MXene intercalation exfoliation method, functionalized MXene and its applications

Abstract

The present application discloses a MXene intercalation and exfoliation method, functionalized MXene, and its application, belonging to the field of functional material technology. The method of the present application comprises: intercalating multilayer MXene with an alcohol solvent to obtain a first pre-intercalated body; intercalating the first pre-intercalated body with deionized water to obtain a second pre-intercalated body; dispersing the second pre-intercalated body in a non-alcoholic solvent and intercalating it with an organic anhydride, centrifuging and washing to obtain a functionalized MXene precipitate, and then subjecting the functionalized MXene precipitate to a molding process. The method of the present application significantly improves the exfoliation efficiency of MXene and enhances the conductivity, dispersion performance, and stability of the intercalated MXene by subjecting multilayer MXene to a three-step intercalation treatment, thereby facilitating the large-scale production, storage, and transportation of high-purity, high-conductivity MXene sheets and high-concentration MXene dispersions.

Description

Technical Field

[0001] The present application belongs to the field of functional material technology, and in particular relates to a MXene intercalation and exfoliation method, functionalized MXene and its application. Background Art

[0002] MXene, a class of materials with high specific surface area, hydrophilicity, adsorption properties, and high surface reactivity, has been widely used in energy storage, catalysis, gas sensing, desalination, electromagnetic shielding, and other fields. However, the related art mainly uses a two-step method to prepare MXene nanosheets: acid etching combined with liquid-phase exfoliation using an intercalating agent. This method results in poor exfoliation and low nanosheet yield. Furthermore, due to the high hydrophilicity of MXene, MXene is easily oxidized and has poor dispersibility in organic solvents, which greatly limits the large-scale production, storage, transportation, and practical application of MXene.

[0003] In order to improve the exfoliation efficiency, dispersion and stability of MXene, a modification method can be designed to intercalate and modify the surface at the same time. For example, Hongbing Wang et al. published a method that can be used in Na + After intercalation, a two-step intercalation modification method of sulfonamide diazonium salt surface modification is carried out, which allows the MXene to be directly exfoliated and delaminated and improves the dispersion and stability of the intercalated MXene.

[0004] However, the surface modifiers introduced in the modification method described above are complex to prepare, costly, environmentally polluting, and have poor synthetic safety, which is not conducive to commercial applications. In addition, the two-step intercalation modification is prone to insufficient intercalation, resulting in low intercalated MXene yield and low intercalated MXene conductivity, which greatly limits the large-scale production, storage, transportation and practical application of high-purity, high-conductivity MXene sheets and high-concentration MXene dispersions. Summary of the Invention

[0005] This application discloses a MXene intercalation exfoliation method, functionalized MXene, and its application, aiming to solve the technical problems of poor exfoliation effect of intercalated MXene prepared in the prior art, low electrical conductivity of intercalated MXene, and poor stability of MXene dispersion.

[0006] In order to achieve the above objectives, the technical solution of this application is:

[0007] The first aspect of the present application discloses a method for intercalation exfoliation of MXene. The intercalation exfoliation method of the present application comprises:

[0008] A fluoride-hydrochloric acid mixture was used to etch Ti3AlC2 to obtain multilayer MXene;

[0009] Dispersing the multilayer MXene in an alcohol solvent, ultrasonically exfoliating and centrifuging to obtain a first pre-intercalated body;

[0010] Dispersing the first pre-intercalation body in deionized water, ultrasonically exfoliating and centrifuging to obtain a second pre-intercalation body;

[0011] dispersing the second pre-intercalation body in a non-alcoholic solvent to obtain a second pre-intercalation body dispersion;

[0012] At temperature T1, the second pre-intercalation dispersion is intercalated with an organic anhydride, followed by centrifugation and washing to obtain a functionalized MXene precipitate;

[0013] The functionalized MXene is precipitated and molded to obtain the functionalized MXene.

[0014] In some embodiments, the forming process comprises:

[0015] The functionalized MXene precipitate is subjected to vacuum freeze drying / vacuum drying to obtain a functionalized MXene sheet material;

[0016] Alternatively, the functionalized MXene precipitate is directly dispersed in a dispersing solvent to form a functionalized MXene dispersion;

[0017] Alternatively, the functionalized MXene precipitate is subjected to vacuum freeze drying / vacuum drying and then dispersed in a dispersion solvent to form a functionalized MXene dispersion.

[0018] In some embodiments, etching Ti3AlC2 with the fluoride salt-hydrochloric acid mixture comprises:

[0019] providing an aqueous solution of hydrochloric acid in which a fluoride salt is dissolved;

[0020] At temperature T2, Ti3AlC2 is etched using the aqueous hydrochloric acid solution containing a fluoride salt, and after etching, the resulting etching solution is centrifuged several times and washed with deionized water until the pH value of the etching solution is neutral, thereby obtaining a multilayer MXene;

[0021] The fluoride salt is at least one of lithium fluoride, sodium fluoride and potassium fluoride;

[0022] The concentration of the hydrochloric acid aqueous solution is 3M-12M;

[0023] The etching temperature is 25-45°C and the etching time is 6-48h.

[0024] In some embodiments, the non-alcoholic solvent includes one or a mixture of deionized water, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

[0025] In some embodiments, the organic anhydride has a general chemical formula of R1-CO-O-CO-R2;

[0026] Wherein, R1 and R2 are different or identical functional groups.

[0027] In some embodiments, the intercalation reaction occurs at a temperature T1 of 25-45° C. and for a time of 6-48 h.

[0028] In some embodiments, the dispersing solvent includes one or a mixture of cyclohexane, toluene, water, methanol, ethanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, acetone, and tetrahydrofuran.

[0029] In some embodiments, the concentration of the functionalized MXene dispersion is 0.01-200 mg / mL.

[0030] The second aspect of the present application discloses a functionalized MXene sheet material or a functionalized MXene dispersion prepared by the intercalation exfoliation method described in the first aspect.

[0031] The third aspect of the present application discloses an application of the functionalized MXene dispersion in conductive additives, water-based coatings, organic coatings, and solution-processed synthetic rubber / plastics.

[0032] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application include at least:

[0033] The intercalation exfoliation method provided in this application sequentially performs two-step pre-intercalation on multilayer MXene using an alcohol solvent and deionized water, and then disperses the two-step pre-intercalation product in a non-alcohol solvent and functionalizes the intercalation with an organic anhydride. On the one hand, the conductivity of the functionalized intercalated MXene can be effectively improved (conductivity > 10,000 S / cm), and the yield of high-conductivity functionalized intercalated MXene can reach 100%. Thus, the method has the advantages of simple exfoliation, high yield, safe operation, and excellent conductive properties of the intercalated MXene, and is particularly suitable for large-scale production applications. On the other hand, the method can effectively improve the dispersion and stability of the intercalated MXene in water / organic solvents, so that the intercalated MXene / various solvent dispersions can be stored stably for a long time, effectively maintaining the various physical and chemical properties of the MXene. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some of the embodiments described in this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0035] Figure 1 This is a photograph of the MXene-COOH / N,N-dimethylformamide dispersion provided in Example 1 of the present application;

[0036] Figure 2 This is a photograph of the MXene-COOH / water dispersion provided in Example 2 of the present application;

[0037] Figure 3 This is a photograph of the MXene-COOH / N-methylpyrrolidone dispersion provided in Example 3 of the present application;

[0038] Figure 4 UV-vis spectrum of the MXene-COOH / N,N-dimethylformamide dispersion provided in Example 1 of the present application;

[0039] Figure 5 UV-vis spectrum of the MXene-COOH / water dispersion provided in Example 2 of the present application;

[0040] Figure 6 This is the UV-vis spectrum of the MXene-COOH / N-methylpyrrolidone dispersion provided in Example 3 of the present application. DETAILED DESCRIPTION

[0041] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0042] In the relevant description of this embodiment, the term "intercalant" is generally understood as the product obtained by the relevant intercalation; the terms "including, containing, having" and the like are open terms and are generally understood as including but not limited to; the term "at least one" is generally understood as one or more, where "plurality" refers to two or more; the term "at least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items, for example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b, c can be single or multiple respectively; the symbol "A / B" is used to describe the selection relationship of associated objects, generally indicating an "or" relationship before and after.

[0043] In the following description of the present embodiment, the terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0044] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0045] It will be understood by those skilled in the art that the numerical ranges in the examples of the present application are to be understood as also specifically disclosing each intermediate value between the upper and lower limits of the ranges. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded within the range.

[0046] Unless otherwise indicated, the technical / scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application belongs. Although this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of any conflict with any incorporated document, the content of this specification shall prevail.

[0047] In a first aspect, the present invention provides a method for intercalation and exfoliation of MXene, the method preferably comprising the following steps:

[0048] A fluoride-hydrochloric acid mixture was used to etch Ti3AlC2 to obtain multilayer MXene;

[0049] Dispersing the multilayer MXene in an alcohol solvent, ultrasonically exfoliating and centrifuging to obtain a first pre-intercalated body;

[0050] Dispersing the first pre-intercalation body in deionized water, ultrasonically exfoliating and centrifuging to obtain a second pre-intercalation body;

[0051] dispersing the second pre-intercalation body in a non-alcoholic solvent to obtain a second pre-intercalation body dispersion;

[0052] At temperature T1, the second pre-intercalation dispersion is intercalated with an organic anhydride, followed by centrifugation and washing to obtain a functionalized MXene precipitate;

[0053] The functionalized MXene is precipitated and molded to obtain the functionalized MXene.

[0054] Based on the description of the intercalation exfoliation method described above, it can be seen that the embodiment of the present application discloses a three-step intercalation treatment method for MXene, which specifically includes sequentially performing a two-step pre-intercalation treatment on the multilayer MXene using an alcohol solvent and deionized water, dispersing the two-step pre-intercalation product in a non-alcohol solvent and undergoing functionalized intercalation treatment with an organic anhydride. On the one hand, it can effectively improve the conductivity of the functionalized intercalated MXene (conductivity > 10000 S / cm) and make the yield of high-conductivity functionalized intercalated MXene reach 100%, thereby having the advantages of simple exfoliation, high yield, safe operation and excellent conductive properties of the intercalated MXene, and is particularly suitable for large-scale production applications; on the other hand, it can effectively improve the dispersion and stability of the intercalated MXene in water / organic solvents, so that the dispersion of the intercalated MXene / various solvents can be stored and transported stably for a long time, effectively maintaining the various physical and chemical properties of the MXene.

[0055] Among them, before the functional intercalation of organic acid anhydrides in the embodiment of the present application, multilayer MXene is pre-intercalated using alcohol solvents and deionized water in sequence, thereby expanding the MXene interlayer spacing and increasing active sites, providing space and insertion sites for the functional intercalation of organic acid anhydrides, enabling successful and efficient intercalation and peeling of functionalized MXene sheets, while giving MXene excellent conductive properties, dispersion properties and stability.

[0056] In a specific embodiment, the molding process preferably includes:

[0057] The functionalized MXene precipitate is subjected to vacuum freeze drying / vacuum drying to obtain a functionalized MXene sheet material;

[0058] Alternatively, the functionalized MXene precipitate is directly dispersed in a dispersing solvent to form a functionalized MXene dispersion;

[0059] Alternatively, the functionalized MXene precipitate is subjected to vacuum freeze drying / vacuum drying and then dispersed in a dispersion solvent to form a functionalized MXene dispersion.

[0060] It should be noted that the above-mentioned ultrasonic and centrifugal treatments are specifically performed according to the general implementation scheme in the field. For example, the ultrasonic stripping time is preferably 10-60 minutes. The specific ultrasonic time can be selected and confirmed according to the intercalation effect. Among them, the preferred ultrasonic time in the embodiment of the present application is 20 minutes, thereby saving time cost while ensuring that the relevant intercalation is fully carried out; the centrifugal speed is preferably 3000-10000 rpm, and the time is 5-60 minutes.

[0061] It should be noted that the vacuum freeze-drying and vacuum drying treatments described above are specifically performed according to the general implementation scheme in this field. For example, vacuum freeze-drying is preferably carried out at a temperature of -50--20°C for 4-120 hours to maintain the MXene flaky morphology and physical properties; vacuum drying is preferably carried out at a temperature of 25-100°C for 0.5-24 hours.

[0062] It should be noted that the alcohol solvent mentioned above is preferably any common alcohol solvent such as ethanol, ethylene glycol, methanol, etc. Among them, the embodiment of the present application specifically selects ethanol which is easy to remove, has low toxicity and is environmentally friendly.

[0063] In a specific embodiment, the etching of Ti3AlC2 by the fluoride salt-hydrochloric acid mixture preferably includes:

[0064] providing an aqueous solution of hydrochloric acid in which a fluoride salt is dissolved;

[0065] At temperature T2, Ti3AlC2 is etched using the aqueous hydrochloric acid solution containing a fluoride salt, and after etching, the resulting etching solution is centrifuged several times and washed with deionized water until the pH value of the etching solution is neutral, thereby obtaining a multilayer MXene;

[0066] Wherein, the fluoride salt is preferably at least one of lithium fluoride, sodium fluoride and potassium fluoride;

[0067] The concentration of the hydrochloric acid aqueous solution is preferably 3M-12M;

[0068] The etching temperature is preferably 25-45° C., and the etching time is preferably 6-48 h.

[0069] In a specific embodiment, the non-alcoholic solvent includes one or a mixture of deionized water, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

[0070] Among them, after the embodiment of the present application uses the non-alcoholic solvent to provide a dispersion system for the second pre-intercalation body, not only can the second pre-intercalation body be uniformly dispersed to form a stable dispersion system, but the organic acid anhydride can also be quickly dissolved in the dispersion system and undergo a functional intercalation reaction with the second pre-intercalation body, thereby greatly improving the intercalation effect.

[0071] In a specific embodiment, the general chemical formula of the organic acid anhydride is R1-CO-O-CO-R2, where R1 and R2 are different or the same functional groups.

[0072] It should be noted that R1 and R2 include at least one functional group selected from the group consisting of an alkyl group, a hydrocarbon group, a hydroxyl group, a carboxyl group, a carbonyl group, and a benzene ring. For example, R1 and R2 may be the same and preferably a carbonyl group.

[0073] Among them, the embodiments of the present application use the organic acid anhydride described above as a functionalized intercalant, which can not only be well dissolved in non-alcoholic solvents, but also can expand the interlayer spacing while functionalizing the surface groups of MXene, thereby promoting the efficient intercalation reaction and giving the intercalated MXene excellent conductivity, dispersion and stability.

[0074] In a specific embodiment, the temperature T1 at which the intercalation reaction occurs is preferably 25-45° C., specifically preferably 35° C., and the intercalation reaction time is preferably 6-48 h.

[0075] In particular, the embodiment of the present application can ensure the efficient performance of the functionalized intercalation reaction by performing the intercalation reaction at a temperature of 35°C.

[0076] In a specific embodiment, the dispersion solvent includes one or a mixture of cyclohexane, toluene, water, methanol, ethanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, acetone, and tetrahydrofuran.

[0077] Among them, after the embodiment of the present application provides a dispersion system for the functionalized MXene precipitate or functionalized MXene sheet material through the dispersing solvent, the functionalized MXene precipitate or functionalized MXene sheet material can form a highly concentrated and stable dispersion liquid.

[0078] In a specific embodiment, the concentration of the functionalized MXene dispersion is 0.01-200 mg / mL.

[0079] It should be noted that after preparing the functionalized MXene using the intercalation exfoliation method described above, the dispersion concentration of the functionalized MXene can be effectively increased when the functionalized MXene is used to prepare a dispersion. Specific test results show that the functionalized MXene used in the present embodiment maintains excellent stability at a concentration of up to 200 mg / mL.

[0080] In a second aspect, the embodiments of the present application also provide a functionalized MXene sheet material or a dispersion of functionalized MXene prepared by the intercalation exfoliation method of the first aspect.

[0081] The intercalation exfoliation method described above can impart excellent dispersion and long-term stability to MXene. Consequently, the functionalized MXene sheet material or dispersion formed from the functionalized MXene exhibits excellent dispersion and stability. For example, it significantly increases the MXene dispersion concentration, achieving a maximum dispersion concentration of 200 mg / mL, while maintaining good stability even at this extremely high concentration.

[0082] Thirdly, the functionalized MXene dispersions provided in the embodiments of this application are used to prepare conductive additives, water-based coatings, organic coatings, and solution-processed synthetic rubber / plastic additives. Based on the excellent conductivity, dispersion, and stability of the functionalized MXene dispersions described above, the addition of these functionalized MXene dispersions to relevant applications can effectively increase the compounding capacity of the MXene dispersions in the relevant applications and improve specific processing properties, thereby significantly enhancing the actual performance of the relevant material products.

[0083] It should be noted that solution-processed synthetic rubber includes an aqueous phase and an organic phase; rubber includes monomers, precursors, oligomers, and matrix polymers; and conductive additives can be specifically used in the preparation of conductive inks, printed electronic devices, and electromagnetic shielding materials.

[0084] The technical solution of the present application will be further described below in conjunction with specific embodiments.

[0085] Example 1

[0086] This embodiment provides a method for preparing a MXene-COOH / N,N-dimethylformamide dispersion, which specifically includes:

[0087] S101: First, accurately weigh 2 g of LiF in a polytetrafluoroethylene tube, add 10 mL of deionized water and 30 mL of 37% hydrochloric acid, and magnetically stir for 30 minutes until the LiF is completely dissolved to obtain a hydrochloric acid aqueous solution containing LiF; then, slowly add 2 g of Ti3AlC2 to the hydrochloric acid aqueous solution containing LiF, and magnetically stir the reaction at 35°C for 24 hours;

[0088] S102: After the stirring reaction is completed, the reaction product is centrifuged and washed with deionized water 8-10 times until the pH value of the reaction product solution is neutral, and the precipitate is collected and marked as precipitate I;

[0089] S103: Precipitate I was dispersed in 40 mL of ethanol, sonicated for 20 min, and centrifuged to collect Precipitate II;

[0090] S104: Disperse precipitate II in 60 mL of deionized water, sonicate for 20 min, centrifuge, and collect precipitate III;

[0091] S105: dispersing the precipitate III in 60 mL of deionized water to obtain a pre-intercalated dispersion;

[0092] S106: Add 5 g of succinic anhydride to the pre-intercalated dispersion, dissolve under ultrasonication, and react under magnetic stirring at 35° C. for 12 h;

[0093] S107: After the magnetic stirring reaction is completed, centrifuge and wash with deionized water three times to collect the precipitate IV;

[0094] S108: Dispersing the precipitate IV in N,N-dimethylformamide, centrifuging and washing with N,N-dimethylformamide three times, and collecting the precipitate V;

[0095] S109: After dispersing the precipitate V in N,N-dimethylformamide, the concentration is adjusted to 40 mg / mL to obtain a MXene-COOH / N,N-dimethylformamide dispersion.

[0096] Example 2

[0097] This embodiment provides a method for preparing a MXene-COOH / water dispersion, which specifically includes:

[0098] S201: First, accurately weigh 2 g of LiF in a polytetrafluoroethylene tube, add 10 mL of deionized water and 30 mL of 37% hydrochloric acid, and magnetically stir for 30 minutes until the LiF is completely dissolved to obtain a hydrochloric acid aqueous solution containing LiF; then, slowly add 2 g of Ti3AlC2 to the hydrochloric acid aqueous solution containing LiF, and magnetically stir the reaction at 35°C for 24 hours;

[0099] S202: After the stirring reaction is completed, the reaction product is centrifuged and washed with deionized water 8-10 times until the pH value of the reaction product solution is neutral, and the precipitate is collected and marked as precipitate I;

[0100] S203: Disperse the precipitate I in 40 mL of ethanol, sonicate for 20 min, centrifuge, and collect the precipitate II;

[0101] S204: Disperse the precipitate II in 60 mL of deionized water, sonicate for 20 min, centrifuge, and collect the precipitate III;

[0102] S205: dispersing the precipitate III in 60 mL of deionized water to obtain a pre-intercalated dispersion;

[0103] S206: adding 1.25 g of succinic anhydride to the pre-intercalated dispersion, dissolving by ultrasonication, and reacting by magnetic stirring at 35° C. for 12 h;

[0104] S207: After the magnetic stirring reaction is completed, centrifugation and deionized water washing are performed three times to collect the precipitate IV, and the precipitate IV is freeze-dried to obtain a functionalized MXene sheet;

[0105] S208: Disperse the functionalized MXene sheets in 1 mL of deionized water and sonicate for 10 min to obtain a MXene-COOH / water dispersion with a concentration of 200 mg / mL.

[0106] Example 3

[0107] This embodiment provides a method for preparing a MXene-COOH / N-methylpyrrolidone dispersion, which specifically includes:

[0108] S301: First, accurately weigh 2 g of LiF in a polytetrafluoroethylene tube, add 10 mL of deionized water and 30 mL of 37% hydrochloric acid, and magnetically stir for 30 minutes until the LiF is completely dissolved to obtain a hydrochloric acid aqueous solution containing LiF; then, slowly add 2 g of Ti3AlC2 to the hydrochloric acid aqueous solution containing LiF, and magnetically stir the reaction at 35°C for 24 hours;

[0109] S302: After the stirring reaction is completed, the reaction product is centrifuged and washed with deionized water 8-10 times until the pH value of the reaction product solution is neutral, and the precipitate is collected and marked as precipitate I;

[0110] S303: Disperse the precipitate I in 40 mL of ethanol, sonicate for 20 min, centrifuge, and collect the precipitate II;

[0111] S304: Disperse the precipitate II in 60 mL of deionized water, sonicate for 20 min, centrifuge, and collect the precipitate III;

[0112] S305: dispersing the precipitate III in 60 mL of N,N-dimethylacetamide to obtain a pre-intercalated dispersion;

[0113] S306: Add 2.5 g of succinic anhydride to the pre-intercalated dispersion, dissolve under ultrasonication, and react under magnetic stirring at 35° C. for 12 h;

[0114] S307: After the magnetic stirring reaction is completed, centrifuge and wash with deionized water three times to collect the precipitate IV;

[0115] S308: Disperse the precipitate IV in N-methylpyrrolidone, centrifuge and wash with N-methylpyrrolidone three times, and collect the precipitate V;

[0116] S309: After dispersing the precipitate V in N-methylpyrrolidone, the concentration was adjusted to 10 mg / mL to obtain a MXene-COOH / N-methylpyrrolidone dispersion.

[0117] In order to verify the actual effect of the intercalation and exfoliation method of Examples 1-3, this application provides Comparisons 1-2 for detailed description.

[0118] The difference between Comparative Example 1 and Example 2 is that the S206 anhydride functionalized intercalation treatment is omitted, specifically comprising:

[0119] S401: First, accurately weigh 2 g of LiF in a polytetrafluoroethylene tube, add 10 mL of deionized water and 30 mL of 37% hydrochloric acid, and magnetically stir for 30 minutes until the LiF is completely dissolved to obtain a hydrochloric acid aqueous solution containing LiF; then, slowly add 2 g of Ti3AlC2 to the hydrochloric acid aqueous solution containing LiF, and magnetically stir the reaction at 35°C for 24 hours;

[0120] S402: After the stirring reaction is completed, the reaction product is centrifuged and washed with deionized water 8-10 times until the pH value of the reaction product solution is neutral, and the precipitate is collected and marked as precipitate I;

[0121] S403: Disperse the precipitate I in 60 mL of ethanol, sonicate for 20 min, centrifuge, and collect the precipitate II;

[0122] S404: Disperse the precipitate II in 60 mL of deionized water, sonicate for 20 min, centrifuge, and collect the precipitate III;

[0123] S405: Disperse the precipitate III in 60 mL of deionized water and freeze-dry to obtain MXene sheets.

[0124] The difference between Comparative Example 2 and Example 2 is that the treatments of S203 ethanol pre-intercalation and S204 deionized water intercalation are omitted, and specifically include:

[0125] S501: First, accurately weigh 2 g of LiF in a polytetrafluoroethylene tube, add 10 mL of deionized water and 30 mL of 37% hydrochloric acid, and magnetically stir for 30 minutes until the LiF is completely dissolved to obtain a hydrochloric acid aqueous solution containing LiF; then, slowly add 2 g of Ti3AlC2 to the hydrochloric acid aqueous solution containing LiF, and magnetically stir the reaction at 35°C for 24 hours;

[0126] S502: After the stirring reaction is completed, the reaction product is centrifuged and washed with deionized water 8-10 times until the pH value of the reaction product solution is neutral, and the precipitate is collected and marked as precipitate I;

[0127] S503: Dispersing the precipitate I in 60 mL of deionized water to obtain a dispersion of the precipitate I;

[0128] S504: Add 1.25 g of succinic anhydride to the dispersion of precipitate I, dissolve it by ultrasonication, and react with magnetic stirring at 35° C. for 12 h;

[0129] S505: After the magnetic stirring reaction is completed, centrifuge and wash with deionized water three times to collect the precipitate II, and freeze-dry the precipitate II to obtain a functionalized MXene sheet.

[0130] First, the detection of stripping efficiency

[0131] The precipitates IV of Examples 1 and 3, the MXene sheets of Comparative Example 1, and the functionalized MXene sheets of Examples 2 and Comparative Example 2 were dispersed in deionized water, respectively, and then filtered to form membranes. The membranes were dried and the electrical conductivity of the precipitate IV / MXene sheet / functionalized MXene sheet of each example was tested to confirm the exfoliation efficiency of the intercalated product. The results are shown in Table 1 below.

[0132] Table 1 - Conductivity of various intercalation products

[0133]

[0134] As can be seen from Table 1, when the yield of the intercalation product is 100%, the conductivity of the intercalation products of Examples 1-3 is much higher than that of Comparative Examples 1-2. This indicates that the present application uses alcohol solvents and deionized water to pre-intercalate the multilayer MXene in sequence, and then disperses the pre-intercalation product in a non-alcohol solvent to undergo functional intercalation with an organic acid anhydride. This can effectively improve the conductivity of the functionalized intercalated MXene (conductivity > 10,000 S / cm), and achieve a yield of 100% for the high-conductivity functionalized intercalated MXene, making it particularly suitable for large-scale production applications.

[0135] Second, the detection of dispersion performance

[0136] The dispersion conditions of MXene-COOH / N,N-dimethylformamide dispersion, MXene-COOH / water dispersion and MXene-COOH / N-methylpyrrolidone dispersion were tested respectively, and the results were as follows: Figure 1-3 As shown. Among them, Figure 1 This is a photo of MXene-COOH / N,N-dimethylformamide dispersion. Figure 2 This is a photo of MXene-COOH / water dispersion; Figure 3 This is a photo of MXene-COOH / N-methylpyrrolidone dispersion.

[0137] according to Figure 1-3 It can be seen that the functionalized MXene dispersion prepared by the intercalation exfoliation method in the embodiment of the present application can be uniformly dispersed at a concentration of 10-200 mg / mL, indicating that the intercalation exfoliation method in the embodiment of the present application can effectively improve the dispersion performance of MXene.

[0138] Third, the detection of stability performance

[0139] After 20 days of storage, the MXene-COOH / N,N-dimethylformamide dispersion, MXene-COOH / water dispersion, and MXene-COOH / N-methylpyrrolidone dispersion were subjected to UV-vis detection and analysis. The results were as follows: Figure 4-6 .in, Figure 4 UV-vis spectrum of MXene-COOH / N,N-dimethylformamide dispersion; Figure 5 UV-vis spectrum of MXene-COOH / water dispersion; Figure 6 UV-vis spectrum of MXene-COOH / N-methylpyrrolidone dispersion.

[0140] according to Figure 4It can be seen that the UV-visible spectrum of the MXene-COOH / N,N-dimethylformamide dispersion stored for 20 days still has two characteristic peaks at approximately 320nm and 780nm generated by the surface plasmon resonance of the MXene flakes, indicating that the dispersion of MXene-COOH in N,N-dimethylformamide remains uniform, achieving the high dispersion stability of high-concentration MXene in N,N-dimethylformamide solvent.

[0141] according to Figure 5 It can be seen that the UV-visible spectrum of the MXene-COOH / water dispersion stored for 20 days still has two characteristic peaks at approximately 320nm and 780nm generated by the surface plasmon resonance of the MXene flakes, indicating that the dispersion of MXene-COOH in water remains uniform, achieving the stability of high-concentration MXene high dispersion in water.

[0142] according to Figure 6 It can be seen that the UV-visible spectrum of the MXene-COOH / N-methylpyrrolidone dispersion stored for 20 days still has two characteristic peaks at approximately 320nm and 780nm generated by the surface plasmon resonance of the MXene flakes, indicating that the dispersion of MXene-COOH in N-methylpyrrolidone remains uniform, achieving the high dispersion stability of high-concentration MXene in N-methylpyrrolidone solvent.

[0143] Figures 1 to 6 It is explained that this application uses alcohol solvents and deionized water to perform two-step pre-intercalation on multilayer MXene, and then disperses the two-step pre-intercalation product in a non-alcohol solvent to undergo functional intercalation with an organic acid anhydride. On the one hand, it can effectively improve the conductivity of the functionalized intercalated MXene (conductivity > 10000 S / cm) and make the yield of high-conductivity functionalized intercalated MXene reach 100%, thereby having the advantages of simple exfoliation, high yield, safe operation and excellent conductive properties of the intercalated MXene, which is particularly suitable for large-scale production applications; on the other hand, it can effectively improve the dispersion and stability of the intercalated MXene in water / organic solvents, so that the intercalated MXene / various solvent dispersions can be stored stably for a long time, effectively maintaining the various physical and chemical properties of the MXene.

[0144] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0145] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A MXene intercalation exfoliation method, characterized in that: The method comprises: A fluoride-hydrochloric acid mixture was used to etch Ti3AlC2 to obtain multilayer MXene; Dispersing the multilayer MXene in an alcohol solvent, ultrasonically exfoliating and centrifuging to obtain a first pre-intercalated body; Dispersing the first pre-intercalation body in deionized water, ultrasonically exfoliating and centrifuging to obtain a second pre-intercalation body; dispersing the second pre-intercalation body in a non-alcoholic solvent to obtain a second pre-intercalation body dispersion; At temperature T1, the second pre-intercalation dispersion is intercalated with succinic anhydride, followed by centrifugation and washing to obtain a functionalized MXene precipitate; The functionalized MXene is precipitated and molded to obtain the functionalized MXene; the electrical conductivity of the functionalized MXene is greater than 10,000 S / cm.

2. The intercalation stripping method according to claim 1, characterized in that: The molding process includes: The functionalized MXene precipitate is subjected to vacuum freeze drying / vacuum drying to obtain a functionalized MXene sheet material; Alternatively, the functionalized MXene precipitate is directly dispersed in a dispersing solvent to form a functionalized MXene dispersion; Alternatively, the functionalized MXene precipitate is subjected to vacuum freeze drying / vacuum drying and then dispersed in a dispersion solvent to form a functionalized MXene dispersion.

3. The intercalation stripping method according to claim 1, wherein: The fluoride salt-hydrochloric acid mixed solution etching Ti3AlC2 includes: providing an aqueous solution of hydrochloric acid in which a fluoride salt is dissolved; At temperature T2, Ti3AlC2 is etched using the aqueous hydrochloric acid solution containing a fluoride salt, and after etching, the resulting etching solution is centrifuged several times and washed with deionized water until the pH value of the etching solution is neutral, thereby obtaining a multilayer MXene; The fluoride salt is at least one of lithium fluoride, sodium fluoride and potassium fluoride; The concentration of the hydrochloric acid aqueous solution is 3M-12M; The etching temperature is 25-45°C and the etching time is 6-48h.

4. The intercalation stripping method according to claim 1, wherein: The non-alcohol solvent includes one or a mixture of deionized water, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

5. The intercalation stripping method according to claim 1, characterized in that: The intercalation reaction occurs at a temperature T1 of 25-45° C. and for a time of 6-48 h.

6. The intercalation stripping method according to claim 2, characterized in that: The dispersing solvent includes one or a mixture of cyclohexane, toluene, water, methanol, ethanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, acetone, and tetrahydrofuran.

7. The intercalation stripping method according to claim 6, characterized in that: The concentration of the functionalized MXene dispersion is 0.01-200 mg / mL.

8. A functionalized MXene sheet material or functionalized MXene dispersion prepared according to the method of claim 2.

9. Use of the functionalized MXene dispersion according to claim 8 in conductive additives, water-based coatings, organic coatings, and solution-processed synthetic rubber / plastic additives.

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