Partially oxidized MXene folded microsphere material as well as preparation method and application thereof

Abstract

The invention provides a partially oxidized MXene wrinkled microsphere material and a preparation method and application thereof, and the preparation method of the partially oxidized MXene wrinkled microsphere material comprises the following steps: S1, carrying out shearing treatment on a Ti3C2TX MXene dispersion liquid, then carrying out centrifugation, and taking a supernatant to obtain an MXene dispersion liquid with defects; and S2, carrying out spray drying on the defective MXene dispersion liquid obtained in the step S1 to obtain the partially oxidized MXene wrinkled microsphere material. The partially oxidized MXene wrinkled microsphere material enhances the interface polarization loss of MXene, so that the electromagnetic wave absorption band of the MXene substrate is moved to low frequency, and excellent electromagnetic wave absorption performance is realized.

Description

Technical Field

[0001] The invention belongs to the field of wave-absorbing materials, and in particular relates to a partially oxidized MXene wrinkled microsphere material and a preparation method and application thereof. Background Art

[0002] With the rapid development of electronic technology, the complex electromagnetic environment has put forward more stringent requirements for electromagnetic protection. In particular, the threat of early warning radars with long-range detection capabilities in low-frequency bands (such as S band, 2-4GHz) and the serious electromagnetic interference generated by the (Sub-6G) band in 5G communications make the development of high-performance, lightweight low-frequency absorbing materials particularly critical. Although there have been many reports showing that lightweight materials such as graphene, CNTs, carbon fiber, etc. exhibit excellent electromagnetic wave absorption capabilities in medium and high frequency bands, their absorption performance in the low-frequency region is poor, and usually requires the use of additional magnetic materials, resulting in high density, complicated processes and low absorption efficiency. Therefore, finding and developing a lightweight absorbing material that can achieve low-frequency absorption without the participation of magnetic components is still a major challenge.

[0003] As an emerging two-dimensional nanomaterial, MXene is considered to be a highly promising electromagnetic wave absorption material due to its advantages such as high conductivity, high specific surface area, multilayer structure, nanosize effect and adjustable surface properties. Controlling the surface properties and morphology of MXene is crucial in optimizing and adjusting its functional properties. However, since MXene nanosheets are prone to aggregation and self-stacking, it is easy to cause uneven electric field distribution in the matrix under an applied alternating electromagnetic field, which in turn causes impedance mismatch and reduces electromagnetic wave absorption performance. Therefore, the practical application of MXene-based electromagnetic wave absorption materials is limited. Summary of the invention

[0004] In order to solve the problems of the above-mentioned prior art, the present invention provides a partially oxidized MXene wrinkled microsphere material and a preparation method and application thereof. The partially oxidized MXene wrinkled microsphere material enhances the interfacial polarization loss of MXene, thereby shifting the electromagnetic wave absorption band of the MXene substrate to low frequency, thereby achieving excellent electromagnetic wave absorption performance.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for preparing a partially oxidized MXene wrinkled microsphere material comprises the following steps:

[0007] S1, for Ti3C2T X The MXene dispersion is sheared and then centrifuged to obtain a supernatant to obtain a MXene dispersion with defects;

[0008] S2, spray drying the defective MXene dispersion obtained in S1 to obtain a partially oxidized MXene wrinkled microsphere material.

[0009] Preferably, in S1, the Ti3C2T X The preparation method of MXene dispersion is as follows: Ti3AlC2 MAX phase powder is added to a mixed solution of LiF and HCl, and the mixture is stirred and etched. After the etching is completed, the reaction solution is centrifuged and washed, and the precipitate is collected and dispersed in water, and ultrasonicated to obtain Ti3C2T X MXene dispersion.

[0010] Preferably, in S1, the shearing speed is 8000-10000 r / min, and the shearing treatment time is 5-15 min.

[0011] Preferably, in S2, the spray drying temperature is 150-200°C.

[0012] Preferably, in S2, the concentration of the defective MXene dispersion is 1 to 10 mg / mL.

[0013] The present invention provides a partially oxidized MXene wrinkled microsphere material obtained by the preparation method, characterized in that the morphology of the material is wrinkled microspheres.

[0014] Preferably, the surface of the material is modified with titanium dioxide nanoparticles.

[0015] Preferably, the electromagnetic wave absorption frequency range of the material is 3.0 to 18.0 GHz.

[0016] Preferably, the RL value of the material is -63.3 to -50.07 dB.

[0017] The present invention provides the application of the partially oxidized MXene wrinkled microsphere material as an absorbing material in electromagnetic wave absorption.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] In the preparation process of MXene, the present invention introduces defects into MXene through a simple, efficient and easily controllable high-speed shearing process. The introduction of defects enhances the electrostatic repulsion between the sheets, effectively inhibiting the agglomeration and self-stacking of MXene. Spray drying technology is used to induce topological deformation of MXene nanosheets and oxidation at defective positions to form MXene wrinkled microspheres with titanium dioxide nanoparticles modified in situ on the surface. Compared with the traditional sheet structure, the large-scale voids between the MXene wrinkled microspheres in this wrinkled microsphere structure and the microscale pores inside the microspheres work synergistically to effectively improve the impedance matching of the material and reduce the reflection of electromagnetic waves. At the same time, the cavity in the wrinkled sphere can more effectively capture and convert the incident electromagnetic energy, and the wrinkled cavity structure also promotes multiple reflections and scattering of electromagnetic waves inside the material, thereby enhancing the interaction time and energy dissipation between microwaves and materials. The unique titanium dioxide structure and defects on the surface provide rich paths and interfaces for the conduction and polarization of electrons and electromagnetic waves. These nanoscale features are key factors leading to conduction loss and polarization loss, and play a vital role in the attenuation of electromagnetic waves. At the same time, by regulating the interface polarization loss of MXene, the contradiction between impedance matching and energy loss is effectively balanced, the opportunity of converting electromagnetic energy into other forms of energy is increased, and the electromagnetic wave absorption band of MXene-based materials is further pushed to move toward low frequencies, ultimately achieving excellent absorption performance. Therefore, the present invention, without introducing magnetic nanoparticles and maintaining low density, exerts the advantages of MXene-based materials by regulating polarization loss and MXene morphology, shifts the absorption band to low frequencies, and obtains excellent electromagnetic wave absorption performance.

[0020] The partially oxidized multi-fold MXene microsphere sample obtained in the present invention has an extremely thin thickness of 1.52 mm, RL min It can reach -63.3~-50.07dB, the absorption rate exceeds 99.999%, and the absorption frequency band is extended to the low frequency 3GHz (S: 2.0~4.0GHz). BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 The SEM image, XRD image and three-dimensional reflection loss image of the material prepared in Example 1 of the present invention.

[0023] Figure 2This is a three-dimensional reflection loss diagram of the material prepared in Example 2 of the present invention.

[0024] Figure 3 This is a three-dimensional reflection loss diagram of the material prepared in Example 3 of the present invention.

[0025] Figure 4 This is a three-dimensional reflection loss diagram of the material prepared in Example 4 of the present invention.

[0026] Figure 5 This is a three-dimensional reflection loss diagram of the material prepared in Example 5 of the present invention.

[0027] Figure 6 This is a three-dimensional reflection loss diagram of the material prepared in Example 6 of the present invention.

[0028] Figure 7 This is a three-dimensional reflection loss diagram of the material prepared in Example 7 of the present invention.

[0029] Figure 8 This is a three-dimensional reflection loss diagram of the material prepared in Example 8 of the present invention.

[0030] Fig. 9 This is a three-dimensional reflection loss diagram of the material prepared in Example 9 of the present invention.

[0031] Fig.10 The SEM image, XRD image, Zeta potential and three-dimensional reflection loss image of the material prepared in Comparative Example 1.

[0032] Fig.11 The SEM image and three-dimensional reflection loss diagram of Comparative Example 2 are shown. DETAILED DESCRIPTION

[0033] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways 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 devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0035] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0036] A partially oxidized MXene wrinkled microsphere material, characterized by comprising the following steps:

[0037] S1, Ti3C2T X The MXene dispersion is added to a high-speed shear emulsifier for shear treatment, and then centrifuged to obtain the supernatant to obtain a MXene dispersion with defects;

[0038] S2, spray drying the defective MXene dispersion obtained in S1 to obtain a partially oxidized MXene wrinkled microsphere material.

[0039] In some specific embodiments of the present invention, the Ti3C2T X The preparation method of MXene dispersion is as follows: Ti3AlC2MAX phase powder is added to a mixed solution of LiF and HCl, and the mixture is stirred and etched. After the etching is completed, the reaction solution is centrifuged and washed, and the precipitate is collected and dispersed in water, and ultrasonicated to obtain Ti3C2T X MXene dispersion.

[0040] In S1 of the present invention, the shearing speed is 8000-10000 r / min, and the shearing treatment time is 5-15 min.

[0041] In some specific embodiments of the present invention, the temperature used for spray drying is 150-200° C., and the concentration of the MXene dispersion is 1-10 mg / mL.

[0042] Example 1

[0043] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0044] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0045] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0046] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 8000 r / min for 5 min. Afterwards, the treated dispersion was centrifuged at a speed of 3500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0047] (4) Preheat the spray dryer to 150°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (1 mg / mL) was added to the feed tube. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-fold MXene microsphere sample was obtained.

[0048] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0049] Example 2

[0050] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0051] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0052] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0053] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 8000 r / min for 5 min. Afterwards, the treated dispersion was centrifuged at a speed of 3500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0054] (4) Preheat the spray dryer to 170°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (1 mg / mL) was added to the feed tube. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-fold MXene microsphere sample was obtained.

[0055] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0056] Example 3

[0057] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0058] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0059] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0060] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 8000 r / min for 5 min. Afterwards, the treated dispersion was centrifuged at a speed of 3500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0061] (4) Preheat the spray dryer to 200°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (1 mg / mL) was added to the feed tube. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-wrinkled MXene microsphere sample was obtained.

[0062] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0063] Example 4

[0064] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0065] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0066] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0067] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 8000 r / min for 5 min. Afterwards, the treated dispersion was centrifuged at a speed of 3500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0068] (4) Preheat the spray dryer to 150°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (5 mg / mL) was added to the feed pipe. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-wrinkled MXene microsphere sample was obtained.

[0069] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0070] Example 5

[0071] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0072] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0073] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0074] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 8000 r / min for 5 min. Afterwards, the treated dispersion was centrifuged at a speed of 3500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0075] (4) Preheat the spray dryer to 150°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (10 mg / mL) was added to the feed tube. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-fold MXene microsphere sample was obtained.

[0076] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0077] Example 6

[0078] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0079] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0080] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0081] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 8000 r / min for 10 min. Afterwards, the treated dispersion was centrifuged at a speed of 3500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0082] (4) Preheat the spray dryer to 150°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (1 mg / mL) was added to the feed tube. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-fold MXene microsphere sample was obtained.

[0083] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0084] Example 7

[0085] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0086] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0087] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0088] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 8000 r / min for 15 min. Afterwards, the treated dispersion was centrifuged at a speed of 3500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0089] (4) Preheat the spray dryer to 150°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (1 mg / mL) was added to the feed tube. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-fold MXene microsphere sample was obtained.

[0090] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0091] Example 8

[0092] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0093] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0094] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0095] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 9000 r / min for 5 min. Afterwards, the treated dispersion was centrifuged at a speed of 3500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0096] (4) Preheat the spray dryer to 150°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (1 mg / mL) was added to the feed tube. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-fold MXene microsphere sample was obtained.

[0097] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0098] Example 9

[0099] The preparation method of the MXene wrinkled microsphere absorbing material of the present invention comprises the following steps:

[0100] (1) 2 g of Ti3AlC2 MAX phase powder was slowly added into a 150 mL reactor containing 2 g of LiF and 9 M HCl (40 mL), and then stirred at 55 °C and 400 rpm for 24 h to etch away the Al layer in Ti3AlC2 to generate Ti3C2T X MXene.

[0101] (2) After the etching is completed, the obtained reaction solution is transferred to a centrifuge tube, repeatedly washed with water and centrifuged, the supernatant is removed, and the precipitate is collected; the speed of each centrifugation is 3500 rpm and the time is 5 minutes, until the pH value of the supernatant is about 6.

[0102] (3) The precipitate obtained from the last centrifugation was dispersed in 60 mL of deionized water, placed in an ice bath, and ultrasonically dispersed at a power of 80 W for 30 min. The obtained dispersion was then added to a high-speed shear emulsifier at a shear rate of 10,000 r / min for 5 min. Afterwards, the treated dispersion was centrifuged at a speed of 3,500 rpm for 30 min, and the supernatant was taken to obtain a high-defect monolayer MXene dispersion.

[0103] (4) Preheat the spray dryer to 150°C and set the fan speed to 50 Hz. Then, a single-layer MXene dispersion with defects (1 mg / mL) was added to the feed tube. After the MXene dispersion at the feed end was sprayed, the heating function was turned off. After the temperature reached room temperature, a partially oxidized multi-fold MXene microsphere sample was obtained.

[0104] (5) A vector network analyzer was used to measure the performance of the above-mentioned partially oxidized multi-fold MXene microspheres (filling amount 15%) in the 2.0-18.0 GHz frequency band.

[0105] Comparative Example 1

[0106] The process is basically the same as Example 1, except that no high-speed shearing treatment is performed in step (3).

[0107] Comparative Example 2

[0108] The process is basically the same as Example 1, except that in step (4), the high-defect monolayer MXene dispersion is freeze-dried.

[0109] The scanning electron microscope (SEM) image of the sample prepared in Example 1 is as follows: Figure 1 As shown in (a) and (b), the partially oxidized multi-fold MXene microspheres successfully synthesized can be clearly shown. The X-ray diffraction (XRD) spectrum shows that the characteristic peaks of titanium dioxide appear in the prepared samples ( Figure 1 (c)) indicates that the MXene sample has been partially oxidized and the particles on the wrinkled MXene are titanium dioxide.

[0110] The sample prepared in Example 1 was mixed with paraffin wax at a mass ratio of 1:9 to prepare a coaxial ring sample with inner and outer diameters of 3 mm and 7 mm, respectively. Electromagnetic parameter testing was performed using a vector network analyzer, and the reflection loss RL value of the material was calculated using the transmission line method based on the test data, in dB. Figure 1 (d) shows the three-dimensional reflection loss diagram of partially oxidized multi-fold MXene microspheres in the frequency range of 2.0 GHz to 18.0 GHz. The test results show that at an extremely thin thickness of only 1.52 mm, the lowest reflection loss (RL min ) can reach -57.8dB, the absorption rate exceeds 99.999%, and the absorption band extends to the low frequency 3GHz (S band: 2-4GHz). This shows that the partially oxidized multi-fold MXene microspheres prepared by the present invention have excellent electromagnetic wave absorption performance.

[0111] According to the same sample preparation method as above, the samples prepared in Example 2 and Example 3 were tested for electromagnetic parameters, and the electromagnetic parameter test results were obtained. Figure 2 and Figure 3 The three-dimensional reflection loss diagram is shown. Figure 2 and Figure 3 It shows that the RL values ​​of partially oxidized multi-fold MXene microspheres prepared at spray drying temperatures of 170°C and 200°C can reach -63.3dB and -57.76dB, respectively, showing excellent electromagnetic wave absorption performance. Compared with complex magnetic particle MXene composite absorbers, this new type of partially oxidized multi-fold MXene microspheres does not require the introduction of magnetic nanomaterials. The electromagnetic parameters of the dielectric material are regulated by the morphology regulation and partial oxidation of MXene to achieve impedance matching. In addition, the electromagnetic wave absorption performance of partially oxidized multi-fold MXene microspheres can remain stable within a certain processing temperature range.

[0112] Example 4 and Example 5 are basically the same as Example 1, except that the concentrations of defective MXene are 5 and 10 mg / mL, respectively. Example 6 and Example 7 are basically the same as Example 1, except that the shearing times are 10 and 15 min, respectively. Example 8 and Example 9 are basically the same as Example 1, except that the shearing speeds are 9000 and 10000 r / min, respectively.

[0113] The electromagnetic parameters of the partially oxidized multi-fold MXene microspheres prepared in Examples 4 to 9 were tested in the same manner as above. According to the electromagnetic parameter calculation results ( Figures 4 to 9 ), it is found that the minimum reflection loss of the partially oxidized multi-fold MXene microsphere material in Examples 4 and 5 can reach -60.27 and -52.4 dB, respectively, the minimum reflection loss of the partially oxidized multi-fold MXene microsphere material in Examples 6 and 7 can reach -50.07 and -57.08 dB, respectively, and the minimum reflection loss of the partially oxidized multi-fold MXene microsphere material in Examples 8 and 9 can reach -58.52 and -50.99 dB, respectively. By comparing Examples 4 to 9, it can be seen that the present invention can effectively control the wave absorption performance of the MXene material by controlling the shear rate, shear time and concentration of the raw materials.

[0114] Fig.10 (a) and (b) are SEM images of the product prepared in Comparative Example 1. As shown in the figure, there are no obvious nanoparticles on the surface of MXene, and the surface is relatively smooth, without showing the morphological characteristics of nanoparticles on the surface of the MXene material prepared in Example 1. Fig.10 (c) is the XRD spectrum of MXene without high-speed shear treatment. No obvious characteristic diffraction peak of titanium dioxide is observed, indicating that it is difficult to form defects without high-speed shear treatment, and therefore partially oxidized MXene materials cannot be effectively obtained in the subsequent spray drying process. Fig.10(d) is the Zeta potential test result of MXene without high-speed shear treatment (no defects) and MXene with high-speed shear treatment (containing defects), the Zeta potential values ​​are -29.3 and -44.5 eV respectively. The Zeta potential results show that the introduction of defects through high-speed shear treatment is conducive to increasing the electrostatic repulsion between the sheets and inhibiting the agglomeration of MXene. It is proved that the introduction of defects during the high-speed shear process in the embodiment of the present invention will promote the subsequent generation of partially oxidized MXene wrinkled microspheres with nanoparticles on the surface. According to the same method as above, the electromagnetic parameters of the MXene without nanoparticles on the surface of Comparative Example 1 were tested, Fig.10 (e) shows that its minimum reflection loss is only -6.38 dB, which further verifies that the partially oxidized MXene wrinkled microspheres with nanoparticles on the surface have excellent microwave absorption properties.

[0115] Fig.11 (a) is a SEM image of the product prepared in comparative example 2. As shown in the figure, MXene shows the morphological characteristics of nanosheets, and does not have the morphological characteristics of the wrinkled microspheres of the MXene material prepared in Example 1. It proves that in the spray drying stage of the embodiment of the present invention, MXene will deform and shrink into microspheres. According to the same method as above, the electromagnetic parameter test of the MXene material of comparative example 2 is carried out. Fig.11 (b) shows that its minimum reflection loss is only -4.51 dB, which further verifies the structural advantages and excellent wave absorption properties of the partially oxidized MXene wrinkled microspheres with nanoparticles on the surface.

Claims

1. A method for preparing a partially oxidized MXene wrinkled microsphere material, characterized in that: The following steps are involved: S1, for Ti3C2T X The MXene dispersion is sheared and then centrifuged to obtain a supernatant to obtain a MXene dispersion with defects; S2, spray drying the defective MXene dispersion obtained in S1 to obtain a partially oxidized MXene wrinkled microsphere material.

2. The method for preparing the partially oxidized MXene wrinkled microsphere material according to claim 1, characterized in that: In S1, the Ti3C2T X The preparation method of MXene dispersion is as follows: Ti3AlC2 MAX phase powder is added to a mixed solution of LiF and HCl, and the mixture is stirred and etched. After the etching is completed, the reaction solution is centrifuged and washed, and the precipitate is collected and dispersed in water, and ultrasonicated to obtain Ti3C2T X MXene dispersion.

3. The method for preparing the partially oxidized MXene wrinkled microsphere material according to claim 1, characterized in that: In S1, the shearing speed is 8000 to 10000 r / min, and the shearing treatment time is 5 to 15 min.

4. The method for preparing the partially oxidized MXene wrinkled microsphere material according to claim 1, characterized in that: In S2, the spray drying temperature is 150 to 200°C.

5. The method for preparing the partially oxidized MXene wrinkled microsphere material according to claim 1, characterized in that: In S2, the concentration of the defective MXene dispersion is 1 to 10 mg / mL.

6. The partially oxidized MXene wrinkled microsphere material obtained by the preparation method according to any one of claims 1 to 5, characterized in that: The material has the morphology of wrinkled microspheres.

7. The partially oxidized MXene wrinkled microsphere material according to claim 6, characterized in that: The surface of the material is modified with titanium dioxide nanoparticles.

8. The partially oxidized MXene wrinkled microsphere material according to claim 6, characterized in that: The electromagnetic wave absorption frequency band of the material is in the range of 3.0 to 18.0 GHz.

9. The partially oxidized MXene wrinkled microsphere material according to claim 6, characterized in that: The RL value of the material is -63.3 to -50.07 dB.

10. Use of the partially oxidized MXene wrinkled microsphere material according to claim 6 as an absorbing material in electromagnetic wave absorption.

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