Composite high-frequency electromagnetic wave absorbing material, preparation method and application thereof

Abstract

The application belongs to the technical field of wave-absorbing materials, and particularly relates to a multilayer composite high-frequency electromagnetic absorbing material and a preparation method and application thereof. The multilayer composite material comprises, from inside to outside, a two-dimensional layered material for electric conduction loss, a flaky material for interface polarization loss, and a flaky material for magnetic loss, which respectively play different electromagnetic loss effects. Meanwhile, the materials are all flaky, and are connected by in-situ polymerization and electrostatic self-assembly, and meanwhile, an ordered layered stacking structure is constructed, a multiple absorbing wall and a reflecting wall are formed, and electromagnetic waves are effectively absorbed.

Description

Technical Field

[0001] This invention belongs to the field of microwave absorbing materials technology, and specifically relates to a composite high-frequency electromagnetic absorbing material, its preparation method, and its application. Background Technology

[0002] With the rapid development of the communications industry, information transmission rates are increasing faster and transmission capacity is growing larger, leading to higher frequencies of electromagnetic waves being used. Core operating frequencies are rapidly moving into the centimeter-wave and even millimeter-wave bands. Higher frequency electromagnetic waves pose greater risks to the human body and cause stronger interference between signals. However, the electromagnetic parameters of most materials attenuate significantly with increasing frequency, resulting in poor high-frequency absorption performance that fails to meet current technological requirements, necessitating composite processes. Conventional composite methods often require complex processes and final high-temperature treatments to improve performance, hindering large-scale production. Summary of the Invention

[0003] The present invention aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial solution. Specifically, the present invention provides a composite high-frequency electromagnetic absorbing material that can exhibit good electromagnetic wave absorption performance in the high-frequency band (15-18GHz).

[0004] The inventive concept of this invention: The composite material of this invention comprises, from the inside out, a two-dimensional layered material with dielectric loss, a spherical material with interfacial polarization loss, and a rod-shaped material with magnetic loss, each playing a different role in electromagnetic loss. At the same time, the selected materials are all layered, and strong connections are formed between the materials through in-situ polymerization and electrostatic self-assembly. This constructs an ordered layered stacking structure, forming multiple absorption walls and reflection walls, thereby effectively absorbing electromagnetic waves.

[0005] Therefore, a first aspect of the present invention provides a composite sheet electromagnetic absorbing material.

[0006] Specifically, the multilayer composite material comprises, from the inside out, a two-dimensional layered material with conductive loss, a sheet-like material with interfacial polarization loss, and a sheet-like material with magnetic loss.

[0007] The two-dimensional layered material for conductive loss is MXene or graphene.

[0008] The sheet material for the interfacial polarization loss is a transition metal sulfide.

[0009] The sheet material for magnetic loss is a layered double hydroxide (LDH).

[0010] Preferably, the MXene material comprises Ti3C2T x MXene.

[0011] Preferably, the transition metal sulfide includes rhenium disulfide (ReS2).

[0012] Preferably, the metal element in the layered double hydroxide includes at least one of iron, cobalt, and nickel.

[0013] More preferably, the metal element in the layered double hydroxide includes three of the following: iron, cobalt, and nickel.

[0014] A second aspect of the present invention provides a method for preparing a composite sheet electromagnetic absorbing material.

[0015] Specifically, the preparation method of the multilayer composite high-frequency electromagnetic absorbing material is characterized by comprising the following steps: (1) Add ammonium perrhenate, hydroxylamine hydrochloride and thiourea to water in a certain proportion and dissolve by ultrasonication. Add the ultrasonically dispersed MXene dispersion solution, carry out hydrothermal reaction, filter, wash with water and ethanol alternately, and dry to obtain MXene-ReS2. (2) Urea and metal ion nitrate are mixed and dissolved in an aqueous solution, and a hydrothermal reaction is carried out. After filtration, the mixture is washed with water and ethanol alternately and then dried to obtain LDH. (3) Add LDH and MXene-ReS2 to water and mix and stir to obtain the multilayer composite electromagnetic absorbing material MXene-ReS2-LDH.

[0016] Preferably, the ratio of ammonium perrhenate, hydroxylamine hydrochloride, and thiourea is 1:20:15.

[0017] Preferably, the hydrothermal method is performed at a temperature of 160-200℃ for 24-72 hours.

[0018] More preferably, the hydrothermal method is performed at a temperature of 180°C for 24 hours.

[0019] The concentration of the metal ions is 0.01-0.1M.

[0020] More preferably, the concentration of the metal ions is 0.02M.

[0021] Preferably, the hydrothermal method is performed at a temperature of 120-150℃ for 24-72 hours.

[0022] More preferably, the hydrothermal method is performed at a temperature of 120°C for 24 hours.

[0023] Preferably, the urea:metal ion (molar ratio) is ≥4:1.

[0024] More preferably, the urea:metal ion (molar ratio) is 4:1.

[0025] Preferably, the stirring time is ≥6h.

[0026] More preferably, the stirring time is 12 hours.

[0027] Preferably, the mass ratio of LDH to MXene-ReS2 is 1:1-10.

[0028] A third aspect of the present invention provides a wave-absorbing device.

[0029] Specifically, the wave-absorbing device comprises the multilayer composite electromagnetic absorbing material described in the first aspect of this invention.

[0030] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows: (1) This invention achieves effective loss of high-frequency electromagnetic waves by organically combining materials with different loss mechanisms; (2) This invention organically combines materials with the same layered structure to form an ordered composite layered material, which greatly improves the wave absorption performance of the material; (3) The present invention can achieve the preparation of materials through a simple hydrothermal method and stirring process. The process is simple, does not require high temperature and high pressure, is convenient for pilot and scale-up production, and is easy to promote and apply in industrial applications. (4) The present invention ultimately achieved an effective absorption of -52.2dB at 17GHz, with an effective absorption bandwidth of 3.2GHz. Attached Figure Description

[0031] Figure 1 The images show scanning electron microscope (SEM) images and absorption performance diagrams of the MXene-ReS2-LDH prepared in Example 1 of this invention. Figure 2 This is a scanning electron microscope image of the MXene prepared in Comparative Example 1 of the present invention; Figure 3 This is a scanning electron microscope image of ReS2 prepared in Comparative Example 2 of the present invention; Figure 4 This is a scanning electron microscope image of the LDH prepared in Comparative Example 3 of the present invention; Figure 5 This is a scanning electron microscope image of MXene-ReS2 prepared in Comparative Example 4 of this invention; Figure 6 The image shows the microwave absorption performance of the MXene-ReS2-LDH prepared in Example 1 of this invention. Figure 7 The image shows the microwave absorption performance of the MXene prepared in Comparative Example 1 of this invention. Figure 8 The image shows the microwave absorption performance of ReS2 prepared in Comparative Example 2 of this invention. Figure 9The image shows the microwave absorption performance of the LDH prepared in Comparative Example 3 of this invention. Figure 10 The image shows the microwave absorption performance of MXene-ReS2 prepared in Comparative Example 4 of this invention. Figure 11 The image shows the microwave absorption performance of the blended MXene-ReS2-LDH prepared in Comparative Example 5 of this invention. Detailed Implementation

[0032] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0033] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0034] Example 1 This embodiment provides a multilayer composite high-frequency electromagnetic absorption material, which consists of, from the inside out, a two-dimensional layered material ReS2 with conductive loss, a sheet-like material ReS2 with interface polarization loss, and a sheet-like material LDH with magnetic loss. This embodiment also provides a method for preparing the above-mentioned multilayer composite high-frequency electromagnetic absorption material, the specific steps of which are as follows: (1) Ammonium perrhenate, hydroxylamine hydrochloride and thiourea were added to water in a molar ratio of 1:20:15 and dissolved by ultrasonication. The ultrasonically dispersed MXene dispersion solution was added and subjected to hydrothermal reaction at 180℃ for 24h. After filtration, the mixture was washed alternately with water and ethanol and then dried to obtain MXene-ReS2. (2) Urea and metal ion nitrate were mixed and dissolved in an aqueous solution. The molar ratio of urea to metal ion was 4:1, Fe³⁺:Co²⁺:Ni²⁺ was 1:1:2, and the concentration of metal ion was 0.02M. The mixture was subjected to a hydrothermal reaction, filtered, washed alternately with water and ethanol, and dried to obtain LDH. (3) Add LDH and MXene-ReS2 to water and mix. Stir for 12 hours to obtain the multilayer composite electromagnetic absorbing material MXene-ReS2-LDH.

[0035] The theoretical mass ratio of the three components is MXene:ReS2:LDH = 1:2:1 Comparative Example 1 Comparative Example 1 provides a microwave absorbing material, denoted as Ti3C2T. x It is available for sale in the market.

[0036] Comparative Example 2 Comparative Example 2 provides a microwave absorbing material, denoted as ReS2.

[0037] The specific steps are: Ammonium perrhenate, hydroxylamine hydrochloride and thiourea are added into water at a molar ratio of 1:20:15, dissolved by ultrasonication, and subjected to a hydrothermal reaction at 180°C for 24h, followed by suction filtration, alternate washing with water and ethanol, and drying to obtain ReS2.

[0038] Comparative Example 3 Comparative Example 3 provides a wave-absorbing material, denoted as LDH.

[0039] The specific steps are: Urea and metal ion nitrates are mixed and dissolved in an aqueous solution, wherein urea : metal ions (molar ratio) = 4:1, Fe³⁺:Co²⁺:Ni²⁺=1:1:2, and the concentration of metal ions is 0.02M; a hydrothermal reaction is carried out, followed by suction filtration, alternate washing with water and ethanol, and drying to obtain LDH.

[0040] Comparative Example 4 Comparative Example 4 provides a wave-absorbing material, denoted as MXene-ReS2.

[0041] The specific steps are: Ammonium perrhenate, hydroxylamine hydrochloride and thiourea are added into water at a molar ratio of 1:20:15, dissolved by ultrasonication, then an ultrasonically dispersed MXene dispersion solution is added, and a hydrothermal reaction is carried out at 180°C for 24h, followed by suction filtration, alternate washing with water and ethanol, and drying to obtain MXene-ReS2.

[0042] Comparative Example 5 Comparative Example 5 provides a wave-absorbing material, denoted as blended MXene-ReS2-LDH.

[0043] The specific steps are: MXene, ReS2 and LDH are dispersed in an aqueous solution according to the ratio in Example 1, and stirred for 12h to obtain blended MXene-ReS2-LDH.

[0044] Performance Testing 1. Morphology test (scanning electron microscope) It can be seen from Figure 1 that MXene-ReS2-LDH is lamellar Ti3C2T x Spherical and rod-shaped particles are wrapped on the surface and between layers of the material. It can be seen from Figure 2 that MXene has a layered accordion structure. It can be seen from Figure 3 that ReS2 has a spherical structure with a size of 100-200 nm. Upon magnification, it can be seen that it is essentially formed by accumulation of acicular structures, has a huge specific surface area, and can provide rich polarization relaxation loss. It can be seen from Figure 4It can be seen that LDH has a rod-like structure approximately 300 nm long and 30 nm wide. (From...) Figure 5 It can be seen that MXene-ReS2 is a layered accordion structure encapsulating a spherical structure.

[0045] Therefore, three structures with different morphologies were successfully prepared.

[0046] 2. Absorption performance test The microwave absorption performance of the composite sheet electromagnetic absorbing material of Example 1 and the microwave absorbing materials of Comparative Examples 1-5 was tested. The specific test process is as follows: The electromagnetic parameters of the samples were tested using a vector network analyzer (Keysight E5080B, Agilent Technologies, USA) and the electromagnetic parameters of the samples in the 1-18 GHz range were tested using the coaxial transmission line method.

[0047] The preparation process of the test samples is as follows: The composite sheet electromagnetic absorbing material of Example 1 and the microwave absorbing materials of Comparative Examples 1-5 are respectively mixed with solid paraffin wax, wherein the filling amount of the microwave absorbing material is 40wt%. After heating at 60°C, the mixture is uniformly mixed, and after cooling, the mixture is placed in a mold and pressed into a coaxial ring with an outer diameter of 7.0mm, an inner diameter of 3.04mm, and a thickness of 2-5mm using a hydraulic press under a pressure of 5MPa.

[0048] Before testing, the measurement system was calibrated using calibration kits, and the test frequency range was set to 1-18 GHz. Finally, the reflection loss of the sample at different thicknesses was calculated based on the dielectric constant (ε) and magnetic permeability (μ).

[0049] Figure 6 As can be seen, the composite electromagnetic absorbing material MXene-ReS2-LDH in Example 1 can achieve effective absorption in the 14.8-18GHz frequency band, with an effective absorption bandwidth of 3.2GHz and a minimum reflection loss of -52.2dB at 16.4GHz, corresponding to a thickness of 6.0mm. This indicates that the composite electromagnetic absorbing material of the present invention has excellent electromagnetic wave absorption performance.

[0050] Depend on Figure 7 It can be seen that the minimum reflection loss of the absorbing material MXene in Comparative Example 1 is only RL. min =-2.9dB, effective absorption width is 0. This is due to excessive conductivity and impedance mismatch, indicating that the electromagnetic absorption performance of the absorbing material in Comparative Example 1 is significantly worse than that in the Example.

[0051] Depend on Figure 8 It can be seen that the minimum reflection loss of the absorbing material ReS2 in Comparative Example 2 at 15.0 GHz is RL. min =-26.8dB. This indicates that it has high-frequency anti-attenuation capability, but its performance is far lower than that of the example.

[0052] Depend on Figure 9 It can be seen that the minimum reflection loss of the absorbing material LDH in Comparative Example 3 at 9.2 GHz is RL. min =-5.7dB. The effective absorption width is 0. This is due to excessively weak electrical losses, resulting in very poor performance, far below that of the example.

[0053] Depend on Figure 10 It can be seen that the minimum reflection loss of the absorbing material MXene-ReS2 in Comparative Example 4 at 15.8 GHz is RL. min =-27.3dB. This indicates that it has high-frequency anti-attenuation capability, similar to ReS2, but its performance is far lower than that of the example.

[0054] Depend on Figure 11 It can be seen that the minimum reflection loss of MXene-ReS2-LDH, a blend of absorbing materials in Comparative Example 5, at 10.8 GHz is RL. min =-49.4dB. This indicates that although it has strong absorption performance, it lacks a reasonable structure and cannot achieve high-frequency absorption.

[0055] In summary, this invention uses multiple composite structural materials to construct an electromagnetic wave absorbing wall, and utilizes the multiple composite structure to achieve high frequency and high absorption.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A composite high-frequency electromagnetic absorbing material, characterized in that, The composite material comprises, from the inside out, a two-dimensional layered material with conductive loss, a spherical material with interfacial polarization loss, and a rod-shaped material with magnetic loss. The two-dimensional layered material for conductive loss is MXene or graphene. The spherical material for the interfacial polarization loss is a transition metal sulfide. The rod-shaped material with magnetic loss is a double hydroxide compound LDH.

2. The composite high-frequency electromagnetic absorbing material according to claim 1, characterized in that, The MXene material includes Ti3C2T. x MXene.

3. The composite high-frequency electromagnetic absorbing material according to claim 1, characterized in that, The transition metal sulfides include rhenium disulfide (ReS2).

4. The composite high-frequency absorbing material according to claim 3, characterized in that, The metallic element in the bis(hydroxide) compound includes at least one of iron, cobalt, and nickel.

5. The method for preparing the composite high-frequency electromagnetic absorbing material according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) Add ammonium perrhenate, hydroxylamine hydrochloride and thiourea to water in a certain proportion and dissolve by ultrasonication. Add the ultrasonically dispersed MXene dispersion solution, carry out hydrothermal reaction, filter, wash with water and ethanol alternately, and dry to obtain MXene-ReS2. (2) Urea and metal ion nitrate are mixed and dissolved in an aqueous solution, and a hydrothermal reaction is carried out. After filtration, the mixture is washed with water and ethanol alternately and then dried to obtain LDH. (3) Add LDH and MXene-ReS2 to water and mix and stir to obtain the multilayer composite electromagnetic absorbing material MXene-ReS2-LDH.

6. The preparation method according to claim 5, characterized in that, In step (1), the ratio of ammonium perrhenate, hydroxylamine hydrochloride, and thiourea is 1:20:

15. And / or, the hydrothermal method is performed at a temperature of 160-200℃ for a time of 24-72 hours.

7. The preparation method according to claim 5, characterized in that, In step (2), the concentration of the metal ions is 0.01-0.1M; And / or, the hydrothermal method is performed at a temperature of 120-150℃ for a time of 24-72 hours; And / or, the urea:metal ion (molar ratio) is ≥4:

1.

8. The preparation method according to claim 5, characterized in that, In step (3), the stirring time is ≥6h; And / or, the mass ratio of LDH to MXene-ReS2 is 1:1-10.

9. A wave-absorbing device, characterized in that, The microwave absorbing device comprises the composite sheet electromagnetic absorbing material as described in any one of claims 1-4.

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