Magnetic-electric double-gradient electromagnetic shielding material and preparation method and application thereof

Abstract

The invention belongs to the field of new materials, and discloses a magnetic-electric double-gradient electromagnetic shielding material and a preparation method and application thereof.The preparation method comprises the steps that cobalt ferrite nanoparticles are synthesized on carbon nanotubes, and ZxCoFe2O4-coated CNT composite particles are obtained; the preparation method comprises the following steps: carrying out protonation treatment on an ANF / DMSO (Dimethylsulfoxide) dispersion liquid by utilizing a ZxCoFe2O4-coated CNT composite particle aqueous dispersion liquid, so as to obtain ZxCoFe2O4-coated CNT / ANF; carrying out protonation treatment on the ANF / DMSO dispersion liquid by utilizing the CNT aqueous dispersion liquid to obtain CNT / ANF; the ZxCoFe2O4 (at) CNT / ANF, the PMXene nanosheet and the CNT / ANF are subjected to stacked assembly, suction filtration treatment and vacuum drying, and the magnetic-electric double gradient type electromagnetic shielding material is obtained. According to the invention, a multi-layer magnetic-electric bicontinuous gradient structure is constructed in an ANF matrix, so that low reflection and high shielding of electromagnetic waves are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, relates to the field of electromagnetic shielding materials, and particularly relates to a magnetic-electric dual gradient electromagnetic shielding material and a preparation method and application thereof. Background Art

[0002] With the rapid development of wireless communication technology, the growing electromagnetic wave radiation has been identified as the fourth largest source of environmental pollution, and it has become an invisible killer of human health and equipment safety. Driven by the miniaturization and integration of electronic devices, electromagnetic interference shielding materials have developed from traditional metals to flexible polymer-based composite materials. Among them, a series of conductive fillers are assembled inside or on the surface of the polymer to achieve excellent electromagnetic interference shielding performance. However, since existing electromagnetic interference shielding composite materials often have high conductivity, there is a serious impedance mismatch between the composite material and the free space, resulting in a shielding mechanism dominated by reflection, so that the incident electromagnetic waves are reflected back to the free space in large quantities. This secondary radiation further aggravates the environmental pollution of electromagnetic interference.

[0003] In order to solve the above problems, researchers gradually introduced magnetic materials such as cobalt ferrite and alloys into the shield to absorb electromagnetic waves through magnetic loss to reduce secondary reflections. However, existing studies usually mix magnetic components with conductive components. The simple blending structure allows the material to only exert limited internal multiple reflections and multi-wave interference. Although the reflection coefficient (R) is reduced, it is impossible to obtain a higher shielding effectiveness (SE). total ); Secondly, low-reflection, high-performance shielding materials made of porous structures such as aerogels and foams cannot meet the requirements of miniaturization, flexibility and good mechanical properties in practical applications. Therefore, it is urgent to prepare advanced low-reflection and high-performance electromagnetic interference shielding materials. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a magnetic-electric dual gradient electromagnetic shielding material and a preparation method and application thereof, so as to solve the technical problems that the existing simple blending structure of magnetic components and conductive components makes the material only able to exert limited internal multiple reflections and multi-wave interference. Although the reflection coefficient is reduced, a higher shielding effectiveness cannot be obtained, and in practical applications, the requirements of miniaturization, flexibility and good mechanical properties cannot be met.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising: Cobalt ferrite nanoparticles were synthesized on carbon nanotubes by solvothermal method to obtain Z x CoFe2O4@CNT composite particles; among them, Z xis the mass fraction of CoFe2O4 compared to CNT, x =1, 2, or 3; MXene nanosheets were modified with polydopamine to obtain PMXene nanosheets; Using Z x CoFe2O4@CNT composite particles were prepared to obtain ZCoFe2O4@CNT composite particle aqueous dispersion; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; Using CNT aqueous dispersion to perform protonation treatment on ANF / DMSO dispersion to obtain CNT / ANF; Z x CoFe2O4@CNT / ANF, PMXene nanosheets and CNT / ANF were stacked and assembled, and then filtered to obtain Z x CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel; Z x The CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel is vacuum dried to obtain a magnetic-electric dual gradient electromagnetic shielding material.

[0006] Furthermore, the mass fraction of CoFe2O4 compared to CNT satisfies: 10wt.%≤Z x ≤80wt.%.

[0007] Furthermore, cobalt ferrite nanoparticles were synthesized on carbon nanotubes by solvothermal method to obtain Z x The process of CoFe2O4@CNT composite particles includes: Mix anhydrous sodium acetate, polyethylene glycol and ethylene glycol, and stir until completely dissolved to obtain a mixed solution; Adding ferric chloride hexahydrate and cobalt dichloride hexahydrate to the mixed solution, and continuing to stir until dissolved; then adding CNT, and transferring to a reaction kettle after ultrasonic treatment, and reacting under heating conditions to obtain a reaction product; The reaction product is washed to neutrality and freeze-dried to obtain Z x CoFe2O4@CNT composite particles.

[0008] Furthermore, the process of modifying MXene nanosheets with polydopamine to obtain PMXene nanosheets includes: The polydopamine solution is added to the MXene nanosheet dispersion, and the mixture is stirred to react to obtain PMXene nanosheets.

[0009] Furthermore, using Z x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x During the process of CoFe2O4@CNT / ANF, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 30-80wt.%.

[0010] Furthermore, the ANF / DMSO dispersion was subjected to protonation reduction treatment using the CNT aqueous dispersion to obtain CNT / ANF, in which the mass fraction of CNT compared to ANF was 0.5-3wt.%.

[0011] Furthermore, for Z x CoFe2O4@CNT / ANF, PMXene nanosheets and CNT / ANF were stacked and assembled, and then filtered to obtain Z x The process of CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel includes: Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene were sequentially stacked and filtered; wherein Z1>Z2>Z3; then, the CNT / ANF dispersion was used as a sealing layer and superimposed and filtered to obtain the (Z1-Z2-Z3) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, namely Z x CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel.

[0012] Furthermore, for Z x During the vacuum drying process of the CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, the drying temperature is 60-120°C and the drying time is 30-120min.

[0013] The present invention also provides a magnetic-electric dual gradient electromagnetic shielding material, which is prepared by using the preparation method of the magnetic-electric dual gradient electromagnetic shielding material.

[0014] The present invention also provides an application of a magnetic-electric dual gradient electromagnetic shielding material, wherein the magnetic-electric dual gradient electromagnetic shielding material is applied to electromagnetic shielding, electronic packaging, flexible wearables and safety protection.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The preparation method of the magnetic-electric dual gradient electromagnetic shielding material provided by the present invention utilizes magnetic CoFe2O4, conductive CNT and PMXene to construct a multilayer magnetic-electric dual continuous gradient structure in an ANF matrix, thereby achieving low reflection and high shielding of electromagnetic waves; specifically, CoFe2O4 is synthesized on CNT to obtain strong magnetic and weak conductive CoFe2O4@CNT composite particles, and a gradient shielding structure in which absorption gradually weakens and reflection gradually increases along the incident direction of the electromagnetic wave is constructed by regulating the mass ratio of CoFe2O4 and CNT in the ANF, thereby significantly reducing the secondary reflection of the electromagnetic wave on the surface of the material; secondly, PMXene modified with PDA is used as a strong reflection layer to form an "absorption-reflection-reabsorption" shielding mechanism together with CoFe2O4@CNT, thereby significantly improving the electromagnetic shielding effectiveness SE of the composite film. total ; Thirdly, CNT-reinforced ANF as an independent substrate not only provides good mechanical support, but also serves as a protective layer to prevent PMXene from oxidative failure, which is beneficial to promoting the environmental stability of the CoC / A-PM-C / A dual-gradient structure composite film. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the conductivity curve of a single ZCoFe2O4@CNT / ANF film in Example 1; Figure 2 Schematic diagram of the hysteresis loop of a single ZCoFe2O4@CNT / ANF film in Example 1; Figure 3 Schematic diagram of the conductivity curve of MXene nanosheets before and after modification in Example 1; Figure 4 The cross-sectional SEM image and EDS element distribution image of the magnetic-electric dual gradient electromagnetic shielding material prepared in Example 1; Figure 5 This is an infrared camouflage performance test image of the magnetic-electric dual gradient electromagnetic shielding material prepared in Example 1. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] The present invention provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising the following steps: Step 1: Using a solvothermal method, cobalt ferrite nanoparticles are synthesized on carbon nanotubes to obtain Z x CoFe2O4@CNT composite particles; among them, Z xis the mass fraction of CoFe2O4 compared to CNT, x = 1, 2 or 3; Specifically, prepare Z x The process of CoFe2O4@CNT composite particles is as follows: Anhydrous sodium acetate (NaAc) and polyethylene glycol (PEG-4000) are added to ethylene glycol (EG) and mixed, and stirred until completely dissolved to obtain a mixed solution; Hexahydrate ferric chloride and hexahydrate cobalt dichloride are added to the mixed solution, and stirred until dissolved; then, CNT is added, and after ultrasonic treatment, it is transferred to a reactor and reacted under heating conditions to obtain a reaction product; the reaction product is washed to neutrality, and Z is obtained after freeze-drying. x CoFe2O4@CNT composite particles; wherein the mass fraction of CoFe2O4 compared to CNT satisfies: 10wt.%≤Z x ≤80wt.%.

[0019] Step 2: Prepare a fluorine-containing solution to selectively etch the MAX precursor to prepare Ti3C2T x MXene (MXene for short) nanosheets; MXene nanosheets are modified with polydopamine to obtain PMXene nanosheets.

[0020] Step 3: Prepare aramid nanofibers (ANF) by chemical splitting method; specifically, potassium hydroxide (KOH) and para-aramid staple fibers (PPTA) are sequentially added to dimethyl sulfoxide (DMSO), and stirred continuously to obtain an ANF / DMSO dispersion.

[0021] Step 4: Use Z x CoFe2O4@CNT composite particles were prepared to obtain ZCoFe2O4@CNT composite particle aqueous dispersion; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; among them, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 30-80wt.%.

[0022] Step 5: Use the CNT aqueous dispersion to perform protonation treatment on the ANF / DMSO dispersion to obtain CNT / ANF; wherein the mass fraction of CNT compared to ANF is 0.5-3wt.%.

[0023] Step 6: Z x CoFe2O4@CNT / ANF, PMXene nanosheets and CNT / ANF were stacked and assembled, and then filtered to obtain Z xCoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel; specifically, Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene are sequentially stacked and filtered; wherein Z1>Z2>Z3; subsequently, the CNT / ANF dispersion is used as a sealing layer, and the (Z1-Z2-Z3) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel is obtained, that is, Z x CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel.

[0024] Step 7: Z x The CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel is vacuum dried to obtain a magnetic-electric dual gradient electromagnetic shielding material; wherein the drying temperature is 60-120°C and the drying time is 30-120min.

[0025] Preparation principle: The preparation method of the magnetic-electric dual gradient electromagnetic shielding material disclosed in the present invention is based on a layer-by-layer assembly method, and introduces a forward absorption strategy, a reverse reflection strategy and a magnetic-electric dual continuous gradient structure strategy, and uses magnetic CoFe2O4, conductive CNT, MXene and ANF matrix to prepare a magnetic-electric dual gradient electromagnetic shielding material. Specifically, CoFe2O4 is synthesized on CNT to obtain CoFe2O4@CNT composite particles with strong magnetic and weak conductive properties; a gradient shielding structure in which absorption gradually weakens and reflection gradually increases along the incident direction of electromagnetic waves is constructed by regulating the mass ratio of CoFe2O4 and CNT in ANF, thereby significantly reducing the secondary reflection of electromagnetic waves on the surface of the material; PMXene modified by PDA is used as a strong reflection layer to form an "absorption-reflection-reabsorption" shielding mechanism together with CoFe2O4@CNT, thereby significantly improving the electromagnetic shielding effectiveness SE of the composite film. total ; CNT-reinforced ANF as an independent substrate not only provides good mechanical support, but also serves as a protective layer to prevent PMXene from oxidative failure, which is beneficial to promoting the environmental stability of the CoC / A-PM-C / A dual-gradient structure composite film.

[0026] In the present invention, magnetic particles are introduced to adjust the impedance matching between the material surface and the air, so that electromagnetic waves can smoothly enter the material and reduce secondary reflection; secondly, the multilayer structure not only provides an effective magnetic-electric dual gradient distribution, but also effectively extends the transmission path of electromagnetic waves; in addition, the low mid-infrared emissivity of MXene and CNT makes the composite film exhibit excellent infrared camouflage performance; overall, compared with homogeneous structure and porous structure materials, the magnetic-electric dual gradient electromagnetic shielding material based on layer-by-layer assembly in the present invention has the characteristics of light weight, flexibility and high strength. On the one hand, it can significantly reduce the reflection coefficient R, and on the other hand, it can obtain excellent electromagnetic shielding effectiveness SE total The magnetic-electric dual gradient electromagnetic shielding material can be applied to electromagnetic shielding, electronic packaging, flexible wearables, safety protection and other fields.

[0027] Example 1 This embodiment 1 provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising the following steps: Step 1: Add 3.6 g of anhydrous sodium acetate (NaAc) and 2.0 g of polyethylene glycol (PEG-4000) to 40 mL of ethylene glycol (EG) solvent and stir until completely dissolved; then, add 0.54 g of ferric chloride hexahydrate (FeCl3·6H2O) and 0.24 g of cobalt dichloride hexahydrate (CoCl2·6H2O) and continue stirring until dissolved; then, add CNT and ultrasonicate in a water bath at 180 W for 1 h; after ultrasonication, transfer the mixture to an autoclave and heat it continuously at 180 ° C for 16 h; finally, wash the reaction product to neutrality and obtain Z after freeze-drying. x CoFe2O4@CNT composite particles; among them, Z x is the mass fraction of CoFe2O4 compared to CNT, x =1, 2 or 3; specifically, Z x The CoFe2O4@CNT composite particles include Z1CoFe2O4@CNT, Z2CoFe2O4@CNT and Z3CoFe2O4@CNT, and Z1 is 80wt.%, Z2 is 40wt.%, and Z3 is 10wt.%.

[0028] Step 2: Prepare 60 mL of 9 mol / L hydrochloric acid solution, add 4.8 g of lithium fluoride (LiF) and stir thoroughly until completely dissolved to prepare a fluorine-containing solution; then slowly add 3 g of MAX precursor to the fluorine-containing solution, and stir and etch the entire system at 35 °C for 48 h; then wash until neutral, ultrasonicate at 180 W for 1 h, and then centrifuge at 3500 rpm for 1 h, collect the supernatant to obtain a MXene nanosheet dispersion; then, adjust the mass fraction of the MXene nanosheet dispersion to 0.2 wt.%, slowly add the prepared PDA solution to the MXene nanosheet dispersion, and stir the reaction for 60 min to obtain a PMXene nanosheet dispersion; wherein the mass fraction of PDA compared to MXene is 4 wt.%.

[0029] Step 3: 1.5 g of potassium hydroxide (KOH) and 1.0 g of para-aramid short fibers (PPTA) are sequentially added to 499.0 g of dimethyl sulfoxide (DMSO) solvent, and stirred continuously to prepare an ANF / DMSO dispersion.

[0030] Step 4: Use Z x CoFe2O4@CNT composite particles were prepared to obtain a ZCoFe2O4@CNT composite particle aqueous dispersion with a mass fraction of 0.2wt.%; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; among them, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 75wt.%.

[0031] Step 5, preparing a CNT aqueous dispersion with a mass fraction of 0.2 wt.%; using the CNT aqueous dispersion to perform protonation treatment on the ANF / DMSO dispersion to obtain CNT / ANF; wherein the mass fraction of CNT compared to ANF is 1 wt.%.

[0032] Step 6. Stack and filter Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene in sequence; use the CNT / ANF dispersion as a sealing layer, stack and filter to obtain (80-40-10) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, named (80-40-10) CoC / A-PM-C / A composite gel.

[0033] Step 7: vacuum dry the (80-40-10) CoC / A-PM-C / A composite gel at 110°C for 30 minutes to obtain a (80-40-10) CoC / A-PM-C / A magnetic-electric dual gradient composite film, that is, a magnetic-electric dual gradient electromagnetic shielding material.

[0034] Performance testing: The (80-40-10) CoC / A-PM-C / A magnetic-electric dual gradient composite film prepared in Example 1 was subjected to performance testing, and the test results were as follows: the electromagnetic shielding effectiveness of the (80-40-10) CoC / A-PM-C / A composite film was 62.6 dB, the reflection coefficient R was reduced to 0.62, the tensile strength was 51.2 MPa, and the infrared emissivity in the range of 7-17 μm was 2.61%; the results showed that the composite film exhibited excellent electromagnetic shielding effectiveness and effectively reduced the reflection of electromagnetic waves; at the same time, the composite film had good mechanical properties and extremely low mid-infrared emissivity, showing excellent infrared camouflage performance.

[0035] As attached Figure 1-2 As shown, attached Figure 1 The conductivity curve of a single ZCoFe2O4@CNT / ANF film in Example 1 is shown in FIG. Figure 2 A schematic diagram of the hysteresis loop of a single ZCoFe2O4@CNT / ANF film is given in the figure. Figure 1-2 It can be seen that with the increase of CoFe2O4 content compared to CNT, the electrical conductivity of the corresponding film gradually decreases; on the contrary, the hysteresis loop shows that the magnetism of the film gradually increases; this shows that the conductivity and magnetism of the film can be controlled by adjusting the proportion of CoFe2O4 and CNT content in the film; therefore, by combining homogeneous composite films with different CoFe2O4 contents, a conductive and magnetic reverse dual gradient structure can be constructed.

[0036] As attached Figure 3 As shown, attached Figure 3 The conductivity curves of MXene nanosheets before and after modification are shown in the figure. Figure 3 It can be seen that the pure MXene nanosheet film exhibits excellent conductivity. After being modified with PDA, the conductivity is further improved. This is because the appropriate amount of PDA can form hydrogen bonds and covalent bonds with the active groups (F, O, OH, etc.) on the surface of the MXene nanosheets, making the MXene nanosheets stacked closely together, eliminating interlayer defects, and increasing the electron transport network, thereby improving the conductivity of the MXene nanosheet film.

[0037] As attached Figure 4 As shown, attached Figure 4The cross-sectional SEM image and EDS element distribution diagram of the magnetic-electric dual gradient electromagnetic shielding material prepared in Example 1 are given in the attached figure; Figure 4 It can be seen that the dual gradient structure area presents a layered structure as a whole, and the cross section contains 7 main elements, namely C, Fe, Co, N, O, F and Ti. From top to bottom, the contents of Fe, Co and O elements gradually increase, and the content of C element gradually decreases, indicating that the content gradient of CoFe2O4 increases and the content gradient of CNT decreases. The highly conductive PMXene nanosheets are concentrated above CoFe2O4@CNT / ANF, and the N element is evenly distributed in the entire area, which mainly comes from the PDA coated on the surface of the PMXene nanosheets and the N element in the ANF molecular chain. The above results show that the magnetic-electric dual gradient structure is successfully constructed in the composite film.

[0038] As shown in the attached Figure 5 As shown, attached Figure 5 The infrared camouflage performance test image of the magnetic-electric dual gradient electromagnetic shielding material prepared in Example 1 is given in the figure; Figure 5 It can be seen that due to the extremely low mid-infrared emissivity of the composite film, the surface temperature of the composite film is much lower than the actual temperature of the covered object and is very close to the ambient temperature, showing an excellent infrared camouflage effect.

[0039] Example 2 This embodiment 2 provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising the following steps: Step 1: Add 2.0 g of anhydrous sodium acetate (NaAc) and 1.0 g of polyethylene glycol (PEG-4000) to 20 mL of ethylene glycol (EG) solvent and stir until completely dissolved; then, add 0.35 g of ferric chloride hexahydrate (FeCl3·6H2O) and 0.2 g of cobalt dichloride hexahydrate (CoCl2·6H2O) and continue stirring until dissolved; then, add CNT and ultrasonicate in a water bath at 180 W for 1 h; after ultrasonication, transfer the mixture to an autoclave and heat continuously at 160 ° C for 18 h; finally, wash the reaction product to neutrality and obtain Z after freeze-drying. x CoFe2O4@CNT composite particles; among them, Z x is the mass fraction of CoFe2O4 compared to CNT, x =1, 2 or 3; specifically, Z x The CoFe2O4@CNT composite particles include Z1CoFe2O4@CNT, Z2CoFe2O4@CNT and Z3CoFe2O4@CNT, and Z1 is 80wt.%, Z2 is 40wt.%, and Z3 is 10wt.%.

[0040] Step 2: Prepare 60 mL of 9 mol / L hydrochloric acid solution, add 4.8 g of lithium fluoride (LiF) and stir thoroughly until completely dissolved to prepare a fluorine-containing solution; then slowly add 3 g of MAX precursor to the fluorine-containing solution, and stir and etch the entire system at 35 °C for 48 h; then wash until neutral, ultrasonicate at 220 W for 1 h, and then centrifuge at 5000 rpm for 1 h, collect the supernatant to obtain a MXene nanosheet dispersion; then, adjust the mass fraction of the MXene nanosheet dispersion to 0.1 wt.%, slowly add the prepared PDA solution to the MXene nanosheet dispersion, and stir the reaction for 90 min to obtain a PMXene nanosheet dispersion; wherein the mass fraction of PDA compared to MXene is 4 wt.%.

[0041] Step 3: 1.5 g of potassium hydroxide (KOH) and 1.0 g of para-aramid short fibers (PPTA) are sequentially added to 499.0 g of dimethyl sulfoxide (DMSO) solvent, and stirred continuously to prepare an ANF / DMSO dispersion.

[0042] Step 4: Use Z x CoFe2O4@CNT composite particles were prepared to obtain a ZCoFe2O4@CNT composite particle aqueous dispersion with a mass fraction of 0.2wt.%; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; among them, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 30wt.%.

[0043] Step 5, preparing a CNT aqueous dispersion with a mass fraction of 0.2 wt.%; using the CNT aqueous dispersion to perform protonation treatment on the ANF / DMSO dispersion to obtain CNT / ANF; wherein the mass fraction of CNT compared to ANF is 2 wt.%.

[0044] Step 6. Stack and filter Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene in sequence; use the CNT / ANF dispersion as a sealing layer, stack and filter to obtain (80-40-10) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, named (80-40-10) CoC / A-PM-C / A composite gel.

[0045] Step 7: vacuum dry the (80-40-10) CoC / A-PM-C / A composite gel at 80°C for 60 minutes to obtain a (80-40-10) CoC / A-PM-C / A magnetic-electric dual gradient composite film, that is, a magnetic-electric dual gradient electromagnetic shielding material.

[0046] Performance testing: The (80-40-10) CoC / A-PM-C / A magnetic-electric dual gradient composite film prepared in Example 2 was subjected to performance testing, and the test results were as follows: the electromagnetic shielding effectiveness of the (80-40-10) CoC / A-PM-C / A composite film was 62.6 dB, the reflection coefficient R was reduced to 0.62, the tensile strength was 51.2 MPa, and the infrared emissivity in the range of 7-17 μm was 2.61%; the results showed that the composite film exhibited excellent electromagnetic shielding effectiveness and effectively reduced the reflection of electromagnetic waves; at the same time, the composite film had good mechanical properties and extremely low mid-infrared emissivity, showing excellent infrared camouflage performance.

[0047] Example 3 This embodiment 3 provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising the following steps: Step 1: Add 1.5 g of anhydrous sodium acetate (NaAc) and 0.5 g of polyethylene glycol (PEG-4000) to 15 mL of ethylene glycol (EG) solvent and stir until completely dissolved; then, add 0.27 g of ferric chloride hexahydrate (FeCl3·6H2O) and 0.12 g of cobalt dichloride hexahydrate (CoCl2·6H2O) and continue stirring until dissolved; then, add CNT and ultrasonicate in a water bath at 180 W for 1 h; after ultrasonication, transfer the mixture to an autoclave and heat continuously at 160 ° C for 20 h; finally, wash the reaction product to neutrality and obtain Z after freeze-drying. x CoFe2O4@CNT composite particles; among them, Z x is the mass fraction of CoFe2O4 compared to CNT, x =1, 2 or 3; specifically, Z x The CoFe2O4@CNT composite particles include Z1CoFe2O4@CNT, Z2CoFe2O4@CNT and Z3CoFe2O4@CNT, and Z1 is 80wt.%, Z2 is 60wt.%, and Z3 is 40wt.%.

[0048] Step 2: Prepare 60 mL of 9 mol / L hydrochloric acid solution, add 4.8 g of lithium fluoride (LiF) and stir thoroughly until completely dissolved to prepare a fluorine-containing solution; then slowly add 3 g of MAX precursor to the fluorine-containing solution, and stir and etch the entire system at 35 °C for 48 h; then wash until neutral, ultrasonicate at 100 W for 1 h, and then centrifuge at 5000 rpm for 1 h, collect the supernatant to obtain a MXene nanosheet dispersion; then, adjust the mass fraction of the MXene nanosheet dispersion to 0.05 wt.%, slowly add the prepared PDA solution to the MXene nanosheet dispersion, and stir the reaction for 30 min to obtain a PMXene nanosheet dispersion; wherein the mass fraction of PDA compared to MXene is 4 wt.%.

[0049] Step 3: 1.5 g of potassium hydroxide (KOH) and 1.0 g of para-aramid short fibers (PPTA) are sequentially added to 499.0 g of dimethyl sulfoxide (DMSO) solvent, and stirred continuously to prepare an ANF / DMSO dispersion.

[0050] Step 4: Use Z x CoFe2O4@CNT composite particles were prepared to obtain a ZCoFe2O4@CNT composite particle aqueous dispersion with a mass fraction of 0.2wt.%; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; among them, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 80wt.%.

[0051] Step 5, preparing a CNT aqueous dispersion with a mass fraction of 0.2 wt.%; using the CNT aqueous dispersion to perform protonation treatment on the ANF / DMSO dispersion to obtain CNT / ANF; wherein the mass fraction of CNT compared to ANF is 2 wt.%.

[0052] Step 6. Stack and filter Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene in sequence; use the CNT / ANF dispersion as a sealing layer, stack and filter to obtain (80-60-40) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, named (80-60-40) CoC / A-PM-C / A composite gel.

[0053] Step 7: vacuum dry the (80-60-40) CoC / A-PM-C / A composite gel at 60°C for 120 minutes to obtain a (80-60-40) CoC / A-PM-C / A magnetic-electric dual gradient composite film, that is, a magnetic-electric dual gradient electromagnetic shielding material.

[0054] Performance testing: The (80-60-40) CoC / A-PM-C / A magnetic-electric dual gradient composite film prepared in this Example 3 was subjected to performance testing, and the test results were as follows: the electromagnetic shielding effectiveness of the (80-60-40) CoC / A-PM-C / A composite film was 60.5 dB, the reflection coefficient R was reduced to 0.68, the tensile strength was 41.4 MPa, and the infrared emissivity in the range of 7-17 μm was 1.96%; the results showed that the composite film exhibited excellent electromagnetic shielding effectiveness and effectively reduced the reflection of electromagnetic waves. At the same time, the composite film had good mechanical properties and extremely low mid-infrared emissivity, showing excellent infrared camouflage performance.

[0055] Example 4 This embodiment 4 provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising the following steps: Step 1: Add 3.6 g of anhydrous sodium acetate (NaAc) and 2.0 g of polyethylene glycol (PEG-4000) to 40 mL of ethylene glycol (EG) solvent and stir until completely dissolved; then, add 0.54 g of ferric chloride hexahydrate (FeCl3·6H2O) and 0.2 g of cobalt dichloride hexahydrate (CoCl2·6H2O) and continue stirring until dissolved; then, add CNT and perform water bath ultrasound at 180 W for 1 h; after ultrasound treatment, transfer the mixture to an autoclave and heat it continuously at 200 ° C for 20 h; finally, wash the reaction product to neutrality and obtain Z after freeze drying. x CoFe2O4@CNT composite particles; among them, Z x is the mass fraction of CoFe2O4 compared to CNT, x =1, 2 or 3; specifically, Z x The CoFe2O4@CNT composite particles include Z1CoFe2O4@CNT, Z2CoFe2O4@CNT and Z3CoFe2O4@CNT, and Z1 is 40wt.%, Z2 is 20wt.%, and Z3 is 10wt.%.

[0056] Step 2: Prepare 60 mL of 9 mol / L hydrochloric acid solution, add 4.8 g of lithium fluoride (LiF) and stir thoroughly until completely dissolved to prepare a fluorine-containing solution; then slowly add 3 g of MAX precursor to the fluorine-containing solution, and stir and etch the entire system at 35 °C for 48 h; then wash until neutral, ultrasonicate at 180 W for 1 h, and then centrifuge at 2000 rpm for 1 h, collect the supernatant to obtain a MXene nanosheet dispersion; then, adjust the mass fraction of the MXene nanosheet dispersion to 0.05 wt.%, slowly add the prepared PDA solution to the MXene nanosheet dispersion, and stir the reaction for 30 min to obtain a PMXene nanosheet dispersion; wherein the mass fraction of PDA compared to MXene is 4 wt.%.

[0057] Step 3: 1.5 g of potassium hydroxide (KOH) and 1.0 g of para-aramid short fibers (PPTA) are sequentially added to 499.0 g of dimethyl sulfoxide (DMSO) solvent, and stirred continuously to prepare an ANF / DMSO dispersion.

[0058] Step 4: Use Z x CoFe2O4@CNT composite particles were prepared to obtain a ZCoFe2O4@CNT composite particle aqueous dispersion with a mass fraction of 0.2wt.%; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; among them, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 75wt.%.

[0059] Step 5, prepare a CNT aqueous dispersion with a mass fraction of 0.2wt.%; use the CNT aqueous dispersion to perform protonation treatment on the ANF / DMSO dispersion to obtain CNT / ANF; wherein the mass fraction of CNT compared to ANF is 0.5wt.%.

[0060] Step 6. Stack and filter Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene in sequence; use the CNT / ANF dispersion as a sealing layer, stack and filter to obtain (40-20-10) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, named (40-20-10) CoC / A-PM-C / A composite gel.

[0061] Step 7: vacuum dry the (40-20-10) CoC / A-PM-C / A composite gel at 60°C for 120 minutes to obtain a (80-60-40) CoC / A-PM-C / A magnetic-electric dual gradient composite film, that is, a magnetic-electric dual gradient electromagnetic shielding material.

[0062] Performance testing: The (40-20-10) CoC / A-PM-C / A magnetic-electric dual gradient composite film prepared in Example 4 was subjected to performance testing, and the test results were as follows: the electromagnetic shielding effectiveness of the (40-20-10) CoC / A-PM-C / A composite film was 55.8 dB, the reflection coefficient R was reduced to 0.88, the tensile strength was 58.2 MPa, and the infrared emissivity in the range of 7-17 μm was 7.74%; the results showed that the composite film exhibited excellent electromagnetic shielding effectiveness and effectively reduced the reflection of electromagnetic waves. At the same time, the composite film had good mechanical properties and extremely low mid-infrared emissivity, showing excellent infrared camouflage performance.

[0063] Example 5 This embodiment 5 provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising the following steps: Step 1: Add 4.8 g of anhydrous sodium acetate (NaAc) and 2.5 g of polyethylene glycol (PEG-4000) to 50 mL of ethylene glycol (EG) solvent and stir until completely dissolved; then, add 0.72 g of ferric chloride hexahydrate (FeCl3·6H2O) and 0.4 g of cobalt dichloride hexahydrate (CoCl2·6H2O) and continue stirring until dissolved; then, add CNT and ultrasonicate in a water bath at 180 W for 1 h; after ultrasonication, transfer the mixture to an autoclave and heat continuously at 180 ° C for 16 h; finally, wash the reaction product to neutrality and obtain Z after freeze-drying. x CoFe2O4@CNT composite particles; among them, Z x is the mass fraction of CoFe2O4 compared to CNT, x =1, 2 or 3; specifically, Z x The CoFe2O4@CNT composite particles include Z1CoFe2O4@CNT, Z2CoFe2O4@CNT and Z3CoFe2O4@CNT, and Z1 is 80wt.%, Z2 is 60wt.%, and Z3 is 40wt.%.

[0064] Step 2: Prepare 60 mL of 9 mol / L hydrochloric acid solution, add 4.8 g of lithium fluoride (LiF) and stir thoroughly until completely dissolved to prepare a fluorine-containing solution; then slowly add 3 g of MAX precursor to the fluorine-containing solution, and stir and etch the entire system at 35 °C for 48 h; then wash until neutral, ultrasonicate at 200 W for 1 h, and then centrifuge at 4500 rpm for 1 h, collect the supernatant to obtain a MXene nanosheet dispersion; then, adjust the mass fraction of the MXene nanosheet dispersion to 0.2 wt.%, slowly add the prepared PDA solution to the MXene nanosheet dispersion, and stir the reaction for 60 min to obtain a PMXene nanosheet dispersion; wherein the mass fraction of PDA compared to MXene is 4 wt.%.

[0065] Step 3: 1.5 g of potassium hydroxide (KOH) and 1.0 g of para-aramid short fibers (PPTA) are sequentially added to 499.0 g of dimethyl sulfoxide (DMSO) solvent, and stirred continuously to prepare an ANF / DMSO dispersion.

[0066] Step 4: Use Z x CoFe2O4@CNT composite particles were prepared to obtain a ZCoFe2O4@CNT composite particle aqueous dispersion with a mass fraction of 0.2wt.%; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; among them, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 55wt.%.

[0067] Step 5, prepare a CNT aqueous dispersion with a mass fraction of 0.2wt.%; use the CNT aqueous dispersion to perform protonation treatment on the ANF / DMSO dispersion to obtain CNT / ANF; wherein the mass fraction of CNT compared to ANF is 1.5wt.%.

[0068] Step 6. Stack and filter Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene in sequence; use the CNT / ANF dispersion as a sealing layer, stack and filter to obtain (80-60-40) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, named (80-60-40) CoC / A-PM-C / A composite gel.

[0069] Step 7: vacuum dry the (80-60-40) CoC / A-PM-C / A composite gel at 120°C for 30 minutes to obtain a (80-60-40) CoC / A-PM-C / A magnetic-electric dual gradient composite film, that is, a magnetic-electric dual gradient electromagnetic shielding material.

[0070] Performance testing: The (80-60-40) CoC / A-PM-C / A magnetic-electric dual gradient composite film prepared in Example 5 was subjected to performance testing, and the test results were as follows: the electromagnetic shielding effectiveness of the (80-60-40) CoC / A-PM-C / A composite film was 60.5 dB, the reflection coefficient R was reduced to 0.68, the tensile strength was 41.4 MPa, and the infrared emissivity in the range of 7-17 μm was 1.96%; the results showed that the composite film exhibited excellent electromagnetic shielding effectiveness and effectively reduced the reflection of electromagnetic waves. At the same time, the composite film had good mechanical properties and extremely low mid-infrared emissivity, showing excellent infrared camouflage performance.

[0071] Example 6 This embodiment 6 provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising the following steps: Step 1: Add 3.0 g of anhydrous sodium acetate (NaAc) and 1.5 g of polyethylene glycol (PEG-4000) to 30 mL of ethylene glycol (EG) solvent and stir until completely dissolved; then, add 0.68 g of ferric chloride hexahydrate (FeCl3·6H2O) and 0.32 g of cobalt dichloride hexahydrate (CoCl2·6H2O) and continue stirring until dissolved; then, add CNT and ultrasonicate in a water bath at 180 W for 1 h; after ultrasonication, transfer the mixture to an autoclave and heat continuously at 220 ° C for 16 h; finally, wash the reaction product to neutrality and obtain Z after freeze-drying. x CoFe2O4@CNT composite particles; among them, Z x is the mass fraction of CoFe2O4 compared to CNT, x =1, 2 or 3; specifically, Z x The CoFe2O4@CNT composite particles include Z1CoFe2O4@CNT, Z2CoFe2O4@CNT and Z3CoFe2O4@CNT, and Z1 is 60wt.%, Z2 is 40wt.%, and Z3 is 20wt.%.

[0072] Step 2: Prepare 60 mL of 9 mol / L hydrochloric acid solution, add 4.8 g of lithium fluoride (LiF) and stir thoroughly until completely dissolved to prepare a fluorine-containing solution; then slowly add 3 g of MAX precursor to the fluorine-containing solution, and stir and etch the entire system at 35 °C for 48 h; then wash until neutral, ultrasonicate at 150 W for 1 h, and then centrifuge at 3000 rpm for 1 h, collect the supernatant to obtain a MXene nanosheet dispersion; then, adjust the mass fraction of the MXene nanosheet dispersion to 0.15 wt.%, slowly add the prepared PDA solution to the MXene nanosheet dispersion, and stir the reaction for 40 min to obtain a PMXene nanosheet dispersion; wherein the mass fraction of PDA compared to MXene is 4 wt.%.

[0073] Step 3: 1.5 g of potassium hydroxide (KOH) and 1.0 g of para-aramid short fibers (PPTA) are sequentially added to 499.0 g of dimethyl sulfoxide (DMSO) solvent, and stirred continuously to prepare an ANF / DMSO dispersion.

[0074] Step 4: Use Z x CoFe2O4@CNT composite particles were prepared to obtain a ZCoFe2O4@CNT composite particle aqueous dispersion with a mass fraction of 0.2wt.%; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; among them, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 45wt.%.

[0075] Step 5, preparing a CNT aqueous dispersion with a mass fraction of 0.2 wt.%; using the CNT aqueous dispersion to perform protonation treatment on the ANF / DMSO dispersion to obtain CNT / ANF; wherein the mass fraction of CNT compared to ANF is 3 wt.%.

[0076] Step 6. Stack and filter Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene in sequence; use the CNT / ANF dispersion as a sealing layer, stack and filter to obtain a (60-40-20) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, named (60-40-20) CoC / A-PM-C / A composite gel.

[0077] Step 7: vacuum dry the (60-40-20) CoC / A-PM-C / A composite gel at 100°C for 90 minutes to obtain a (80-60-40) CoC / A-PM-C / A magnetic-electric dual gradient composite film, that is, a magnetic-electric dual gradient electromagnetic shielding material.

[0078] Performance testing: The (80-60-40) CoC / A-PM-C / A magnetic-electric dual gradient composite film prepared in Example 6 was subjected to performance testing, and the test results were as follows: the electromagnetic shielding effectiveness of the (80-60-40) CoC / A-PM-C / A composite film was 58.3 dB, the reflection coefficient R was reduced to 0.77, the tensile strength was 54.7 MPa, and the infrared emissivity in the range of 7-17 μm was 2.55%; the results showed that the composite film exhibited excellent electromagnetic shielding effectiveness and effectively reduced the reflection of electromagnetic waves. At the same time, the composite film had good mechanical properties and extremely low mid-infrared emissivity, showing excellent infrared camouflage performance.

[0079] Example 7 This embodiment 7 provides a method for preparing a magnetic-electric dual gradient electromagnetic shielding material, comprising the following steps: Step 1: Add 3.6 g of anhydrous sodium acetate (NaAc) and 2.5 g of polyethylene glycol (PEG-4000) to 50 mL of ethylene glycol (EG) solvent and stir until completely dissolved; then, add 0.54 g of ferric chloride hexahydrate (FeCl3·6H2O) and 0.24 g of cobalt dichloride hexahydrate (CoCl2·6H2O) and continue stirring until dissolved; then, add CNT and ultrasonicate in a water bath at 180 W for 1 h; after ultrasonication, transfer the mixture to an autoclave and heat it continuously at 180 ° C for 24 h; finally, wash the reaction product to neutrality and obtain Z after freeze-drying. x CoFe2O4@CNT composite particles; among them, Z x is the mass fraction of CoFe2O4 compared to CNT, x = 1, 2 or 3; specifically, Z x The CoFe2O4@CNT composite particles include Z1CoFe2O4@CNT, Z2CoFe2O4@CNT and Z3CoFe2O4@CNT, and Z1 is 40wt.%, Z2 is 20wt.%, and Z3 is 10wt.%.

[0080] Step 2: Prepare 60 mL of 9 mol / L hydrochloric acid solution, add 4.8 g of lithium fluoride (LiF) and stir thoroughly until completely dissolved to prepare a fluorine-containing solution; then slowly add 3 g of MAX precursor to the fluorine-containing solution, and stir and etch the entire system at 35 °C for 48 h; then wash until neutral, ultrasonicate at 150 W for 1 h, and then centrifuge at 3000 rpm for 1 h, collect the supernatant to obtain a MXene nanosheet dispersion; then, adjust the mass fraction of the MXene nanosheet dispersion to 0.15 wt.%, slowly add the prepared PDA solution to the MXene nanosheet dispersion, and stir the reaction for 40 min to obtain a PMXene nanosheet dispersion; wherein the mass fraction of PDA compared to MXene is 4 wt.%.

[0081] Step 3: 1.5 g of potassium hydroxide (KOH) and 1.0 g of para-aramid short fibers (PPTA) are sequentially added to 499.0 g of dimethyl sulfoxide (DMSO) solvent, and stirred continuously to prepare an ANF / DMSO dispersion.

[0082] Step 4: Use Z x CoFe2O4@CNT composite particles were prepared to obtain a ZCoFe2O4@CNT composite particle aqueous dispersion with a mass fraction of 0.2wt.%; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; among them, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 45wt.%.

[0083] Step 5, preparing a CNT aqueous dispersion with a mass fraction of 0.2 wt.%; using the CNT aqueous dispersion to perform protonation treatment on the ANF / DMSO dispersion to obtain CNT / ANF; wherein the mass fraction of CNT compared to ANF is 3 wt.%.

[0084] Step 6. Stack and filter Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene in sequence; use the CNT / ANF dispersion as a sealing layer, stack and filter to obtain (40-20-10) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, named (40-20-10) CoC / A-PM-C / A composite gel.

[0085] Step 7: vacuum dry the (40-20-10) CoC / A-PM-C / A composite gel at 100°C for 90 minutes to obtain a (40-20-10) CoC / A-PM-C / A magnetic-electric dual gradient composite film, that is, a magnetic-electric dual gradient electromagnetic shielding material.

[0086] Performance testing: The (40-20-10) CoC / A-PM-C / A magnetic-electric dual gradient composite film prepared in Example 7 was subjected to performance testing, and the test results were as follows: the electromagnetic shielding effectiveness of the (40-20-10) CoC / A-PM-C / A composite film was 55.8 dB, the reflection coefficient R was reduced to 0.88, the tensile strength was 58.2 MPa, and the infrared emissivity in the range of 7-17 μm was 7.74%; the results showed that the composite film exhibited excellent electromagnetic shielding effectiveness and effectively reduced the reflection of electromagnetic waves. At the same time, the composite film had good mechanical properties and extremely low mid-infrared emissivity, showing excellent infrared camouflage performance.

[0087] The preparation method of the magnetic-electric dual gradient electromagnetic shielding material described in the present invention adjusts the impedance matching between the material surface and the air by introducing magnetic particles, so that electromagnetic waves can smoothly enter the interior of the material and reduce secondary reflection; secondly, the multilayer structure not only provides an effective magnetic-electric dual gradient distribution, but also effectively extends the transmission path of the electromagnetic wave; the low mid-infrared emissivity of MXene and CNT makes the composite film exhibit excellent infrared camouflage performance; overall, the magnetic-electric dual gradient electromagnetic shielding material has the characteristics of light weight, flexibility and high strength, and can be applied to electromagnetic shielding, electronic packaging, flexible wearables and safety protection and other fields.

[0088] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A method for preparing a magnetic-electric dual gradient electromagnetic shielding material, characterized in that: include: Cobalt ferrite nanoparticles were synthesized on carbon nanotubes by solvothermal method to obtain Z x CoFe2O4@CNT composite particles; among them, Z x is the mass fraction of CoFe2O4 compared to CNT, x =1, 2, or 3; MXene nanosheets were modified with polydopamine to obtain PMXene nanosheets; Using Z x CoFe2O4@CNT composite particles were prepared to obtain ZCoFe2O4@CNT composite particle aqueous dispersion; x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x CoFe2O4@CNT / ANF; Using CNT aqueous dispersion to perform protonation treatment on ANF / DMSO dispersion to obtain CNT / ANF; Z x CoFe2O4@CNT / ANF, PMXene nanosheets and CNT / ANF were stacked and assembled, and then filtered to obtain Z x CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel; Z x The CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel is vacuum dried to obtain a magnetic-electric dual gradient electromagnetic shielding material.

2. The method for preparing a magnetic-electric dual gradient electromagnetic shielding material according to claim 1, characterized in that: The mass fraction of CoFe2O4 compared to CNT satisfies: 10wt.%≤Z x ≤80wt.%.

3. The method for preparing a magnetic-electric dual gradient electromagnetic shielding material according to claim 1, characterized in that: Cobalt ferrite nanoparticles were synthesized on carbon nanotubes by solvothermal method to obtain Z x The process of CoFe2O4@CNT composite particles includes: Mix anhydrous sodium acetate, polyethylene glycol and ethylene glycol, and stir until completely dissolved to obtain a mixed solution; Adding ferric chloride hexahydrate and cobalt dichloride hexahydrate to the mixed solution, and continuing to stir until dissolved; then adding CNT, and transferring to a reaction kettle after ultrasonic treatment, and reacting under heating conditions to obtain a reaction product; The reaction product is washed to neutrality and freeze-dried to obtain Z x CoFe2O4@CNT composite particles.

4. The method for preparing a magnetic-electric dual gradient electromagnetic shielding material according to claim 1, characterized in that: The process of modifying MXene nanosheets with polydopamine to obtain PMXene nanosheets includes: The polydopamine solution is added to the MXene nanosheet dispersion, and the mixture is stirred to react to obtain PMXene nanosheets.

5. The method for preparing a magnetic-electric dual gradient electromagnetic shielding material according to claim 1, characterized in that: Using Z x The CoFe2O4@CNT composite particle aqueous dispersion was treated with protonation of the ANF / DMSO dispersion to obtain Z x During the process of CoFe2O4@CNT / ANF, Z x The mass fraction of CoFe2O4@CNT composite particles compared to ANF is 30-80wt.%.

6. The method for preparing a magnetic-electric dual gradient electromagnetic shielding material according to claim 1, characterized in that: The ANF / DMSO dispersion is subjected to protonation reduction treatment using the CNT aqueous dispersion to obtain CNT / ANF, in which the mass fraction of CNT compared to ANF is 0.5-3wt.%.

7. The method for preparing a magnetic-electric dual gradient electromagnetic shielding material according to claim 1, characterized in that: Z x CoFe2O4@CNT / ANF, PMXene nanosheets and CNT / ANF were stacked and assembled, and then filtered to obtain Z x The process of CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, include: Z1CoFe2O4@CNT / ANF, Z2CoFe2O4@CNT / ANF, Z3CoFe2O4@CNT / ANF and PMXene were sequentially stacked and filtered; wherein Z1>Z2>Z3; then, the CNT / ANF dispersion was used as a sealing layer and superimposed and filtered to obtain the (Z1-Z2-Z3) CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, namely Z x CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel.

8. The method for preparing a magnetic-electric dual gradient electromagnetic shielding material according to claim 1, characterized in that: Z x During the vacuum drying process of the CoFe2O4@CNT / ANF-PMXene-CNT / ANF composite gel, the drying temperature is 60-120°C and the drying time is 30-120min.

9. A magnetic-electric dual gradient electromagnetic shielding material, characterized in that: The material is prepared by the method for preparing a magnetic-electric dual gradient electromagnetic shielding material as described in any one of claims 1 to 8.

10. The use of a magnetic-electric dual gradient electromagnetic shielding material as claimed in claim 9, characterized in that: The magnetic-electric dual gradient electromagnetic shielding material is applied to electromagnetic shielding, electronic packaging, flexible wearables and safety protection.

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