Preparation method of supercapacitor diaphragm material

Abstract

The invention belongs to the technical field of supercapacitors, and particularly relates to a preparation method of a supercapacitor diaphragm material. The graphene composite material and the silicon dioxide aerogel are selected as raw materials, high polymers in the graphene composite material and the silicon dioxide aerogel are combined through non-covalent bonds and carbonized in the subsequent high-temperature heat treatment process to form a graphene porous membrane with a porous carbon network, and the supercapacitor diaphragm material is prepared in cooperation with coating treatment of cellulose slurry. The tensile strength of the material is effectively improved, and meanwhile, better porosity and air permeability are obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of supercapacitors, and in particular relates to a method for preparing a supercapacitor diaphragm material. Background Art

[0002] Supercapacitors have both the fast charging and discharging characteristics of capacitors and the energy storage characteristics of electrochemical batteries. They store and release energy by polarizing electrolytes and utilizing the double-layer effect of the electrode / electrolyte interface. The charging and discharging process is a physical process released through an electrostatic field. The energy storage process is reversible and can be repeatedly charged and discharged hundreds of thousands of times. As an important component of supercapacitors, the diaphragm directly affects the performance of the capacitor. The main functions of the diaphragm in supercapacitors are: separating the positive and negative electrodes to avoid short circuits caused by contact between the electrodes; forming an ion circulation channel to ensure the normal passage of electrolyte ions, and the supercapacitor charging and discharging process is fast.

[0003] A Chinese patent (publication number CN111508732B) discloses a composite diaphragm for supercapacitors and a preparation method thereof. The invention prepares a porous graphene film by introducing silicon dioxide to ensure the normal movement of anions and cations in the electrolyte during charging and discharging; by combining the high tensile strength of graphene and introducing a binder with a fiber structure into the cellulose pulp, it is ensured that the processed composite diaphragm has good tensile strength, uniform thickness and pore size, and is assembled into a supercapacitor product. It is beneficial to its application in a high temperature environment, and the preparation method is simple and suitable for continuous production. However, the patent requires the use of dangerous chemical reagent hydrofluoric acid to etch silicon dioxide in the process of preparing the porous graphene film. At the same time, the tensile strength of the diaphragm material obtained is insufficient, and the porosity and permeability also need to be improved, which affects its application and promotion.

[0004] Therefore, how to prepare supercapacitor diaphragm materials by modifying the diaphragm material components while avoiding the use of hydrofluoric acid, effectively improving the tensile strength of the material, and obtaining better porosity and permeability has become a direction that needs to be focused on. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a supercapacitor diaphragm material, aiming to solve the problems in the prior art that hydrofluoric acid needs to be used in the preparation process of the diaphragm material, and the material has insufficient tensile strength, and the porosity and permeability also need to be improved.

[0006] The present invention uses graphene composite materials and silica aerogel as raw materials. The polymers in the two are bonded by non-covalent bonds and carbonized during subsequent high-temperature heat treatment to form a graphene porous membrane with a porous carbon network. Combined with the coating treatment of cellulose slurry, a supercapacitor diaphragm material is prepared, which effectively improves the tensile strength of the material and obtains better porosity and air permeability.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0008] The present invention provides a method for preparing a supercapacitor diaphragm material, comprising the following steps:

[0009] S1: By weight, 90 to 100 parts of the graphene composite material and 40 to 50 parts of silicon dioxide are uniformly mixed at high speed, and 500 to 600 parts of deionized water are added and stirred and dispersed to obtain a slurry;

[0010] S2: coating the slurry on a PET substrate, drying, peeling off the PET substrate, and performing heat treatment to obtain a graphene porous membrane;

[0011] S3: 40-50 parts of cellulose, 5-10 parts of a binder and 45-50 parts of deionized water are mixed and stirred to obtain a coating liquid, the coating liquid is coated on both sides of the graphene porous membrane, and dried to obtain a supercapacitor diaphragm material.

[0012] As a preferred technical solution of the present invention, the weight proportions of the graphene composite material can be 90 parts, 92 parts, 94 parts, 96 parts, 98 parts or 100 parts, etc.

[0013] As a preferred technical solution of the present invention, the weight proportion of the silicon dioxide can be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts or 50 parts.

[0014] As a preferred technical solution of the present invention, the weight proportion of the cellulose can be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts or 50 parts.

[0015] As a preferred technical solution of the present invention, the weight proportion of the binder can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0016] As a preferred technical solution of the present invention, the preparation method of the graphene composite material includes: dispersing 4 to 6 parts of commercially available graphene oxide in 400 to 500 parts of deionized water, adding 10 to 16 parts of 1 mol / L hydrochloric acid solution and 2 to 4 parts of ferric chloride and stirring evenly to obtain liquid A, dissolving 16 to 20 parts of aniline in 400 to 500 parts of carbon tetrachloride to form liquid B, and slowly pouring 400 to 500 parts of liquid A onto 400 to 500 parts of liquid B for in-situ polymerization to obtain a graphene composite material.

[0017] As a preferred technical solution of the present invention, the in-situ polymerization conditions include: first standing for 40 to 48 hours, then centrifugally washing the composite material generated by the aqueous phase, drying at 30 to 40° C. for 30 to 40 hours, and crushing.

[0018] When graphene composites are subjected to high-temperature heat treatment, the nitrogen atoms in polyaniline will migrate into the graphene lattice to form nitrogen-doped graphene. Nitrogen doping can repair some defects of graphene and increase the interaction force between the layers, thereby improving the overall mechanical strength of the composite material and effectively improving the tensile strength.

[0019] As a preferred technical solution of the present invention, the silicon dioxide is silicon dioxide aerogel;

[0020] The preparation method of the silica aerogel comprises: in parts by weight, 30 to 40 parts of formaldehyde and 450 to 500 parts of isopropanol are mixed evenly, then 40 to 50 parts of resorcinol are added and stirred sufficiently, and then 50 to 60 parts of deionized water and 200 to 220 parts of 3-aminopropyltriethoxysilane are added for gelation treatment to obtain the silica aerogel.

[0021] As a preferred technical solution of the present invention, the gelation treatment conditions include: first stirring at a speed of 80 to 100 r / min for 50 to 60 minutes, then keeping warm at 60 to 65°C for 40 to 48 hours to obtain a wet gel, then replacing it with ethanol at 60 to 65°C, and freeze-drying it.

[0022] Silica aerogel is an ultra-light nanoporous material composed of silica. It is a nanoporous material with ultra-high porosity and low density. Its unique three-dimensional network structure can effectively improve the porosity of the diaphragm material.

[0023] As a preferred technical solution of the present invention, the cellulose is modified cellulose;

[0024] The preparation method of the modified cellulose comprises: adding 4 to 6 parts of cellulose to 240 to 250 parts of deionized water for pretreatment, adding 0.4 to 0.8 parts of carbon nanotubes for uniform dispersion, and finally adding 40 to 50 parts of 8 to 10% polyvinyl alcohol aqueous solution by weight for stirring for 1 to 3 hours, freeze drying, and crushing to obtain the modified cellulose.

[0025] As a preferred technical solution of the present invention, the pretreatment conditions include: first stirring at a speed of 200 to 240 r / min for 30 to 40 min, and then ultrasonicating for 50 to 60 min.

[0026] The carbon nanotubes introduced into the modified cellulose have a high aspect ratio and good dispersibility, and can form a three-dimensional network structure in the cellulose matrix, optimizing the pore size and distribution on the surface, thereby improving the air permeability of the diaphragm material.

[0027] As a preferred technical solution of the present invention, the binder is selected from polytetrafluoroethylene or ethylene-tetrafluoroethylene copolymer.

[0028] As a preferred technical solution of the present invention, in step S2, the drying temperature is 40-60° C. and the drying time is 6-8 hours.

[0029] As a preferred technical solution of the present invention, the heat treatment conditions in step S2 include: first hot rolling at 180-220°C, then placing under argon protection, and high-temperature calcining at 600-650°C for 2-4h.

[0030] As a preferred technical solution of the present invention, the drying conditions in step S3 include: a temperature of 70 to 90° C. and a time of 8 to 10 minutes.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The present invention first mixes the graphene composite material and the silica aerogel. The resorcinol in the silica aerogel contains a benzene ring and can form π-π stacking with the polyaniline in the graphene composite material, and form a non-covalent bond through the interaction of the π electron cloud. The graphene porous membrane with a porous carbon network is carbonized during the subsequent high-temperature heat treatment. The network structure of the graphene porous membrane cooperates with the silica to improve the tensile strength of the diaphragm material, and the porous structure can effectively improve the porosity and air permeability of the material. Then, a cellulose slurry is coated on the graphene porous membrane. The carbon nanotubes of the modified cellulose in the cellulose slurry and the graphene surface are both sp 2The hybridized carbon atoms have a conjugated electron system. The two are stacked face to face or offset, and the electron clouds overlap to form a stable interaction, thereby ensuring a good combination between cellulose and the graphene porous membrane and improving the mechanical properties and air permeability of the diaphragm material.

[0033] (2) When the graphene composite material of the present invention is subjected to high-temperature heat treatment, the nitrogen atoms in the polyaniline will migrate into the graphene lattice to form nitrogen-doped graphene. Nitrogen doping can repair some defects of the graphene and increase the interaction force between the layers, thereby improving the overall mechanical strength of the composite material and effectively improving the tensile strength.

[0034] (3) The silica aerogel of the present invention is an ultralight nanoporous material composed of silica, and is a nanoporous material with ultrahigh porosity and low density. Its unique three-dimensional network structure can effectively improve the porosity of the diaphragm material.

[0035] (4) The carbon nanotubes introduced into the modified cellulose of the present invention have a high aspect ratio and good dispersibility, and can form a three-dimensional network structure in the cellulose matrix, thereby optimizing the pore size and distribution on the surface, thereby improving the air permeability of the diaphragm material. DETAILED DESCRIPTION

[0036] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0037] The sources of some components in the embodiments and comparative examples are as follows:

[0038] Commercially available graphene oxide, product number G139803, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0039] Commercially available silica, product number S433666, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0040] Commercially available cellulose, product number C104841, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0041] Polytetrafluoroethylene, product number P434338, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0042] Ethylene-tetrafluoroethylene copolymer, model LC031, was purchased from Ganzhou Lichang New Materials Co., Ltd.;

[0043] Aniline, CAS No. 62-53-3, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0044] Carbon tetrachloride, CAS No. 56-23-5, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0045] Ferric chloride, CAS No. 7705-08-0, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0046] Formaldehyde, CAS No. 50-00-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0047] Isopropanol, CAS67-63-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0048] Resorcinol, CAS108-46-3, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0049] 3-Aminopropyltriethoxysilane, CAS919-30-2, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0050] Carbon nanotubes, catalog number C313046, were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0051] Polyvinyl alcohol, product number P139543, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0052] Example 1

[0053] This embodiment provides a method for preparing a supercapacitor diaphragm material, comprising the following steps:

[0054] S1: In parts by weight, 100 parts of graphene composite material and 50 parts of silica aerogel are mixed at high speed and uniformly mixed, and 600 parts of deionized water are added and stirred and dispersed to obtain a slurry;

[0055] S2: coating the slurry on a PET substrate, drying (drying temperature is 60° C., drying time is 8 h), peeling off the PET substrate, and performing heat treatment, first hot rolling at 220° C., and then placing it under argon protection, high-temperature calcining at 650° C. for 2 h to obtain a graphene porous membrane;

[0056] S3: 50 parts of modified cellulose, 5 parts of binder polytetrafluoroethylene and 45 parts of deionized water are mixed and stirred to obtain a coating liquid, the coating liquid is coated on both sides of the graphene porous membrane, and dried (temperature is 90° C., time is 8 min) to obtain a supercapacitor diaphragm material;

[0057] Preparation of the graphene composite material: by weight, 6 parts of commercially available graphene oxide are dispersed in 500 parts of deionized water, then 16 parts of 1 mol / L hydrochloric acid solution and 4 parts of ferric chloride are added and stirred evenly to obtain liquid A, 20 parts of aniline are dissolved in 500 parts of carbon tetrachloride to form liquid B, 500 parts of liquid A are slowly poured on top of 500 parts of liquid B for in-situ polymerization, first standing for 48 hours, then centrifugally washing the composite material generated by the aqueous phase, drying at 40° C. for 30 hours, and crushing to obtain the graphene composite material.

[0058] The preparation of the silica aerogel is as follows: by weight, 40 parts of formaldehyde and 500 parts of isopropanol are mixed evenly, then 50 parts of resorcinol are added and stirred thoroughly, and then 60 parts of deionized water and 220 parts of 3-aminopropyltriethoxysilane are added for gelation treatment, first stirred at a speed of 100 r / min for 50 minutes, then kept warm at 65° C. for 40 hours to obtain a wet gel, then replaced with ethanol at 65° C., freeze-dried to obtain the silica aerogel.

[0059] Preparation of the modified cellulose: by weight, 6 parts of cellulose are added to 250 parts of deionized water for pretreatment, first stirred at a speed of 240r / min for 30 minutes, then ultrasonicated for 60 minutes, then 0.8 parts of carbon nanotubes are added to disperse evenly, and finally 50 parts of a 10% by weight aqueous solution of polyvinyl alcohol are added and stirred for 3 hours, freeze-dried, and crushed to obtain modified cellulose.

[0060] Example 2

[0061] This embodiment provides a method for preparing a supercapacitor diaphragm material, comprising the following steps:

[0062] S1: By weight, 90 parts of graphene composite material and 40 parts of silica aerogel were mixed at high speed and uniformly mixed, and 500 parts of deionized water were added and stirred to disperse to obtain a slurry;

[0063] S2: coating the slurry on a PET substrate, drying (drying temperature is 40° C., drying time is 8 h), peeling off the PET substrate, and performing heat treatment, first hot rolling at 180° C., and then placing it under argon protection, high-temperature calcining at 600° C. for 4 h to obtain a graphene porous membrane;

[0064] S3: 40 parts of modified cellulose, 10 parts of binder ethylene-tetrafluoroethylene copolymer and 50 parts of deionized water are mixed and stirred to obtain a coating liquid, the coating liquid is coated on both sides of the graphene porous membrane, and dried (temperature is 70° C., time is 10 min) to obtain a supercapacitor diaphragm material;

[0065] Preparation of the graphene composite material: in parts by weight, 4 parts of commercially available graphene oxide are dispersed in 400 parts of deionized water, then 10 parts of 1 mol / L hydrochloric acid solution and 2 parts of ferric chloride are added and stirred evenly to obtain liquid A, 16 parts of aniline are dissolved in 400 parts of carbon tetrachloride to form liquid B, 400 parts of liquid A are slowly poured on top of 400 parts of liquid B for in-situ polymerization, first standing for 40 hours, then centrifugally washing the composite material generated by the aqueous phase, drying at 30° C. for 40 hours, and crushing to obtain the graphene composite material.

[0066] Preparation of the silica aerogel: by weight, 30 parts of formaldehyde and 450 parts of isopropanol are mixed evenly, then 40 parts of resorcinol are added and stirred thoroughly, then 50 parts of deionized water and 200 parts of 3-aminopropyltriethoxysilane are added for gelation treatment, first stirred at a speed of 80 r / min for 60 minutes, then kept warm at 60° C. for 48 hours to obtain a wet gel, then replaced with ethanol at 60° C., freeze-dried to obtain the silica aerogel.

[0067] Preparation of the modified cellulose: by weight, 4 parts of cellulose are added to 240 parts of deionized water for pretreatment, first stirred at a speed of 200 r / min for 40 minutes, then ultrasonicated for 50 minutes, then 0.4 parts of carbon nanotubes are added to disperse evenly, and finally 40 parts of 8% by weight polyvinyl alcohol aqueous solution are added and stirred for 3 hours, freeze-dried, and crushed to obtain modified cellulose.

[0068] Example 3

[0069] This embodiment provides a method for preparing a supercapacitor diaphragm material, comprising the following steps:

[0070] S1: By weight, 95 parts of graphene composite material and 45 parts of silica aerogel were mixed at high speed and uniformly mixed, and 550 parts of deionized water were added and stirred to disperse to obtain a slurry;

[0071] S2: coating the slurry on a PET substrate, drying (drying temperature is 50° C., drying time is 7 h), peeling off the PET substrate, and performing heat treatment, first hot rolling at 200° C., and then placing it under argon protection, high-temperature calcining at 620° C. for 3 h to obtain a graphene porous membrane;

[0072] S3: 45 parts of modified cellulose, 8 parts of binder polytetrafluoroethylene and 47 parts of deionized water are mixed and stirred to obtain a coating liquid, the coating liquid is coated on both sides of the graphene porous membrane, and dried (temperature is 80° C., time is 9 minutes) to obtain a supercapacitor diaphragm material;

[0073] Preparation of the graphene composite material: by weight, 5 parts of commercially available graphene oxide are dispersed in 450 parts of deionized water, then 14 parts of 1 mol / L hydrochloric acid solution and 3 parts of ferric chloride are added and stirred evenly to obtain liquid A, 18 parts of aniline are dissolved in 450 parts of carbon tetrachloride to form liquid B, 450 parts of liquid A are slowly poured on top of 450 parts of liquid B for in-situ polymerization, first standing for 44, then centrifugally washing the composite material generated by the aqueous phase, drying at 35° C. for 35 hours, and crushing to obtain the graphene composite material.

[0074] Preparation of the silica aerogel: by weight, 35 parts of formaldehyde and 480 parts of isopropanol are mixed evenly, then 45 parts of resorcinol are added and stirred thoroughly, then 55 parts of deionized water and 210 parts of 3-aminopropyltriethoxysilane are added for gelation treatment, first stirred at a speed of 90 r / min for 55 minutes, then kept warm at 62° C. for 44 hours to obtain a wet gel, then replaced with ethanol at 62° C., freeze-dried to obtain the silica aerogel.

[0075] Preparation of the modified cellulose: by weight, 5 parts of cellulose are added to 245 parts of deionized water for pretreatment, first stirred at a speed of 220 r / min for 35 minutes, then ultrasonicated for 55 minutes, then 0.6 parts of carbon nanotubes are added to disperse evenly, and finally 45 parts of 9% by weight polyvinyl alcohol aqueous solution are added and stirred for 2 hours, freeze-dried, and crushed to obtain modified cellulose.

[0076] Example 4

[0077] The difference between this embodiment and embodiment 1 is that commercially available silicon dioxide (article number S433666) is used instead of silicon dioxide aerogel.

[0078] Example 5

[0079] The difference between this embodiment and embodiment 1 is that commercially available cellulose (product number C104841) is used instead of modified cellulose.

[0080] Comparative Example 1

[0081] The difference between this comparative example and Example 1 is that commercially available graphene oxide (article number G139803) is used instead of the graphene composite material.

[0082] Comparative Example 2

[0083] The difference between this comparative example and Example 1 is that 50 parts of silica aerogel are not added to the slurry in step S1.

[0084] The performance of the diaphragm materials provided in the above embodiments and comparative examples was tested, and the testing method was as follows:

[0085] (1) Tensile strength test: The test was conducted in accordance with the requirements of GB / T 12914-2018 Paper and paperboard - Determination of tensile strength - Constant rate tensile method (20 mm / min).

[0086] (2) Porosity test: The porosity of the diaphragm material was tested using a fully automatic nitrogen adsorption micropore distribution tester (model: QUADRASORB SI, Quantachrome Corporation, USA).

[0087] (3) Air permeability test: refer to the requirements of GB / T 458-2008 Determination of air permeability of paper and paperboard for testing.

[0088] The above performance test data is shown in Table 1.

[0089] Table 1 Performance test results

[0090]

[0091] From the above content, it can be seen that the present invention selects graphene composite materials and silica aerogel as raw materials, the polymers in the two are bonded by non-covalent bonds, and carbonized during the subsequent high-temperature heat treatment to form a graphene porous membrane with a porous carbon network, and the supercapacitor diaphragm material (Examples 1 to 3) is prepared by coating with cellulose slurry. The comprehensive performance is better, the tensile strength is 909-914 N / m, the porosity is 77.1-77.8%, and the air permeability is 44.7-45.2 μm / (Pa·s).

[0092] Compared with Example 1, commercially available silica (Article No. S433666) is used instead of silica aerogel, the tensile strength is reduced, the porosity is reduced, and the air permeability is weakened (Example 4); compared with Example 1, commercially available cellulose (Article No. C104841) is used instead of modified cellulose, the tensile strength is reduced, the porosity is reduced, and the air permeability is weakened (Example 5); compared with Example 1, commercially available graphene oxide (Article No. G139803) is used instead of graphene composite materials, the tensile strength is reduced, the porosity is reduced, and the air permeability is weakened (Comparative Example 1); compared with Example 1, 50 parts of silica aerogel are not added to the slurry in step S1, the tensile strength is reduced, the porosity is reduced, and the air permeability is weakened (Comparative Example 2).

[0093] In summary, the present invention selects graphene composite materials and silica aerogel as raw materials. The polymers in the two are bonded by non-covalent bonds and carbonized during the subsequent high-temperature heat treatment to form a graphene porous membrane with a porous carbon network. Combined with the coating treatment of cellulose slurry, a supercapacitor diaphragm material is prepared, which effectively improves the tensile strength of the material and obtains better porosity and air permeability.

Claims

1. A method for preparing a supercapacitor diaphragm material, characterized in that: include: S1: By weight, 90 to 100 parts of the graphene composite material and 40 to 50 parts of silicon dioxide are uniformly mixed at high speed, and 500 to 600 parts of deionized water are added and stirred and dispersed to obtain a slurry; S2: coating the slurry on a PET substrate, drying, peeling off the PET substrate, and performing heat treatment to obtain a graphene porous membrane; S3: Mixing and stirring 40-50 parts of cellulose, 5-10 parts of a binder and 45-50 parts of deionized water to obtain a coating liquid, coating the coating liquid on both sides of the graphene porous membrane, and drying to obtain a supercapacitor diaphragm material; The preparation method of the graphene composite material comprises: dispersing 4 to 6 parts of commercially available graphene oxide in 400 to 500 parts of deionized water by weight, then adding 10 to 16 parts of 1 mol / L hydrochloric acid solution and 2 to 4 parts of ferric chloride and stirring evenly to obtain liquid A, dissolving 16 to 20 parts of aniline in 400 to 500 parts of carbon tetrachloride to form liquid B, and slowly pouring 400 to 500 parts of liquid A onto 400 to 500 parts of liquid B for in-situ polymerization to obtain the graphene composite material.

2. The method for preparing a supercapacitor diaphragm material according to claim 1, characterized in that: The in-situ polymerization conditions include: first standing for 40 to 48 hours, then centrifugally washing the composite material generated by the water phase, drying at 30 to 40° C. for 30 to 40 hours, and crushing.

3. The method for preparing a supercapacitor diaphragm material according to claim 1, characterized in that: The silicon dioxide is silicon dioxide aerogel; The preparation method of the silica aerogel comprises: in parts by weight, 30 to 40 parts of formaldehyde and 450 to 500 parts of isopropanol are mixed evenly, then 40 to 50 parts of resorcinol are added and stirred sufficiently, and then 50 to 60 parts of deionized water and 200 to 220 parts of 3-aminopropyltriethoxysilane are added for gelation treatment to obtain the silica aerogel.

4. The method for preparing a supercapacitor diaphragm material according to claim 3, characterized in that: The gelation treatment conditions include: stirring at a speed of 80-100 r / min for 50-60 min, then keeping warm at 60-65° C. for 40-48 h to obtain a wet gel, then replacing with ethanol at 60-65° C., and freeze-drying.

5. The method for preparing a supercapacitor diaphragm material according to claim 1, characterized in that: The cellulose is modified cellulose; The preparation method of the modified cellulose comprises: adding 4 to 6 parts of cellulose to 240 to 250 parts of deionized water for pretreatment, adding 0.4 to 0.8 parts of carbon nanotubes for uniform dispersion, and finally adding 40 to 50 parts of 8 to 10% polyvinyl alcohol aqueous solution by weight for stirring for 1 to 3 hours, freeze drying, and crushing to obtain the modified cellulose.

6. The method for preparing a supercapacitor diaphragm material according to claim 5, characterized in that: The pretreatment conditions include: stirring at a speed of 200 to 240 r / min for 30 to 40 minutes, and then ultrasonicating for 50 to 60 minutes.

7. The method for preparing a supercapacitor diaphragm material according to claim 1, characterized in that: The binder is selected from polytetrafluoroethylene or ethylene-tetrafluoroethylene copolymer.

8. The method for preparing a supercapacitor diaphragm material according to claim 1, characterized in that: In step S2, the drying temperature is 40-60° C. and the drying time is 6-8 hours.

9. The method for preparing a supercapacitor diaphragm material according to claim 1, characterized in that: The heat treatment conditions in step S2 include: firstly hot rolling at 180-220° C., and then calcining at 600-650° C. for 2-4 hours under argon protection.

10. The method for preparing a supercapacitor diaphragm material according to claim 1, characterized in that: The drying conditions in step S3 include: a temperature of 70 to 90° C. and a drying time of 8 to 10 minutes.

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