Nano-silver graphene electric heating flexible composite material and preparation method thereof

Abstract

The application provides a kind of nanometer silver graphene electric heating flexible composite material and preparation method thereof, it is related to high-performance textile field, wherein preparation method is as follows: S1: cotton fabric is immersed in GO dispersion, and GO / cotton is obtained: S2: the BTCA / GO / cotton obtained in S1 is immersed in finishing liquor, and BTCA / GO / cotton is obtained;S3: the BTCA / GO / cotton obtained in S2 is immersed in silver ammonia solution, and Ag / BTCA / GO / cotton is obtained;S4: hydrazine hydrate reduction obtains Ag / BTCA / rGO / cotton.The smart textile prepared according to the above preparation method has high soaping fastness, can realize rapid heating in a short time, and has good application prospect in the field of flexible smart wearable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-performance textile fabrics, and particularly relates to a nano-silver graphene electric heating flexible composite material and a preparation method thereof. BACKGROUND

[0002] In recent years, with the development of science and technology and the change of people's concept of clothing, wearable smart products have attracted widespread attention due to their potential applications in health monitoring, portable energy collection and storage, wireless communication and the like. Integrating wearable sensing devices into textiles or clothing has become a trend of flexible smart wearables.

[0003] Graphene is a two-dimensional honeycomb lattice structure material with a single-atom thickness. Since graphene and its derivatives have thermal stability and are considered to be the most stable carbon isomer in thermodynamics, they have become one of the hottest candidate materials in the field of electronic components of conductive and heat-conductive textiles. As a highly conductive material, nano metal has a large number of free electrons that can move freely inside. These free electrons move directionally under the action of electric field force to form electric current, so that the nano metal has conductivity. Meanwhile, the internal phonon and electron diffusion movement makes the nano metal have excellent Joule heating performance, and it is widely used due to its flexibility compared with traditional metal materials.

[0004] CN 104277592A discloses a graphene-based water-based ink and its application in inkjet printing of transparent patterned conductive electrodes. The minimum resistance of the obtained transparent pattern is 170Ω / Sq, which is obtained by printing the ink prepared by mixing silver nanosheets and graphene. The preparation of silver nanosheets involves two reductions of sodium borohydride and ascorbic acid, cleaning, vacuum filtration and dispersion. The process is time-consuming and the adhesion of the conductive material to the base is low. CN 114477152A discloses a silver nanoparticle / multilayer graphene composite material and a preparation method. The method uses expanded graphite to prepare a multilayer graphene dispersion liquid, combines silver ammine complex with graphene through a hydrothermal reaction, and then uses ascorbic acid for reduction to prepare a silver nanoparticle / multilayer graphene composite material. However, due to the weak intermolecular force, the silver ammine complex cannot be adsorbed in large quantities, resulting in an increase in the resistance of the final product. CN 110060886A discloses a preparation method of a fiber / graphene / FeOF / Ag flexible electrode material. The method processes graphene, FeOF and Ag to the fabric through layer-by-layer self-assembly and screen printing. However, the process is time-consuming and requires reduction at high temperature with inert gas protection.

[0005] Therefore, there is a need to provide a preparation method of an electric heating material with low-temperature preparation, high adhesion and excellent conductive and heating performance. SUMMARY

[0006] The present application aims at solving the technical problems of long process time and reduction at high temperature and the need for inert gas protection in the prior art.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A preparation method of a flexible electrothermal composite material, comprising the following steps:

[0009] S1: immersing cotton fabric in a GO dispersion solution to obtain GO / Cotton:

[0010] S2: immersing the BTCA / GO / Cotton obtained in S1 in a finishing solution to obtain BTCA / GO / Cotton

[0011] S3: immersing the BTCA / GO / Cotton obtained in S2 in a silver-ammonia solution to obtain

[0012] Ag / BTCA / GO / cotton;

[0013] S4: reducing Ag / BTCA / GO / cotton by using hydrazine hydrate to obtain Ag / BTCA / rGO / cotton.

[0014] Preferably, the specific steps of S1 are as follows: immersing the cotton fabric in the GO dispersion solution for stirring for 20 min, and then taking out and drying at 80 DEG C, which is one-time immersion, and the immersion is repeated for 5 times to obtain GO / Cotton.

[0015] Preferably, the average size of GO used in S1 is 35 μm, and the concentration of the GO dispersion solution is 5 g / L.

[0016] Preferably, the specific steps of S2 are as follows: immersing the GO / Cotton in the finishing solution containing 80-120 g / L of BTCA, 36-100 g / L of SHP and 60 g / L of DMSO according to a bath ratio of 50:1, double immersion and double rolling, the pick-up rate is 100%, pre-drying at 80 DEG C for 5 min, and curing at 120-160 DEG C for 3 min to obtain BTCA / GO / Cotton.

[0017] Preferably, the finishing solution is 120 g / L of BTCA, 100 g / L of SHP and 60 g / L of DMSO, and the time for immersing in the finishing solution is 3 min.

[0018] Preferably, the specific step of S3 is to immerse the BTCA / GO / cotton prepared in S2 into silver amide solution after wetting and place it in a water bath shaker and shake vigorously for 30 min. During the immersion process, keep the room temperature (20±2℃). After the shaking is completed, add an appropriate amount of reducing agent dropwise, mix uniformly, and then stand for 2h. Then take out and dry to prepare Ag / BTCA / GO / cotton.

[0019] Preferably, the reducing agent is glyoxal.

[0020] Preferably, the specific step of S4 is to reduce Ag / BTCA / GO / cotton obtained in S3 with hydrazine hydrate at 90℃ for 2h to prepare Ag / BTCA / rGO / cotton.

[0021] The application also provides a nano-silver graphene flexible composite material prepared by using the preparation method.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] (1) The preparation method in the application adopts in-situ deposition and padding-drying processes to finish the functional materials such as graphene and nano-silver on the surface of the fabric. The fabric is finished with BTCA, and is reduced by a reducing agent, so that the Ag ions are reduced to nano-silver at room temperature.

[0024] (2) The application also reduces the fabric with hydrazine hydrate, which reduces the GO to graphene and further reduces the Ag ions that are not completely reduced to silver single element. In addition, hydrazine hydrate can condense with BTCA to form an amide bond to form a film-like substance on the surface of the fabric to enhance the adhesion and wash fastness of the silver single element and graphene to the fabric.

[0025] (3) The smart textile prepared by the above preparation method has high soaping fastness, can realize rapid heating in a short time, and has good application prospect in the field of flexible smart wearable. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a GO morphology diagram prepared in an embodiment of the application.

[0027] Figure 2 It is a SEM image of Ag / BTCA / rGO / Cotton obtained in Example 2 of the application, magnified by 50000 times.

[0028] Figure 3 It is an infrared imaging diagram of Ag / BTCA / rGO / Cotton obtained in the embodiment of the application under a voltage of 2.5V and powered for 2min. DETAILED DESCRIPTION

[0029] The application will be further described in detail below in connection with specific embodiments.

[0030] A method for preparing a flexible electrothermal composite material, comprising the following steps:

[0031] S1: immersing cotton fabric into a GO dispersion solution to obtain GO / Cotton:

[0032] Specifically, in an embodiment, the cotton fabric is wetly immersed into the GO dispersion solution and stirred for 20 min, and then taken out and dried at 80°C. This process is one-time immersion, and the immersion is repeated 1-9 times to obtain the GO / Cotton. Preferably, the number of repetitions is 5.

[0033] In an embodiment, the GO dispersion solution is self-made graphene oxide, and the preparation steps are as follows: first, graphite foil is used as the positive electrode, platinum wire is used as the negative electrode, concentrated sulfuric acid solution is used as the electrolyte, the electrochemical workstation is connected, the direct current power supply is input, and after power-on for 30 min, the electrochemically modified graphite is collected by filtration, and then the improved hummers method is used to prepare graphene oxide. Specifically, in an embodiment, 6 g of graphite powder is added to a beaker containing 500 mL of concentrated sulfuric acid under ice bath condition, and 30 g of potassium permanganate is slowly added in batches under stirring condition; after stirring for 6 h at room temperature, 500 mL of deionized water and 50 mL of hydrogen peroxide are added to the beaker; after the solution turns into brown yellow, 50 mL of hydrochloric acid (5%) and 500 mL of deionized water are added, and after the solution is layered, the solid is washed to neutral with deionized water, and after freeze-drying, the obtained solid is GO.

[0034] In an embodiment, the prepared GO has a diameter distribution of about 35 μm, and the SEM morphology diagram thereof is as shown in FIG. 1; and the concentration of the GO dispersion solution is 5 g / L. Figure 1

[0035] S2: immersing the BTCA / GO / Cotton obtained in S1 into a finishing solution to obtain BTCA / GO / Cotton; according to the bath ratio of 50:1, the GO / Cotton in S1 is immersed into a finishing solution containing 80-120 g / L butane tetracarboxylic acid (BTCA), 36-100 g / L sodium hypophosphite (SHP), and 60 g / L dimethyl sulfoxide (DMSO), double-immersed and double-rolled, the pick-up rate is 100%, the pre-drying is performed at 80°C for 5 min, and the curing is performed at 120-160°C for 3 min to obtain the BTCA / GO / Cotton.

[0036] In an embodiment, the finishing solution is 120 g / L BTCA, 100 g / L SHP, and 60 g / L DMSO, and the immersion time of the finishing solution is 3 min.

[0037] ​S3: The BTCA / GO / Cotton obtained in S2 is immersed in silver-ammonia solution to obtain Ag / BTCA / GO / cotton;

[0038] Specifically, in an embodiment, the BTCA / GO / Cotton prepared in S2 is immersed in silver-ammonia solution after being wetted and is placed in a water bath shaker for vigorous shaking for 30 min. During the immersion process, the room temperature condition (20±2℃) is maintained. After the shaking is completed, an appropriate amount of reducing agent is added dropwise and mixed uniformly, and then is left to stand for 2 h. Then, Ag / BTCA / GO / cotton is prepared by taking out and drying. In an embodiment, the reducing agent is glyoxal.

[0039] In an embodiment, the silver-ammonia solution is prepared as follows: 1 mM-0.15 M silver nitrate is taken, and an appropriate amount of ammonia water is added dropwise to the silver nitrate to make the precipitate in the solution disappear to prepare the silver-ammonia solution. Preferably, the concentration of the silver nitrate is 0.1 M, and the pH value of the prepared silver-ammonia solution is 9-10.

[0040] S4: Hydrazine hydrate reduction

[0041] In an embodiment, the Ag / BTCA / GO / cotton obtained in S3 is reduced by hydrazine hydrate at 90℃ for 2 h to prepare Ag / BTCA / rGO / cotton.

[0042] In an embodiment, the bath ratio of S3 and S4 is 50:1.

[0043] The application also provides a nano-silver graphene electric heating flexible composite material prepared by the above preparation method.

[0044] The following are six groups of nano-silver graphene electric heating flexible composite materials prepared according to the above preparation method.

[0045] Example 1:

[0046] (1) The cotton fabric is wetted and immersed in a 5 g / L GO dispersion liquid for stirring for 20 min, and is taken out and dried at 80℃. The above operation is repeated 5 times to prepare GO / Cotton;

[0047] (2) According to the bath ratio of 50:1, the GO / Cotton in step (1) is immersed in a finishing liquid containing 120 g / L BTCA, 100 g / L SHP and 60 g / L DMSO for 3 min, and is double-immersed and double-rolled. The pre-drying is performed at 80℃ for 5 min, and the curing is performed at 120℃ for 3 min to prepare BTCA / GO / Cotton;

[0048] (3) According to a bath ratio of 50:1, 0.1M silver nitrate was taken, and an appropriate amount of ammonia water was added dropwise to make the precipitate in the solution disappear to prepare a silver ammonia solution. The BTCA / GO / Cotton prepared in step (2) was wetted and then immersed in the silver ammonia solution (pH value = 9-10) at room temperature (20±2℃) and placed in a water bath shaker for vigorous shaking for 30 min. After 1 mL of glyoxal (n (silver nitrate) : n (glyoxal) = 4:7) was added dropwise and mixed uniformly, it was left to stand for 2 h, and then taken out and dried at 80℃ to obtain Ag / BTCA / GO / cotton;

[0049] (4) The Ag / BTCA / GO / cotton obtained in step (3) was reduced by hydrazine hydrate at 90℃ for 2 h to prepare Ag / BTCA / rGO / cotton.

[0050] Example 2:

[0051] (1) Cotton fabric was wetted and immersed in a 5g / L GO dispersion solution and stirred for 20 min. It was taken out and dried at 80℃. The above operation was repeated 5 times to prepare GO / Cotton;

[0052] (2) According to a bath ratio of 50:1, the GO / Cotton in step (1) was immersed in a finishing liquor containing 120g / L BTCA, 100g / L SHP and 60g / L DMSO for 3 min, double-dip-double-nip, pre-dried at 80℃ for 5 min, and cured at 130℃ for 3 min to prepare BTCA / GO / Cotton;

[0053] (3) According to a bath ratio of 50:1, 0.1M silver nitrate was taken, and an appropriate amount of ammonia water was added dropwise to make the precipitate in the solution disappear to prepare a silver ammonia solution. The BTCA / GO / Cotton prepared in step (2) was wetted and then immersed in the silver ammonia solution (pH value = 9-10) at room temperature (20±2℃) and placed in a water bath shaker for vigorous shaking for 30 min. After 1 mL of glyoxal (n (silver nitrate) : n (glyoxal) = 4:7) was added dropwise and mixed uniformly, it was left to stand for 2 h, and then taken out and dried at 80℃ to obtain Ag / BTCA / GO / cotton;

[0054] (4) The Ag / BTCA / GO / cotton obtained in step (3) was reduced by hydrazine hydrate at 90℃ for 2 h to prepare Ag / BTCA / rGO / cotton.

[0055] Example 3:

[0056] (1) Cotton fabric was wetted and immersed in a 5g / L GO dispersion solution and stirred for 20 min. It was taken out and dried at 80℃. The above operation was repeated 5 times to prepare GO / Cotton;

[0057] (2) According to the bath ratio of 50:1, the GO / Cotton in step (1) was immersed in a finishing liquor containing 120 g / L BTCA, 100 g / L SHP and 60 g / L DMSO for 3 min, double-dip-double-nip, pre-dried at 80°C for 5 min, and cured at 130°C for 3 min to prepare BTCA / GO / Cotton;

[0058] (3) According to the bath ratio of 50:1, 0.1M silver nitrate was taken, and an appropriate amount of ammonia water was added dropwise to make the precipitate in the solution disappear to prepare a silver ammonia solution. The prepared BTCA / GO / Cotton in step (2) was wetted and then immersed in the silver ammonia solution (pH value = 9-10) at room temperature (20±2°C) and placed in a water bath shaker for vigorous shaking for 30 min. After uniformly mixing 143 μL of glyoxal (n(silver nitrate):n(glyoxal) = 4:1) was added dropwise, it was left to stand for 2 h, and then taken out and dried at 80°C to obtain Ag / BTCA / GO / cotton;

[0059] (4) The Ag / BTCA / GO / cotton obtained in step (3) was reduced by hydrazine hydrate at 90°C for 2 h to prepare Ag / BTCA / rGO / cotton.

[0060] Example 4:

[0061] (1) Cotton fabric was wetted and immersed in a 5 g / L GO dispersion solution for stirring for 20 min, taken out and dried at 80°C, and the above operation was repeated 5 times to prepare GO / Cotton;

[0062] (2) According to the bath ratio of 50:1, the GO / Cotton in step (1) was immersed in a finishing liquor containing 120 g / L BTCA, 100 g / L SHP and 60 g / L DMSO for 3 min, double-dip-double-nip, pre-dried at 80°C for 5 min, and cured at 130°C for 3 min to prepare BTCA / GO / Cotton;

[0063] (3) According to the bath ratio of 50:1, 0.1M silver nitrate was taken, and an appropriate amount of ammonia water was added dropwise to make the precipitate in the solution disappear to prepare a silver ammonia solution. The prepared BTCA / GO / Cotton in step (2) was wetted and then immersed in the silver ammonia solution (pH value = 9-10) at room temperature (20±2°C) and placed in a water bath shaker for vigorous shaking for 30 min. After uniformly mixing 143 μL of glyoxal (n(silver nitrate):n(glyoxal) = 4:1) was added dropwise, it was left to stand for 2 h, and then taken out and dried at 80°C to obtain Ag / BTCA / GO / cotton;

[0064] (4) The Ag / BTCA / GO / cotton obtained in step (3) was reduced by hydrazine hydrate at 90°C for 2 h to prepare Ag / BTCA / rGO / cotton.

[0065] Example 5:

[0066] (1) Cotton fabric was immersed in 5 g / L GO dispersion solution for 20 min with stirring, taken out and dried at 80°C, and the above operation was repeated 5 times to prepare GO / Cotton;

[0067] (2) According to the bath ratio of 50:1, the GO / Cotton prepared in step (1) was immersed in a finishing liquor containing 120 g / L BTCA, 100 g / L SHP and 60 g / L DMSO for 3 min, double-dip-double-nip, pre-dried at 80°C for 5 min, and cured at 160°C for 3 min to prepare BTCA / GO / Cotton;

[0068] (3) According to the bath ratio of 50:1, 0.1M silver nitrate was taken, and an appropriate amount of ammonia water was added to the solution to make the precipitate disappear to prepare a silver ammonia solution. The BTCA / GO / Cotton prepared in step (2) was immersed in the silver ammonia solution (pH value = 9-10) at room temperature (20±2°C) and placed in a water bath shaker for vigorous shaking for 30 min. After 1 mL of glyoxal (n(silver nitrate):n(glyoxal) = 4:7) was added and mixed uniformly, it was placed for 2 h, taken out and dried at 80°C to obtain Ag / BTCA / GO / cotton;

[0069] (4) The Ag / BTCA / GO / cotton obtained in step (3) was reduced by hydrazine hydrate at 90°C for 2 h to prepare Ag / BTCA / rGO / cotton.

[0070] Example 6:

[0071] (1) Cotton fabric was immersed in 5 g / L GO dispersion solution for 20 min with stirring, taken out and dried at 80°C, and the above operation was repeated 5 times to prepare GO / Cotton;

[0072] (2) According to the bath ratio of 50:1, the GO / Cotton prepared in step (1) was immersed in a finishing liquor containing 120 g / L BTCA, 100 g / L SHP and 60 g / L DMSO for 3 min, double-dip-double-nip, pre-dried at 80°C for 5 min, and cured at 130°C for 3 min to prepare BTCA / GO / Cotton;

[0073] (3) According to the bath ratio of 50:1, 0.1M silver nitrate was taken, and an appropriate amount of ammonia water was added to the solution to make the precipitate disappear to prepare a silver ammonia solution. The BTCA / GO / Cotton prepared in step (2) was immersed in the silver ammonia solution (pH value = 9-10) at room temperature (20±2°C) and placed in a water bath shaker for vigorous shaking for 30 min. After 1 mL of glyoxal (n(silver nitrate):n(glyoxal) = 4:7) was added and mixed uniformly, it was placed for 2 h, taken out and dried at 80°C to obtain Ag / BTCA / GO / cotton.

[0074] The obtained fiber-based graphene electrothermal material was tested as follows:

[0075] Test 1: Conductive property test

[0076] The square resistance of any five positions on the fabric was measured using a four-probe resistance tester, and the average value was taken as the square resistance of the fabric.

[0077] Table 1 Surface resistance of each example

[0078]

[0079] Table 2 Surface resistance of fabric after soaping of Example 2 and Example 6

[0080]

[0081] Table 1 is the surface resistance measured in Example 1-5 and Example 6. As can be seen from the surface resistance measured in Example 1, 2 and 5, with the increase of the curing temperature, the surface resistance of the fabric first decreases and then increases, and the surface resistance is the lowest at 0.638 Ω / Sq when the curing temperature is 130°C. As can be seen from Example 2-4, with the increase of the amount of glyoxal, the surface resistance first decreases and then increases, and the minimum surface resistance is obtained when the molar ratio is 4:7.

[0082] Table 2 is the surface resistance of the fabric after soaping of Example 2 and Example 6. In Example 6, no hydrazine hydrate reduction is performed based on Example 2. As can be directly seen from the data in Table 2, the resistance of the Ag / BTCA / rGO / Cotton prepared in Example 2 increases from 0.638 Ω / Sq to 4.487 Ω / Sq after 5 washes, while the resistance of the Ag / BTCA / GO / Cotton prepared in Example 6 increases from 1.696 Ω / Sq to 3066.785 Ω / Sq after 4 washes, and the fabric is not conductive after the 5th wash. The difference between the data of the two can indicate that the fastness of the conductive material to the fabric is improved after the reduction of hydrazine hydrate, and the conductive performance is excellent.

[0083] Test 2: Electrothermal property characterization

[0084] The stabilized power supply line was connected to both ends of the fabric, the distance between the power supply connection was controlled to be 3 cm, and the apparent heating temperature and infrared imaging of the fabric were tested under different voltage conditions and different electrifying time using an infrared imaging instrument.

[0085] Please refer to Figure 2 and Figure 3 , wherein Figure 2 is the SEM image of Ag / BTCA / rGO / Cotton obtained in Example 2 of the present application, magnified by 50000 times, which can be directly seen that after the reduction of hydrazine hydrate (attached Figure 1) The film-like substance is formed on the fabric surface, so that the nano-silver element is more firmly wrapped on the fabric surface.

[0086] The fabric is immersed in the solution of the reducing agent and the reducing agent is allowed to react with the Ag ions on the fabric surface. Figure 3 The infrared imaging diagram of the Ag / BTCA / rGO / Cotton obtained in Example 2 is measured when the fabric is powered for 2 min under a voltage of 2.5 V.

[0087] Based on the above preparation method, the nano-silver graphene electric heating flexible composite material obtained in the application adopts in-situ deposition and padding and drying processes to arrange functional materials such as graphene and nano-silver on the fabric surface. In the application, the fabric is arranged by using BTCA and is reduced by using a reducing agent, so that the Ag element is reduced to nano-silver element at normal temperature.

[0088] In the application, the fabric is reduced by using hydrazine hydrate. The hydrazine hydrate can reduce the Ag ions which are not completely reduced to silver element while reducing GO to graphene. In addition, the hydrazine hydrate can be condensed with BTCA to form an amide bond, so as to form a film-like substance on the fabric surface to enhance the adhesion and washing fastness of the silver element and graphene to the fabric. The smart textile prepared in the application has high washing fastness, can realize rapid heating in a short time, and has a good application prospect in the field of flexible smart wearable devices.

Claims

1. A method for preparing a flexible electrothermal composite material, characterized in that: Includes the following steps: S1: Immerse cotton fabric in GO dispersion to obtain GO / Cotton: The cotton fabric was moistened and immersed in the GO dispersion and stirred for 20 minutes. After being removed, it was dried at 80°C. This process was one immersion. The immersion was repeated 5 times to obtain GO / Cotton. The average GO flake diameter used in S1 is 35 μm, and the concentration of the GO dispersion is 5 g / L; S2: Use the GO / Cotton impregnation finishing solution obtained in S1 to obtain BTCA / GO / Cotton. Specifically, according to a liquor ratio of 50:1, GO / Cotton in S1 is immersed in a finishing solution containing 80-120 g / L BTCA, 36-100 g / L SHP and 60 g / L DMSO, with two dips and two nipples, 100% nip, pre-drying at 80℃ for 5 min, and curing at 120-160℃ for 3 min to obtain BTCA / GO / Cotton; S3: Immerse the BTCA / GO / Cotton obtained in S2 in a silver ammonia solution to obtain Ag / BTCA / GO / cotton; S4: Reduce hydrazine hydrate to obtain Ag / BTCA / rGO / cotton.

2. The method for preparing the flexible electrothermal composite material according to claim 1, characterized in that: The finishing solution consisted of 120 g / L BTCA, 100 g / L SHP, and 60 g / L DMSO, and the immersion time in the finishing solution was 3 minutes.

3. The method for preparing the flexible electrothermal composite material according to claim 1, characterized in that: The specific steps of S3 are as follows: after wetting the BTCA / GO / Cotton prepared in S2, immerse it in silver ammonia solution and place it in a water bath shaker to shake vigorously for 30 minutes. During the immersion process, maintain the room temperature condition of 20 ± 2℃. After shaking, add an appropriate amount of reducing agent and mix evenly. Let it stand for 2 hours, and then take it out and dry it to obtain Ag / BTCA / GO / cotton.

4. The method for preparing the flexible electrothermal composite material according to claim 3, characterized in that: The reducing agent is glyoxal.

5. The method for preparing the flexible electrothermal composite material according to claim 1, characterized in that: The specific step S4 involves reducing the Ag / BTCA / GO / cotton obtained in S3 with hydrazine hydrate at 90°C for 2 hours to prepare Ag / BTCA / rGO / cotton.

6. A flexible electrothermal composite material, characterized in that: It is prepared using the preparation method described in any one of claims 1-5.

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