Silica modified molybdenum disulfide carbon nanotube composite film, preparation method and application thereof

Abstract

The present application relates to a kind of silica modified molybdenum disulfide carbon nanotube composite film and its preparation method and application, the silica modified molybdenum disulfide carbon nanotube composite film is by silica modified molybdenum disulfide powder and carbon nanotube composite film;The structure of the silica modified molybdenum disulfide powder is that molybdenum disulfide is attached to the surface of silica.Compared with MoS2 / carbon nanotube composite film, the Seebeck coefficient of silica modified molybdenum disulfide and carbon nanotube composite is further improved;Compared with pure MoS2, the layer number of modified MoS2 is less, and the dispersibility of MoS2 is better;Silica modified molybdenum disulfide / carbon nanotube composite film is good in flexibility, and power factor is high, and the composite film has good application prospect in the field of flexible wearable thermoelectric equipment.

Description

Technical Field

[0001] This invention relates to the field of nanocomposite materials technology, specifically to a silica-modified molybdenum disulfide carbon nanotube composite film, its preparation method, and its application. Background Technology

[0002] Molybdenum disulfide (MoS2) is an abundant inorganic compound on Earth, possessing a stable semiconductor 1H phase and a metastable metallic 2T phase. Due to its high S (≈10 mV / K) content... -1 MoS2 is considered a promising candidate for thermoelectric applications. However, its low electrical conductivity limits its application in thermoelectric materials. Single-walled carbon nanotubes (SWCNTs) have attracted widespread attention due to their high aspect ratio, high flexibility, low density, and excellent mechanical properties. 2 The hybrid structure endows it with excellent electrical conductivity, thus making it a potential conductive filler. Therefore, MoS2 can be combined with SWCNT to improve thermoelectric properties. However, the prepared MoS2 often exhibits agglomeration. How to improve the dispersibility of MoS2 and suppress its agglomeration is a key and challenging research problem. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a silica-modified molybdenum disulfide carbon nanotube composite film, its preparation method, and its application. This invention modifies MoS2 with SiO2, and then composites the silica-modified molybdenum disulfide with carbon nanotubes, thereby solving the problem of MoS2 agglomeration.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a silicon dioxide modified molybdenum disulfide carbon nanotube composite film, wherein the film is formed by combining silicon dioxide modified molybdenum disulfide powder and carbon nanotubes;

[0005] The structure of the silicon dioxide modified molybdenum disulfide powder is that molybdenum disulfide is attached to the surface of silicon dioxide.

[0006] The principle of this invention is as follows: Silica particles possess unique properties, such as high specific surface area, significant toughening and strengthening, and large pore volume. Therefore, by modifying MoS2 with SiO2, the modified MoS2 has fewer layers compared to pure MoS2, and the dispersion of MoS2 is improved, thereby increasing the Seebeck coefficient of the composite film. Furthermore, SiO2 may increase the conductivity of the composite material by forming an isolated carbon nanotube network.

[0007] The beneficial effects of this invention are as follows: compared with MoS2 / carbon nanotube composite films, the silica-modified molybdenum disulfide composite with carbon nanotubes further improves the Seebeck coefficient; compared with pure MoS2, the modified MoS2 has fewer layers and better MoS2 dispersion; the silica-modified molybdenum disulfide / carbon nanotube composite film has good flexibility and high power factor, and this composite film has good application prospects in the field of flexible wearable thermoelectric devices.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the mass ratio of the silica-modified molybdenum disulfide powder to the carbon nanotubes is 1:(1-100);

[0010] The carbon nanotubes have a diameter of 1–3 nm and a length of 5–15 μm;

[0011] The carbon nanotubes are one or more of single-walled carbon nanotubes, multi-walled carbon nanotubes, and double-walled carbon nanotubes.

[0012] The thickness of the composite film is 8–14 μm.

[0013] The beneficial effect of adopting the above-mentioned further scheme is that the performance of the film can be further improved by controlling the ratio of silicon dioxide modified molybdenum disulfide powder and carbon nanotubes, the size of carbon nanotubes, and the film thickness.

[0014] To achieve the second objective mentioned above, this invention provides a method for preparing a silicon dioxide-modified molybdenum disulfide carbon nanotube composite film.

[0015] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing a silica-modified molybdenum disulfide carbon nanotube composite film, the method comprising:

[0016] Thiol-modified silica nanospheres were mixed with sulfur and molybdenum sources and subjected to a hydrothermal reaction. The mixture was then cooled, filtered, washed, and dried to obtain silica-modified molybdenum disulfide powder.

[0017] The silica-modified molybdenum disulfide powder was mixed with carbon nanotubes in an organic solvent and then filtered to obtain a silica-modified molybdenum disulfide carbon nanotube composite film.

[0018] The beneficial effects of the above scheme are as follows: This invention first uses silica nanospheres containing thiol groups, with SiO2-SH as part of the sulfur source, and then selects appropriate sulfur and molybdenum sources to control the Si:S ratio to prepare silica-modified molybdenum disulfide powder. Then, the silica-modified molybdenum disulfide powder is uniformly dispersed in single-walled carbon nanotubes. Based on the energy filtering effect, the carrier concentration is reduced, thereby improving the Seebeck coefficient and forming a composite film with a high power factor, which fully utilizes the advantages of composite materials.

[0019] Based on the above technical solution, the present invention can be further improved as follows.

[0020] Furthermore, the molybdenum source is molybdenum pentachloride or ammonium molybdate;

[0021] The sulfur source is one or more of thiourea, sodium sulfide, ammonium tetrathiomolybdate, L-cysteine, or thiolated silica nanospheres.

[0022] The beneficial effect of adopting the above-mentioned further scheme is that MoS2 with different thicknesses, morphologies and structures can be synthesized by using different sulfur sources and molybdenum sources.

[0023] Furthermore, the molar amount of Si in the hydrothermal reaction is 1 / 20 to 10 of the molar amount of S; and / or

[0024] The mass ratio of the silica-modified molybdenum disulfide powder to the carbon nanotubes is 1:(1-100).

[0025] The beneficial effects of adopting the above-mentioned further scheme are as follows: By controlling the ratio of Si to S, the quantitative relationship between silicon dioxide and molybdenum disulfide in the formed silicon dioxide-modified molybdenum disulfide powder is controlled, thereby controlling the structure of the silicon dioxide-modified molybdenum disulfide powder and improving the dispersibility of molybdenum disulfide. By controlling the mass ratio of silicon dioxide-modified molybdenum disulfide powder and carbon nanotubes, the structure of the composite film is controlled, thereby improving the Seebeck coefficient of the composite film.

[0026] Furthermore, the process parameters of the hydrothermal reaction include: a reaction temperature of 160–200°C and a reaction time of 14–24 h;

[0027] The mixing methods of the silica-modified molybdenum disulfide powder and carbon nanotubes include shearing, ultrasonic dispersion and stirring.

[0028] The ultrasonic dispersion time is 20–40 min, and the power is 100–200 W;

[0029] The stirring time is 24–48 h, and the stirring speed is 1000–2600 rpm;

[0030] The shearing time is 1 to 5 minutes, the shearing speed is 5000 to 35000 rpm, and the shearing power is 150 to 200 W.

[0031] The beneficial effects of adopting the above-mentioned further scheme are: by controlling the process parameters of the hydrothermal reaction, the reaction between mercapto-modified silica nanospheres and sulfur and molybdenum sources can be controlled, thereby controlling the products generated by the reaction. By controlling the relevant parameters of mixing silica-modified molybdenum disulfide powder and carbon nanotubes, the silica-modified molybdenum disulfide powder and carbon nanotubes can be fully mixed, thereby improving the uniformity and power factor of the composite film.

[0032] Furthermore, the method for preparing the thiolized silica nanospheres includes:

[0033] Hexadecyltrimethylammonium bromide and N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine were dissolved in water, and then heated and stirred. Tetraethyl orthosilicate was added and stirred to react, resulting in a SiO2 solution.

[0034] The SiO2 solution was added to a mixed solution of tetraethyl orthosilicate and (3-mercaptopropyl)trimethoxysilane under a second heating and stirring process to carry out a condensation reaction, thereby obtaining mercapto-functionalized silica nanospheres.

[0035] The beneficial effects of adopting the above-mentioned further scheme are: the silica nanospheres prepared by this method have good dispersibility, avoiding cross-linking and aggregation of silica, which would aggravate the aggregation of MoS2 nanosheets.

[0036] Furthermore, the molar ratio of SiO2, hexadecyltrimethylammonium bromide, N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine and water in the SiO2 solution is (0.9-1.1):(0.05-0.07):(0.025-0.027):(80-85).

[0037] Furthermore, the process parameters for the first heating and stirring include: water bath temperature of 40-80°C, stirring speed of 600-2500 rpm, and time of 20-50 min;

[0038] The reaction time for the tetraethyl orthosilicate stirring reaction is 20–50 min, and the stirring speed is 600–2500 rpm;

[0039] The second heating and stirring process parameters include: water bath temperature of 40-80℃, stirring speed of 600-2500rpm, and time of 2-3h.

[0040] The beneficial effect of adopting the above-mentioned further scheme is that by controlling the reaction parameters, the reaction can be controlled, thus ensuring the effective generation of thiol-functionalized silica nanospheres.

[0041] To achieve the third objective mentioned above, this invention provides the application of the aforementioned silica-modified molybdenum disulfide carbon nanotube composite film in thermoelectric equipment. Attached Figure Description

[0042] Figure 1 These are SEM images of the present invention, wherein (a) is an SEM image of the MoS2 powder prepared in Comparative Example 2 of the present invention, and (b) is an SEM image of the silica-modified molybdenum disulfide powder prepared in Example 2.

[0043] Figure 2 This is a mapping diagram of the composite film prepared in Example 2 of the present invention;

[0044] Figure 3 This is a comparison diagram of the thermoelectric properties of the thin films prepared in Examples 1-3 and Comparative Examples 2-3 of the present invention;

[0045] Figure 4 This is a schematic diagram of the process for modifying molybdenum disulfide with silicon dioxide according to an embodiment of the present invention. Detailed Implementation

[0046] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0047] Example 1

[0048] A silica-modified molybdenum disulfide / carbon nanotube composite film is prepared by the following method:

[0049] (1) Preparation of silica-modified molybdenum disulfide powder: 0.15 g of hexadecyltrimethylammonium bromide and 0.04 g of N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine were dissolved in deionized water, and then stirred in a water bath at 60 °C for 30 min at a stirring speed of 1200 rpm. Subsequently, 1.2 ml of tetraethyl orthosilicate was added and reacted for 30 min to obtain a SiO2 solution (the molar ratio of SiO2, hexadecyltrimethylammonium bromide, N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine and water in the SiO2 solution was 1.0:0.06:0.026:83;

[0050] Add 0.3 ml of a mixed solution of tetraethyl orthosilicate and 250 μl of (3-mercaptopropyl)trimethoxysilane to the obtained SiO2 solution, and continue stirring for 2.5 h to obtain SiO2-SH solution;

[0051] 0.138 g of sodium molybdate was ultrasonically dispersed for 30 min, then added to a SiO2-SH solution and ultrasonically dispersed for another 30 min. The resulting mixed solution was then transferred to a 50 ml stainless steel autoclave lined with Teflon and hydrothermally reacted at 180 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature and filtered. The resulting precipitate was washed three times each with deionized water and ethanol, and then vacuum dried overnight at 60 °C with a vacuum degree of 0.09 MPa to obtain silica-modified molybdenum disulfide powder, in which the molar ratio of Si:S was approximately 5:1.

[0052] (2) Preparation of silica-modified molybdenum disulfide / carbon nanotube composite film: 0.5 mg of the obtained silica-modified molybdenum disulfide powder and 0.01 g of single-walled carbon nanotubes were added to a beaker, and then 7 ml of N,N-dimethylformamide (DMF) was added. The mixture was ultrasonically dispersed for 30 min at an ultrasonic power of 150 W. Then, it was stirred with a magnetic stirrer for 24 h at a stirring speed of 1400 rpm. The mixture was then sheared with a homogenizer for 3 min at a shearing speed of 5000 rpm and a shearing power of 180 W. The film was then filtered under reduced pressure and finally dried under vacuum at 60 °C overnight to obtain a silica-modified molybdenum disulfide / carbon nanotube composite film with a thickness of 11 μm.

[0053] Example 2

[0054] A silica-modified molybdenum disulfide / carbon nanotube composite film is prepared by the following method:

[0055] (1) Preparation of silica-modified molybdenum disulfide powder: 0.15 g of hexadecyltrimethylammonium bromide and 0.04 g of N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine were dissolved in deionized water and stirred in a water bath at 40°C for 50 min at a stirring speed of 600 rpm. Then 1.2 ml of tetraethyl orthosilicate was added and reacted for 20 min to obtain a SiO2 solution (the molar ratio of SiO2, hexadecyltrimethylammonium bromide, N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine and water in the SiO2 solution was 1.0:0.06:0.026:83;

[0056] Add 0.3 ml of a mixed solution of tetraethyl orthosilicate and 62 μl of (3-mercaptopropyl)trimethoxysilane to the obtained SiO2 solution, and continue stirring for 2 h to obtain SiO2-SH solution;

[0057] 1.05 g of sodium molybdate and 1.19 g of L-cysteine ​​were ultrasonically dispersed for 30 min each, then mixed with SiO2-SH solution and ultrasonically dispersed for another 30 min. The resulting mixture was then transferred to a 50 ml Teflon-lined stainless steel autoclave and hydrothermally reacted at 160 °C for 24 h. After the reaction, the mixture was cooled to room temperature and filtered. The resulting precipitate was washed three times each with deionized water and ethanol, and then vacuum-dried overnight at 60 °C with a vacuum degree of 0.09 MPa to obtain silica-modified molybdenum disulfide powder, in which the molar ratio of Si:S was approximately 1:10. (SEM image of the obtained silica-modified molybdenum disulfide powder is shown below.) Figure 1 (b)

[0058] (2) Preparation of silica-modified molybdenum disulfide / carbon nanotube composite film: 0.25 mg of the obtained silica-modified molybdenum disulfide powder and 0.01 g of single-walled carbon nanotubes were added to a beaker, and then 7 ml of N,N-dimethylformamide (DMF) was added. The mixture was ultrasonically dispersed for 20 min at an ultrasonic power of 200 W. Then, it was stirred with a magnetic stirrer for 24 h at a stirring speed of 2600 rpm. After that, it was sheared with a homogenizer for 1 min at a shearing power of 200 W and a shearing speed of 35000 rpm. The film was then filtered under reduced pressure and finally dried under vacuum at 60 °C overnight to obtain a silica-modified molybdenum disulfide / carbon nanotube composite film with a thickness of 9 μm.

[0059] Example 3

[0060] A silica-modified molybdenum disulfide / carbon nanotube composite film is prepared by the following method:

[0061] (1) Preparation of silica-modified molybdenum disulfide powder: 0.15 g of hexadecyltrimethylammonium bromide and 0.04 g of N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine were dissolved in deionized water and stirred in a water bath at 80 °C for 50 min at a stirring speed of 2500 rpm. Then 1.2 ml of tetraethyl orthosilicate was added and reacted for 50 min to obtain a SiO2 solution (the molar ratio of SiO2, hexadecyltrimethylammonium bromide, N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine and water in the SiO2 solution was 1.0:0.06:0.026:83;

[0062] Add 0.3 ml of a mixed solution of tetraethyl orthosilicate and 62 μl of (3-mercaptopropyl)trimethoxysilane to the obtained SiO2 solution, and continue stirring for 3 h to obtain SiO2-SH solution;

[0063] 1.05 g of sodium molybdate and 1.19 g of L-cysteine ​​were ultrasonically dispersed for 30 min each, then mixed with SiO2-SH solution and ultrasonically dispersed for another 30 min. The resulting mixture was then transferred to a 50 ml stainless steel autoclave lined with Teflon and hydrothermally reacted at 200 °C for 14 h. After the reaction was completed, the mixture was cooled to room temperature and filtered. The resulting precipitate was washed three times each with deionized water and ethanol, and then vacuum dried overnight at 60 °C with a vacuum degree of 0.09 MPa to obtain silica-modified molybdenum disulfide powder, wherein the molar ratio of Si:S was approximately 1:10.

[0064] (2) Preparation of silica-modified molybdenum disulfide / carbon nanotube composite film: 1.7 mg of the obtained silica-modified molybdenum disulfide powder and 0.01 g of single-walled carbon nanotubes were added to a beaker, 7 ml of DMF was added, and the mixture was ultrasonically dispersed for 40 min at an ultrasonic power of 100 W. Then, the mixture was stirred with a magnetic stirrer for 48 h at a stirring speed of 1000 rpm. The mixture was then sheared with a homogenizer for 5 min at a shearing speed of 5000 rpm and a shearing power of 150 W. The film was then filtered under reduced pressure and finally dried under vacuum at 60 °C overnight to obtain a silica-modified molybdenum disulfide / carbon nanotube composite film with a thickness of 12 μm.

[0065] Comparative Example 1

[0066] The specific preparation method for single-walled carbon nanotube thin films is as follows:

[0067] 0.01 g of single-walled carbon nanotubes were added to a beaker, along with 7 ml of DMF. The mixture was ultrasonically dispersed for 30 min at a power of 150 W. Then, it was stirred with a magnetic stirrer for 24 h at a stirring speed of 1400 rpm. The mixture was then sheared with a homogenizer for 3 min at a speed of 5000 rpm and a shearing power of 180 W. The mixture was filtered under reduced pressure to form a film, and finally, it was vacuum dried overnight at 60 °C to obtain a single-walled carbon nanotube film with a thickness of 9 μm.

[0068] Comparative Example 2

[0069] The preparation method of MoS2 / carbon nanotube composite thin film is as follows:

[0070] (1) Preparation of MoS2 powder: 0.206 g sodium molybdate and 0.152 g L-cysteine ​​were dissolved in 30 ml deionized water and ultrasonically dispersed for 1 h to obtain a mixed solution. The obtained mixed solution was transferred to a 50 ml stainless steel autoclave lined with Teflon and hydrothermally reacted at 180 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature and filtered. The precipitate was washed three times each with deionized water and ethanol, and then vacuum dried overnight at 60 °C with a vacuum degree of 0.09 MPa to obtain MoS2 powder; (SEM image of the obtained MoS2 powder is shown below) Figure 1 (a) shown)

[0071] (2) Preparation of MoS2 / carbon nanotube composite film: 1.7 mg of the obtained MoS2 powder and 0.01 g of single-walled carbon nanotubes were added to a beaker, 7 ml of DMF was added, and the mixture was ultrasonically dispersed for 30 min at an ultrasonic power of 150 W. Then, the mixture was stirred with a magnetic stirrer for 24 h at a stirring speed of 1400 rpm. The mixture was then sheared with a homogenizer for 3 min at a shearing speed of 5000 rpm and a shearing power of 180 W. The mixture was then filtered under reduced pressure to form a film. Finally, the film was vacuum dried overnight at 60 °C to obtain a MoS2 / carbon nanotube composite film with a thickness of 12 μm.

[0072] Comparative Example 3

[0073] A SiO2 / carbon nanotube composite thin film is prepared by the following method:

[0074] (1) Preparation of SiO2 powder: 0.15g hexadecyltrimethylammonium bromide and 0.04g N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine were dissolved in deionized water and stirred in a water bath at 60℃ for 30min at a stirring speed of 1200rpm. Then 1.5ml tetraethyl orthosilicate was added and reacted for 30min to obtain SiO2 solution. After centrifugation, the solution was precipitated and dried overnight in a vacuum environment at 60℃ with a vacuum degree of 0.09MPa to obtain SiO2 powder.

[0075] (2) Preparation of SiO2 / carbon nanotube composite film: 1.7 mg of obtained SiO2 powder and 0.01 g of single-walled carbon nanotubes were added to a beaker, 7 ml of DMF was added, and ultrasonic dispersion was carried out for 30 min with an ultrasonic power of 100 W. Then, the film was stirred with a magnetic stirrer for 24 h at a stirring speed of 1400 rpm. The film was then sheared with a homogenizer for 3 min at a shearing speed of 5000 rpm and filtered under reduced pressure to form a film with a thickness of 14 μm.

[0076] The thermoelectric performance parameters of the thin films obtained in Examples 1-3 and Comparative Examples 1-3 of this application were tested using the MRS variable temperature series thin film thermoelectric parameter testing system. The results are shown in Table 1 and... Figure 3 As shown.

[0077] Table 1. Thermoelectric performance parameters of the thin films obtained in Examples 1-3 and Comparative Examples 1-3

[0078]

[0079] From Table 1 and Figure 3It can be seen that adding only SiO2 does not significantly change the Seebeck coefficient, and because SiO2 is an insulator, excessive addition leads to a decrease in conductivity. However, adding only MoS2 improves the Seebeck coefficient of the composite film. After modifying MoS2, the Seebeck coefficient of the prepared composite film is further improved, exhibiting a high power factor. The composite film prepared in Example 2 achieves a power factor of 277.8 μW / m. -1 K -2 .

[0080] Figure 1 (a) is a SEM image of the MoS2 powder prepared in Comparative Example 2 of this invention. Figure 1 (b) is a SEM image of the silica-modified molybdenum disulfide powder prepared in Example 2. Figure 1 It can be observed that, compared with pure MoS2, SiO2-MoS2 nanosheets stack to form nanoflowers, with increased pore size. The intersecting petals prevent interlayer stacking and expose more active sites.

[0081] Figure 2 This is a mapping image of the composite film obtained in Example 2 of the present invention. Figure 2 The uniform distribution of S, Mo, Si, O and C can be observed, confirming the successful composite of SiO2, MoS2 and single-walled carbon nanotubes (SWCNTs).

[0082] In summary, this invention improves the Seebeck coefficient and MoS2 dispersion by modifying molybdenum disulfide with silica and then compositing it with carbon nanotubes. The resulting silica-modified molybdenum disulfide / carbon nanotube composite film has good flexibility and a high power factor, and this composite film has good application prospects in the field of flexible wearable thermoelectric devices.

[0083] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0084] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A silica-modified molybdenum disulfide carbon nanotube composite thermoelectric thin film, characterized in that, The composite film is formed by combining silicon dioxide-modified molybdenum disulfide powder with carbon nanotubes. The structure of the silicon dioxide-modified molybdenum disulfide powder is that molybdenum disulfide is attached to the surface of silicon dioxide; The mass ratio of the silica-modified molybdenum disulfide powder to the carbon nanotubes is 1:(1~100). The silica used in the silica-modified molybdenum disulfide powder is mercapto-modified silica nanospheres.

2. The silica-modified molybdenum disulfide carbon nanotube composite thermoelectric thin film according to claim 1, characterized in that, The carbon nanotubes have a diameter of 1~3nm and a length of 5~15μm; The carbon nanotubes are one or more of single-walled carbon nanotubes, multi-walled carbon nanotubes, and double-walled carbon nanotubes. The thickness of the composite film is 8~14μm.

3. The method for preparing the silica-modified molybdenum disulfide carbon nanotube composite thermoelectric thin film according to any one of claims 1 to 2, characterized in that, include: Thiol-modified silica nanospheres were mixed with sulfur and molybdenum sources and subjected to a hydrothermal reaction. The mixture was then cooled, filtered, washed, and dried to obtain silica-modified molybdenum disulfide powder. The silica-modified molybdenum disulfide powder was mixed with carbon nanotubes in an organic solvent and then filtered to obtain a silica-modified molybdenum disulfide carbon nanotube composite film.

4. The method for preparing the silica-modified molybdenum disulfide carbon nanotube composite thermoelectric thin film according to claim 3, characterized in that, The molybdenum source is molybdenum pentachloride or ammonium molybdate; The sulfur source is any one or at least a combination of two of the following: thiourea, sodium sulfide, ammonium tetrathiomolybdate, L-cysteine, or thiolated silica nanospheres.

5. The method for preparing the silica-modified molybdenum disulfide carbon nanotube composite thermoelectric thin film according to claim 3, characterized in that, In the hydrothermal reaction, the molar amount of Si is equal to the molar amount of S. ~10; and / or The mass ratio of the silica-modified molybdenum disulfide powder to the carbon nanotubes is 1:(1~100).

6. The method for preparing the silica-modified molybdenum disulfide carbon nanotube composite thermoelectric thin film according to claim 3, characterized in that, The process parameters for the hydrothermal reaction include: a reaction temperature of 160~200℃ and a reaction time of 14~24h; The mixing methods of the silica-modified molybdenum disulfide powder and carbon nanotubes include shearing, ultrasonic dispersion and stirring. The ultrasonic dispersion time is 20-40 min, and the power is 100-200 W; The stirring time is 24~48h, and the stirring speed is 1000~2600rpm; The shearing time is 1~5 min, the shearing speed is 5000~35000 rpm, and the shearing power is 150~200W.

7. The method for preparing the silica-modified molybdenum disulfide carbon nanotube composite thermoelectric thin film according to claim 3, characterized in that, The method for preparing the thiolized silica nanospheres includes: Hexadecyltrimethylammonium bromide and N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine were dissolved in water, and then heated and stirred. Tetraethyl orthosilicate was added and stirred to react, resulting in a SiO2 solution. The SiO2 solution was added to a mixed solution of tetraethyl orthosilicate and (3-mercaptopropyl)trimethoxysilane under a second heating and stirring process to carry out a condensation reaction, thereby obtaining mercapto-functionalized silica nanospheres.

8. The preparation method according to claim 7, characterized in that, The molar ratio of SiO2, hexadecyltrimethylammonium bromide, N,N,N',N'-tetra(2-hydroxyethyl)ethylenediamine and water in the SiO2 solution is (0.9~1.1):(0.05~0.07):(0.025~0.027):(80~85).

9. The method for preparing the silica-modified molybdenum disulfide carbon nanotube composite thermoelectric thin film according to claim 7, characterized in that, The process parameters for the first heating and stirring include: water bath temperature of 40~80℃, stirring speed of 600~2500rpm, and time of 20~50min; The reaction time for the stirring reaction of the tetraethyl orthosilicate is 20-50 min, and the stirring speed is 600-2500 rpm; The second heating and stirring process parameters include: water bath temperature of 40~80℃, stirring speed of 600~2500rpm, and time of 2~3h.

10. The application of the silica-modified molybdenum disulfide carbon nanotube composite thermoelectric film according to any one of claims 1 to 2 in thermoelectric equipment.

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