep the pressure, naturally cool to below 60℃, then release the pressure and open the tank; Step six: after taking out of the tank, trim the shape to obtain the heating structure.

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