Flexible graphene-carbon nanotube composite conductive film and preparation method and application thereof

Abstract

The invention discloses a flexible graphene-carbon nanotube composite conductive film and a preparation method and application thereof. The graphene-carbon nanotube composite conductive thin film is prepared by coating a water-based graphene-carbon nanotube conductive paste composed of a water-based graphene dispersion liquid, a water-based carbon nanotube dispersion liquid, water-based resin, a defoaming agent and a thickening agent. Wherein the graphene and the carbon nanotubes form a three-dimensional elastic net-shaped conductive structure under an ultrasonic condition, so that the influence of deformation on resistance is reduced. The graphene-carbon nanotube conductive film prepared by the invention has the advantages of good conductivity, low deformation resistance change rate, environmental friendliness, simple production, low cost and the like.

Description

Technical Field

[0001] The present invention belongs to the field of carbon materials, and particularly relates to a flexible graphene-carbon nanotube composite conductive film, a preparation method thereof, and an application thereof. Background Art

[0002] In the fields of electronic devices, sensors, and energy, the resistance stability of materials is one of the key indicators for measuring their performance. First of all, stable resistance ensures consistent circuit signal transmission, reduces distortion and noise, and improves the accuracy and reliability of electronic devices and sensors. Secondly, resistance stability slows down material aging, extends the service life of devices, and reduces the failure rate. In addition, resistance stability ensures consistent performance of mass-produced products and simplifies the quality control process in production. In a complex environment, resistance stability ensures that devices can work normally under high temperature, low temperature, or humid environments. Resistance stability can also reduce energy loss, improve energy efficiency, and help design more efficient circuits and systems. Long-term stability ensures that the performance of devices remains unchanged during long-term use, reducing the frequency of maintenance and replacement. Application examples include flexible electronics, transparent conductive films, high-frequency electronic devices, and sensors, etc. In short, resistance stability is crucial for improving device performance, extending lifespan, ensuring consistency, adapting to complex environments, improving energy efficiency, and enhancing reliability, and is widely used in the fields of electronics, sensors, and energy.

[0003] In the two-dimensional structure of graphene, when forming a conductive path, the graphene sheets are in contact and overlap with each other. When such graphene conductive materials undergo tensile deformation, it is easy to occur the phenomenon of sliding layers between the graphene sheets, and the conductive network is damaged, resulting in a sharp increase in the resistance of the material, which undoubtedly severely limits its application scope. How to prepare a flexible graphene conductive material with a low rate of change of resistance during deformation and good conductivity has become a major problem urgently to be solved in industrial applications. Summary of the Invention

[0004] In view of the above problems, the present invention provides a flexible graphene-carbon nanotube composite conductive film, a preparation method thereof and an application. The composite conductive film has the advantages of excellent conductivity, low deformation resistance change rate, environmental friendliness, simple production and low cost. An aqueous graphene-carbon nanotube composite conductive paste is prepared by ultrasonic mixing of aqueous graphene and aqueous carbon nanotubes. The composite conductive paste is coated on a PET release film and dried at a certain temperature to obtain a flexible graphene-carbon nanotube composite conductive film with a stable resistance value. By optimizing the composition and proportion of the composite material, including but not limited to selecting array-type carbon nanotubes with a tube diameter of 8-15 nm, controlling the mass ratio of aqueous graphene and aqueous carbon nanotubes, and the content of aqueous resin, the carbon nanotubes are uniformly interspersed between the graphene sheets to form anchoring points. The carbon nanotubes act as a bridge between the graphene sheets, enriching the conductive network between the graphene sheets, and finally forming a three-dimensional elastic network conductive structure that can resist the resistance change caused by deformation.

[0005] One of the technical solutions of the present invention is to provide a preparation method of the above flexible graphene-carbon nanotube composite conductive film, and the specific steps are as follows: (1) Stir 10 parts by weight of the dispersion of aqueous graphene and 20-40 parts by weight of the dispersion of aqueous carbon nanotubes evenly, and then perform ultrasonic treatment; the solid content of the dispersion of aqueous graphene and the dispersion of aqueous carbon nanotubes is 5 wt%. (2) Add 5-20 parts by weight of aqueous resin and stir evenly; (3) Add 0.01-0.1 parts by weight of defoaming agent and stir evenly; (4) Add 0.2-1 part by weight of thickener and stir evenly to obtain an aqueous graphene-carbon nanotube conductive paste; (5) Uniformly coat the aqueous graphene-carbon nanotube composite conductive paste on a PET release film through a knife coater, and put it into an oven to dry into a film.

[0006] The drying conditions are: the oven temperature is 100-150 °C, preferably 110-130 °C, and the baking time is 10-40 min, preferably 20-30 min.

[0007] Further, the graphene is few-layer graphene with a sheet diameter of 0.5-2.5 μm, preferably 1-2 μm. The carbon nanotubes are array-type carbon nanotubes with a tube diameter of 8-15 nm.

[0008] Further, the aqueous graphene dispersion is ground by a sand mill until graphene sheets with the required particle size are obtained. The rotation speed of the sand mill is 2000-2800 r / min, preferably 2600-2800 r / min. Preferably, after being ground by the sand mill, the few-layer graphene has a sheet diameter of 1-2 μm.

[0009] Furthermore, the water-based resin is one or more of polyurethane resin and acrylate resin, preferably acrylate resin.

[0010] Furthermore, the water-based resin is one or more of Wanhua 5531, BASF A970, Silok 3041, and Jinrunna 8107.

[0011] After ultrasonic treatment, carbon nanotubes are evenly interspersed between graphene sheets to form anchor points. Carbon nanotubes act as bridges between graphene sheets, enriching the conductive network between graphene sheets and eventually forming a three-dimensional elastic mesh conductive structure. Graphene of a certain size has both high conductivity and composite material flexibility. At the same time, due to the existence of carbon nanotube bridges, there is a certain elasticity between the conductive networks, which hinders the slippage between graphene sheets during deformation, thereby reducing the influence of deformation on the conductivity of the material.

[0012] The second technical solution of the present invention is to provide the above-mentioned aqueous graphene-carbon nanotube conductive slurry, including 10 parts by weight of aqueous graphene dispersion; 20-40 parts by weight of aqueous carbon nanotube dispersion, preferably 25-35 parts by weight; 5-20 parts by weight of aqueous resin, preferably 5-10 parts by weight; 0.01-0.1 parts by weight of defoaming agent, preferably 0.05-0.1 parts by weight.

[0013] The third technical solution of the present invention is to provide a graphene-carbon nanotube composite conductive film prepared by the above preparation method.

[0014] The fourth technical solution of the present invention is to provide the application of the above-mentioned conductive film in the fields of anti-static, electromagnetic shielding, electronic smart wearables, and electric heating.

[0015] The beneficial effect of the present invention is that ultrasound causes carbon nanotubes to be interspersed and distributed between graphene sheets, and at the same time forms anchor points, and carbon nanotubes and graphene eventually form a three-dimensional elastic network conductive structure, reducing the influence of deformation on resistance. The resistance change rate of the prepared conductive film after stretching by 10% can be as low as 13.49%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a preparation flow chart of the present invention; Figure 2 is a schematic diagram of a conductive network of the conductive film of the present invention; Figure 3 This is a scanning electron microscope image of Example 1. DETAILED DESCRIPTION

[0017] The following examples are used to further illustrate the present invention. Their purpose is to explain the present invention rather than to limit the scope of the present invention. Unless otherwise specified, all parts and percentages hereinafter are by weight.

[0018] The raw materials used in the present invention are all conventional commercially available products unless otherwise specified; the methods used in the present invention are all conventional methods in the art unless otherwise specified.

[0019] In the present invention, the method of dispersion is common knowledge in the art, and those skilled in the art can achieve it through common technical means.

[0020] The array-type carbon nanotubes have a cylindrical straight tube structure perpendicular to the substrate or arranged in parallel, with a tube diameter of 8 - 15 nm and a tube length of 10 - 20 microns; the wound-type carbon nanotubes have a tube diameter of 10 - 15 nm and a tube length of 3 - 12 microns.

[0021] The following aqueous graphene dispersion is prepared by dispersing few-layer graphene with a sheet diameter of 7 - 12 microns and less than 10 layers.

[0022] The aqueous resin is one or more of Wanhua 5531, BASF A970, Sloke 3041, and Jinrunna 8107.

[0023] The defoamer can be selected from one or more of BYK-019, TEGO-3062, and Wannuo 8835.

[0024] The thickener can be selected from one or more of Wannuo M23, Tongtai 8070, and BASF 1341.

[0025] In the following examples and comparative examples, the morphology determination method of the conductive film is characterized by scanning electron microscopy, and the method for determining the average particle size of graphene is laser particle size analysis.

[0026] In the following examples and comparative examples, the resistance of the conductive film is measured according to the voltammetry using a resistance meter; According to GB / T 1040.3 - 2006 and the voltammetry for measuring resistance, the change in the deformation resistance of the conductive film is measured using a universal material testing machine and a resistance meter; The following further illustrates the embodiments of the present invention with multiple examples.

[0027] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0028] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0029] Example 1 Put the aqueous graphene dispersion with a solid content of 5 wt% into a sand mill and grind it at a speed of 2000 rpm for 10 min. The measured particle size is 1.8 μm. Take 10 g of the sand-milled aqueous graphene dispersion and 30 g of the aqueous carbon nanotube dispersion with a solid content of 5 wt%, stir them at a speed of 600 rpm for 10 min, then ultrasonicate for 30 min. Add 5 g of the aqueous acrylic emulsion A970, stir at a speed of 500 rpm for 40 min, then add 0.05 g of the defoamer BYK-019, stir at a speed of 400 rpm for 30 min, and finally add 0.5 g of the thickener M23, stir at a speed of 600 rpm for 30 min and then discharge to obtain the aqueous graphene-carbon nanotube composite conductive paste. Coat the prepared aqueous graphene-carbon nanotube composite conductive paste evenly on the PET release film with a doctor blade coater. Put the coated wet film into an oven and bake it at 120 °C for 30 min to obtain a conductive film. The resistance of the conductive film is 43.32 Ω, and the resistance change rate after 10% stretching is 14.47%. The scanning electron microscope image of the conductive film is as Figure 3 shown. The carbon nanotubes are evenly dispersed between the graphene sheets, forming a three-dimensional sheet-wire cross-linked conductive structure. The carbon nanotubes are interspersed between the graphene sheets, forming anchoring points and acting as bridges between the graphene sheets, enriching the conductive network between the graphene sheets and improving the conductivity of the material. Graphene of a certain size takes into account both high conductivity and the flexibility of the composite material. At the same time, due to the existence of the array-type carbon nanotube bridges, there is a certain elasticity between the conductive networks, which hinders the slippage between the graphene sheets during the deformation process, thereby reducing the influence of deformation on the conductivity of the material. The resistance of the conductive film is 43.32 Ω, and the resistance change rate after 10% stretching is 14.17%. To meet the requirement of maintaining signal stability for flexible electrodes under human movement (15 - 20% stretching), its lower resistance change rate is significantly better than that of commercially available conductive fabrics; In terms of electromagnetic shielding (EMI), it meets the requirement of maintaining the shielding efficiency of the shielding layer of 5G devices such as foldable mobile phones under 10% bending deformation. The shielding efficiency attenuation after stretching ≤ 3 dB (the attenuation of conventional materials is 5 - 10 dB), meeting the GB / T 30142-2013 dynamic shielding standard; In terms of electrothermal devices, it is suitable for the mechanical stress of the automotive seat heating film that endures 10% installation deformation for a long time, and the resistance fluctuation < 15% can avoid local overheating; In the field of anti-static, its low resistance change rate can prevent the risk of charge accumulation caused by deformation.

[0030] Example 2 Put the aqueous graphene dispersion into a sand mill and grind it at a speed of 2800 rpm for 10 min. The measured particle size is 1.6 μm. Take 10 g of the sand-milled aqueous graphene dispersion with a solid content of 5 wt%, 30 g of the array-type carbon nanotube dispersion with a solid content of 5 wt%, stir at a speed of 600 rpm for 10 min, then ultrasonicate for 30 min, add 5 g of aqueous acrylic emulsion A970, stir at a speed of 500 rpm for 40 min, then add 0.05 g of defoamer BYK-019, stir at a speed of 400 rpm for 30 min, and finally add 0.5 g of thickener M23, stir at a speed of 600 rpm for 30 min and then discharge to obtain the aqueous graphene-carbon nanotube composite conductive paste. Coat the prepared aqueous graphene-carbon nanotube composite conductive paste evenly on a PET release film with a doctor blade coater, put the coated wet film into an oven, and bake it at 120 °C for 30 min to obtain a conductive film. The resistance of the conductive film is 46.21 Ω, and the resistance change rate after 10% stretching is 13.98%.

[0031] Example 3 Put the aqueous graphene dispersion into a sand mill and grind it at a speed of 2600 rpm for 20 min. The measured particle size is 1.5 μm. Take 10 g of the sand-milled aqueous graphene dispersion with a solid content of 5 wt%, 20 g of the array-type carbon nanotube dispersion with a solid content of 5 wt%, stir at a speed of 600 rpm for 10 min, then ultrasonicate for 30 min, add 5 g of aqueous acrylic emulsion A970, stir at a speed of 500 rpm for 40 min, then add 0.01 g of defoamer 8835, stir at a speed of 400 rpm for 30 min, and finally add 0.2 g of thickener M23, stir at a speed of 600 rpm for 30 min and then discharge to obtain the aqueous graphene-carbon nanotube composite conductive paste. Coat the prepared aqueous graphene-carbon nanotube composite conductive paste evenly on a PET release film with a doctor blade coater, put the coated wet film into an oven, and bake it at 120 °C for 30 min to obtain a conductive film. The resistance of the conductive film is 41.46 Ω, and the resistance change rate after 10% stretching is 23.30%.

[0032] Example 4 The aqueous graphene dispersion was put into a sand mill and ground at a rotation speed of 2800 rpm for 20 min. The measured particle size was 1.4 μm. 10 g of the sanded aqueous graphene dispersion with a solid content of 5 wt%, and 30 g of the array-type carbon nanotube dispersion with a solid content of 5 wt% were stirred at a rotation speed of 600 rpm for 10 min, then ultrasonicated for 30 min. 5 g of aqueous acrylic emulsion 8107 was added, and after stirring at a rotation speed of 500 rpm for 40 min, 0.05 g of defoamer 8835 was added and stirred at a rotation speed of 400 rpm for 30 min. Finally, 0.5 g of thickener 8070 was added and stirred at a rotation speed of 600 rpm for 30 min, and then discharged to obtain the aqueous graphene-carbon nanotube composite conductive paste. The prepared aqueous graphene-carbon nanotube composite conductive paste was evenly coated on a PET release film with a doctor blade coater. The coated wet film was put into an oven and baked at 150 °C for 10 min to obtain a conductive film. The resistance of the conductive film was 47.38 Ω, and the resistance change rate after 10% stretching was 13.85%.

[0033] Example 5 The aqueous graphene dispersion was put into a sand mill and ground at a rotation speed of 2800 rpm for 40 min. The measured particle size was 1.0 μm. 5 g of the sanded aqueous graphene dispersion with a solid content of 5 wt%, and 20 g of the array-type carbon nanotube dispersion with a solid content of 5 wt% were stirred at a rotation speed of 600 rpm for 10 min, then ultrasonicated for 30 min. 10 g of aqueous acrylic emulsion 8107 was added, and after stirring at a rotation speed of 500 rpm for 40 min, 0.05 g of defoamer 8835 was added and stirred at a rotation speed of 400 rpm for 30 min. Finally, 0.5 g of thickener 8070 was added and stirred at a rotation speed of 600 rpm for 30 min, and then discharged to obtain the aqueous graphene-carbon nanotube composite conductive paste. The prepared aqueous graphene-carbon nanotube composite conductive paste was evenly coated on a PET release film with a doctor blade coater. The coated wet film was put into an oven and baked at 100 °C for 40 min to obtain a conductive film. The resistance of the conductive film was 51.65 Ω, and the resistance change rate after 10% stretching was 13.49%.

[0034] Example 6 Put the aqueous graphene dispersion into a sand mill and grind it at a speed of 2800 rpm for 40 min. The measured particle size is 0.5 μm. Take 15 g of the sand-milled aqueous graphene dispersion with a solid content of 5 wt%, and 25 g of the array-type carbon nanotube dispersion with a solid content of 5 wt%. Stir them at a speed of 600 rpm for 10 min, then ultrasonicate for 30 min. Add 5 g of the aqueous acrylic emulsion 8107, stir at a speed of 500 rpm for 40 min, then add 0.05 g of the defoamer 8835, stir at a speed of 400 rpm for 30 min, and finally add 0.5 g of the thickener 8070. Stir at a speed of 600 rpm for 30 min and then discharge to obtain the aqueous graphene-carbon nanotube composite conductive paste. Coat the prepared aqueous graphene-carbon nanotube composite conductive paste evenly on a PET release film with a doctor blade coater. Put the coated wet film into an oven and bake it at 120 °C for 30 min to obtain a conductive film. The resistance of the conductive film is 46.54 Ω, and the resistance change rate after 10% stretching is 17.43%.

[0035] Example 7 Put the aqueous graphene dispersion into a sand mill and grind it at a speed of 2800 rpm for 20 min. The measured particle size is 1.4 μm. Take 10 g of the aqueous graphene dispersion with a solid content of 5 wt%, and 40 g of the array-type carbon nanotube dispersion with a solid content of 5 wt%. Stir them at a speed of 600 rpm for 10 min, then ultrasonicate for 30 min. Add 20 g of the aqueous acrylic emulsion 8107, stir at a speed of 500 rpm for 40 min, then add 0.1 g of the defoamer 8835, stir at a speed of 400 rpm for 30 min, and finally add 1 g of the thickener 8070. Stir at a speed of 600 rpm for 30 min and then discharge to obtain the aqueous graphene-carbon nanotube composite conductive paste. Coat the prepared aqueous graphene-carbon nanotube composite conductive paste evenly on a PET release film with a doctor blade coater. Put the coated wet film into an oven and bake it at 120 °C for 30 min to obtain a conductive film. The resistance of the conductive film is 52.16 Ω, and the resistance change rate after 10% stretching is 16.49%.

[0036] Comparative Example 1 40 g of an aqueous graphene dispersion with a solid content of 5 wt% and a measured particle size of 2.5 μm was added with 4 g of aqueous acrylic emulsion A970 and stirred at 600 rpm for 10 min, then sonicated for 30 min. Then 0.05 g of defoamer BYK-019 was added and stirred at 400 rpm for 30 min. Finally, 0.5 g of thickener M23 was added and stirred at 600 rpm for 30 min, and then discharged to obtain the conductive paste. The prepared conductive paste was evenly coated on a PET release film with a doctor blade coater. The coated wet film was placed in an oven and baked at 120 °C for 30 min to obtain the conductive film. The resistance of the conductive film was 38.93%, and the resistance change rate after 10% stretching was 50.57%, which was significantly higher than that of the examples.

[0037] Comparative Example 2 The aqueous graphene dispersion was put into a sand mill and ground at 2000 rpm for 5 min, and the measured particle size was 2.2 μm. 30 g of the sand-milled aqueous graphene dispersion with a solid content of 5 wt% and 30 g of an array-type carbon nanotube dispersion with a solid content of 5 wt% were stirred at 600 rpm for 10 min, then sonicated for 30 min. 5 g of aqueous acrylic emulsion 8107 was added and stirred at 500 rpm for 40 min. Then 0.05 g of defoamer BYK-019 was added and stirred at 400 rpm for 30 min. Finally, 0.5 g of thickener M23 was added and stirred at 600 rpm for 30 min, and then discharged to obtain the conductive paste. The prepared conductive paste was evenly coated on a PET release film with a doctor blade coater. The coated wet film was placed in an oven and baked at 120 °C for 30 min to obtain the conductive film.

[0038] Comparative Example 3 The aqueous graphene dispersion was put into a sand mill and ground at 2800 rpm for 80 min, and the measured particle size was 0.6 μm. 10 g of the sand-milled aqueous graphene dispersion with a solid content of 5 wt% and 30 g of an array-type carbon nanotube dispersion with a solid content of 5 wt% were stirred at 600 rpm for 10 min, then sonicated for 30 min. 30 g of aqueous acrylic emulsion 8107 was added and stirred at 500 rpm for 40 min. Then 0.05 g of defoamer 8835 was added and stirred at 400 rpm for 30 min. Finally, 0.5 g of thickener 8070 was added and stirred at 600 rpm for 30 min, and then discharged to obtain the conductive paste. The prepared conductive paste was evenly coated on a PET release film with a doctor blade coater. The coated wet film was placed in an oven and baked at 120 °C for 30 min to obtain the conductive film.

[0039] Comparative Example 4 The aqueous graphene dispersion was put into a sand mill and ground at a speed of 2800 rpm for 80 min. The measured particle size was 0.6 μm. 10 g of the sand-milled aqueous graphene dispersion with a solid content of 5 wt% and 30 g of the wound carbon nanotube dispersion with a solid content of 5 wt% were stirred at a speed of 600 rpm for 10 min, then ultrasonicated for 30 min. 5 g of the aqueous acrylic emulsion 8107 was added and stirred at a speed of 500 rpm for 40 min. Then 0.05 g of the defoamer 8835 was added and stirred at a speed of 400 rpm for 30 min. Finally, 0.5 g of the thickener 8070 was added and stirred at a speed of 600 rpm for 30 min, and then discharged to obtain the conductive paste. The prepared conductive paste was evenly coated on the PET release film with a doctor blade coater. The coated wet film was put into an oven and baked at 120 °C for 30 min to obtain the conductive film.

[0040] The test results are shown in Table 1.

[0041] Conductive thin film number Resistance / Ω Resistance after 10% stretching / Ω Resistance change rate Example 1 43.32 49.59 14.47% Example 2 46.21 52.67 13.98% Example 3 41.46 51.12 23.30% Example 4 47.38 53.94 13.85% Example 5 51.65 58.62 13.49% Example 6 46.54 54.65 17.43% Example 7 52.16 60.76 16.49% Comparative example 1 38.93 58.62 50.57% Comparative example 2 46.35 57.67 24.42% Comparative example 3 62.82 79.85 27.10% Comparative example 4 55.64 68.53 23.17% From the data of the above examples and comparative examples, combined with Table 1, it can be seen that: for the aqueous graphene-carbon nanotube composite conductive paste prepared with the component contents defined in the present invention, the conductive film prepared after film coating and drying has a relatively small resistance fluctuation caused by deformation. Under a 10% tensile deformation, the lowest resistance change rate is only 13.49%. The composite conductive film of the present invention can be used in the fields of smart wearables, smart electrothermal, flexible electronic devices, and electromagnetic shielding, etc. A flexible graphene-carbon nanotube composite conductive film and its preparation method of the present invention provide a theoretical basis for actual large-scale production.

[0042] The above examples have detailedly illustrated the structure, characteristics, and function effects of the present invention. The above are only the preferred embodiments of the present invention. Any changes made according to the concept of the present invention, or equivalent embodiments modified into equivalent changes, still within the scope covered by the specification, shall be within the protection scope of the present invention.

Claims

1. A method for preparing a flexible graphene-carbon nanotube composite conductive film, characterized in that: The following steps are involved: (1) 10 parts by weight of an aqueous graphene dispersion and 20-40 parts by weight of an aqueous carbon nanotube dispersion are stirred uniformly, and then subjected to ultrasonic treatment for 30 minutes; the aqueous graphene dispersion and the aqueous carbon nanotube dispersion have a solid content of 5wt%; (2) Add 5-20 parts by weight of water-based resin and stir evenly; (3) Add 0.01-0.1 parts by weight of defoamer and stir evenly; (4) adding 0.2-1 parts by weight of a thickener and stirring evenly to obtain an aqueous graphene-carbon nanotube conductive slurry; (5) The water-based graphene-carbon nanotube composite conductive slurry is evenly coated on the PET release film by a doctor blade coater and placed in an oven for drying to form a film.

2. The preparation method according to claim 1, characterized in that: The water-based graphene is a few-layer graphene with a sheet diameter of 0.5-2.5 μm; the water-based carbon nanotube is an array-type carbon nanotube with a tube diameter of 8-15 nm.

3. The preparation method according to claim 1, characterized in that: The aqueous graphene dispersion in step 1 is sand-milled by a sand mill at a speed of 2000-2800 r / min.

4. The preparation method according to claim 1, characterized in that: The water-based resin is one or more of polyurethane resin and acrylate resin.

5. The preparation method according to claim 4, characterized in that: The water-based resin is one or more of Wanhua 5531, BASF A970, Silok 3041, and Jinrunna 8107.

6. The preparation method according to claim 1, characterized in that: The drying conditions in step 5 are: oven temperature of 100-150° C., and baking time of 10-40 min.

7. A graphene-carbon nanotube composite conductive film prepared by the preparation method according to claim 1, characterized in that: The coating is prepared using an aqueous graphene-carbon nanotube conductive slurry, wherein the aqueous graphene-carbon nanotube conductive slurry includes 10 parts by weight of an aqueous graphene dispersion, 20-40 parts by weight of an aqueous carbon nanotube dispersion, 5-20 parts by weight of an aqueous resin, 0.01-0.1 parts by weight of a defoamer, and 0.2-1 parts by weight of a thickener; the solid content of the aqueous graphene dispersion and the aqueous carbon nanotube dispersion is 5wt%.

8. An application of the graphene-carbon nanotube composite conductive film as claimed in claim 7 in the fields of anti-static, electromagnetic shielding, electronic smart wearables, and electric heating.

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