Electromagnetic shielding film and intelligent control device based on electromagnetic shielding film

Abstract

The invention discloses an electromagnetic shielding film and an intelligent control device based on the electromagnetic shielding film, and belongs to the field of electromagnetic shielding films, and the electromagnetic shielding film comprises a first shielding layer, a second shielding layer and a third shielding layer which are sequentially connected from outside to inside; the first shielding layer is made of an Mxene material capable of reflecting electromagnetism; the second shielding layer is made of an MXene material which can absorb electromagnetism and is of a porous structure; the third shielding layer is made of a magnetic composite material capable of dissipating electromagnetism; the conductivity of the first shielding layer is greater than that of the second shielding layer and greater than that of the third shielding layer; the continuous impedance matching value of the first shielding layer is smaller than the continuous impedance matching value of the second shielding layer and smaller than the continuous impedance matching value of the third shielding layer. The electric conductivity of the three shielding layers increases gradually in sequence to form an electromagnetic transmission path, and reflection, absorption and dissipation can be performed sequentially when the electromagnetic waves are received, so that the electromagnetic waves are attenuated gradually, the electromagnetic waves are eliminated and shielded, the shielding effect is improved, and secondary interference is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding films, and in particular to an electromagnetic shielding film and an intelligent control device based on the electromagnetic shielding film. Background Art

[0002] With the widespread application of modern power systems and intelligent control equipment, the electromagnetic interference generated by the equipment during operation can cause electronic equipment failures and endanger the health of humans and other organisms. Therefore, the problem of electromagnetic interference (EMI) has become increasingly prominent. Grid fluctuations, transient interference, and a sharp increase in electromagnetic radiation in the surrounding environment pose a serious threat to the stable operation of intelligent control equipment.

[0003] To this end, the demand for materials with high electromagnetic interference shielding capabilities is rapidly increasing to protect the normal operation of electronic equipment and human health. Currently, commonly used electromagnetic shielding films are generally made of metal foil (aluminum, copper, etc.), metal mesh, foam materials, metal and metal-based composites, or polymers. These materials reflect electromagnetic radiation to achieve electromagnetic shielding.

[0004] However, the commonly used films currently have the following technical problems: films made of a single material often require a certain thickness (on the order of several millimeters) to meet higher shielding requirements, increasing production costs and manufacturing process difficulty. In addition, the reflected electromagnetic waves will cause secondary interference in the integrated circuit, increasing the impact of electromagnetic waves on the internal equipment. Summary of the Invention

[0005] The present invention provides an electromagnetic shielding film and an intelligent control device based on the electromagnetic shielding film, which can solve the technical problems of the existing electromagnetic shielding film structure being thick and causing secondary interference due to reflected electromagnetic waves.

[0006] A first aspect of an embodiment of the present invention provides an electromagnetic shielding film, the electromagnetic shielding film comprising: a first shielding layer, a second shielding layer, and a third shielding layer connected in sequence from outside to inside;

[0007] The first shielding layer is made of MXene material that can reflect electromagnetic waves; the second shielding layer is made of MXene material that can absorb electromagnetic waves and has a porous structure; the third shielding layer is made of a magnetic composite material that can dissipate electromagnetic waves;

[0008] The electrical conductivity of the first shielding layer is greater than the electrical conductivity of the second shielding layer, and the electrical conductivity of the second shielding layer is greater than the electrical conductivity of the third shielding layer;

[0009] The continuous impedance matching value of the first shielding layer is smaller than the continuous impedance matching value of the second shielding layer, and the continuous impedance matching value of the second shielding layer is smaller than the continuous impedance matching value of the third shielding layer.

[0010] In combination with the first aspect, in one implementation, the first shielding layer is made of Ti3C2T x Mxene material.

[0011] In combination with the first aspect, in one implementation, the thickness of the first shielding layer is 100-200 nanometers.

[0012] In combination with the first aspect, in one implementation, the conductivity of the first shielding layer is greater than 10 4 S / cm, and the continuous impedance matching value of the first shielding layer is 5-20 ohms.

[0013] In combination with the first aspect, in one implementation, the second shielding layer adopts V2CT x MXene materials.

[0014] In combination with the first aspect, in one implementation, the thickness of the second shielding layer is in the range of 10-50 microns.

[0015] In combination with the first aspect, in one implementation, the conductivity of the second shielding layer is greater than 10 3 S / m, the conductivity of the second shielding layer is less than 10 4 S / cm, and the continuous impedance matching value of the second shielding layer is 20-100 ohms.

[0016] In combination with the first aspect, in one implementation, the third shielding layer is made of iron oxide, and the thickness of the third shielding layer is 5-20 microns.

[0017] In combination with the first aspect, in one implementation, the conductivity of the third shielding layer is less than 10 2 S / cm, and the continuous impedance matching value of the third shielding layer is 100-200 ohms.

[0018] A second aspect of the embodiments of the present invention provides an intelligent control device based on an electromagnetic shielding film, the device comprising: a device body and the electromagnetic shielding film as described above;

[0019] The electromagnetic shielding film is attached to the outer shell surface of the device body or the surface of the circuit board.

[0020] Compared with the prior art, the electromagnetic shielding film and the intelligent control device based on the electromagnetic shielding film provided by the embodiments of the present invention have the following beneficial effects: the present invention includes a first shielding layer that can reflect electromagnetics, a second shielding layer that can absorb electromagnetics, and a third shielding layer that can dissipate electromagnetics, and the conductivity of the three shielding layers increases successively to form an electromagnetic transmission path. When receiving electromagnetics, they can reflect, absorb and dissipate in turn to gradually attenuate the electromagnetic waves, eliminate and shield the electromagnetics, improve the shielding effect, and avoid secondary interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of an electromagnetic shielding film provided by one embodiment of the present invention;

[0022] Figure 2 is a comparison diagram of material properties of the first shielding layer, the second shielding layer, and the third shielding layer provided in one embodiment of the present invention;

[0023] Figure 3 This is a comparison diagram of magnetic field distributions of different methods provided by an embodiment of the present invention;

[0024] Figure 4 This is a schematic structural diagram of an intelligent control device based on an electromagnetic shielding film provided by one embodiment of the present invention;

[0025] In the figure: first shielding layer 1, second shielding layer 2, third shielding layer 3. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] With the widespread application of modern power systems and intelligent control equipment, the electromagnetic interference generated by the equipment during operation can cause electronic equipment failures and endanger the health of humans and other organisms. Therefore, the problem of electromagnetic interference (EMI) has become increasingly prominent. Grid fluctuations, transient interference, and a sharp increase in electromagnetic radiation in the surrounding environment pose a serious threat to the stable operation of intelligent control equipment.

[0028] To this end, the demand for materials with high electromagnetic interference shielding capabilities is rapidly increasing to protect the normal operation of electronic equipment and human health. Currently, commonly used electromagnetic shielding films are generally made of metal foil (aluminum, copper, etc.), metal mesh, foam materials, metal and metal-based composites, or polymers. These materials reflect electromagnetic radiation to achieve electromagnetic shielding.

[0029] However, the commonly used films currently have the following technical problems: films made of a single material often require a certain thickness (on the order of several millimeters) to meet higher shielding requirements, increasing production costs and manufacturing process difficulty. In addition, the reflected electromagnetic waves will cause secondary interference in the integrated circuit, increasing the impact of electromagnetic waves on the internal equipment.

[0030] In order to solve the above problems, an electromagnetic shielding film and an intelligent control device based on the electromagnetic shielding film provided in the embodiments of the present application will be introduced and explained in detail through the following specific embodiments.

[0031] In order to solve the technical problem that the existing electromagnetic shielding film structure is thick and reflects electromagnetic and causes secondary interference, Figure 1 , showing a schematic structural diagram of an electromagnetic shielding film provided by an embodiment of the present invention.

[0032] Wherein, as an example, the electromagnetic shielding film may include: a first shielding layer 1, a second shielding layer 2 and a third shielding layer 3 connected in sequence from the outside to the inside;

[0033] The first shielding layer 1 is made of MXene material that can reflect electromagnetic waves; the second shielding layer 2 is made of MXene material that can absorb electromagnetic waves and has a porous structure; the third shielding layer 3 is made of a magnetic composite material that can dissipate electromagnetic waves;

[0034] The electrical conductivity of the first shielding layer 1 is greater than the electrical conductivity of the second shielding layer 2, and the electrical conductivity of the second shielding layer 2 is greater than the electrical conductivity of the third shielding layer 3;

[0035] The continuous impedance matching value of the first shielding layer 1 is smaller than the continuous impedance matching value of the second shielding layer 2 , and the continuous impedance matching value of the second shielding layer 2 is smaller than the continuous impedance matching value of the third shielding layer 3 .

[0036] Because the conductivity of the three-layer structure decreases from the outside to the inside, a gradient conductivity is formed. At the same time, the continuous impedance matching value increases from the outside to the inside, forming a gradient continuous impedance. In addition, the first shielding layer 1 can reflect electromagnetic waves, the second shielding layer 2 can absorb electromagnetic waves, and the third shielding layer 3 can dissipate electromagnetic waves. When electromagnetic waves are present, the electromagnetic wave energy can be forced to decay step by step along the "reflection-absorption-dissipation" path.

[0037] The outer first shielding layer (1) is made of MXene, a reflective material that effectively reflects incident electromagnetic waves, particularly at high frequencies. The middle second shielding layer (2) utilizes MXene, a material with moderate conductivity and significant dielectric loss properties, to efficiently absorb electromagnetic waves in the mid-frequency band, further attenuating their energy. The inner third shielding layer (3) utilizes a magnetic composite material system, which achieves deep absorption of low-frequency electromagnetic waves through a magnetic-dielectric synergistic loss mechanism, thoroughly reducing residual electromagnetic interference. The three-layer structure uses gradient conductivity and continuous impedance matching to gradually attenuate electromagnetic wave energy and optimize the effectiveness of the electromagnetic shielding film. This makes the electromagnetic shielding film suitable for a variety of electronic devices, including intelligent control structures and communications equipment, effectively preventing electromagnetic interference and improving device stability and reliability.

[0038] Furthermore, during use, the outer first shielding layer 1 reflects electromagnetic waves through the electromagnetic mirror effect, significantly improving reflection efficiency and reducing the penetration depth of electromagnetic waves. The middle second shielding layer 2 absorbs electromagnetic waves not reflected by the first shielding layer 1 through its dielectric loss characteristics, further attenuating the electromagnetic wave energy. The inner third shielding layer 3 further weakens electromagnetic waves through the synergistic effect of magnetic loss and dielectric loss, especially in the low-frequency range.

[0039] The three-layer structure gradually attenuates the energy of electromagnetic waves through a reasonable conductivity gradient and impedance matching to maximize shielding effectiveness. The high conductivity of the MXene material in the first shielding layer 1 enables it to effectively block high-frequency electromagnetic waves and prevent them from entering the internal structure. The magnetic composite material in the internal third shielding layer 3 effectively absorbs low-frequency electromagnetic waves and converts them into heat energy through its unique magnetic-dielectric loss mechanism, thereby reducing interference to the equipment. Its gradient structure has wide-band compatibility and can effectively cope with multi-band electromagnetic interference. The overall shielding effectiveness is significantly better than that of traditional shielding structures, while meeting the requirements of ultra-thin and lightweight design.

[0040] In one manufacturing method, the second shielding layer 2 and the third shielding layer 3 can be fixed to the material of the first shielding layer 1 by physical coating, sintering, or solution method (such as solution spin coating) to form an electromagnetic shielding film.

[0041] Reference Figure 2 In one embodiment, the first shielding layer 1 is made of Ti3C2T x Mxene material.

[0042] In one embodiment, the thickness of the first shielding layer 1 is 100-200 nanometers.

[0043] In one embodiment, the conductivity of the first shielding layer 1 is greater than 10 4 S / cm, the continuous impedance matching value of the first shielding layer 1 is 5-20 ohms.

[0044] In practical applications, the first shielding layer 1 is made of highly conductive and highly reflective Ti3C2T x MXene materials need to have ultra-high conductivity greater than 10,000 S / cm and a thickness of 200 nm.

[0045] In actual use, Ti3C2T x MXene materials can quickly stimulate induced current in the outer layer when electromagnetic waves are incident, mainly due to its high conductivity, layered structure, skin effect and electromagnetic mirror effect. x It has an extremely high electrical conductivity (>10,000S / cm), which allows a large number of free electrons to be quickly excited when electromagnetic waves are incident, forming an induced current. At the same time, its layered structure provides a large surface area, enhancing the response to electromagnetic waves and promoting the formation of induced current. Due to its high conductivity, electromagnetic waves can only propagate on the surface of the material (skin effect), and most of the electromagnetic waves will be reflected back by the surface. In addition, Ti3C2T x It can also produce a mirror-like reflection effect, effectively preventing the further propagation of electromagnetic waves.

[0046] Ti3C2T x The material uses a film size of 100-200 nanometers (nm), a size range that significantly influences the material's electromagnetic shielding performance. Thinner layers enhance the skin effect, making electromagnetic waves more effectively reflected from the surface, especially at high frequencies. Furthermore, the ultra-thin submicron structure not only meets design requirements for lightweight and miniaturization, but also provides flexible adaptability to curved or deformable electronic devices, further enhancing its applicability in various applications.

[0047] Using Ti3C2T x MXene material can quickly excite induced current when electromagnetic waves are incident, forming a low skin depth effect and an "electromagnetic mirror" effect, thereby reflecting most of the incident electromagnetic waves, effectively blocking the transmission of electromagnetic energy, and reducing internal burden.

[0048] In the gradient electromagnetic shielding structure of the present invention, the first shielding layer 1 is made of Ti3C2T x The MXene material is used as the outer layer, and its main function is to initially and strongly reflect most of the electromagnetic interference waves. x The reasons and how it works are as follows:

[0049] Ti3C2T x MXene materials have a layered structure and contain a large number of free electrons, which gives them extremely high electrical conductivity. xWhen the MXene material is on its surface, the incident electric field quickly drives the free electrons to generate an induced current, which in turn generates an electromagnetic field, thereby achieving an "electromagnetic mirror" effect, reflecting most of the electromagnetic energy back and preventing it from entering the interior of the material.

[0050] Ti3C2T x It is a type of MXene material, a two-dimensional material with a layered structure consisting of multiple atomic layers. Each layer is composed of Ti3C2 units (composed of titanium atoms and carbon atoms), which are arranged in a two-dimensional plane and are held together by weak interaction forces (such as van der Waals forces). This structure makes Ti3C2T x There is a certain sliding property between the material layers, so it not only has the form of a film or sheet, but also has good flexibility and adjustability. Although the layered structure presents the form of a flat plate, it is not a rigid fixed plane, but has a certain flexibility and adaptability. In addition, Ti3C2T x The layered structure of Ti3C2T is not limited to flat plate morphology, and other morphologies can also be obtained through different synthesis methods and post-processing processes. For example, by stacking or curling, Ti3C2T x It can form a nanosheet structure, or generate a more complex three-dimensional structure through chemical modification and functionalization. These different structural forms can be optimized according to application requirements, such as improving electromagnetic shielding performance or energy absorption efficiency. x Although the layered structure usually appears as a flat plate, its diverse morphology and structural adjustment capabilities make it more flexible and applicable in practical applications.

[0051] In addition, due to the Ti3C2T x It has extremely high conductivity and its skin effect is very significant. According to the skin depth formula:

[0052]

[0053] Where ω is the angular frequency of the electromagnetic wave, μ is the magnetic permeability of the material, and σ is the electrical conductivity.

[0054] Due to the large value of σ, δ is very small, which means that electromagnetic waves can only penetrate in a very thin surface layer, further enhancing the reflection effect. x The surface exhibits low impedance characteristics. When electromagnetic waves enter this low-impedance interface from air or other media, they will be strongly reflected due to the significant impedance discontinuity, reducing the penetration of electromagnetic waves and ensuring that most of the energy is reflected externally.

[0055] Finally, Ti3C2T xIt can be prepared into a film with submicron thickness, which not only meets the design requirements of lightweight and integration, but also its high conductivity at such an ultra-thin level can still effectively realize the electromagnetic mirror effect, providing a good foundation for subsequent multi-layer shielding structures.

[0056] In one application, Ti3C2T x The preparation method of MXene is as follows: Ti3AlC2 is selected as the precursor material. Ti3AlC2 is a MAX phase material containing an aluminum layer. The aluminum layer can be removed by fluorination treatment to obtain Ti3C2T x The synthesis process of MXene usually uses ammonium fluoride (NH4HF2) or hydrofluoric acid (HF) to react with Ti3AlC2 to selectively etch the aluminum layer. In this process, Ti3AlC2 reacts with fluoride and the aluminum layer is removed, leaving Ti3C2T x The reaction usually lasts for 24 to 48 hours, and the temperature is kept at room temperature or low temperature. x MXene is usually dispersed in a solvent (such as water or an organic solvent) and dispersed by ultrasound. Then, the MXene solution is evenly coated on the surface of the substrate using spin coating or spray coating technology. Common substrates include glass, circuit boards or plastic films. The coated film is dried by natural drying or heating (about 200°C to 500°C). In some cases, in order to further improve the performance of Ti3C2T x To improve the conductivity and stability of the film, annealing treatment is performed under argon atmosphere. Finally, after these steps, highly conductive, ultra-thin and stable Ti3C2T x MXene film, used as the outer layer of reflective shielding material.

[0057] Reference Figure 2 In one embodiment, the second shielding layer 2 adopts V2CT x MXene materials.

[0058] In one embodiment, the thickness of the second shielding layer 2 is in the range of 10-50 microns.

[0059] In one embodiment, the conductivity of the second shielding layer 2 is greater than 10 3 S / m, the conductivity of the second shielding layer 2 is less than 10 4 S / cm, the continuous impedance matching value of the second shielding layer 2 is 20-100 ohms.

[0060] The second shielding layer 2 adopts V2CT xMXene materials also have a layered structure, and their porous structure means that there are tiny pores between each layer of the material or on its surface. The formation of these pores helps to enhance the material's electromagnetic wave absorption capacity, especially by extending the propagation path of electromagnetic waves in the material, thereby improving its energy attenuation efficiency. Specifically, V2CT x The layered structure of MXene itself provides opportunities for multiple reflections of electromagnetic waves, and the pore structure further enhances this effect.

[0061] The formation of porous structure includes two main mechanisms. The first is interlayer pores, V2CT x There may be tiny gaps between the layers of the material. The size of these gaps depends on the synthesis method and post-processing process of the material. These pores help scatter and reflect electromagnetic waves inside the material, thereby enhancing the absorption of electromagnetic waves. x The surface of a material is rich in functional groups, such as -O and -OH. These functional groups can generate tiny pores through specific chemical modification or synthesis processes. These surface pores are usually small, usually at the nanometer level, but they can also enhance the material's ability to absorb high-frequency electromagnetic waves.

[0062] The second shielding layer 2 can be combined with the first shielding layer 1 to form a highly reflective Ti3C2T x MXene forms a synergistic complement to build a three-level electromagnetic attenuation system of "reflection-absorption-dissipation". Specifically, V2CT x Moderate conductivity (about 10 3 S / m) is significantly lower than that of the outer layer Ti3C2T x (about 10 4 -10 5 S / m), thus forming a continuous conductive gradient distribution in the structure from the outside to the inside. This design not only effectively reduces the secondary reflection caused by impedance mutation between layers, but also allows some electromagnetic waves to penetrate into the interior of the material, providing the necessary space for subsequent energy absorption. At the same time, V2CT x The high dielectric loss of V2CT is due to the synergistic effect of multiple microscopic polarization mechanisms: on the one hand, the -O and -OH functional groups rich in the surface of the material produce dipole orientation relaxation under the alternating electric field, converting electromagnetic energy into thermal energy; on the other hand, the nano-gap less than 2nm between the layers induces interfacial polarization (Maxwell-Wagner effect), while the uneven distribution of local charge caused by lattice defects also contributes to energy dissipation. By precisely controlling the functional group ratio and interlayer spacing, V2CT xThe equivalent impedance of the outer layer can smoothly transition to about 100Ω from about 5Ω in the third shielding layer 3, so that the electromagnetic wave can be gradually attenuated in the progressive process of reflection-absorption-dissipation, meeting the 2-40GHz broadband shielding requirements, among which the high frequency band (18-40GHz) mainly relies on the skin effect reflection of the outer layer, while the low frequency band (2-18GHz) is dominated by the porous structure of the second shielding layer 2 for absorption. This porous network (pore size 1-5μm, porosity greater than 65%) not only prolongs the propagation path of electromagnetic waves in the material, inducing multiple reflections and scattering, but also forms a local electric field concentration effect in the pore edge area, thereby greatly improving the energy dissipation efficiency of interface polarization and conduction current, and the high specific surface area (200-300m 2 / g) further increases the density of polarization active sites. x The layer can be prepared into an ultra-thin film of 10-50 μm by solution methods such as spin coating and spray coating, and can be bonded to Ti3C2T through Ti-OV interface bonding. x The seamless integration of the layers meets the requirements of surface density below 0.5g / cm 2 lightweight requirements.

[0063] Use V2CT with moderate conductivity and large dielectric loss x The MXene material efficiently absorbs the residual electromagnetic waves that are not completely reflected by the first shielding layer 1 , further attenuates the electromagnetic wave energy, and provides a more ideal electromagnetic environment for the third shielding layer 3 .

[0064] In terms of size parameters, the thickness of the second shielding layer 2 ranges from 10 to 50 μm, and in the embodiment, a thickness of 20 μm is specifically adopted to meet the design requirements of ultra-thin and lightweight while taking into account the effective depth of electromagnetic wave absorption; the width is flexibly customized according to the actual application scenario (such as the size of intelligent control equipment or high-density integrated circuits) to ensure seamless integration with the adjacent first shielding layer 1 and third shielding layer 3. The moderate conductivity condition is reflected in the material's conductivity of about 10 3 S / m, between the high conductive MXene (10 4 -10 5 S / m) and the third shielding layer 3 low conductivity magnetic composite material (<10 -2 This gradient conductivity design not only achieves continuous impedance matching from the outside to the inside (the first shielding layer is about 5Ω →

[0065] The second shielding layer 2 is about 20Ω → the third shielding layer 3 is about 150Ω). It also significantly reduces the secondary reflection caused by the impedance mutation between layers, forcing the electromagnetic wave energy to decay step by step along the "reflection-absorption-dissipation" path, thereby improving the overall shielding effectiveness. The dielectric loss characteristics are achieved through the synergy of multiple microscopic mechanisms; at the same time, if the conductivity of the second shielding layer 2 is too high (such as close to the first shielding layer 1), the electromagnetic wave reflection ratio will be too large and it will not be able to penetrate the second shielding layer 2 for absorption; if the conductivity is too low (such as close to the third shielding layer 3), it will not be able to effectively guide the electromagnetic wave into the absorption layer. Therefore, 10 3 S / m is the balance point between electromagnetic wave penetration and energy absorption. The conditional parameters for large dielectric loss are closely related to the structural characteristics of the material and the mechanism of interaction between electromagnetic waves and materials. First, the functional groups on the surface of the material (such as -O, -OH, etc.) can induce dipole orientation relaxation under an alternating electric field. When the direction of the electric field changes, the dipoles of these functional groups will rotate accordingly, causing the energy of the electromagnetic wave to be converted into heat energy, thereby increasing dielectric loss. Secondly, the interlayer nanogaps in the material (usually less than 2nm) can induce interface polarization. This phenomenon will enhance the electric field distribution of the material under the action of the electric field, forming a local electric field effect (i.e., the Maxwell-Wagner effect), further enhancing the efficiency of energy absorption and conversion into heat. Lattice defects are also an important factor affecting dielectric loss. Defects in the material will lead to uneven local charge distribution, thereby strengthening the disturbance of the electric field and increasing energy loss.

[0066] In one embodiment, the V2CT of the second shielding layer 2 x MXene preparation method: V2CT x The precursors of MXene are V2AlC and Ti3C2T x Like MXene, the aluminum layer is removed by reacting ammonium fluoride (NH4HF2) or hydrofluoric acid (HF) with V2AlC to obtain V2CT x MXene. The principle of this process is similar to that of Ti3C2T x The synthesis is similar, but V2CT x The conductivity and absorption characteristics of V2AlC are different. During the reaction, V2AlC reacts with fluoride, and the aluminum layer is selectively etched to form a layered structure of V2CT. x MXene. V2CT x The preparation method of MXene film usually uses spin coating or spray coating technology. First, V2CT x The MXene material is dispersed in a suitable solvent (such as water, ethanol, etc.) and ultrasonically dispersed to ensure uniform distribution. Next, the V2CT is applied by spin coating or spray coating. x The solution is coated on the substrate. With the first shielding layer 1Ti3C2T x MXene films are different, with V2CT in the middle layerx The thickness of the film is usually thick, generally 10 to 50 microns, to ensure that the medium frequency electromagnetic waves can be effectively absorbed. The coated film needs to be dried at a temperature of 150 to 200 degrees Celsius to remove the solvent, and finally obtain V2CT with good electromagnetic wave absorption performance. x MXene film.

[0067] In one embodiment, the third shielding layer 3 is made of iron oxide, and the thickness of the third shielding layer 3 is 5-20 microns.

[0068] In one embodiment, the conductivity of the third shielding layer 3 is less than 10 2 S / cm, the continuous impedance matching value of the third shielding layer 3 is 100-200 ohms.

[0069] The third shielding layer 3 is made of Fe3O4 or ferrite, and uses its unique electromagnetic wave absorption and energy conversion mechanism to deeply absorb the afterwave transmitted by the middle second shielding layer 2, completely weakening the residual electromagnetic interference and preventing it from having adverse effects on the inside of the device.

[0070] Fe3O4 or ferrite materials can deeply absorb the afterwaves transmitted by the middle second shielding layer 2, mainly due to their unique magnetic and dielectric loss properties. The magnetic loss mechanism of this material converts the magnetic field component of the electromagnetic wave into thermal energy through the hysteresis loss of the magnetic particles, which is particularly significant in the low-frequency band. At the same time, the dielectric loss mechanism of Fe3O4 or ferrite enhances the unevenness of the electric field distribution through lattice defects and heterogeneous interfaces, converting the electric field component of the electromagnetic wave into thermal energy. In addition, the synergistic effect of magnetism and dielectric loss further enhances the absorption capacity of electromagnetic waves, especially in the medium to low frequency bands. The energy absorption efficiency is further improved through multiple reflections and local electric field enhancement effects. Therefore, the Fe3O4 / ferrite material can effectively absorb the afterwaves transmitted by the middle layer and reduce the impact of electromagnetic interference on the equipment.

[0071] Comprehensive utilization of Ti3C2T in the first shielding layer 1 x Achieve most of the electromagnetic wave reflection in the high frequency band, V2CT of the second shielding layer 2 x Due to the absorption in the mid-frequency band and the dissipative effect of the Fe3O4 / ferrite of the third shielding layer 3 in the low-frequency band, this design can achieve high shielding effectiveness (SE) in a wide frequency band. At the same time, compared with traditional shielding structures, it greatly reduces the overall weight, effectively solving the problem of multi-band electromagnetic compatibility of highly integrated electronic devices, and providing an efficient, lightweight and easy-to-mass-manufacture solution for comprehensive protection against electromagnetic interference.

[0072] In one operating mode, the Fe3O4 or ferrite composite material of the third shielding layer 3 is prepared as follows: Fe3O4 (magnetic ferrite) is typically synthesized via coprecipitation or hydrothermal synthesis. The coprecipitation method involves mixing an iron source (such as iron sulfate (FeSO4) or iron chloride (FeCl3)) with an alkaline solution (such as sodium hydroxide (NaOH)) to chemically react and form a Fe3O4 precipitate. After precipitation, the product is filtered and washed to produce a pure Fe3O4 powder. This powder is typically sintered at a temperature of approximately 500°C to enhance its magnetic properties. To enhance its absorption of low-frequency electromagnetic waves, Fe3O4 powder is often mixed with other materials (such as silicates or zinc oxide) to form a composite material. High-temperature sintering or sol-gel methods combine Fe3O4 with other materials to form a stable composite structure. This composite material exhibits enhanced magnetic and electromagnetic absorption properties. The synthesized Fe3O4 / ferrite composite powder is then mixed with a solvent (such as water or ethanol) to form a slurry. Then, the composite material is evenly coated on the second shielding layer 2V2CT by spin coating, spray coating or dip coating. x The coated composite film needs to be dried by heating (200°C to 250°C) to remove the solvent and ensure the stability of the composite material. To further enhance the composite material's electromagnetic wave absorption capacity, the coated film can be sintered at high temperatures, typically between 300°C and 500°C, to maximize the material's magnetic properties and absorption properties.

[0073] The third shielding layer 3 of the present invention adopts Fe3O4 or ferrite composite system as energy dissipation layer, based on the dual design concept of "magnetic-dielectric cooperative loss" and "impedance continuous gradient", and the second shielding layer 2 (V2CT x MXene) and the first shielding layer 1 (Ti3C2T x MXene) synergistically constructs a "reflection-absorption-dissipation" three-level attenuation system, achieving excellent performance in broadband electromagnetic shielding. Fe3O4 or ferrite materials simultaneously exhibit high magnetic loss (μ">2 in 2-18GHz) and significant dielectric relaxation loss (ε">10 in 2-18GHz) through their unique mechanism: In terms of magnetic loss, Fe3O4 nanoparticles (particle size 20-50nm) induce natural resonance due to magnetocrystalline anisotropy, converting electromagnetic energy into heat energy in the 2-8GHz frequency band, while the multi-domain structure of the ferrite matrix undergoes domain wall displacement under an alternating magnetic field, further enhancing the hysteresis loss in the 8-18GHz frequency band; in terms of dielectric loss, the heterogeneous interface formed between Fe3O4 and the ferrite matrix produces the Maxwell-Wagner effect, and Fe 3+ / Fe 2+The asymmetric lattice charge distribution caused by mixed valence states also greatly enhances the local electric field perturbation, thereby increasing the overall dielectric loss.

[0074] In view of the insufficient attenuation of the first shielding layer 1 and the second shielding layer 2 in the low and medium frequency band (2-18GHz), the material of the third shielding layer 3 is doped with Zn 2+ / Co 2+ By regulating the magnetocrystalline anisotropy field of ferrite, the natural resonance peak is shifted to low frequency, and a hierarchical porous structure is constructed. The matching of pore size and electromagnetic wavelength is used to induce a local field enhancement effect in a specific frequency band (5GHZ-6GHz), thereby achieving enhanced low-frequency performance. At the same time, by regulating the volume ratio of Fe3O4 / ferrite (30-60vol%), its low conductivity (σ<10 -2 S / m) and the second shielding layer 2 (σ≈10 3 S / m) and the first shielding layer 1 (σ≈10 5 S / m) forms a conductivity gradient of three orders of magnitude, achieving a smooth transition between the equivalent impedance (Z≈150-300Ω) and the second shielding layer 2 (Z≈20-50Ω), significantly reducing the interlayer reflection coefficient (Γ drops below 0.1), and forcing the electromagnetic wave energy to be converted into surface waves along the gradient interface, making it easier to be captured by the magnetic medium and converted into heat energy. In terms of technology, by using magnetron sputtering combined with low-temperature annealing (300℃) technology, the Fe3O4 / ferrite composite film is prepared in the range of 5-20μm in thickness, with an area density of less than 0.4g / cm 2 , and use epoxy resin or silane coupling agent to achieve strong interface bonding with the MXene layer (peel strength>1MPa). At the same time, a 2-5nm thick SiO2 insulating layer is coated on the surface of Fe3O4 nanoparticles to block the eddy current effect and further improve the magnetic loss efficiency.

[0075] It should be noted that the materials used for the first shielding layer 1, the second shielding layer 2, and the third shielding layer 3 are designed based on their different electromagnetic wave absorption, reflection, and attenuation characteristics. In theory, other materials can be used to replace these materials, as long as they have similar electromagnetic properties and can perform the corresponding functions. However, while these alternative materials may function similarly to the original design materials, each material may differ in electromagnetic shielding performance, manufacturing process, cost, and applicable scenarios. Therefore, these factors need to be comprehensively considered when selecting alternative materials. For example, while copper and aluminum can replace MXene in terms of conductivity, they may sacrifice some lightweight and flexible properties. Graphene, on the other hand, offers similar high conductivity and thin-film advantages, but at a higher cost and processing difficulty.

[0076] Reference Figure 3, shows a comparison diagram of the material properties of the first shielding layer, the second shielding layer and the third shielding layer provided by an embodiment of the present invention.

[0077] This embodiment verifies its excellent performance in electromagnetic shielding by finely setting and simulating the materials and processes in the ANSYS HFSS electromagnetic simulation platform. First, in terms of material selection and layered design, the first shielding layer 1 adopts a high conductivity (>10 4 S / cm)Ti3C2T x MXene film; the second shielding layer 2 uses V2CT x MXene film; and on Ti3C2T x The surface of the layer is further sprayed or spin-coated with a film layer of 10-50μm thickness. The second shielding layer 2 has the characteristic of high dielectric loss; the innermost third shielding layer 3 is a Fe3O4 / ferrite composite layer. x A mixed composite film (thickness 5-20 μm) of nano-Fe3O4 particles and ferrite powder is deposited on the layer, and after appropriate annealing or epoxy curing, the synergy of high magnetic loss and dielectric loss is achieved. A three-layer stacked geometry model is created in ANSYS HFSS. The first shielding layer 1 is Ti3C2T x The thickness t1 is 0.2 μm, and the V2CT of the second shielding layer 2 is x The thickness t2 is 20 μm, the thickness t3 of the Fe3O4 / ferrite of the third shielding layer 3 is 10 μm, and the wave port excitation and the radiation boundary of the other surfaces are set for each boundary to approximately simulate the plane electromagnetic wave incident situation. Then, in the material parameter input, Ti3C2T x Set conductivity to 10 4 -10 5 S / m, relative dielectric constant of about 5-10, V2CT x Set the conductivity to about 10 3 The S / m and dielectric constant of the Fe3O4 / ferrite composite layer can vary with frequency by 10-30, while the conductivity is only 10-2S / m and the relative dielectric constant is about 10-15. A set of comparative experiments were also conducted, namely the magnetic field distribution diagram of the traditional sandwich structure and the magnetic field distribution diagram after adding a single MXene material shield. The results are as follows Figure 2 shown.

[0078] Figure 2 The characteristics of three different materials in different frequency bands are shown, including the changes in reflectivity (R), transmittance (T) and absorptivity (A). Specifically, the three curves in the figure represent: the red curve (Ti3C2T x Outer layer): This curve represents Ti3C2T x The properties of the material in the outer layer. The blue dashed line (V2CTx Middle layer): This curve represents V2CT x Green dashed line (Fe3O4 / Ferrite): This curve represents the characteristics of the Fe3O4 / Ferrite material in the inner layer.

[0079] For curve analysis:

[0080] Reflectivity (R):

[0081] At low frequencies (0-5 GHz), the reflectivity of all three materials is close to 1, but as the frequency increases, the reflectivity of Ti3C2T x The reflectivity remains high, while V2CT x The reflectivity of Fe3O4 / ferrite begins to decrease gradually.

[0082] The reflectivity of Fe3O4 / ferrite material shows a relatively gentle downward trend in the medium and high frequency bands (10-25GHz), indicating that its reflection ability is relatively stable.

[0083] Transmittance (T):

[0084] In the low frequency band, Ti3C2T x and V2CT x The transmittance of the materials remains low (close to 0), indicating that these two materials can effectively prevent the penetration of electromagnetic waves.

[0085] As the frequency increases, the transmittance gradually increases, especially for Ti3C2T x The transmittance changes of Fe3O4 / ferrite are more obvious.

[0086] The transmittance of Fe3O4 / ferrite material gradually increases in the mid-frequency band, especially in the 20-30 GHz range, indicating that it has a certain degree of tolerance for the transmission of electromagnetic waves in these frequency bands.

[0087] Absorption rate (A):

[0088] The absorption rate increases with the increase of frequency, especially in the higher frequency band (30-40GHz), where the absorption rate of Fe3O4 / ferrite material increases significantly.

[0089] Ti3C2T x The absorption rate of the material is relatively stable, and the increase is relatively small, indicating that its absorption efficiency is relatively limited.

[0090] V2CT x The absorption rate of the material also shows a gradually increasing trend, but its growth rate is slightly lower than that of Fe3O4 / ferrite material.

[0091] Ti3C2T x(The first shielding layer 1 material) has a strong reflection effect in the low frequency band, and the reflectivity is stable in the medium and high frequency bands, but the transmittance is low and the absorption rate is relatively small. x The material for the second shielding layer (2) exhibits relatively flat reflection, transmission, and absorption characteristics, making it suitable for regulating electromagnetic wave transmission within specific frequency bands. Fe3O4 / ferrite (the material for the third shielding layer (3)) exhibits excellent absorption properties in the mid- to high-frequency bands, effectively absorbing high-frequency electromagnetic waves and suitable for enhancing absorption efficiency. This result is consistent with expectations.

[0092] Reference Figure 3 , which shows a comparison diagram of magnetic field distribution of different methods provided by an embodiment of the present invention.

[0093] The purple curve represents the shielding effect after adding a single MXene material. This curve shows a low magnetic induction intensity, indicating that the MXene material can effectively reflect and absorb electromagnetic waves, providing good shielding performance across the entire frequency band.

[0094] The black curve represents the shielding effect of the traditional sandwich structure. The magnetic induction intensity of this curve is lower than that of the purple curve, indicating that the shielding effect of the traditional structure is similar to that of a single MXene material. Especially at longer distances, the magnetic field intensity remains high.

[0095] The red curve represents the shielding effectiveness of the present invention. This curve shows significant attenuation of magnetic flux density, particularly at longer distances, where the magnetic field intensity is significantly lower than that of the purple and black curves. This demonstrates that the optimized material and structural combination of this design method more effectively attenuates electromagnetic waves, thereby reducing their impact on devices and exhibiting superior performance. The design scheme offers excellent broadband absorption and lightweight advantages, making it suitable for electromagnetic compatibility and protection of high-density integrated circuits and intelligent electronic devices, and possesses significant potential for expansion and application.

[0096] The present invention uses a gradient design with the first shielding layer 1 reflecting, the second shielding layer 2 absorbing, and the third shielding layer 3 dissipating, so that the electromagnetic can be transmitted along the path of conductivity and polarization relaxation and conduction loss can be used to efficiently absorb the residual wave during the transmission process, so as to absorb most of the electromagnetic, and then achieve deep conversion of low-frequency afterwaves through the inner layer of Fe3O4 or ferrite.

[0097] In this embodiment, an embodiment of the present invention provides an electromagnetic shielding film, the beneficial effect of which is that the present invention includes a first shielding layer that can reflect electromagnetic waves, a second shielding layer that can absorb electromagnetic waves, and a third shielding layer that can dissipate electromagnetic waves, and the conductivity of the three shielding layers increases successively to form an electromagnetic transmission path. When receiving electromagnetic waves, they can reflect, absorb and dissipate in sequence to gradually attenuate the electromagnetic waves, thereby eliminating and shielding electromagnetic waves, improving the shielding effect, and avoiding secondary interference.

[0098] The embodiment of the present invention also provides an intelligent control device based on electromagnetic shielding film, see Figure 4 , which shows a structural schematic diagram of an intelligent control device based on an electromagnetic shielding film provided by an embodiment of the present invention.

[0099] As an example, the intelligent control device based on the electromagnetic shielding film may include: a device body and the electromagnetic shielding film as described in the above embodiment;

[0100] The electromagnetic shielding film is attached to the outer shell surface of the device body or the surface of the circuit board.

[0101] In one embodiment, the materials of the second and third shielding layers of the electromagnetic shielding film are designed with reasonable thickness and conductivity, and are fixed to the material of the first shielding layer through physical bonding or chemical interface treatment to ensure that electromagnetic waves are absorbed or dissipated layer by layer. For example: the first shielding layer is Ti3C2T x The film can be fixed to the circuit board of the device body or the device housing by bonding or coating processes (such as spraying, spin coating).

[0102] After being equipped with the electromagnetic shielding film described in the above embodiment, the intelligent control device of the present invention does not require active control circuits, and has the advantages of wide-band compatibility, ultra-thinness and lightness, and flexible adaptation. It can be widely used in electromagnetic protection of intelligent control equipment and high-density integrated circuits, and provides a solution for equipment stability in complex electromagnetic environments.

[0103] Those skilled in the art can clearly understand that, for the sake of convenience and brevity, the specific working process of the device described above can refer to the corresponding process in the aforementioned method embodiment and will not be repeated here.

[0104] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation of the present invention. When an element such as a layer, region or substrate is referred to as being "on" or "above" another element, it can be directly on the other element, or there can be an intermediate element. In contrast, when an element is referred to as being "directly on" or "above" another element, there are no intermediate elements. It should also be understood that when an element is referred to as being "under" or "below" another element, it can be directly under or below the other element, or there can be an intermediate element. In contrast, when an element is referred to as being "directly under" or "below" another element, there are no intermediate elements. Unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0105] Those skilled in the art will appreciate that the embodiments of the present application may also provide computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0106] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), apparatuses and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0107] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0108] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0109] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An electromagnetic shielding film, characterized in that: The electromagnetic shielding film comprises: a first shielding layer, a second shielding layer and a third shielding layer connected in sequence from the outside to the inside; The first shielding layer is made of MXene material that can reflect electromagnetic waves; the second shielding layer is made of MXene material that can absorb electromagnetic waves and has a porous structure; the third shielding layer is made of a magnetic composite material that can dissipate electromagnetic waves; The electrical conductivity of the first shielding layer is greater than the electrical conductivity of the second shielding layer, and the electrical conductivity of the second shielding layer is greater than the electrical conductivity of the third shielding layer; The continuous impedance matching value of the first shielding layer is smaller than the continuous impedance matching value of the second shielding layer, and the continuous impedance matching value of the second shielding layer is smaller than the continuous impedance matching value of the third shielding layer.

2. The electromagnetic shielding film according to claim 1, wherein The first shielding layer is made of Ti3C2T x Mxene material.

3. The electromagnetic shielding film according to claim 2, wherein: The thickness of the first shielding layer is 100-200 nanometers.

4. The electromagnetic shielding film according to claim 2, wherein The conductivity of the first shielding layer is greater than 10 4 S / cm, and the continuous impedance matching value of the first shielding layer is 5-20 ohms.

5. The electromagnetic shielding film according to claim 1, wherein The second shielding layer adopts V2CT x MXene materials.

6. The electromagnetic shielding film according to claim 5, characterized in that The thickness of the second shielding layer is in the range of 10-50 microns.

7. The electromagnetic shielding film according to claim 5, characterized in that The conductivity of the second shielding layer is greater than 10 3 S / m, the conductivity of the second shielding layer is less than 10 4 S / cm, and the continuous impedance matching value of the second shielding layer is 20-100 ohms.

8. The electromagnetic shielding film according to claim 1, wherein The third shielding layer is made of iron oxide, and the thickness of the third shielding layer is 5-20 microns.

9. The electromagnetic shielding film according to claim 1, wherein The conductivity of the third shielding layer is less than 10 2 S / cm, and the continuous impedance matching value of the third shielding layer is 100-200 ohms.

10. An intelligent control device based on electromagnetic shielding film, characterized in that: The device comprises: a device body and the electromagnetic shielding film according to any one of claims 1 to 9; The electromagnetic shielding film is attached to the outer shell surface of the device body or the surface of the circuit board.

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