A mxene material and a preparation method thereof

Abstract

This invention belongs to the field of two-dimensional material preparation technology, and provides an MXene material and its preparation method. The preparation method of the MXene material includes: mixing a MAX phase precursor to be etched with an organic halide reagent and a morphology modifier, performing a solvothermal etching reaction, and after the reaction, washing and drying the resulting product to obtain the MXene material; wherein the organic halide reagent is triethylamine trihydrofluoride, triethylamine hydrochloride, or dichloroethylamine hydrochloride, and the morphology modifier is ethylene glycol, dimethyl sulfoxide, or cyclohexane. The method of this invention can effectively control the microstructure and pore structure of the MXene material.

Description

Technical Field

[0001] This invention belongs to the field of two-dimensional material preparation technology, specifically relating to an MXene material and its preparation method. Background Technology

[0002] Transition metal carbide / nitride (MXene) materials are layered materials obtained by etching aluminum sublayer atoms in the MAX phase of layered ceramic materials. Their chemical formula can be represented as M. n+1 X n T x In this composition, M is mainly a transition metal element (such as Ti, V, Cr, etc.), X is carbon or nitrogen, T represents a surface end group (such as -OH, -O, -F, etc.), and n is usually 1, 2, or 3. MXene materials possess metal-like conductivity, high density, and adjustable end groups and composition, making them promising for applications in energy storage, catalysis, and microwave absorption.

[0003] Hydrofluoric acid etching was the earliest method for preparing MXene materials, as fluoride ions are highly effective at etching aluminum. Subsequent methods, such as in-situ production hydrofluoric acid etching and fluoride salt etching, are closely related to fluoride ion etching. However, the etching solutions used in hydrofluoric acid etching or in-situ production hydrofluoric acid etching typically have a pH value less than 1, making them highly acidic and posing significant safety risks and adverse environmental impacts. This severely limits the application potential of MXene materials. Furthermore, current MXene material preparation methods cannot control the microstructure of MXene powder, making it difficult to design and construct porous structures within the matrix. These problems significantly hinder the widespread application of MXene materials in electromagnetic protection or microwave absorption. For example, Chinese invention patent application CN118384851A discloses a method for preparing MXene materials and its application in hydrogen purification. This method uses molten salt etching to prepare Cu-loaded MXene materials, a simple and environmentally friendly process; however, this method cannot control the microstructure of the MXene material. Chinese invention patent application CN119284906A discloses a large-sheet MXene material, its preparation method and application. It uses an in-situ hydrofluoric acid method to etch the MAX phase and prepare a large-sheet two-dimensional MXene material with a size of more than 4.2 μm. However, it is obvious that this method cannot control the microstructure of the MXene material.

[0004] It is evident that current processes still struggle to control the microstructure of MXene materials, and overcoming this bottleneck has become crucial for its further development. Summary of the Invention

[0005] To address the problem of difficulty in controlling the microstructure of MXene materials in the prior art, this invention provides an MXene material and its preparation method. The preparation method of this invention can effectively control the microstructure and pore structure of MXene materials, thereby improving their electromagnetic protection or microwave absorption performance.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing MXene material, comprising: mixing a MAX phase precursor to be etched with an organic halogenating agent and a morphology modifier, performing a solvothermal etching reaction, and after the reaction is completed, cleaning and drying the resulting product to obtain MXene material; wherein the organic halogenating agent is triethylamine trihydrofluoride, triethylamine hydrochloride or dichloroethylamine hydrochloride, and the morphology modifier is ethylene glycol, dimethyl sulfoxide or cyclohexane.

[0008] Preferably, the mass ratio of the MAX phase precursor to be etched to the organic halide reagent is 1:(3~15).

[0009] Preferably, the mass ratio of the MAX phase precursor to the morphology modifier to be etched is 1:(2~5).

[0010] Preferably, the temperature of the solvothermal etching reaction is 120~200 °C and the time is 0.5~8 h.

[0011] Preferably, the MAX phase precursor to be etched is Ti3AlC2, Ti2AlC, V2AlC, V4AlC3, Nb2AlC, or Nb4AlC3.

[0012] Preferably, the MAX phase precursor to be etched is obtained by the following pretreatment method: grinding the MAX phase precursor and potassium chloride to obtain a first powder; performing wet ball milling on the first powder, and cleaning and drying after ball milling to obtain a second powder; reacting the second powder with dilute hydrochloric acid, and cleaning and drying the resulting product after the reaction to obtain the MAX phase precursor to be etched.

[0013] Furthermore, the molar ratio of the MAX phase precursor to potassium chloride is 1:(4.05~4.15).

[0014] Furthermore, the concentration of the dilute hydrochloric acid is 0.5~3 mol / L.

[0015] Furthermore, the reaction temperature of the second powder with dilute hydrochloric acid is room temperature, and the reaction time is 0.5~11 h.

[0016] Secondly, the present invention provides an MXene material obtained by the preparation method described above.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention uses an organic halide reagent as an etching agent. Under solvothermal conditions, the organic halide reagent decomposes to produce trace amounts of hydrofluoric acid or hydrochloric acid, thereby etching the MAX phase precursor. Under solvothermal conditions, the organic halide reagent only produces trace amounts of hydrofluoric acid or hydrochloric acid (pH value between 5 and 6, belonging to weak acids), avoiding the use of highly corrosive acids and improving the safety of the preparation process. Simultaneously, this invention introduces a morphology modifier into the etching reaction system, which can regulate the morphology of the MXene material. This is because the morphology modifier adsorbs and aggregates at the inherent defect sites on the surface of the MAX phase precursor to be etched, and undergoes a series of redox reactions with it, changing the surface activity state of the MAX phase and forming high-energy sites. Subsequently, these high-energy sites react with the generated trace amounts of hydrofluoric acid or hydrochloric acid, thereby forming an MXene material with a specific morphology. Therefore, the method of the present invention can effectively regulate the microstructure and pore structure of MXene powder by adjusting the morphology modifier. MXene materials with different morphologies and pore structures have different microwave absorption properties. Thus, the present invention can regulate the microwave absorption properties of MXene materials by controlling the morphology of the materials.

[0019] Furthermore, this invention uses potassium chloride as a buffer to ball mill the MAX phase precursor. Ball milling reduces the size of the MAX phase precursor, while potassium chloride acts as a buffer, preventing direct ball milling from causing fragmentation damage to the MAX phase precursor. Ball milling yields a MAX phase precursor with uniform size. Since the MAX phase precursor typically contains some intermediate phase metal compound particles as impurities, this invention introduces dilute hydrochloric acid for impurity removal, resulting in a purer MAX phase precursor and increasing the active sites for subsequent morphology control.

[0020] This invention utilizes different morphology modifiers to prepare MXene materials with varying morphologies, resulting in different microwave absorption properties. Specifically, the MXene material prepared using dimethyl sulfoxide exhibits superior microwave absorption performance compared to those prepared using cyclohexane and ethylene glycol. Therefore, this invention enables the regulation of the microwave absorption properties of MXene materials by controlling their morphology. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The image shows the XRD pattern of the MXene material prepared in Example 1.

[0023] Figure 2 The image shows a SEM image of the MXene material prepared in Example 1.

[0024] Figure 3 The image shows the XRD pattern of the MXene material prepared in Example 2.

[0025] Figure 4 The image shows a SEM image of the MXene material prepared in Example 2.

[0026] Figure 5 The image shows the XRD pattern of the MXene material prepared in Example 3.

[0027] Figure 6 The image shows a SEM image of the MXene material prepared in Example 3.

[0028] Figure 7 The image shows a SEM image of the MXene material prepared in Example 4.

[0029] Figure 8 This is a SEM image of the MXene material prepared in Example 5.

[0030] Figure 9 This is a SEM image of the MXene material prepared in Example 6.

[0031] Figure 10 This is a SEM image of the MXene material prepared in Example 7.

[0032] Figure 11 The images show the microwave absorption performance of the MXene materials prepared in Examples 1-3; (a) is the MXene material with a flower-like porous structure in Example 1; (b) is the MXene material with a groove-like porous structure in Example 2; and (c) is the MXene material with a tunnel-like porous structure in Example 3. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0034] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0035] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not intended to limit the order of the method steps or define the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0036] The method for preparing MXene material according to the present invention includes: mixing the MAX phase precursor to be etched with an organic halogenating agent and a morphology modifier, performing a solvothermal etching reaction, and after the reaction is completed, cleaning and drying the obtained product to obtain MXene material; wherein, the organic halogenating agent is triethylamine trihydrofluoride, triethylamine hydrochloride or dichloroethylamine hydrochloride, and the morphology modifier is ethylene glycol, dimethyl sulfoxide or cyclohexane.

[0037] This invention uses an organic halide reagent as an etching agent. Under solvothermal conditions, the organic halide reagent decomposes to produce trace amounts of hydrofluoric acid or hydrochloric acid, thereby etching the MAX phase precursor. Simultaneously, this invention introduces a morphology modifier into the reaction system, which can regulate the morphology of the MXene material. Specifically, the morphology modifier adsorbs and accumulates at inherent defect sites on the surface of the MAX phase precursor to be etched, and undergoes a series of redox reactions, altering the surface activity state of the MAX phase and forming high-energy sites. Subsequently, these high-energy sites react with the generated trace amounts of hydrofluoric acid or hydrochloric acid, thereby forming an MXene material with a specific morphology.

[0038] In some preferred embodiments of the present invention, the mass ratio of the MAX phase precursor to be etched to the organic halide reagent is 1:(3~15), for example, it can be 1:3, 1:5, 1:8, 1:10, 1:12, 1:15, etc.

[0039] In some preferred embodiments of the present invention, the mass ratio of the MAX phase precursor to the morphology modifier to be etched is 1:(2~5), for example, it can be 1:2, 1:3, 1:4, 1:5, etc.

[0040] In some preferred embodiments of the present invention, the temperature of the solvothermal etching reaction is 120~200 ℃ and the time is 0.5~8 h; for example, the temperature can be 120 ℃, 150 ℃, 200 ℃, etc., and the time can be 0.5 h, 1.5 h, 2 h, 5 h, 8 h, etc.

[0041] In some preferred embodiments of the present invention, the MAX phase precursor to be etched is an Al-based MAX phase, for example, it can be Ti3AlC2, Ti2AlC, V2AlC, V4AlC3, Nb2AlC or Nb4AlC3.

[0042] In some preferred embodiments of the present invention, the preparation method of the MXene material is as follows: the MAX phase precursor to be etched is thoroughly stirred and mixed with an organic halide reagent, a morphology modifier is added, and after stirring and mixing again, the mixture is transferred to a reaction vessel and subjected to a solvothermal etching reaction at 120~200 °C for 0.5~8 h. After the reaction is completed, the product is washed with ethanol and water alternately 3~5 times, and then dried in a vacuum oven for 12~15 h to obtain the MXene material.

[0043] In some preferred embodiments of the present invention, the MAX phase precursor to be etched is obtained by the following pretreatment method: grinding the MAX phase precursor and potassium chloride to obtain a first powder; performing wet ball milling on the first powder, and cleaning and drying after ball milling to obtain a second powder; reacting the second powder with dilute hydrochloric acid, and cleaning and drying the resulting product after the reaction to obtain the MAX phase precursor to be etched.

[0044] This invention uses potassium chloride as a buffer to ball mill the MAX phase precursor. Ball milling reduces the size of the MAX phase precursor, while potassium chloride acts as a buffer, preventing direct ball milling from causing fragmentation damage to the MAX phase precursor. Ball milling yields a MAX phase precursor with uniform size. Since the MAX phase precursors typically contain some intermediate phase metal compound particles as impurities, this invention introduces dilute hydrochloric acid for impurity removal, resulting in a purer MAX phase precursor and increasing the active sites for subsequent morphology control.

[0045] In a further preferred embodiment of the present invention, the molar ratio of the precursor MAX phase to potassium chloride is 1:(4.05~4.15), for example, it can be 1:4.05, 1:4.1, 1:4.15, etc.

[0046] In a further preferred embodiment of the present invention, the concentration of the dilute hydrochloric acid is 0.5~3 mol / L, for example, it can be 0.5 mol / L, 1 mol / L, 3 mol / L, etc.

[0047] In a further preferred embodiment of the present invention, the reaction temperature of the second powder with dilute hydrochloric acid is room temperature, and the reaction time is 0.5 to 11 h, for example, 0.5 h, 4 h, 11 h, etc.

[0048] In a further preferred embodiment of the present invention, the method for preparing the MAX phase precursor to be etched is as follows: the MAX phase precursor and potassium chloride are placed in a mortar and ground thoroughly for 16-23 min to obtain a first powder. The first powder is then transferred to a ball mill jar, alcohol is added and the powder is ground thoroughly for 1-9 h. After ball milling, the powder is washed with deionized water and then dried to obtain a second powder. The second powder is then immersed in dilute hydrochloric acid and stirred thoroughly at room temperature for 0.5-11 h. The resulting product is washed and vacuum dried to obtain the MAX phase precursor to be etched.

[0049] This invention uses different morphology modifiers to prepare MXene materials with different morphologies, and the MXene materials with different morphologies have different microwave absorption properties. Among them, the microwave absorption properties of the MXene material prepared by dimethyl sulfoxide are better than those of the MXene material prepared by cyclohexane and ethylene glycol.

[0050] Example 1

[0051] The MAX phase Ti3AlC2 and potassium chloride were ground together in a mortar at a molar ratio of 1:4.1 for 18 min to obtain the first powder. The first powder was then transferred to a ball mill jar, and an appropriate amount of alcohol was added for ball milling for 2 h. After ball milling, the powder was washed with deionized water and then dried to obtain the second powder. The second powder was then immersed in 1 mol / L dilute hydrochloric acid and stirred thoroughly at room temperature for 4 h. The product was then washed and vacuum dried to obtain the MAX phase precursor to be etched.

[0052] The MAX phase precursor to be etched and triethylamine trihydrofluoride were placed in a beaker at a mass ratio of 1:10 and thoroughly mixed. Then, cyclohexane was added at a mass ratio of 1:4 (MAX phase precursor to cyclohexane). After mixing again, the mixture (pH 5.5) was transferred to a reactor and subjected to solvothermal etching at 150 °C for 1.5 h. After the reaction was completed, the product was washed 5 times with alternating ethanol and water, and dried to obtain the MXene material.

[0053] Example 2

[0054] The MAX phase Ti3AlC2 and potassium chloride were ground together in a mortar at a molar ratio of 1:4.1 for 18 min to obtain the first powder. The first powder was then transferred to a ball mill jar, and an appropriate amount of alcohol was added for ball milling for 2 h. After ball milling, the powder was washed with deionized water and then dried to obtain the second powder. Finally, the second powder was immersed in 1 mol / L dilute hydrochloric acid and stirred thoroughly at room temperature for 4 h. The product was then washed and vacuum dried to obtain the MAX phase precursor to be etched.

[0055] The MAX phase precursor to be etched and triethylamine trihydrofluoride were placed in a beaker at a mass ratio of 1:10 and thoroughly mixed. Then, ethylene glycol was added at a mass ratio of 1:4 (MAX phase precursor to ethylene glycol). After mixing again, the mixture (pH 5.4) was transferred to a reactor and subjected to solvothermal etching at 150 °C for 1.5 h. After the reaction was completed, the product was washed 5 times with alternating ethanol and water. After drying, the MXene material was obtained.

[0056] Example 3

[0057] The MAX phase Ti3AlC2 and potassium chloride were ground together in a mortar at a molar ratio of 1:4.1 for 18 min to obtain the first powder. The first powder was then transferred to a ball mill jar, and an appropriate amount of alcohol was added for ball milling for 2 h. After ball milling, the powder was washed with deionized water and then dried to obtain the second powder. Finally, the second powder was immersed in 1 mol / L dilute hydrochloric acid and stirred thoroughly at room temperature for 4 h. The product was then washed and vacuum dried to obtain the MAX phase precursor to be etched.

[0058] The MAX phase precursor to be etched and triethylamine trihydrofluoride were placed in a beaker at a mass ratio of 1:10 and thoroughly mixed. Then, dimethyl sulfoxide was added at a mass ratio of 1:4 to the MAX phase precursor to be etched. After mixing again, the mixture (pH 5.6) was transferred to a reactor and subjected to solvothermal etching at 150 °C for 1.5 h. After the reaction was completed, the product was washed 5 times with alternating ethanol and water. After drying, the MXene material was obtained.

[0059] Example 4

[0060] The MAX phase Ti3AlC2 and potassium chloride were ground together in a mortar at a molar ratio of 1:4.1 for 18 min to obtain the first powder. The first powder was then transferred to a ball mill jar, and an appropriate amount of alcohol was added for ball milling for 2 h. After ball milling, the powder was washed with deionized water and then dried to obtain the second powder. Finally, the second powder was immersed in 0.5 mol / L dilute hydrochloric acid and stirred thoroughly at room temperature for 11 h. The product was then washed and vacuum dried to obtain the MAX phase precursor to be etched.

[0061] The MAX phase precursor to be etched and triethylamine trihydrofluoride were placed in a beaker at a mass ratio of 1:3 and thoroughly mixed. Then, ethylene glycol was added at a mass ratio of 1:4 to the MAX phase precursor to be etched. After mixing again, the mixture (pH 5.7) was transferred to a reactor and subjected to a solvothermal etching reaction at 120 °C for 8 h. After the reaction was completed, the product was washed 5 times with alternating ethanol and water. After drying, the MXene material was obtained.

[0062] Example 5

[0063] The MAX phase Ti3AlC2 and potassium chloride were ground together in a mortar at a molar ratio of 1:4.1 for 18 min to obtain the first powder. The first powder was then transferred to a ball mill jar, and an appropriate amount of alcohol was added for ball milling for 2 h. After ball milling, the powder was washed with deionized water and then dried to obtain the second powder. Finally, the second powder was immersed in 1 mol / L dilute hydrochloric acid and stirred thoroughly at room temperature for 4 h. The product was then washed and vacuum dried to obtain the MAX phase precursor to be etched.

[0064] The MAX phase precursor to be etched and triethylamine trihydrofluoride were placed in a beaker at a mass ratio of 1:15 and thoroughly mixed. Then, ethylene glycol was added at a mass ratio of 1:4 (MAX phase precursor to ethylene glycol). After mixing again, the mixture (pH 5.1) was transferred to a reactor and subjected to solvothermal etching at 200 °C for 0.5 h. After the reaction was completed, the product was washed 5 times with alternating ethanol and water. After drying, the MXene material was obtained.

[0065] Example 6

[0066] The MAX phase Ti3AlC2 and potassium chloride were ground together in a mortar at a molar ratio of 1:4.1 for 18 min to obtain the first powder. The first powder was then transferred to a ball mill jar, and an appropriate amount of alcohol was added for ball milling for 2 h. After ball milling, the powder was washed with deionized water and then dried to obtain the second powder. Finally, the second powder was immersed in 3 mol / L dilute hydrochloric acid and stirred thoroughly at room temperature for 0.5 h. The product was then washed and vacuum dried to obtain the MAX phase precursor to be etched.

[0067] The MAX phase precursor to be etched and triethylamine hydrochloride were placed in a beaker at a mass ratio of 1:10 and thoroughly mixed. Then, dimethyl sulfoxide was added at a mass ratio of 1:2 to dimethyl sulfoxide. After mixing again, the mixture (pH 5.4) was transferred to a reactor and subjected to solvothermal etching at 150 °C for 1.5 h. After the reaction was completed, the product was washed 5 times with alternating ethanol and water. After drying, MXene material was obtained.

[0068] Example 7

[0069] The MAX phase Ti3AlC2 and potassium chloride were ground together in a mortar at a molar ratio of 1:4.1 for 18 min to obtain the first powder. The first powder was then transferred to a ball mill jar, and an appropriate amount of alcohol was added for ball milling for 2 h. After ball milling, the powder was washed with deionized water and then dried to obtain the second powder. Finally, the second powder was immersed in 1 mol / L dilute hydrochloric acid and stirred thoroughly at room temperature for 4 h. The product was then washed and vacuum dried to obtain the MAX phase precursor to be etched.

[0070] The MAX phase precursor to be etched and dichloroethylamine hydrochloride were placed in a beaker at a mass ratio of 1:10 and thoroughly mixed. Then, dimethyl sulfoxide was added at a mass ratio of 1:5 between the MAX phase precursor to be etched and dimethyl sulfoxide. After mixing again, the mixture (pH 5.5) was transferred to a reactor and subjected to a solvothermal etching reaction at 150 °C for 1.5 h. After the reaction was completed, the product was washed 5 times alternately with ethanol and water, and then dried to obtain the MXene material.

[0071] XRD analysis was performed on the MXene material prepared in Example 1, and the results are as follows: Figure 1 As shown, it can be seen that, compared to the MAX phase Ti3AlC2, the (002) characteristic peak of the MXene material shifts towards a smaller angle, indicating that its interlayer spacing is larger, which is consistent with the typical characteristics of MXene materials. From Figure 2 As can be seen from the SEM image, the MXene material obtained in Example 1 has a flower-like porous structure.

[0072] XRD analysis was performed on the MXene material prepared in Example 2, and the results are as follows: Figure 3 As shown, it can be seen that, compared to the MAX phase Ti3AlC2, the (002) characteristic peak of the MXene material shifts towards a smaller angle, which is consistent with the typical characteristics of MXene materials. From Figure 4 As can be seen from the SEM image, the MXene material obtained in Example 2 has a groove-like porous structure.

[0073] XRD analysis was performed on the MXene material prepared in Example 3, and the results are as follows: Figure 5 As shown, it can be seen that, compared to the MAX phase Ti3AlC2, the (002) characteristic peak of the MXene material shifts towards a smaller angle, which is consistent with the typical characteristics of MXene materials. From Figure 6 As can be seen from the SEM images, the MXene material obtained in Example 3 has a tunnel-like porous structure.

[0074] Comparing Examples 1, 2, and 3, it can be seen that, under the same conditions, the morphology of MXene materials obtained by using different morphology modifiers is different. The MXene material obtained by using cyclohexane as a morphology modifier has a flower-like porous structure, the MXene material obtained by using ethylene glycol as a morphology modifier has a groove-like porous structure, and the MXene material obtained by using dimethyl sulfoxide as a morphology modifier has a tunnel-like porous structure. This shows that the morphology modifier used in this invention can regulate the morphology of MXene materials.

[0075] SEM images of the MXene materials prepared in Examples 4 and 5 are shown below. Figure 7 and Figure 8 As shown, combined with Figure 4 It can be seen that the temperature and time of the solvothermal etching reaction have little effect on the morphology of MXene materials. When the same morphology modifier is used, the obtained MXene materials are similar, indicating that the morphology of MXene materials is mainly affected by the morphology modifier.

[0076] SEM images of the MXene materials prepared in Examples 6 and 7 are shown below. Figure 9 and Figure 10 As shown, combined with Figure 6 It can be seen that different organic halogenating agents have little effect on the morphology of MXene materials. When the same morphology modifier is used, the obtained MXene materials are similar, indicating that the morphology of MXene materials is mainly affected by the morphology modifier.

[0077] The MXene materials obtained in Examples 1-3 were combined with paraffin to prepare microwave absorbing materials (MXene material content was 35 wt%). The microwave absorbing performance of these materials was then tested, and the results are as follows: Figure 11 As shown. From Figure 11 It can be observed that the MXene material with a flower-like porous structure in Example 1 has an effective absorption width (EAB) of 4.3 GHz when the absorbing material thickness is 1.60 mm; the MXene material with a trench-like porous structure in Example 2 has an effective absorption width of 3.9 GHz when the absorbing material thickness is 1.90 mm; and the MXene material with a tunnel-like porous structure in Example 3 has an effective absorption width of 4.6 GHz when the absorbing material thickness is 1.450 mm. These results indicate that the microwave absorption performance of MXene materials with different morphologies varies greatly. Among them, the MXene material with a tunnel-like porous structure has better microwave absorption performance than the other two morphologies, exhibiting the best microwave absorption performance.

[0078] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing MXene material, characterized in that, include: The MAX phase precursor to be etched is mixed with an organic halogenating agent and a morphology modifier, and a solvothermal etching reaction is carried out. After the reaction, the resulting product is cleaned and dried to obtain MXene material. The organic halogenating agent is triethylamine trihydrofluoride, triethylamine hydrochloride, or dichloroethylamine hydrochloride, and the morphology modifier is ethylene glycol, dimethyl sulfoxide, or cyclohexane. The mass ratio of the MAX phase precursor to the morphology modifier to be etched is 1:(2~5). The temperature of the solvothermal etching reaction is 120~200 ℃, and the time is 0.5~8 h.

2. The method for preparing MXene material according to claim 1, characterized in that, The mass ratio of the MAX phase precursor to be etched to the organic halide reagent is 1:(3~15).

3. The method for preparing MXene material according to claim 1, characterized in that, The MAX phase precursor to be etched is Ti3AlC2, Ti2AlC, V2AlC, V4AlC3, Nb2AlC, or Nb4AlC3.

4. The method for preparing MXene material according to claim 1, characterized in that, The MAX phase precursor to be etched is obtained by the following pretreatment method: the MAX phase precursor and potassium chloride are ground to obtain a first powder; the first powder is subjected to wet ball milling, and after ball milling, it is cleaned and dried to obtain a second powder; the second powder is reacted with dilute hydrochloric acid, and after the reaction is completed, the resulting product is cleaned and dried to obtain the MAX phase precursor to be etched.

5. The method for preparing MXene material according to claim 4, characterized in that, The molar ratio of the MAX phase precursor to potassium chloride is 1:(4.05~4.15).

6. The method for preparing MXene material according to claim 4, characterized in that, The concentration of the dilute hydrochloric acid is 0.5~3 mol / L.

7. The method for preparing MXene material according to claim 4, characterized in that, The reaction temperature of the second powder with dilute hydrochloric acid is room temperature, and the reaction time is 0.5~11 h.

8. MXene material obtained by the preparation method according to any one of claims 1 to 7.

Images