Graphene carbon nanotube PTFE composite material and preparation method and application thereof

Abstract

The invention discloses a graphene carbon nanotube PTFE composite material as well as a preparation method and application thereof, and belongs to the technical field of PTFE materials. According to the graphene carbon nanotube PTFE composite material provided by the invention, PTFE is modified, and TEOS is subjected to hydrolytic polycondensation around fibers and nodes of a PTFE film under the hydrophobic action of a fluorocarbon surfactant, so that PTFE / SiO2 with good hydrophilicity and a stable and firm coating is obtained; and on the other hand, the carbon nanotubes are modified by the coupling agent, so that the compatibility and dispersity of the carbon nanotubes and other components are improved, the hydrophilicity is improved, silicon-oxygen bonds can be formed with PTFE / SiO2, and the dispersion uniformity of the carbon material in PTFE is greatly improved. The prepared graphene carbon nanotube PTFE composite material has excellent mechanical strength and chemical stability, preparation raw materials are environmentally friendly and easy to obtain, and the graphene carbon nanotube PTFE composite material has good application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of PTFE materials, and specifically relates to a graphene carbon nanotube PTFE composite material and a preparation method and application thereof. Background Art

[0002] Polytetrafluoroethylene (PTFE) has excellent electrical properties, ultra-pure cleanliness, high and low temperature resistance, biocompatibility, UV resistance, low friction coefficient, chemical inertness and flame retardancy. When PTFE is prepared into porous or non-porous composite materials, while ensuring that the original performance is basically unchanged, PTFE is further given other physical properties, such as electrical conductivity, thermal conductivity, catalytic activity, etc. However, due to the high melt viscosity, PTFE cannot be melt-extruded or injection molded like other traditional thermoplastics. When preparing PTFE composite materials, filling carbon materials usually leads to a large amount of inhomogeneity in the final product, and these fillers may fall off or leach out when facing major external environmental challenges and various environmental stresses.

[0003] The patent application with publication number CN 115011049 A discloses a method for preparing a PTFE composite nanofiber material, which specifically includes the following steps: step S1, taking polytetrafluoroethylene micropowder, fluorinated graphene, glass fiber, inorganic nanofiller and sodium alginate in proportion, adding water, emulsifier and initiator in sequence for polymerization to form an aqueous emulsion; step S2, adding hydroxypropyl methylcellulose ether to the aqueous emulsion and continuing to stir for 2-4 hours, cooling to room temperature, performing solid-liquid separation, collecting solids and drying; step S3, mixing the dried solids evenly and pressing them to obtain a molding material; step S4, placing the molding material in a sintering box for sintering to obtain a PTFE composite nanofiber material. The application claims that the modified carbon nanotube powder is modified by nano silver powder, which can greatly enhance the performance of the polytetrafluoroethylene composite nanofiber material itself.

[0004] However, the traditional paste making process is just a simple mechanical mixing of the above carbon materials, water and sulfuric acid. The carbon material is light and easy to float on the water surface, and it is difficult to achieve uniformity. The dry physical mixing on the PTFE secondary structure and the dispersion of the filler in the PTFE matrix are not particularly ideal, thus affecting the performance of the PTFE composite material. Summary of the invention

[0005] The purpose of the present invention is to provide a graphene carbon nanotube PTFE composite material and a preparation method and application thereof, so as to improve the dispersion uniformity of carbon material in PTFE.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A graphene carbon nanotube PTFE composite material, the raw materials are calculated by weight, including 80-100 parts of modified PTFE / SiO 2 , 10-20 parts of modified carbon nanotubes, 5-15 parts of fluorinated graphene, 10-20 parts of emulsifier, 2-5 parts of initiator, 100-150 parts of water and 3-8 parts of flocculant;

[0008] The modified PTFE / SiO 2 , obtained by the following steps:

[0009] In the first step, a fluorocarbon surfactant is dissolved in deionized water to obtain an active agent solution; PTFE micropowder is added to the active agent solution and soaked; after soaking, the powder is dried to obtain modified PTFE;

[0010] In the second step, glacial acetic acid is added to deionized water, the pH is adjusted, and the TEOS solution is slowly added with continuous stirring to obtain a TEOS hydrolysis solution. A fluorocarbon surfactant is added to the TEOS hydrolysis solution and stirred evenly to obtain a modified solution. The modified PTFE is immersed in the modified solution for deposition. After the deposition is completed, the modified PTFE is washed and dried to obtain a modified PTFE / SiO 2 .

[0011] Furthermore, in the first step, the usage ratio of the fluorocarbon surfactant, deionized water and PTFE micropowder is (0.05-0.15) g: (100-150) mL: (10-15) g.

[0012] Furthermore, in the second step, the usage ratio of deionized water, TEOS solution, fluorocarbon surfactant and modified PTFE is (100-200) mL: (20-40) mL: (0.02-0.04) g: (10-20) g.

[0013] Furthermore, the fluorocarbon surfactant is FS-31.

[0014] Furthermore, the concentration of the TEOS solution is 0.25-0.75 mol / L.

[0015] Furthermore, the drying is vacuum drying at 40-60° C. for 2-4 hours; and the pH is adjusted to 3-4.

[0016] Furthermore, the soaking time is 4-8 hours; and the deposition time is 6-10 hours.

[0017] Furthermore, the modified carbon nanotubes are prepared by the following steps:

[0018] The carbon nanotubes are placed in a mixed acid of concentrated sulfuric acid and concentrated nitric acid, heated and ultrasonically washed to neutrality, and dried to obtain acidified carbon nanotubes; the acidified carbon nanotubes are dissolved in deionized water and dispersed evenly, a coupling agent ethanol solution is added, stirred, washed and dried to obtain modified carbon nanotubes.

[0019] Furthermore, the usage ratio of the carbon nanotubes and the mixed acid is (0.1-0.2) g: (60-80) mL; the usage ratio of the acidified carbon nanotubes, deionized water and coupling agent ethanol solution is (0.1-0.2) g: (60-80) mL: (2-4) mL.

[0020] Furthermore, the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1; the mass fraction of the coupling agent ethanol solution is 30% to 40%; the heating ultrasound is ultrasound at 40-60° C. for 12-14 hours; and the stirring time is 22-24 hours.

[0021] Furthermore, the coupling agent is one or a combination of 3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane and 3-ureapropyltrimethoxysilane.

[0022] A method for preparing a graphene carbon nanotube PTFE composite material comprises the following steps:

[0023] S1, modified PTFE / SiO 2 , modified carbon nanotubes, fluorinated graphene, an emulsifier, an initiator and water are polymerized to form an aqueous emulsion; a flocculant is added to the aqueous emulsion, stirred for 2-4 hours, and then cooled to room temperature, solid-liquid separation is performed, and solids are collected and dried for later use;

[0024] S2, mixing the dried solids evenly and then pressing them to obtain a molding material; sintering the molding material to obtain a graphene carbon nanotube PTFE composite material.

[0025] Furthermore, the flocculant is one or a combination of polyaluminium chloride and polyaluminium sulfate.

[0026] Furthermore, the emulsifier is one or a combination of hexafluoropropylene oxide dimer acid, perfluorobutyric acid and perfluorohexylammonium acetate.

[0027] Furthermore, the initiator is one or a combination of potassium persulfate, sodium persulfate and ammonium persulfate.

[0028] The pressing and sintering processes in S2 are existing technologies and will not be described in detail here.

[0029] A graphene carbon nanotube PTFE composite material is applied to batteries.

[0030] Beneficial effects of the present invention:

[0031] (1) The present invention provides a graphene carbon nanotube PTFE composite material, which is obtained by modifying PTFE, hydrolyzing and polycondensing TEOS around the fibers and nodes of the PTFE membrane under the hydrophobic effect of a fluorocarbon surfactant, thereby obtaining a PTFE / SiO2 composite material with good hydrophilicity and a stable and firm coating. 2 On the other hand, the carbon nanotubes are modified with coupling agents to improve the compatibility and dispersibility of carbon nanotubes with other components, improve the hydrophilicity and can be combined with PTFE / SiO 2 The formation of silicon-oxygen bonds greatly improves the dispersion uniformity of carbon materials in PTFE.

[0032] (2) The modified PTFE / SiO 2 After the modified carbon nanotubes form silicon-oxygen bonds, the gaps between the materials increase the specific surface area of ​​the entire material and improve the reaction activity. The emulsifier used in the present invention has low bioaccumulation and environmental risk, which is beneficial to environmental protection and large-scale production. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a graphene carbon nanotube PTFE composite material, which is prepared by the following steps:

[0036] S1. Dissolve 0.1 g of fluorocarbon surfactant FS-31 in 120 mL of deionized water to obtain an active agent solution; add 15 g of PTFE powder to the active agent solution and soak for 6 hours; after soaking, vacuum dry at 60° C. for 3 hours to obtain modified PTFE;

[0037] Add glacial acetic acid to 120 mL of deionized water, adjust the pH to 3, continue stirring, slowly add 30 mL of 0.5 mol / L TEOS solution to obtain a TEOS hydrolysis solution, add 0.03 g of fluorocarbon surfactant FS-31 to the TEOS hydrolysis solution and stir evenly to obtain a modified solution; immerse 15 g of modified PTFE in the modified solution and deposit for 8 h. After the deposition is completed, wash and dry to obtain a modified PTFE / SiO 2 ;

[0038] S2, placing 0.2g of carbon nanotubes in 60mL of a mixed acid of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, ultrasonically treating at 60°C for 12h, washing to neutrality, and drying to obtain acidified carbon nanotubes; dissolving 0.2g of the acidified carbon nanotubes in 60mL of deionized water and dispersing them evenly, adding 3mL of a 33% mass fraction 3-aminopropyltriethoxysilane ethanol solution, stirring for 24h, washing and drying to obtain modified carbon nanotubes;

[0039] S3, 90 parts of modified PTFE / SiO 2 , 15 parts of modified carbon nanotubes, 10 parts of fluorinated graphene, 15 parts of hexafluoropropylene oxide dimer acid, 4 parts of sodium persulfate and 130 parts of water are polymerized to form an aqueous emulsion; 6 parts of polyaluminium chloride are added to the aqueous emulsion, stirred for 3 hours, cooled to room temperature, solid-liquid separation is performed, and the solid is collected and dried for later use;

[0040] S4, mixing the dried solids evenly and pressing them to obtain a molding material; sintering the molding material to finally obtain a graphene carbon nanotube PTFE composite material.

[0041] The graphene carbon nanotube PTFE composite material is applied to batteries.

[0042] Example 2

[0043] The difference between this embodiment and embodiment 1 is that the 90 parts of modified PTFE / SiO 2 , 15 parts of modified carbon nanotubes, 10 parts of fluorinated graphene" to "80 parts of modified PTFE / SiO 2 , 20 parts of modified carbon nanotubes, 15 parts of fluorinated graphene", S3 specific implementation steps are:

[0044] S3, 80 parts of modified PTFE / SiO 2 , 20 parts of modified carbon nanotubes, 15 parts of fluorinated graphene, 15 parts of hexafluoropropylene oxide dimer acid, 4 parts of sodium persulfate and 130 parts of water are polymerized to form an aqueous emulsion; 6 parts of polyaluminium chloride are added to the aqueous emulsion, stirred for 3 hours, cooled to room temperature, solid-liquid separation is performed, and the solid is collected and dried for later use;

[0045] The remaining raw materials and preparation process remain the same as in Example 1.

[0046] Example 3

[0047] The difference between this embodiment and embodiment 1 is that the 90 parts of modified PTFE / SiO 2 , 15 parts of modified carbon nanotubes, 10 parts of fluorinated graphene" to "100 parts of modified PTFE / SiO 2, 10 parts of modified carbon nanotubes, 5 parts of fluorinated graphene", S3 specific implementation steps are:

[0048] S3, 100 parts of modified PTFE / SiO 2 , 10 parts of modified carbon nanotubes, 5 parts of fluorinated graphene, 15 parts of hexafluoropropylene oxide dimer acid, 4 parts of sodium persulfate and 130 parts of water are polymerized to form an aqueous emulsion; 6 parts of polyaluminium chloride are added to the aqueous emulsion, stirred for 3 hours, cooled to room temperature, solid-liquid separation is performed, and the solid is collected and dried for later use;

[0049] The remaining raw materials and preparation process remain the same as in Example 1.

[0050] Example 4

[0051] Compared with Example 1, the difference between this example and Example 1 is that the "0.2 g of acidified carbon nanotubes, 3 mL of 3-aminopropyl triethoxysilane ethanol solution" in S2 is changed to "0.1 g of acidified carbon nanotubes, 2 mL of 3-aminopropyl triethoxysilane ethanol solution". The specific implementation steps of S2 are:

[0052] S2, placing 0.2g of carbon nanotubes in 60mL of a mixed acid of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, ultrasonically treating at 60°C for 12h, washing to neutrality, and drying to obtain acidified carbon nanotubes; dissolving 0.1g of the acidified carbon nanotubes in 60mL of deionized water and dispersing them evenly, adding 2mL of a 33% mass fraction 3-aminopropyltriethoxysilane ethanol solution, stirring for 24h, washing and drying to obtain modified carbon nanotubes;

[0053] The remaining raw materials and preparation process remain the same as in Example 1.

[0054] Example 5

[0055] Compared with Example 1, the difference between this example and Example 1 is that "15 g PTFE powder, 30 mL TEOS solution" in S1 is changed to "10 g PTFE powder, 40 mL TEOS solution". The specific implementation steps of S1 are:

[0056] S1. Dissolve 0.1 g of fluorocarbon surfactant FS-31 in 120 mL of deionized water to obtain an active agent solution; add 10 g of PTFE powder to the active agent solution and soak for 6 hours; after soaking, vacuum dry at 60° C. for 3 hours to obtain modified PTFE;

[0057] Add glacial acetic acid to 120 mL of deionized water, adjust the pH to 3, continue stirring, slowly add 40 mL of 0.5 mol / L TEOS solution to obtain a TEOS hydrolysis solution, add 0.03 g of fluorocarbon surfactant FS-31 to the TEOS hydrolysis solution and stir evenly to obtain a modified solution; immerse 15 g of modified PTFE in the modified solution and deposit for 8 h. After the deposition is completed, wash and dry to obtain a modified PTFE / SiO 2 ;

[0058] The remaining raw materials and preparation process remain the same as in Example 1.

[0059] Example 6

[0060] Compared with Example 1, the difference between this example and Example 1 is that the "3-aminopropyltriethoxysilane" in S2 is replaced by "3-glycidyloxypropyltrimethoxysilane". The specific implementation steps of S2 are:

[0061] S2, placing 0.2g of carbon nanotubes in 60mL of a mixed acid of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, ultrasonically treating at 60°C for 12h, washing to neutrality, and drying to obtain acidified carbon nanotubes; dissolving 0.2g of the acidified carbon nanotubes in 60mL of deionized water and dispersing them evenly, adding 3mL of a 33% mass fraction 3-glycidyloxypropyltrimethoxysilane ethanol solution, stirring for 24h, washing and drying to obtain modified carbon nanotubes;

[0062] The remaining raw materials and preparation process remain the same as in Example 1.

[0063] Example 7

[0064] Compared with Example 1, the difference between this example and Example 1 is that the "hexafluoropropylene oxide dimer acid" in S3 is changed to "perfluorobutyric acid and perfluorohexylammonium acetate", and the specific implementation steps of S3 are:

[0065] S3, 90 parts of modified PTFE / SiO 2 , 15 parts of modified carbon nanotubes, 10 parts of fluorinated graphene, 15 parts of perfluorobutyric acid and perfluorohexylammonium acetate, 4 parts of sodium persulfate and 130 parts of water are polymerized to form an aqueous emulsion; 6 parts of polyaluminium chloride are added to the aqueous emulsion, stirred for 3 hours, cooled to room temperature, solid-liquid separation is performed, and the solid is collected and dried for later use;

[0066] The remaining raw materials and preparation process remain the same as in Example 1.

[0067] Comparative Example 1

[0068] Compared with Example 1, the difference between this comparative example and Example 1 is that the carbon nanotubes are not modified. The specific implementation steps are as follows:

[0069] S1. Dissolve 0.1 g of fluorocarbon surfactant FS-31 in 120 mL of deionized water to obtain an active agent solution; add 15 g of PTFE powder to the active agent solution and soak for 6 hours; after soaking, vacuum dry at 60° C. for 3 hours to obtain modified PTFE;

[0070] Add glacial acetic acid to 120 mL of deionized water, adjust the pH to 3, continue stirring, slowly add 30 mL of 0.5 mol / L TEOS solution to obtain a TEOS hydrolysis solution, add 0.03 g of fluorocarbon surfactant FS-31 to the TEOS hydrolysis solution and stir evenly to obtain a modified solution; immerse 15 g of modified PTFE in the modified solution and deposit for 8 h. After the deposition is completed, wash and dry to obtain a modified PTFE / SiO 2 ;

[0071] S2, 90 parts of modified PTFE / SiO 2 , 15 parts of carbon nanotubes, 10 parts of fluorinated graphene, 15 parts of hexafluoropropylene oxide dimer acid, 4 parts of sodium persulfate and 130 parts of water are polymerized to form an aqueous emulsion; 6 parts of polyaluminium chloride are added to the aqueous emulsion, stirred for 3 hours, cooled to room temperature, solid-liquid separation is performed, and the solid is collected and dried for later use;

[0072] S3, mixing the dried solids evenly and pressing them to obtain a molding material; sintering the molding material to finally obtain a graphene carbon nanotube PTFE composite material.

[0073] The remaining raw materials and preparation process remain the same as in Example 1.

[0074] Comparative Example 2

[0075] Compared with Example 1, the difference between this comparative example and Example 1 is that the modified PTFE is not subjected to SiO 2 Coating, S1 specific implementation steps are:

[0076] S1. Dissolve 0.1 g of fluorocarbon surfactant FS-31 in 120 mL of deionized water to obtain an active agent solution; add 15 g of PTFE powder to the active agent solution and soak for 6 hours; after soaking, vacuum dry at 60° C. for 3 hours to obtain modified PTFE;

[0077] The remaining raw materials and preparation process remain the same as in Example 1.

[0078] Comparative Example 3

[0079] Compared with Example 1, the difference between this comparative example and Example 1 is that the modified PTFE is not subjected to SiO 2 The carbon nanotubes are not modified during coating, and the specific implementation steps are as follows:

[0080] S1. Dissolve 0.1 g of fluorocarbon surfactant FS-31 in 120 mL of deionized water to obtain an active agent solution; add 15 g of PTFE powder to the active agent solution and soak for 6 hours; after soaking, vacuum dry at 60° C. for 3 hours to obtain modified PTFE;

[0081] S2, polymerizing 90 parts of modified PTFE, 15 parts of carbon nanotubes, 10 parts of fluorinated graphene, 15 parts of hexafluoropropylene oxide dimer acid, 4 parts of sodium persulfate and 130 parts of water to form an aqueous emulsion; adding 6 parts of polyaluminium chloride to the aqueous emulsion, stirring for 3 hours and then cooling to room temperature, performing solid-liquid separation and collecting the solid, and drying for later use;

[0082] S3, mixing the dried solids evenly and pressing them to obtain a molding material; sintering the molding material to finally obtain a graphene carbon nanotube PTFE composite material.

[0083] The remaining raw materials and preparation process remain the same as in Example 1.

[0084] The performance tests were performed on Examples 1 to 7 and Comparative Examples 1 to 3.

[0085] (1) According to GB / T1040-2018, the graphene carbon nanotube PTFE composite materials obtained in each embodiment and comparative example of the present application were tested for tensile strength and elongation at break;

[0086] (2) immersing the graphene carbon nanotube PTFE composite material in a 5wt / % hydrochloric acid solution and allowing it to stand for 72 hours, washing and drying it after the end of the standing period, and testing its acid immersion weight loss rate;

[0087] The results are shown in Table 1:

[0088] Table 1

[0089] project Tensile strength(MPa) Elongation at break (%) Acid immersion weight loss (%) Example 1 25.1 345 0.45 Example 2 24.5 337 0.52 Example 3 24.3 334 0.49 Example 4 23.6 325 0.61 Example 5 23.9 329 0.68 Example 6 24.4 335 0.55 Example 7 24.4 336 0.50 Comparative Example 1 23.4 322 0.92 Comparative Example 2 22.6 310 1.06 Comparative Example 3 21.5 295 1.26

[0090] As can be seen from Table 1, the graphene carbon nanotube PTFE composite material prepared by the present invention has excellent mechanical strength and chemical stability. Compared with Example 1, the difference between Examples 2-7 is only in the raw material ratio and the replacement or change of the raw materials within a reasonable range. After testing, composite materials with good performance can be obtained.

[0091] Comparative Example 1 Compared with Example 1, the hydrophilicity of carbon nanotubes and the hydrophilicity of PTFE / SiO 2 The degree of bonding is greatly reduced, which will lead to uneven dispersion of carbon nanotubes, thereby causing a decrease in the mechanical properties of the composite material; Comparative Example 2 is compared with Example 1 in that the modified PTFE is not subjected to SiO 2Although the modified PTFE has a certain hydrophilic property, its combination with the modified carbon nanotubes is not high, which still causes the problem of uneven dispersion of carbon nanotubes. 2 Due to its own characteristics, when the graphene carbon nanotube PTFE composite material is applied to batteries, it has excellent performance in all aspects; compared with comparative examples 1-2 and embodiment 1, it can be seen that by modifying PTFE and carbon nanotubes, not only the performance of the PTFE and carbon nanotubes is improved, but also the carbon nanotubes can have good dispersion in the composite material, thereby improving the performance of the composite material.

[0092] In summary, the present invention provides a graphene carbon nanotube PTFE composite material and a preparation method and application thereof. The prepared composite material has good mechanical strength and chemical stability and has good application prospects.

[0093] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0094] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A graphene carbon nanotube PTFE composite material, characterized in that: The raw materials include, by weight, 80-100 parts of modified PTFE / SiO2, 10-20 parts of modified carbon nanotubes, 5-15 parts of fluorinated graphene, 10-20 parts of emulsifier, 2-5 parts of initiator, 100-150 parts of water and 3-8 parts of flocculant; The modified PTFE / SiO2 is prepared by the following steps: In the first step, a fluorocarbon surfactant is dissolved in deionized water to obtain an active agent solution; PTFE powder is added to the active agent solution and soaked; after soaking, the powder is dried to obtain modified PTFE; The second step is to add glacial acetic acid into deionized water, adjust the pH, continue stirring, slowly add TEOS solution to obtain TEOS hydrolysis solution, add fluorocarbon surfactant into the TEOS hydrolysis solution and stir evenly to obtain modified solution; The modified PTFE is immersed in the modification solution for deposition, and after the deposition is completed, it is washed and dried to obtain the modified PTFE / SiO2.

2. A graphene carbon nanotube PTFE composite material according to claim 1, characterized in that: In the first step, the usage ratio of the fluorocarbon surfactant, deionized water and PTFE micropowder is (0.05-0.15) g: (100-150) mL: (10-15) g.

3. A graphene carbon nanotube PTFE composite material according to claim 1, characterized in that: In the second step, the usage ratio of deionized water, TEOS solution, fluorocarbon surfactant and modified PTFE is (100-200) mL: (20-40) mL: (0.02-0.04) g: (10-20) g.

4. The graphene carbon nanotube PTFE composite material according to claim 1, characterized in that: The fluorocarbon surfactant is FS-31; the concentration of the TEOS solution is 0.25-0.75 mol / L; the drying is vacuum drying at 40-60° C. for 2-4 hours; the pH is adjusted to 3-4; the soaking time is 4-8 hours; and the deposition time is 6-10 hours.

5. The graphene carbon nanotube PTFE composite material according to claim 1, characterized in that: The modified carbon nanotubes are prepared by the following steps: The carbon nanotubes are placed in a mixed acid of concentrated sulfuric acid and concentrated nitric acid, heated and ultrasonically washed to neutrality, and dried to obtain acidified carbon nanotubes; the acidified carbon nanotubes are dissolved in deionized water and dispersed evenly, a coupling agent ethanol solution is added, stirred, washed and dried to obtain modified carbon nanotubes.

6. The graphene carbon nanotube PTFE composite material according to claim 5, characterized in that: The dosage ratio of the carbon nanotubes and the mixed acid is (0.1-0.2) g: (60-80) mL; the dosage ratio of the acidified carbon nanotubes, deionized water and the coupling agent ethanol solution is (0.1-0.2) g: (60-80) mL: (2-4) mL; the volume ratio of the concentrated sulfuric acid to the concentrated nitric acid is 3:1; the mass fraction of the coupling agent ethanol solution is 30% to 40%; the heating ultrasound is ultrasound at 40-60° C. for 12-14 hours; and the stirring time is 22-24 hours.

7. The graphene carbon nanotube PTFE composite material according to claim 5, characterized in that: The coupling agent is one or a combination of 3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane and 3-ureapropyltrimethoxysilane.

8. A method for preparing the graphene carbon nanotube PTFE composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, polymerizing modified PTFE / SiO2, modified carbon nanotubes, fluorinated graphene, an emulsifier, an initiator and water to form an aqueous emulsion; adding a flocculant to the aqueous emulsion, stirring for 2-4 hours and then cooling to room temperature, performing solid-liquid separation and collecting the solid, and drying for later use; S2, mixing the dried solids evenly and then pressing them to obtain a molding material; sintering the molding material to obtain a graphene carbon nanotube PTFE composite material.

9. The method for preparing a graphene carbon nanotube PTFE composite material according to claim 8, characterized in that: The flocculant is one or a combination of polyaluminium chloride and polyaluminium sulfate; the emulsifier is one or a combination of hexafluoropropylene oxide dimer acid, perfluorobutyric acid and perfluorohexylammonium acetate; the initiator is one or a combination of potassium persulfate, sodium persulfate and ammonium persulfate.

10. Use of the graphene carbon nanotube PTFE composite material according to any one of claims 1 to 9 in a battery.