Ti3C2Tx MXene material prepared by gradient etching method and application of Ti3C2Tx MXene material

Abstract

The invention belongs to the technical field of two-dimensional materials, and particularly relates to a Ti3C2Tx MXene material prepared through a gradient etching method and application of the Ti3C2Tx MXene material. According to the method, the single-layer MXene is prepared in a gradient etching mode combining fused salt etching and chemical etching. In the first step, CuCl2 is adopted to carry out preliminary fused salt etching on Ti3AlC2, a partially etched material is generated, and the generated copper elementary substance is removed through an ammonium persulfate solution. In the second step, LiF and HF generated by hydrochloric acid in situ are adopted for further etching the material, and stripping of the single-layer Ti < 3 > C < 2 > T < x > MXene is achieved through multiple times of ultrasonic treatment. The obtained MXene dispersion liquid has a good Tyndall effect and an obvious ultraviolet absorption characteristic, and especially has an obvious peak value at 751nm. The single-layer MXene has good water dispersibility and standard curve characteristics, a peelable film can be obtained through vacuum filtration, and the single-layer MXene has wide potential in flexible electronic application.

Description

Technical Field

[0001] The present invention belongs to the technical field of two-dimensional materials, and specifically relates to a method for preparing Ti3C2T x MXene materials and their applications. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] MXene is a two-dimensional material obtained by selective etching of the MAX phase. It has high conductivity, large specific surface area and excellent electrochemical properties. The MAX phase material consists of a transition metal element (M), an A-group element (such as aluminum), and carbon or nitrogen (X). MXene can be obtained by etching away the A-group element. x MXene is one of the most common MXenes and shows great application potential in supercapacitors, batteries and other energy storage devices.

[0004] Traditional MXene preparation methods usually involve the use of high concentrations of HF, which is highly corrosive and dangerous. In recent years, researchers have been committed to developing safer methods for preparing MXene and improving its electrochemical properties through different functionalization methods. At present, traditional single chemical etching methods (such as HF etching) and single molten salt etching methods (such as CuCl2 etching) have certain advantages in their respective applications, but there are also some limitations. Single chemical etching methods usually have high corrosiveness and environmental risks, and although single molten salt etching methods can be carried out under milder conditions, their etching effect is limited and the product surface is easily contaminated, resulting in a low yield of MXene and poor single-layer film formation. Summary of the invention

[0005] In view of the above problems, the present invention aims to provide a gradient etching method for preparing Ti3C2T x MXene materials and their applications. The present invention prepares a single-layer Ti3C2T by combining molten salt etching and chemical etching. x MXene, specifically, first uses copper salt to treat Ti3C2T x A preliminary molten salt etching was performed, followed by washing with ammonium persulfate solution to remove the generated copper element; then LiF and hydrochloric acid were used to generate HF for chemical etching in situ, combined with DMSO intercalation and ice bath ultrasonic treatment to achieve a single layer of Ti3C2T x Efficient exfoliation of MXene (Tyndall phenomenon is more obvious), the prepared Ti3C2T xMXene has significant application prospects in the field of electrochemical energy storage.

[0006] Specifically, the present invention provides the following technical solutions:

[0007] In a first aspect of the present invention, a Ti3C2T x The preparation method of MXene material comprises the following steps:

[0008] S1, mixing Ti3AlC2 and copper salt powder, grinding and heating to react, to obtain a partially etched material;

[0009] S2, mixing the partially etched material with an ammonium persulfate solution to obtain a clean material;

[0010] S3. After the cleaned material is dried, it is subjected to etching reaction with a chemical etching solution, and the reaction product is subjected to intercalation treatment to obtain the product.

[0011] Preferably, in step S1, the copper salt is selected from one or more of CuCl2, CuBr2, and CuI, preferably CuCl2.

[0012] Preferably, in step S1, the mass ratio of Ti3AlC2 to copper salt powder is 1:1-5, preferably 1:4.

[0013] Preferably, in step S1, the heating reaction is carried out in an inert atmosphere, and the inert atmosphere is selected from one or a combination of hydrogen, nitrogen and argon.

[0014] Preferably, in step S1, the heating reaction is heated to 500-800°C at a heating rate of 3-5°C / min, and the insulation time is 5-8h; further preferably, the heating reaction is heated to 700°C at a heating rate of 5°C / min, and the insulation time is 6h.

[0015] Preferably, in step S2, the concentration of the ammonium persulfate solution is 0.05-0.15M, preferably 0.1M.

[0016] Preferably, in step S2, the cleaned material refers to using ammonium persulfate solution to remove the generated copper element, and then repeatedly washing with deionized water until the solution is colorless and transparent.

[0017] Preferably, in step S3, the etching reaction is to first mix the dried powder with LiF powder, and then add hydrochloric acid solution after ensuring that LiF is evenly dispersed to generate HF and perform etching;

[0018] The mass ratio of the dried powder to the LiF powder is 1:1.5 to 1:2, preferably 1:1.8.

[0019] The mass volume ratio of the mixed powder formed by the dried powder and LiF powder to the hydrochloric acid solution is 1.56g:15-35mL; the concentration of the hydrochloric acid solution is 7-10M, preferably 9M.

[0020] Preferably, in step S3, the temperature of the etching reaction is room temperature, and the time is 10 to 15 hours, preferably 12 hours.

[0021] Preferably, in step S3, after the etching reaction is completed, the product needs to be centrifuged and washed in sequence, the supernatant is discarded after centrifugation, deionized water is added to the precipitate, and the precipitate is washed repeatedly until the pH value of the supernatant is close to neutral;

[0022] Wherein, the centrifugal speed is 3300-3700 rpm / min, the centrifugal time is 3-8 min, and the number of washing times is 5-10 times; further preferably, the centrifugal speed is 3500 rpm / min, and the centrifugal time is 5 min.

[0023] Preferably, in step S3, the intercalation treatment refers to mixing the washed product with an organic solvent for reaction, and then placing the intercalated mixture in an ice bath for ultrasonication to obtain a single-layer Ti3C2T x MXene;

[0024] Wherein, the organic solvent is dimethyl sulfoxide (DMSO), the mass volume ratio of the washed product to the organic solvent is 0.5-0.56 g:15-35 mL; the temperature of the mixed reaction is room temperature, and the reaction time is 20-36 h, preferably 24 h;

[0025] The ultrasonic time is 0.5 to 3 hours, preferably 1 hour, and the ultrasonic is used to promote the single-layer Ti3C2T x During the exfoliation of MXene, an ice bath was maintained during the ultrasonic process to prevent excessive temperature from causing material degradation;

[0026] After the ultrasonic treatment, the supernatant obtained by centrifugation is the single-layer Ti3C2T x MXene dispersion; the centrifugal speed is 2500-3700 rpm / min, and the centrifugal time is 5-15 min; more preferably, the centrifugal speed is 3000 rpm / min, and the centrifugal time is 10 min.

[0027] A second aspect of the present invention provides a Ti3C2T x The MXene material is prepared by the preparation method described in the first aspect.

[0028] The third aspect of the present invention provides a Ti3C2T prepared by the preparation method described in the first aspect.x MXene material and / or Ti3C2T described in the second aspect x Application of MXene materials in electrochemical energy storage devices.

[0029] One or more embodiments of the present invention have at least the following beneficial effects:

[0030] (1) The present invention prepares a monolayer MXene by a gradient etching method combining molten salt etching and chemical etching. In the first step, CuCl2 is used to perform preliminary molten salt etching on Ti3AlC2 to generate partially etched material, and the generated copper element is removed by ammonium persulfate solution. In the second step, HF generated in situ by LiF and hydrochloric acid is used to further etch the material, and multiple ultrasonic treatments are performed to achieve a monolayer Ti3C2T x MXene exfoliation. The entire process is safe, efficient, clean, environmentally friendly, and low in energy consumption, making it suitable for industrial large-scale production.

[0031] (2) Ti3C2T prepared by the present invention x The MXene material dispersion has a good Tyndall effect and significant ultraviolet absorption characteristics, especially a clear characteristic peak at 751nm, which proves that the single-layer MXene has good water dispersibility. From the standard curve characteristics, it can be seen that it has a good stability effect under different dilution multiples, indicating that the single-layer MXene solution is stable and not easily oxidized.

[0032] (3) Ti3C2T prepared by the present invention x MXene materials can be obtained into peelable films through vacuum filtration, which has excellent flexibility and will have certain application prospects in flexible electronics-related fields in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0034] Figure 1 Ti3C2T prepared in Example 1 of the present invention x Scanning electron micrograph of MXene;

[0035] Figure 2 Ti3C2T prepared in Example 1 of the present invention x Polarized microscope image of MXene material;

[0036] Figure 3 Ti3C2T prepared in Example 1 of the present invention xX-ray diffraction comparison of MXene material and raw material Ti3AlC2;

[0037] Figure 4 This is a comparison diagram of the suction filtration film-forming effects of Example 1 of the present invention and Comparative Examples 1-2;

[0038] Figure 5 It is a comparison diagram of X-ray diffraction of Example 1 of the present invention and Comparative Examples 1-2;

[0039] Figure 6 Ti3C2T prepared in Example 1 of the present invention x UV-visible absorption spectrum of MXene materials;

[0040] Figure 7 Ti3C2T prepared in Example 1 of the present invention x Standard curve diagram of MXene materials;

[0041] Figure 8 Ti3C2T prepared in Example 1 of the present invention x Schematic diagram of the Tyndall phenomenon of MXene materials. DETAILED DESCRIPTION

[0042] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0043] As mentioned above, in recent years, people have tried to develop safer methods for preparing MXene and improve its electrochemical performance through different functionalization methods. However, due to the complexity of the process and the limitations of safety, the current preparation methods still need to be further optimized.

[0044] A first typical embodiment of the present invention provides a Ti3C2T x The preparation method of MXene material comprises the following steps:

[0045] S1, mixing Ti3AlC2 and copper salt powder, grinding and heating to react, to obtain a partially etched material;

[0046] S2, mixing the partially etched material with an ammonium persulfate solution to obtain a clean material;

[0047] S3. After the cleaned material is dried, it is subjected to etching reaction with a chemical etching solution, and the reaction product is subjected to intercalation treatment to obtain the product.

[0048] In one or more examples of this embodiment, in step S1, the copper salt is selected from one or more of CuCl2, CuBr2, and CuI, preferably CuCl2.

[0049] In one or more examples of this embodiment, in step S1, the molar ratio of Ti3AlC2 to copper salt powder is 1:1 to 1:5, preferably 1:4.

[0050] In one or more examples of this embodiment, in step S1, the heating reaction is carried out in an inert atmosphere, and the inert atmosphere is selected from one or a combination of hydrogen, nitrogen, and argon.

[0051] In one or more examples of this embodiment, in step S1, the heating reaction is heated to 500-800°C at a heating rate of 3-5°C / min, and the insulation time is 5-8h.

[0052] In one or more examples of this embodiment, the heating reaction is heated to 700° C. at a heating rate of 5° C. / min, and the insulation time is 6 hours.

[0053] In one or more examples of this embodiment, in step S2, the concentration of the ammonium persulfate solution is 0.05-0.15M, preferably 0.1M.

[0054] In one or more examples of this implementation mode, in step S2, the clean material refers to using ammonium persulfate solution to remove the generated copper element, and then repeatedly washing with deionized water until the solution is colorless and transparent.

[0055] In one or more examples of this embodiment, in step S3, the etching reaction is to mix the dried powder with LiF powder first, and then add hydrochloric acid solution after ensuring that LiF is evenly dispersed to generate HF and perform etching;

[0056] The mass ratio of the dried powder to LiF powder is 1:1.5 to 1:2, preferably 1:1.8.

[0057] The mass volume ratio of the mixed powder formed by the dried powder and LiF powder to the hydrochloric acid solution is 1.56g:15-35mL; the concentration of the hydrochloric acid is 7-10M, preferably 9M.

[0058] In one or more examples of this implementation mode, in step S3, the temperature of the etching reaction is room temperature, and the time is 10 to 15 hours, preferably 12 hours.

[0059] In one or more examples of this implementation, in step S3, after the etching reaction is completed, the product needs to be centrifuged and washed in sequence, the supernatant is discarded after centrifugation, deionized water is added to the precipitate, and the precipitate is washed repeatedly until the pH value of the supernatant is close to neutral;

[0060] Wherein, the centrifugal speed is 3300-3700 rpm / min, the centrifugal time is 3-8 min, and the washing times are 5-7 times.

[0061] In one or more examples of this embodiment, the centrifugal rotation speed is 3500 rpm / min, and the centrifugal time is 5 min.

[0062] In one or more examples of this embodiment, in step S3, the intercalation treatment refers to mixing the washed product with an organic solvent for reaction, and then placing the intercalated mixture in an ice bath for ultrasonication to obtain a single-layer Ti3C2T x MXene;

[0063] Wherein, the organic solvent is dimethyl sulfoxide (DMSO), the mass volume ratio of the washed product to the organic solvent is 0.5-0.56 g:15-35 mL; the temperature of the mixed reaction is room temperature, and the reaction time is 20-36 h, preferably 24 h;

[0064] The ultrasonic time is 0.5 to 3 hours, preferably 1 hour, and the ultrasonic is used to promote the single-layer Ti3C2T x During the exfoliation of MXene, an ice bath was maintained during the ultrasonic process to prevent excessive temperature from causing material degradation;

[0065] After the ultrasonic treatment, the supernatant obtained by centrifugation is the single-layer Ti3C2T x MXene dispersion; the centrifugal speed is 2500-3700 rpm / min, and the centrifugal time is 5-15 min.

[0066] In one or more examples of this embodiment, the centrifugal rotation speed is 3000 rpm / min, and the centrifugal time is 10 min.

[0067] A second typical embodiment of the present invention provides a Ti3C2T x MXene material is prepared by the above-mentioned preparation method.

[0068] A third typical embodiment of the present invention provides a Ti3C2T prepared by the above-mentioned preparation method. x MXene materials and / or the above-mentioned Ti3C2T x Application of MXene materials in electrochemical energy storage devices.

[0069] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0070] Example 1 :This embodiment provides a Ti3C2T prepared by gradient etching method x MXene materials, specifically including the following steps:

[0071] 1. Molten salt etching and cleaning

[0072] (1) Mix 0.5 g of Ti3AlC2 powder and 2 g of CuCl2 powder and grind them thoroughly using an agate mortar for 30 min to ensure uniform mixing.

[0073] (2) The ground mixture was placed in an alumina crucible, placed in a tube furnace under an argon atmosphere, heated to 700° C. at a heating rate of 5° C. / min, kept at that temperature for 6 h, and then naturally cooled to room temperature to obtain a partially etched material.

[0074] (3) The material obtained in step (3) was transferred to a beaker, 100 mL of 0.1 M ammonium persulfate solution was added, and the mixture was stirred at room temperature for 1 h to remove the generated copper element, and then repeatedly washed with deionized water until the solution was colorless and transparent to obtain a clean material.

[0075] 2. Chemical Etching and Stripping

[0076] (1) 0.56 g of the dry powder obtained by drying the clean material obtained in step 1 was mixed with 1 g of LiF powder, and dispersed in 20 mL of deionized water. The mixture was stirred for 30 min using a magnetic stirrer to ensure that the LiF was evenly dispersed.

[0077] (2) Under stirring conditions, 20 mL of hydrochloric acid solution (9 M) was gradually added in batches to generate HF and perform etching. The reaction was continued at room temperature for 12 h.

[0078] (3) After etching, the product was centrifuged at 3500 rpm for 5 min, and the supernatant was discarded; deionized water was added to the precipitate, resuspended, and centrifuged again. The washing steps were repeated at least 5-7 times until the pH value of the supernatant was close to neutral.

[0079] (4) 0.56 g of the washed product was mixed with 20 mL of dimethyl sulfoxide (DMSO) and stirred at room temperature for 24 h for intercalation treatment.

[0080] (5) The intercalated mixture was placed in an ice bath and ultrasonically treated for 1 h to promote the formation of the monolayer Ti3C2T xDuring the exfoliation of MXene, an ice bath was maintained during the ultrasonic process to prevent excessive temperature from causing material degradation.

[0081] (6) After ultrasound, the supernatant was collected by centrifugation at 3000 rpm for 10 min to obtain a single-layer Ti3C2T x Dispersion of MXene.

[0082] (7) Store the dispersion at low temperature to prevent oxidation of the material and degradation of its performance.

[0083] Example 2 :This embodiment is for the Ti3C2T prepared in Example 1 x MXene materials for material characterization

[0084] like Figure 1 As shown, the Ti3C2T x In the optical microscope image of MXene material, the peeled MXene flakes show a uniform flaky structure.

[0085] like Figure 2 As shown, the Ti3C2T x In the polarizing microscope image of MXene material, the peeled MXene flakes have good dispersion.

[0086] like Figure 3 As shown, compared with the raw material Ti3AlC2, the Ti3C2T x After gradient etching of the MXene material, the diffraction peak of phase A (aluminum) disappears, indicating that the aluminum element has been completely removed.

[0087] Comparative Example 1 :This comparative example provides a MXene material prepared by a molten salt etching method, which specifically includes the following steps:

[0088] (1) Mix 0.5 g of Ti3AlC2 powder and 2 g of CuCl2 powder and grind them thoroughly using an agate mortar for 30 min to ensure uniform mixing.

[0089] (2) The ground mixture was placed in an alumina crucible, placed in a tube furnace under an argon atmosphere, heated to 700° C. at a heating rate of 5° C. / min, kept at that temperature for 6 h, and then naturally cooled to room temperature to obtain an etched material.

[0090] (3) The etched material was transferred to a beaker, 100 mL of 0.1 M ammonium persulfate solution was added, and the mixture was stirred at room temperature for 1 h to remove the generated copper element, and then washed repeatedly with deionized water until the solution was colorless and transparent to obtain a clean material.

[0091] (4) The washed product was mixed with 20 mL of dimethyl sulfoxide (DMSO) and stirred at room temperature for 24 h for intercalation treatment.

[0092] (5) The intercalated mixture was placed in an ice bath and ultrasonically treated for 1 h to promote the exfoliation of the single-layer MXene. The ice bath was maintained during the ultrasonic process to prevent the material from being degraded due to excessive temperature.

[0093] (6) After ultrasonication, the mixture was centrifuged at 3000 rpm for 10 min, and the supernatant was collected to obtain a dispersion containing a monolayer MXene.

[0094] (7) Store the dispersion at low temperature to prevent oxidation of the material and degradation of its performance.

[0095] Comparative Example 2 :This comparative example provides a MXene material prepared by a chemical etching method, which specifically includes the following steps:

[0096] (1) 0.5 g of Ti3AlC2 powder was mixed with 2 g of CuCl2 powder and ground thoroughly for 30 min using an agate mortar to ensure uniform mixing. The mixture was then mixed with 1 g of LiF powder and dispersed in 20 mL of deionized water and stirred for 30 min using a magnetic stirrer to ensure uniform dispersion of LiF.

[0097] (2) Under stirring conditions, 20 mL of 9 M hydrochloric acid solution was gradually added in batches to generate HF and perform etching. The reaction was continued at room temperature for 72 h.

[0098] (3) After etching, the product was centrifuged at 3500 rpm for 5 min, and the supernatant was discarded; deionized water was added to the precipitate, resuspended, and centrifuged again. The washing steps were repeated at least 5-7 times until the pH value of the supernatant was close to neutral.

[0099] (4) The washed product was mixed with 20 mL of dimethyl sulfoxide (DMSO) and stirred at room temperature for 24 h for intercalation treatment.

[0100] (5) The intercalated mixture was placed in an ice bath and ultrasonically treated for 1 h to promote the exfoliation of the single-layer MXene. The ice bath was maintained during the ultrasonic process to prevent the material from being degraded due to excessive temperature.

[0101] (6) After ultrasonication, the mixture was centrifuged at 3000 rpm for 10 min, and the supernatant was collected to obtain a dispersion containing a monolayer MXene.

[0102] (7) Store the dispersion at low temperature to prevent oxidation of the material and degradation of its performance.

[0103] Test Example 1:This embodiment is based on the Ti3C2T prepared in Example 1 and Comparative Examples 1-2 x MXene materials were filtered and XRD tested

[0104] (1) Since the single-layer MXene has a good dispersion effect and can be filtered to form a film (with a certain metallic luster), the vacuum filtration method is directly used to judge the preparation effect of the MXene single-layer solution. This measurement method is more intuitive and the operation method is simple and easy.

[0105] This test example conducted vacuum filtration experiments on solutions prepared by three methods to screen out the synthesis method. The experimental results are as follows Figure 4 As shown, Figure 4 In the figure a, the solution obtained in Example 1 was filtered, and it was difficult to form a film, and the material could not adhere to the filter membrane and was easily broken, indicating that the etching effect was poor; Figure 4 Figure b shows the effect of filtering the solution obtained in Example 2. It can be seen that although the film can be formed and has a certain metallic luster, there is still damage, which means that the preparation method can obtain a single-layer MXene solution, but the film-forming effect is poor. Figure 4 Figure c is the effect of Example 1. It can be clearly seen that after filtration, not only a film is formed, but also it can naturally separate from the filter membrane and has a distinct metallic luster. These are the characteristics of a single-layer MXene solution with excellent dispersion effect, achieving the expected effect.

[0106] (2) In order to further compare the results, the X-ray diffraction sample analysis of the three materials obtained by filtration in (1) was supplemented, and the results of the characteristic peak of the interlayer spacing (the diffraction peak before 10° is the characteristic peak of the interlayer spacing of MXene) and the peak stronger than (1) were mutually verified. Figure 5 As shown in Figure 1, no interlayer spacing characteristic peak appears in Comparative Example 1. This indicates that the etching effect is not good. Figure 4 The comparative example 2 has a characteristic peak, but the peak intensity is small, which is also consistent with Figure 4 The phenomenon in b is consistent with that in Example 1, while the characteristic peak of Example 1 is more obvious and the characteristic peak intensity is higher, which is consistent with the effect of single-layer MXene filtration film formation ( Figure 4 The above test is sufficient to illustrate the effect of the embodiment, and a more detailed test of the embodiment is carried out later.

[0107] Test Example 2 :This embodiment is for the Ti3C2T prepared in Example 1 x MXene material performance testing

[0108] (1) Testing of single-layer Ti3C2T using UV-visible spectrophotometer x The absorbance of MXene dispersion, such as Figure 6As shown, it shows an obvious characteristic peak at 751nm, which is the characteristic peak of the single-layer Ti3C2T x The most significant feature of MXene is that it can be used to determine the synthesis effect of the monolayer solution and also shows that it has good monolayer dispersion characteristics;

[0109] The dispersion can obtain a good standard curve in the UV-visible region such as Figure 7 As shown, the fitted linear equation is y = 15.61429x + 0.00486, R 2 =0.9986, indicating that at different dilution times, the monolayer solution tends to be stable and there is no multilayer MXene doping, which further indicates that the relative purity of the monolayer solution is high and suitable for subsequent quantitative analysis and characterization;

[0110] And the preparation effect of single-layer Ti3C2T x MXene is a colloidal solution and has the basic characteristics of the Tyndall phenomenon, such as Figure 8 , indicating that it is a good colloidal dispersion system, which is consistent with the analytical test results of UV absorbance and standard curve.

[0111] (2) The MXene dispersion was vacuum filtered to prepare a thin film. The obtained film was observed to have a uniform lamellar structure and good dispersibility under a scanning electron microscope and a polarizing microscope. Figures 1-2 shown.

[0112] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Ti3C2T x The method for preparing MXene material is characterized in that: The following steps are involved: S1, mixing Ti3AlC2 and copper salt powder, grinding and heating to react, to obtain a partially etched material; S2, mixing the partially etched material with an ammonium persulfate solution to obtain a clean material; S3. After the cleaned material is dried, it is subjected to etching reaction with a chemical etching solution, and the reaction product is subjected to intercalation treatment to obtain the product.

2. The preparation method according to claim 1, characterized in that In step S1, the copper salt is selected from one or more of CuCl2, CuBr2, and CuI; and the mass ratio of the Ti3AlC2 to the copper salt powder is 1:1 to 5.

3. The preparation method according to claim 1, characterized in that: In step S1, the heating reaction is carried out in an inert atmosphere, and the inert atmosphere is selected from one or a combination of hydrogen, nitrogen, and argon.

4. The preparation method according to claim 1, characterized in that: In step S1, the heating reaction is heated to 500-800°C at a heating rate of 3-5°C / min, and the insulation time is 5-8h; preferably, the heating reaction is heated to 700°C at a heating rate of 5°C / min, and the insulation time is 6h.

5. The preparation method according to claim 1, characterized in that: In step S2, the concentration of the ammonium persulfate solution is 0.05-0.15M; Preferably, the clean material refers to using ammonium persulfate solution to remove the generated copper element, and then repeatedly washing with deionized water until the solution is colorless and transparent.

6. The preparation method according to claim 1, characterized in that: In step S3, the etching reaction is to mix the dried powder with LiF powder first, and then add hydrochloric acid solution after ensuring that LiF is evenly dispersed to generate HF and perform etching; Wherein, the mass ratio of the dried powder to the LiF powder is 1:1.5 to 1:2, preferably 1:1.8; The mass volume ratio of the mixed powder formed by the dried powder and the LiF powder to the hydrochloric acid solution is 1.56 g:15-35 mL; the concentration of the hydrochloric acid solution is 7-10 M; The temperature of the etching reaction is room temperature, and the time is 10 to 15 hours, preferably 12 hours.

7. The preparation method according to claim 1, characterized in that: In step S3, after the etching reaction is completed, the product needs to be centrifuged and washed in sequence, the supernatant is discarded after centrifugation, deionized water is added to the precipitate, and washing is repeated until the pH value of the supernatant is close to neutral; Wherein, the centrifugal speed is 3300-3700 rpm / min, the centrifugal time is 3-8 min, and the number of washing times is 5-10 times; preferably, the centrifugal speed is 3500 rpm / min, and the centrifugal time is 5 min.

8. The preparation method according to claim 1, characterized in that: In step S3, the intercalation treatment refers to mixing the washed product with an organic solvent for reaction, and then placing the intercalated mixture in an ice bath for ultrasonication to obtain a single-layer Ti3C2T x MXene; Wherein, the organic solvent is dimethyl sulfoxide, the mass volume ratio of the washed product to the organic solvent is 0.5-0.56 g:15-35 mL; the temperature of the mixed reaction is room temperature, and the reaction time is 20-36 h, preferably 24 h; The ultrasonic time is 0.5 to 3 hours, preferably 1 hour, and the ultrasonic is used to promote the formation of a single layer of Ti3C2T x During the exfoliation of MXene, an ice bath was maintained during the ultrasonic process to prevent excessive temperature from causing material degradation; After the ultrasonic treatment, the supernatant obtained by centrifugation is the single-layer Ti3C2T x MXene dispersion; the centrifugal speed is 2500-3700 rpm / min, and the centrifugal time is 5-15 min; preferably, the centrifugal speed is 3000 rpm / min, and the centrifugal time is 10 min.

9. A Ti3C2T x MXene material, characterized in that It is prepared by the preparation method according to any one of claims 1 to 8.

10. Ti3C2T prepared by the preparation method according to any one of claims 1 to 8 x MXene material and / or Ti3C2T as claimed in claim 9 x Application of MXene materials in electrochemical energy storage devices.

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