Method for preparing modified clay mineral composite nanomaterial based on "click" reaction and application thereof

Abstract

The application discloses a method for preparing modified clay mineral composite nanomaterial based on a "Click" reaction and application of the modified clay mineral composite nanomaterial in preparation of a composite solid electrolyte. The method comprises the following steps: firstly, preparing a clay mineral composite nanomaterial modified by vinyl silane by hydrolysis and condensation of the vinyl silane on a surface of the clay mineral; secondly, adding a mercapto compound containing different functional groups into the clay mineral composite nanomaterial modified by the vinyl silane, and performing a "Click" reaction to graft the different functional groups on the surface of the clay mineral composite nanomaterial modified by the vinyl silane, so as to obtain the modified clay mineral composite nanomaterial; and finally, preparing the composite solid electrolyte by using the modified clay mineral composite nanomaterial. The method is simple and efficient, has mild operation conditions, has wide applicability, can accurately and efficiently graft various functional groups on the surface of the clay mineral composite nanomaterial modified by the vinyl silane in a controllable manner, and thus can significantly improve the surface performance of the clay mineral composite nanomaterial modified by the vinyl silane.

Description

TECHNICAL FIELD

[0001] The present application relates to a modification method of clay mineral composite nanomaterials, in particular to a method for preparing modified clay mineral composite nanomaterials based on "Click" reaction and its application in preparing composite solid electrolyte, belonging to the technical field of composite nanomaterials. BACKGROUND

[0002] Clay minerals are a kind of layered silicate materials widely existing in nature. Due to their abundant reserves, low cost and excellent physical and chemical properties, they have wide application prospects in catalysis, adsorption, especially in the field of polymer composite solid electrolyte. The layered structure and high specific surface area of clay minerals can provide abundant transmission channels for ion conduction, and their good thermal stability and mechanical strength can help improve the thermal stability and mechanical properties of polymer composite solid electrolyte. However, clay minerals often have some limitations in practical application, such as low surface chemical activity, poor dispersibility and single function, etc. These defects limit their deep development and utilization in polymer composite solid electrolyte.

[0003] Through modification treatment of clay minerals, specific functions can be given to them, and their application range in polymer composite solid electrolyte can be broadened. At present, common modification methods of clay minerals mainly include physical modification, chemical modification and composite modification. Physical modification usually changes the physical properties of clay minerals through mechanical crushing, heat treatment or ultrasonic dispersion, but this method has limited effect on improving the properties of clay minerals (CN202111655886.X, CN202311818828.3). Chemical modification includes intercalation reaction, acid treatment or organic molecule modification, which can give clay minerals new surface chemical activity and interfacial compatibility (CN202210379321.1, CN202410819724.2); for example, by intercalating lithium salt or other ion-conducting components, the ion conduction performance of clay minerals in polymer composite solid electrolyte can be significantly improved. Composite modification combines clay minerals with functional materials (such as metal oxides, polymers or carbon-based materials) to prepare clay mineral composite nanomaterials with multiple functions. Modified clay minerals can effectively improve their adsorption, ion exchange performance, and dispersibility and interfacial stability in polymer composite solid electrolyte (CN116124671A, CN117060009A, CN116836570A).

[0004] Although the above modification methods have made some progress in improving the performance and functionalization of clay minerals, there are still some technical bottlenecks to be broken through. For example, the introduction of functional components in the modification process of clay minerals often lacks precision, and it is difficult to use specific functional groups to regulate the physical and chemical properties of clay minerals (CN 116836570 A,

[0005] Angew. Chem. Int. Ed. 2024, 63, e202400091). Unlike conventional modification methods of clay mineral composite nanomaterials, the present application uses "Click" reaction to precisely introduce specific functional groups on the surface of modified clay mineral composite nanomaterials, giving them specific physical and chemical properties. The polymer composite solid-state electrolyte prepared with the composite nanomaterial as an additive can significantly improve its electrochemical properties such as ionic conductivity, and is expected to promote the wide application of modified clay mineral composite nanomaterials in polymer composite solid-state electrolytes. SUMMARY

[0006] The present application aims to provide a method for preparing modified clay mineral composite nanomaterials based on "Click" reaction and its application in preparing composite solid-state electrolytes. The surface interface of clay mineral composite nanomaterials is precisely modified to prepare clay mineral composite nanomaterials with multiple specific functions. The present application aims to precisely graft various functional groups to the surface of clay mineral composite nanomaterials, significantly improving their functionalization degree and thus broadening their application range.

[0007] I. Preparation of modified vinyl silane@clay mineral composite nanomaterials by "Click" reaction

[0008] (1) Preparation of vinyl silane@clay mineral composite nanomaterials

[0009] The clay mineral is dispersed in a solvent, and ultrasonic and stirring treatment is used to form a uniform suspension. Then, a nitrogen gas stream is introduced into the suspension to control the moisture content of the suspension to 50-400 ppm, and vinyl silane is added to modify the clay mineral through hydrolysis and condensation reaction (hydrolysis and condensation reaction is carried out at 25-55 ℃ for 3-72 h). After centrifugation, washing and drying, vinyl silane@clay mineral composite nanomaterials are obtained, which contain abundant vinyl functional groups on the surface.

[0010] The clay mineral is at least one of diatomite, illite, montmorillonite, kaolinite and sepiolite, and the concentration of clay mineral in the suspension is 0.5-30 mg / mL.

[0011] The solvent is at least one of ethanol, methanol, butyl ester, toluene, isopropyl alcohol, N -methyl- 2 -pyrrolidone.

[0012] The vinyl silane is at least one of dimethyl vinyl chlorosilane, vinyl trimethoxysilane, vinyl triethoxysilane, and vinyl trichlorosilane. The mass ratio of the clay mineral to the vinyl silane is 1:0.1-1:1. (2) Preparation of modified vinyl silane@clay mineral composite nanomaterial

[0013] The vinyl silane@clay mineral composite nanomaterial is prepared by using a "Click" reaction, is dispersed into a solvent, azobisisobutyronitrile and a mercapto compound are added, and the reaction is carried out at 20-80 ℃ for 2-48 h under nitrogen protection. Different functional groups are grafted on the surface of the vinyl silane@clay mineral composite nanomaterial by using a "Click" reaction. Finally, the modified vinyl silane@clay mineral composite nanomaterial is obtained by centrifugation, washing, and drying.

[0014] The solvent is at least one of deionized water, methanol, butyl ester, toluene, isopropyl alcohol, and dimethylformamide. The mercapto compound is at least one of propyl mercaptan, 3-mercaptopropionic acid, β mercaptoethanol, β mercaptoethylamine.

[0015] The mass ratio of the vinyl silane@clay mineral composite nanomaterial to azobisisobutyronitrile is 1:0.1-1:8, and the mass ratio of the vinyl silane@clay mineral composite nanomaterial to the mercapto compound is 1:0.1-1:5.

[0016] The synthesis mechanism of the present application: based on the fact that the surface of the prepared vinyl silane@clay mineral composite nanomaterial contains abundant vinyl functional groups, different functional groups are successfully grafted on the surface of the vinyl silane@clay mineral composite nanomaterial by a "Click" reaction between the vinyl silane@clay mineral composite nanomaterial and a mercapto compound containing different functional groups.

[0017] Figure 1 The micro-morphology of the vinyl silane@clay mineral composite nanomaterial in Example 2 is shown. The experimental results show that the surface of the vinyl silane@clay mineral prepared by the method is distributed with rice noodles, the length of which ranges from 100-1500 nm, and the diameter is about 10-70 nm, which is uniformly distributed on the surface of the clay mineral.

[0018] II. Application of the modified vinyl silane@clay mineral composite nanomaterial

[0019] To embody the excellent performance of the modified vinyl silane@clay mineral composite nanomaterial in the application, the modified vinyl silane@clay mineral composite nanomaterial in the application is used as a filler, dispersed in an organic solvent, added to a polymer, and stirred at 20-80 ℃ for 2-72 h to obtain a uniform slurry. The slurry is coated in a polytetrafluoroethylene mold by a solution casting method, dried and solidified at 30-50 ℃ for 12-72 h, and a modified vinyl silane@kaolinite composite nanomaterial / polymer composite solid-state electrolyte is prepared.

[0020] The organic solvent is one of a dimethylformamide solution, anhydrous acetonitrile, N -methyl- 2 -pyrrolidone solution, and tetrahydrofuran. The polymer is at least one of polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, and polymethyl methacrylate. The mass ratio of the modified vinyl silane@clay mineral composite nanomaterial to the polymer is 1:0.1-1:10.

[0021] Ion transfer: as shown in Figure 2 , the polymer composite solid-state electrolyte prepared by using the modified vinyl silane@clay mineral composite nanomaterial of the application in Example 2 as an additive has a maximum ion conductivity as high as 0.69×10 -3 Scm -1 , which is 1.2 times that of Example 1 and 2.8 times that of the comparative example.

[0022] Electrochemical stability: as shown in Figure 3 , the experimental results show that the polymer composite solid-state electrolyte prepared by using the modified vinyl silane@clay mineral composite nanomaterial of the application in Example 2 as an additive has an electrochemical stability of 5.5 V, which is obviously better than the electrochemical stability (5.1 V) of the polymer composite solid-state electrolyte in the comparative example.

[0023] Advantages of the application: the application provides an efficient, accurate and controllable method, which can successfully graft various functional groups to the surface of the vinyl silane@clay mineral composite nanomaterial. By this method, not only the efficiency and accuracy of the grafting process are realized, but also the controllable adjustment of the grafting density and distribution is ensured. This technical breakthrough significantly improves the surface performance of the composite nanomaterial, including surface activity, chemical stability and compatibility with other materials. In addition, the method is simple to operate, has strong repeatability, has good industrial application potential, and provides a new idea and technical support for the functionalization of the composite nanomaterial. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The micro-morphology of the vinyl silane@clay mineral composite nanomaterial in Example 2.

[0025] Figure 2 This study aims to compare the ionic conductivity of modified vinylsilane@clay mineral composite nanomaterials in polymer composite solid electrolytes at different contents in the samples and Examples 1 and 2.

[0026] Figure 3 Electrochemical stability of comparative example 2.

[0027] Figure 4 The lithium-ion transfer number is for comparative examples, Example 2, Example 3, and Example 4.

[0028] Figure 5 The cycle stability of the lithium iron phosphate batteries assembled in the comparative example and Example 2 is evaluated. Detailed Implementation

[0029] The present invention will be further explained and described below with reference to specific embodiments.

[0030] Example 1

[0031] (1) Preparation of vinylsilane@kaolinite composite nanomaterials: 0.3 g of kaolinite was dispersed in 240 mL of N-methyl-2-pyrrolidone solution, sonicated for 0.5 h, and then magnetically stirred for 12 h to form a uniform suspension. Subsequently, nitrogen gas was introduced into the suspension to adjust the water content of the suspension to 180 ppm, and 1.5 g of vinyltrimethoxysilane was added to the above suspension. The mixture was shaken at room temperature for 24 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain vinylsilane@clay mineral composite nanomaterials.

[0032] (2) Preparation of modified vinylsilane@kaolinite composite nanomaterials: Take 100 mL of ethanol solution, add 0.4 g vinylsilane@kaolinite composite nanomaterials, 0.08 g azobisisobutyronitrile and 0.2 g propanethiol, and react under nitrogen protection at 50 °C for 8 h. Wash with ethanol solution 6 times, centrifuge to collect the precipitate, and dry it for later use.

[0033] (3) Preparation of modified vinylsilane@kaolinite composite nanomaterial / polyacrylonitrile composite solid electrolyte: 0.3 g of modified vinylsilane@kaolinite composite nanomaterial was dispersed in 30 mL of dimethylformamide solution, and 0.6 g of polyacrylonitrile was added. After magnetic stirring (600 RPM, stirring time 12 h, temperature 25℃), a uniform slurry was obtained. The slurry was coated into a polytetrafluoroethylene mold by solution casting and dried and cured at 30℃ for 24 h to obtain the modified vinylsilane@kaolinite composite nanomaterial / polyacrylonitrile composite solid electrolyte. The highest ionic conductivity of this composite solid electrolyte at room temperature reached 0.48 × 10⁻⁶.-3 Scm -1 ; electrochemical stability voltage reached 5.2 V.

[0034] Example 2

[0035] (1) Preparation of vinyl silane@montmorillonite composite nanomaterial: 0.1 g of montmorillonite was dispersed in 80 mL of toluene solution, ultrasonicated for 1 h, and then magnetically stirred for 12 h to form a uniform suspension. Subsequently, a nitrogen gas stream was introduced into the suspension to control the moisture content of the suspension to 200 ppm, and 1 g of vinyltrichlorosilane was added to the suspension, which was shaken at room temperature for 12 h. After the reaction was completed, the vinyl silane@clay mineral composite nanomaterial was obtained by centrifugation, washing, and drying.

[0036] (2) Preparation of modified vinyl silane@montmorillonite composite nanomaterial: 50 mL of dimethylacetamide solution was taken, 0.5 g of vinyl silane@montmorillonite composite nanomaterial, 0.2 g of azobisisobutyronitrile, and 0.5 g of 3-mercaptopropionic acid were added, and the reaction was carried out at 70°C under nitrogen protection for 12 h. The reaction mixture was washed with dimethylacetamide solution for 6 times and ethanol solution for 2 times. The precipitate was collected by centrifugation and dried for later use.

[0037] (3) Preparation of modified vinyl silane@montmorillonite composite nanomaterial / polyethylene oxide composite solid-state electrolyte: 0.6 g of vinyl silane@modified montmorillonite composite nanomaterial was dispersed in 70 mL of anhydrous acetonitrile, and 0.6 g of polyethylene oxide was added. After magnetic stirring (speed of 600 RPM, stirring time of 12 h, and temperature of 25°C), a uniform slurry was obtained. The slurry was coated in a polytetrafluoroethylene mold by a solution casting method, and dried and cured at 50°C for 24 h to obtain the modified vinyl silane@montmorillonite composite nanomaterial / polyethylene oxide composite solid-state electrolyte. The test results showed that the maximum ionic conductivity of the modified vinyl silane@montmorillonite composite nanomaterial / polyethylene oxide composite solid-state electrolyte at room temperature could reach 0.69×10 -3 Scm -1 ; electrochemical stability voltage reached 5.5 V, lithium ion transfer number was 0.75, and the capacity retention rate of the assembled lithium iron phosphate battery was 95.5% after 500 cycles.

[0038] Example 3

[0039] (1) Preparation of vinylsilane@haloysite composite nanomaterials: 0.2 g halloysite was dispersed in 120 mL isopropanol solution, sonicated for 1 h, and then magnetically stirred for 12 h to form a uniform suspension. Subsequently, nitrogen gas was introduced into the suspension to adjust the water content of the suspension to 300 ppm, and 1.2 g dimethylvinylchlorosilane was added to the above suspension. The mixture was shaken at room temperature for 12 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain vinylsilane@clay mineral composite nanomaterials.

[0040] (2) Preparation of modified vinylsilane@haloite composite nanomaterials: Take 20 mL of methanol solution, add 0.3 g of vinylsilane@haloite composite nanomaterials, 0.24 g of azobisisobutyronitrile and 0.4 g of [other materials]. β β-Mercaptoethanol was reacted at 40 °C under nitrogen protection for 10 h, washed 6 times with methanol solution and 2 times with ethanol solution, centrifuged to collect the precipitate, and dried for later use.

[0041] (3) Preparation of modified vinylsilane@halolite composite nanomaterial / polyvinylidene fluoride composite solid electrolyte: 0.2 g of modified vinylsilane@halolite composite nanomaterial was dispersed in 20 mL N -methyl- 2 In a pyrrolidone solution, 0.4 g of polyvinylidene fluoride (PVDF) was added and magnetically stirred (600 RPM, 12 h, 25°C) to obtain a homogeneous slurry. This slurry was then coated onto a PTFE mold using a solution casting method and dried and cured at 50°C for 24 h to obtain a modified vinylsilane@halolite composite nanomaterial / PVDF composite solid electrolyte. Testing showed that the modified vinylsilane@halolite composite nanomaterial / PVDF composite solid electrolyte achieved a maximum ionic conductivity of 0.5 × 10⁻⁶ at room temperature. -3 S cm -1 The electrochemical stable voltage reaches 4.8 V, and the lithium-ion transfer number is 0.65.

[0042] Example 4

[0043] (1) Preparation of vinylsilane@diatomite composite nanomaterials: 0.1 g of diatomite was dispersed in 180 mL of butyl ester solution, sonicated for 1 h, and then magnetically stirred for 12 h to form a uniform suspension. Subsequently, nitrogen gas was introduced into the suspension to adjust the water content of the suspension to 100 ppm, and 1 g of dimethylvinylchlorosilane was added to the above suspension. The mixture was shaken at room temperature for 12 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain vinylsilane@clay mineral composite nanomaterials.

[0044] (2) Preparation of modified vinyl silane @ diatomite composite nanomaterial: 40 mL of toluene solution was taken, 0.3 g of vinyl silane @ diatomite composite nanomaterial, 0.15 g of azobisisobutyronitrile and 0.2 g of 2,2'-azobis-2-methylpropionitrile were added, and the mixture was stirred at 60 ℃ for 6 h under nitrogen protection. The mixture was washed with toluene solution for 6 times, washed with ethanol solution for 2 times, and the precipitate was collected by centrifugation and dried for standby. β - mercaptoethylamine, reaction under nitrogen protection at 80 ℃ for 6 h, washed with toluene solution for 6 times, washed with ethanol solution for 2 times, the precipitate was collected by centrifugation and dried for standby.

[0045] (3) Preparation of modified vinyl silane @ diatomite composite nanomaterial / poly (methyl methacrylate) composite solid-state electrolyte: 0.9 g of modified vinyl silane @ diatomite composite nanomaterial was dispersed in 50 mL of tetrahydrofuran, 0.8 g of poly (methyl methacrylate) was added, and a uniform slurry was obtained after magnetic stirring (speed of 600 RPM, stirring time of 12 h, temperature of 25 ℃). The slurry was coated in a polytetrafluoroethylene mold by a solution casting method, and the modified vinyl silane @ diatomite composite nanomaterial / poly (methyl methacrylate) composite solid-state electrolyte was prepared after drying and curing at 40 ℃ for 12 h. The highest ionic conductivity of the modified vinyl silane @ diatomite composite nanomaterial / poly (methyl methacrylate) composite solid-state electrolyte at room temperature can reach 0.3×10 -3 Scm -1 ; the electrochemical stability voltage reaches 4.6 V.

[0046] Comparative example:

[0047] Montmorillonite nanosheet: The thickness of the montmorillonite nanosheet is about 1 nm, and the average diameter is about 1 μm.

[0048] Application and performance: The montmorillonite nanosheet was used as an additive to prepare a polymer composite solid-state electrolyte, and the preparation method was the same as that of Example 1. The highest ionic conductivity of the polymer composite solid-state electrolyte at 30 ℃ was 0.25×10 -3 Scm -1 , the electrochemical stability was 5.1 V, the lithium ion transfer number was 0.50, and the capacity retention rate of the assembled lithium iron phosphate battery after 500 cycles was 78.1%.

Claims

1. Use of a modified clay mineral composite nanomaterial in the preparation of a composite solid-state electrolyte, characterized in that: The modified vinyl silane@clay mineral composite nanomaterial is dispersed in an organic solvent, a polymer is added, and after stirring at 20-80 DEG C for 2-72 h, a uniform slurry is obtained; the slurry is coated in a polytetrafluoroethylene mold by a solution casting method, and a modified vinyl silane@clay mineral composite nanomaterial / polymer composite solid-state electrolyte is prepared by drying and curing at 30-50 DEG C for 12-72 h. The preparation method of the modified clay mineral composite nanomaterial comprises the following steps: (1) Preparation of the vinyl silane@clay mineral composite nanomaterial: the clay mineral is dispersed in a solvent, and is treated by ultrasonic and stirring to form a uniform suspension; then, the moisture content of the suspension is regulated to 50-400 ppm by passing a nitrogen gas stream through the suspension, and vinyl silane is added to modify the clay mineral by hydrolysis and condensation reaction, and the vinyl silane@clay mineral composite nanomaterial is obtained by centrifugation, washing and drying; the hydrolysis and condensation reaction is carried out at 25-55 DEG C for 3-72 h; (2) The vinyl silane@clay mineral composite nanomaterial is dispersed in a solvent, azobisisobutyronitrile and a mercapto compound are added, and different functional groups are grafted on the surface of the vinyl silane@clay mineral composite nanomaterial by "Click" reaction under nitrogen protection at 20-80 DEG C for 2-48 h, and the modified vinyl silane@clay mineral composite nanomaterial is obtained by centrifugation, washing and drying.

2. Use according to claim 1, characterized in that: In step (1) of the preparation method of the modified clay mineral composite nanomaterial, the clay mineral is at least one of diatomite, illite, montmorillonite, kaolinite and sepiolite, and the concentration of the clay mineral in the suspension is 0.5-30 mg / mL.

3. Use according to claim 1, characterized in that: In step (1) of the method for preparing modified clay mineral composite nanomaterials, the solvent is at least one of ethanol, methanol, butyl ester, toluene, isopropyl alcohol, N - methyl- 2 - pyrrolidone.

4. Use according to claim 1, characterized in that: In step (1) of the preparation method of the modified clay mineral composite nanomaterial, the vinyl silane is at least one of dimethyl vinyl chlorosilane, vinyl trimethoxysilane, vinyl triethoxysilane and vinyl trichlorosilane; and the mass ratio of the clay mineral to the vinyl silane is 1:0.1-1:

10.

5. The use according to claim 1, characterized in that: In step (2) of the preparation method of the modified clay mineral composite nanomaterial, the solvent is at least one of deionized water, methanol, butyl ester, toluene, isopropyl alcohol and dimethylformamide.

6. The use according to claim 1, characterized in that: In step (2) of the method for preparing the modified clay mineral composite nanomaterial, the mercapto compound is at least one of propyl mercaptan, 3-mercaptopropionic acid, β mercaptoethanol, β mercaptoethylamine.

7. Use according to claim 1, characterized in that: In step (2) of the preparation method of the modified clay mineral composite nanomaterial, the mass ratio of the vinyl silane@clay mineral composite nanomaterial to azobisisobutyronitrile is 1:0.1-1:8; and the mass ratio of the vinyl silane@clay mineral composite nanomaterial to the mercapto compound is 1:0.1-1:

5.

8. The use according to claim 1, characterized in that: The organic solvent is one of dimethylformamide solution, anhydrous acetonitrile, N - methyl- 2 - one of pyrrolidone solution, tetrahydrofuran.

9. The use according to claim 1, characterized in that: The polymer is at least one of polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile and polymethyl methacrylate; and the mass ratio of the modified vinyl silane@clay mineral composite nanomaterial to the polymer is 1:0.5-1:10.

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