Zn-Fe-Mn oxide-hard carbon composite material and preparation method and application thereof

Abstract

The invention relates to the technical field of wave-absorbing materials, and particularly discloses a Zn-Fe-Mn oxide-hard carbon composite material and a preparation method and application thereof. The preparation method comprises the following steps: preparing pomegranate-shaped spheres through a coprecipitation-calcination method; then, uniformly dispersing the mixture in a self-made solvent composition, and curing and molding the mixture through heating treatment; and finally, carrying out annealing treatment in a high-temperature tube furnace at the temperature of 800 DEG C in an argon protective atmosphere (the flow rate is 100 sccm), so as to prepare the Zn-Fe-Mn oxide-hard carbon composite material. The composite material has a unique three-dimensional layered structure, shows excellent broadband microwave absorption characteristics, and can realize efficient electromagnetic wave attenuation. And a new way is opened up for structural design and optimization of the high-performance wave-absorbing material, and the wave-absorbing material has a wide application prospect in the application fields of advanced stealth technology and novel electromagnetic shielding.

Description

Technical Field

[0001] The present invention belongs to the field of microwave absorbing materials, and in particular relates to a Zn-Fe-Mn oxide-hard carbon composite material and a preparation method and application thereof. Background Art

[0002] With the rapid development of modern technology, devices such as mobile communications, intelligent robots, 5G base stations, satellite navigation, electronic radar, and stealth equipment have become widely used in defense equipment and daily life. While bringing convenience to people, they also cause electromagnetic pollution. For example, electromagnetic interference can affect the normal operation of electronic devices, and electromagnetic radiation can pose a threat to human health. Therefore, it is extremely urgent to find absorbing materials that can attenuate electromagnetic waves and reduce or eliminate electromagnetic pollution. Traditional absorbing materials (such as ferrites and ceramics) also have shortcomings such as high density, narrow absorption bandwidth, and difficulty in processing. Therefore, the development of broadband, high-efficiency absorbing materials is an urgent problem that needs to be solved.

[0003] Pomegranate-like metal oxide microspheres have attracted much attention in recent years due to their unique multi-level pore structure and potential for application in energy, electronics, catalysis and other fields. However, as microwave absorbing materials, their inherent defects such as high density and insufficient dielectric loss limit their practical application performance. Among them, hard carbon materials are ideal conductive components due to their rich structural defects and chemical stability. The nanopores and functional groups generated by their non-graphitizing properties can effectively enhance the dielectric polarization loss. However, the current research and development of pomegranate-like metal oxide-hard carbon composites faces the dual challenges of uniform dispersion of metal oxide nanoparticles and control of structural morphology, which has become a key factor restricting the improvement of their microwave absorbing performance.

[0004] Hard carbon materials exhibit unique advantages in microwave absorption: their non-graphitization properties create structural defects, residual functional groups, and nanopores that act as polarization centers to enhance dielectric loss. Their excellent chemical stability and facile synthesis make them valuable for practical applications. However, the dual technical requirements of combining hard carbon with pomegranate-like metal oxides, such as maintaining a uniform dispersion of metal oxide nanoparticles and a well-organized pomegranate-like porous structure, present significant challenges in the development of such composites. Summary of the Invention

[0005] Based on the above problems, the present invention provides a method for preparing a Zn-Fe-Mn oxide-hard carbon composite material. The Zn-Fe-Mn oxide-hard carbon composite material prepared by this method forms a three-dimensional interconnected network structure through a hard carbon matrix. This unique composite structure can effectively enhance the interface polarization effect and multiple scattering mechanism, significantly improve the electromagnetic wave absorption performance of the material and broaden the effective absorption band, and to a certain extent solve the problems of high density, narrow absorption bandwidth, and difficult processing of traditional absorbing materials in the prior art.

[0006] The present invention provides a Zn-Fe-Mn oxide-hard carbon composite material and its preparation method and application. The technical solution proposed by the present invention is: In a first aspect, the present invention provides a method for preparing a Zn-Fe-Mn oxide-hard carbon composite material, comprising the following steps: Step a, preparing a metal organic complex of Zn, a metal organic complex of Mn, a metal organic complex of Fe and NaHCO3 powder by coprecipitation-calcination method powder; Step b, The powder is slowly stirred and added to the homemade solvent combination to mix well. Mixing solution; Step c, raising the temperature and increasing the stirring speed to fully solidify the mixed solution to obtain a solidified product; Step d, performing a high-temperature annealing treatment on the cured product under an inert atmosphere to carbonize the organic solvent to obtain a Zn-Fe-Mn oxide-hard carbon composite material; Compared with the prior art, the preparation method of the Zn-Fe-Mn oxide-hard carbon composite material provided by the present invention is firstly prepared by co-precipitation-calcination of Zn metal organic complex, Mn metal organic complex, Fe metal organic complex and NaHCO3 powder. The powder is then mixed with a homemade solvent The powders are mixed, and the solution is fully solidified by increasing the temperature and stirring speed. Finally, the organic solvent is carbonized by high-temperature annealing to obtain a Zn-Fe-Mn oxide-hard carbon composite material.

[0007] Furthermore, in step a, the metal organic complex of Zn may be Zn(acac)2; the metal organic complex of Mn may be Mn(acac)2; and the metal organic complex of Fe may be Fe(acac)3.

[0008] In the present application, the metal organic complex of Zn, the metal organic complex of Mn, the metal organic complex of Fe and the NaHCO3 powder are first dissolved in a sufficient amount of deionized water to obtain a single solution, and then all the metal organic complexes and the NaHCO3 solution are mixed and reacted to form a coprecipitate. It should be further explained that in a specific embodiment of the present invention, the metal organic complex of Zn is Zn(acac)2, the metal organic complex of Mn can be Mn(acac)2, and the metal organic complex of Fe can be Fe(acac)3. For example, Zn(acac)2 and NaHCO3 react in an aqueous solution, and Zn(acac)2 will dissociate into Zn in the aqueous solution.2+ and two acac- ions, NaHCO3 completely dissociates into Na + and HCO3 - , and HCO3 - Secondary dissociation and hydrolysis will also occur in water, HCO3 - Secondary dissociation into H + and CO3 2- ,HCO3 - Further hydrolysis can produce H2CO3 and OH - ions, and acac - It is a weakly basic ligand, and its conjugate acid is acetylacetone acacH, with a pKa≈9.0, which is weaker than the second step dissociation of H2CO3, with a pKa2≈10.33. When [Zn (acac)2] dissociates into Zn 2+ With HCO3 - CO3 provided 2- OH - When in contact, they will preferentially combine to form basic zinc carbonate precipitate, prompting the dissociation equilibrium of [Zn (acac) 2] to continuously move forward (Le Chatelier principle). Similarly, when the metal organic complexes of Fe (acac) 3 and Mn (acac) 2 and NaHCO 3 are in aqueous solution, they will also combine to form basic iron carbonate precipitate and basic manganese carbonate precipitate. Because in the present invention, the metal organic complexes of Zn (acac) 2, Fe (acac) 3 and Mn (acac) 2 are reacted with the aqueous solution of NaHCO 3 at the same time, when the three metal ions coexist, they react with HCO 3 - The reactions proceed synchronously, and each metal ion generates its own basic carbonate. However, since the precipitation process occurs simultaneously, these basic carbonates will not crystallize individually, but will intermingle and precipitate together to form a mixed phase co-precipitate.

[0009] The coprecipitate is then calcined under the protection of inert gas and annealed at high temperature to obtain powder.

[0010] Furthermore, in step b, the self-made solvent combination includes a carbon source, a curing agent, an organic solvent and a leavening agent.

[0011] Furthermore, the carbon source may be at least one of phenolic resin and epoxy resin; the curing agent includes ethylenediamine; the organic solvent includes at least one of anhydrous ethanol and acetone; and the leavening agent includes at least one of sodium bicarbonate and sodium carbonate.

[0012] Further, the mass ratio of the carbon source, the curing agent, the organic solvent and the bulk agent is (10-15):(0.1-1):(0.5-5):(0.5-4), for example, the mass ratio of the carbon source, the curing agent, the organic solvent and the bulk agent is 10:0.1:0.5:0.2, 11:0.2:1.5:0.8, 12:0.4:2.5:1.5, 13:0.6:3.5:2.5, 14:0.8:4.5:3.5, 15:1:5:4, or a range formed by any two of the above ratios.

[0013] In a specific embodiment, the mass ratio of the carbon source, the curing agent, the organic solvent and the bulk agent is 12:1:1:1, and the ratio is adjusted according to the actual situation. Since the curing agent will carbonize at high temperature, which may increase the additional carbon source, the concentration of the curing agent is in the range of 0.1-1 parts; since the increase of the content of the organic solvent will lead to the increase of the solidification time, the content of the organic solvent is in the range of 0.5-5 parts; in the actual process, the bulk agent can increase the porosity of the product, thereby optimizing the spatial layout of the product, but when the content of the bulk agent is too high, the product may have too many pores, which may reduce the wave absorption performance of the product, so the content of the bulk agent in the present application is in the range of 0.5-4 parts.

[0014] By controlling the content of the carbon source, the curing agent, the organic solvent and the bulk agent in the self-made solvent combination, the dispersion and mixing process can be further optimized to ensure the uniformity of the structure and the stability of the performance of the material.

[0015] Further, the self-made solvent combination and The mass ratio of the powder is (1-6):(1-6), and further, in the experiment, the ratio can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 2:1, 2:3, 2:5, 2:6, 3:1, 3:2, 3:4,..., 6:5, or a range formed by any two of the above ratios, i.e., the mass ratio of the self-made solvent combination and Any mass ratio in the range of (1-6):(1-6) of the powder can achieve the purpose of the present application.

[0016] Further, in step b, the stirring rate is 0.1 rpm-1.5 rpm, for example, 0.1 rpm, 0.2 rpm, 0.3 rpm, 0.4 rpm, 0.5 rpm, 0.6 rpm, 0.7 rpm, 0.8 rpm, 0.9 rpm, 1.1 rpm, 1.2 rpm, 1.3 rpm, 1.4 rpm, 1.6 rpm, or a range formed by any two of the above ratios. It should be further pointed out that in step b of the present application, a lower stirring rate is used considering that the obtained product in step a is a gel, and the stirring rate is too high may cause the product to be broken. The powder structure is relatively loose, and slow stirring can speed up the process in step a. Powder homemade solvent combination mixed without destroying The structure of the powder, at the same time makes The powder is coated with a homemade solvent combination, which is further strengthened by a curing agent. Powder structure.

[0017] As a further improvement, the homemade solvent combination was slowly added via a syringe pump at a low speed of 0.05 mL / min. In powder, low speed injection can reduce The structural destruction of the powder ensures that the subsequent Zn-Fe-Mn oxide-hard carbon composite material has better performance stability.

[0018] Further, in step c, the heating temperature is 60°C-90°C, and the stirring rate is 100 rpm-300 rpm, for example, 100 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm, 300 rpm, or a range consisting of any two ratios thereof. In step c, the present invention significantly accelerates the stirring speed because the homemade solvent combination in step b is The powder is wrapped and the structure of the powder is strengthened. Therefore, the main purpose of step c is to speed up the stirring speed so that The powder can be quickly and evenly dispersed in the homemade solvent combination.

[0019] Through step b and step c, a slow and a slow different stirring rate, so that The powder is evenly distributed in the solution of the homemade solvent combination, which can further optimize the dispersion and mixing process and ensure the structural uniformity and performance stability of the material.

[0020] Furthermore, in step a, the coprecipitation-calcination method comprises the following steps: a-1: Dissolve the metal organic complex of Zn, the metal organic complex of Mn, the metal organic complex of Fe and NaHCO3 powder in sufficient amount of deionized water to obtain a single solution; a-2: All the single solutions obtained in a-1 are mixed to obtain a coprecipitate; a-3: calcining the coprecipitate under the protection of inert gas and performing high temperature annealing to obtain powder.

[0021] Furthermore, in step a-1, the mass ratio of the metal organic complex of Zn, the metal organic complex of Mn, the metal organic complex of Fe and NaHCO3 is 44:100:(1-60):107.

[0022] Furthermore, the mass ratio of the metal organic complex of Zn, the metal organic complex of Mn, the metal organic complex of Fe and NaHCO3 is 44:100:(5-40):107.

[0023] Furthermore, in the examples of the present invention, a single variable example design was carried out for the metal organic complex of Fe. The results showed that when the content of the metal organic complex of Fe in the system increased, the microwave absorption characteristics of the Zn-Fe-Mn oxide-hard carbon composite material would also be significantly changed. Similarly, when the mass of the metal organic complexes of Zn and Mn in the system was adjusted individually or in combination, it also had a great influence on the microwave absorption characteristics of the Zn-Fe-Mn oxide-hard carbon composite material.

[0024] Furthermore, in step a-3, the annealing temperature is 800° C.-1000° C., for example, 800° C., 820° C., 840° C., 860° C., 880° C., 900° C., 920° C., 940° C., 960° C., 980° C., 1000° C., or a range consisting of any two ratios thereof, the annealing time is 2-3 hours, and the annealing is performed under vacuum conditions. During the annealing process, the organic solvent is carbonized. The powder is converted into Zn, Fe and Mn oxides (chemical formula ZnFe2O4, FeO and MnO, etc.) under carbon reduction.

[0025] This method ensures the structural uniformity and performance stability of the material by optimizing the dispersion, mixing and carbonization processes.

[0026] As a further improvement, the The powder is pomegranate-shaped with a particle size of 0.8-1.2 microns.

[0027] Furthermore, the The particle size of the powder is 1 micron.

[0028] In a second aspect, the present invention further provides a Zn-Fe-Mn oxide-hard carbon composite material, which is prepared by any of the above-mentioned methods for preparing the Zn-Fe-Mn oxide-hard carbon composite material.

[0029] In a third aspect, the present invention also provides an application of the above-mentioned Zn-Fe-Mn oxide-hard carbon composite material, and the above-mentioned Zn-Fe-Mn oxide-hard carbon composite material is used as an absorbing material in aircraft stealth, electromagnetic absorption, electromagnetic protection or microwave darkroom.

[0030] Compared with the prior art, the present invention has the following beneficial effects: The Zn-Fe-Mn oxide-hard carbon composite material proposed in this paper features a three-dimensional interconnected network of Zn-Fe-Mn oxide particles within a hard carbon matrix. This unique composite structure effectively enhances interfacial polarization and multiple scattering mechanisms, significantly improving the material's electromagnetic wave absorption performance and broadening its effective absorption band. The composite material achieves a minimum reflection loss of -59.4 dB and an effective absorption band of 4.5-18 GHz, exhibiting excellent microwave absorption properties and promising applications in stealth technology and electromagnetic protection.

[0031] The preparation method of the present invention utilizes a process combining coprecipitation and calcination with resin carbonization, enabling the efficient preparation of Zn-Fe-Mn oxide-hard carbon composites. This method features a simple process flow, manageable costs, and high yield, effectively addressing the shortcomings of existing absorbers in terms of structural design and preparation. By manipulating the ratio of the metal-organic complex and the carbonization conditions, a series of composite materials with varying electromagnetic properties can be obtained to meet diverse application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 It is pomegranate-shaped SEM image of the sphere; Figure 2 is the SEM image of Zn-Fe-Mn oxide particles; Figure 3 is a three-dimensional reflection loss spectrum of Zn-Fe-Mn oxide-hard carbon composite material Example 1; Figure 4 is a three-dimensional reflection loss spectrum of Zn-Fe-Mn oxide-hard carbon composite material Example 2; Figure 5 is a three-dimensional reflection loss spectrum of Zn-Fe-Mn oxide-hard carbon composite material Example 3; Figure 6 is a three-dimensional reflection loss spectrum of Zn-Fe-Mn oxide-hard carbon composite material Example 4; Figure 7 is a three-dimensional reflection loss spectrum of Zn-Fe-Mn oxide-hard carbon composite material Example 5; Figure 8 is a three-dimensional reflection loss plot of Zn-Fe-Mn oxide-hard carbon composite Example 6; Figure 9 is a three-dimensional reflection loss plot of Zn-Fe-Mn oxide-hard carbon composite Example 7; Figure 10 is a three-dimensional reflection loss plot of Zn-Fe-Mn oxide-hard carbon composite Example 8.

[0034] For the purpose of promoting an understanding of the application, the application will be described in greater detail below with reference to the drawings illustrative of preferred embodiments of the application, but the scope of the application is not limited to the specific embodiments described below.

[0035] Unless otherwise defined, all terms used in connection with the present application are to be interpreted in accordance with their ordinary meaning. The professional terms used in the present application are used only for the purpose of describing the specific embodiments of the present application and are not intended to limit the scope of the present application. DETAILED DESCRIPTION

[0036] The application will be further described with reference to the drawings, in which the embodiments of the application will be explained. It should be understood that these embodiments are only meant to illustrate the application and not to limit the scope of the application.

[0037] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The endpoints of the ranges and any values are provided as approximate descriptions of the ranges and are understood to be open-ended. Each range endpoint is independently combinable with each other range endpoint or individual value to form a new range or a new value, as understood by persons of ordinary skill in the art. The disclosure is not limited to the exemplary ranges or values, but rather to the full extent of the ranges and values.

[0038] If not specifically explained, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0039] If not specifically explained, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0040] In the context of the specification, including in the examples below, tests were performed according to the following methods: SEM image scanning of powders A small amount Powder, add ethanol and ultrasonically disperse for 5 minutes, sprinkle the ultrasonic powder evenly on the sample holder with conductive glue, blow off the excess powder, fix the sample holder on the sample stage of SEM, vacuum and test, set the parameters as 10KV acceleration voltage, 5mm working distance, medium scanning speed, 5nm beam spot size, select secondary electron detector (SE), and image resolution . Output and save the image.

[0041] SEM image scanning of Zn-Fe-Mn oxide-hard carbon composite material Take a small amount of Zn-Fe-Mn oxide-hard carbon composite powder, add ethanol and ultrasonically disperse for 5 minutes, evenly sprinkle the powder after ultrasonication on the sample holder with conductive glue, blow off the excess powder, fix the sample holder on the sample stage of SEM, vacuumize and test, set the parameters as 15KV acceleration voltage, 5mm working distance, slow scanning speed, 3nm beam spot size, select secondary electron detector (SE), and image resolution. , the picture is output and saved.

[0042] Three-dimensional reflection loss (RL) spectrum measurement The obtained Zn-Fe-Mn oxide-hard carbon composite material was pressed into a coaxial ring, and samples with different thicknesses of 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, and 4 mm were prepared. The frequency range of the test instrument was set to 2 GHz to 18 GHz. The sample was placed in a test fixture and connected to a vector network analyzer to measure the reflection coefficient (S11) of the sample. Each thickness of each sample was tested 3 times and the average value was taken. The measured sample reflection coefficient data was used to calculate the reflection loss value using the formula RL=20log10|S11|. The three-dimensional reflection spectrum was drawn using the Origin data processing software with frequency as the X-axis, sample thickness as the Y-axis, and reflection loss value as the Z-axis.

[0043] The present invention is described in detail below with reference to the examples, but the implementation and protection of the present invention are not limited thereto. The following examples are only partial examples of the present invention and are not intended to limit the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this field or the product instructions are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially.

[0044] Example 1 Powder preparation Zn(acac)2(2.1948g), Mn(acac)2(4.9g), Fe(acac)2(0.233g) and 50ml of NaHCO3 solution (1.25mol / L) were dissolved in 40ml of water to produce a coprecipitation reaction to obtain a mixed phase coprecipitate. The mixed phase coprecipitate was then calcined at 750℃ under the protection of helium to obtain powder, and scanning electron microscopy (SEM) was used to The powder is scanned and obtained The SEM image of the sphere is shown in Figure 2. Figure 1 shown.

[0045] Preparation of Zn-Fe-Mn oxide-hard carbon composites Take 10g The powder (particle size 0.8-1.2μm) was dissolved in 120mL of anhydrous ethanol to form a uniform suspension at a mechanical stirring rate of 0.5rpm. A 50wt% homemade solvent combination (the mass ratio of carbon source, curing agent, organic solvent and leavening agent is 12:1:1:1) was slowly added at a rate of 0.05mL / min using a syringe pump. The addition was stopped when the amount of homemade solvent combination added reached 10g (the mass ratio of powder to homemade solvent combination was 1:1). The system was then heated to 60°C and the stirring rate was increased to 100rpm, and maintained for 2 hours to complete the curing process. Finally, under argon protection, the temperature was raised to 800°C at a heating rate of 5°C / min and annealed for 2 hours to obtain a Zn-Fe-Mn oxide-hard carbon composite material with a porous structure, named M-HC-A1. The Zn-Fe-Mn oxide-hard carbon composite material was scanned using a scanning electron microscope (SEM) to obtain an SEM image of the Zn-Fe-Mn oxide-hard carbon composite material. The results are shown as follows. Figure 2 As shown. At the same time, the reflection loss value of the composite material is detected. The three-dimensional reflection loss spectrum of the composite material is shown as Figure 3 shown.

[0046] Example 2 The difference is The raw material ratio of the powder particles is A2 in Table 1. The other steps and parameters are the same as those in Example 1. The product is named M-HC-A2. The three-dimensional reflection loss spectrum of the composite material is shown in FIG. Figure 4 shown.

[0047] Example 3 The difference is The raw material ratio of the powder particles is A3 in Table 1. The other steps and parameters are the same as those in Example 1. The product is named M-HC-A3. The three-dimensional reflection loss spectrum of the composite material is shown in FIG. Figure 5 shown.

[0048] Example 4 The difference is The raw material ratio of the powder particles is A4 in Table 1. The other steps and parameters are the same as those in Example 1. The product is named M-HC-A4. The three-dimensional reflection loss spectrum of the composite material is shown in FIG. Figure 6 shown.

[0049] Example 5 The difference is that the mass ratio of the powder to the homemade solvent is 1:3. The other steps and parameters are the same as those in Example 1. The product is named M-HC2-A1. The three-dimensional reflection loss spectrum of the composite material is shown in FIG. Figure 7 shown.

[0050] Example 6 The difference is that the mass ratio of the powder to the homemade solvent is 1:6. The other steps and parameters are the same as those in Example 1. The product is named M-HC3-A1. The three-dimensional reflection loss spectrum of the composite material is shown in Figure 2. Figure 8 shown.

[0051] Products synthesized using four different raw material ratios—M-HC-A1, M-HC-A2, M-HC-A3, M-HC-A4, M-HC2-A1, and M-HC3-A1—were characterized and analyzed. Their micromorphologies were observed using scanning electron microscopy (SEM). Zn-Fe-Mn oxide-hard carbon composites were thoroughly mixed with paraffin wax, with a Zn-Fe-Mn oxide-hard carbon composite content of 30%. The results showed that samples synthesized under different conditions exhibited differences in microwave absorption properties, providing valuable data for further research into the performance optimization and application of Zn-Fe-Mn oxide-hard carbon composites.

[0052] Table 1 Parameters of Zn-Fe-Nn oxide-hard carbon composites

[0053] according to Figure 3-Figure 8 As shown in the figure, the Zn-Fe-Mn oxide-hard carbon composite material exhibits excellent microwave absorption properties, with the lowest reflection loss reaching -59.4 dB. The experimental results show that by adjusting the amount of Fe(acac)3 added and the ratio of the homemade solvent combination, the microwave absorption performance of the material can be effectively optimized, and its effective absorption band can be widened to the range of 4.5-18 GHz. Further analysis Figure 3-Figure 8 It shows that the change in the content of the combination of Fe(acac)3 and homemade solvent during the reaction and carbonization process will significantly affect the distribution state of the magnetic components and the content of the carbon matrix in the composite material, thereby regulating the electromagnetic parameters of the material and ultimately improving its microwave absorption performance.

[0054] Example 7 The difference is that the mass ratio of carbon source, curing agent, organic solvent and leavening agent in the homemade solvent combination is 12:1.5:1:1.5. The other steps and parameters are the same as those in Example 1. The product is named M-HC4-A1. The three-dimensional reflection loss spectrum of the composite material is shown in FIG. Figure 9 shown.

[0055] Example 8 The difference is that the mass ratio of carbon source, curing agent, organic solvent and leavening agent in the homemade solvent combination is 12:0.5:1:0.5. The other steps and parameters are the same as those in Example 1. The product is named M-HC4-A2. The three-dimensional reflection loss spectrum of the composite material is shown in FIG. Figure 10 shown.

[0056] according to Figure 9-10 As shown in the results, adjusting the principle ratio of the homemade solvent combination can also regulate the microwave absorption performance of the Zn-Fe-Mn oxide-hard carbon composite material, and can achieve very good results. These research findings confirm that the Zn-Fe-Mn oxide-hard carbon composite material has important application prospects and research value in the field of electromagnetic wave absorption.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any form. Therefore, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical solution of the present invention and are based on the technical essence of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a Zn-Fe-Mn oxide-hard carbon composite material, characterized in that: The following steps are involved: Step a, preparing a precursor by coprecipitation-calcination of a metal organic complex of Zn, a metal organic complex of Mn, a metal organic complex of Fe and NaHCO3 powder powder; Step b, The powder is slowly stirred and added to the homemade solvent combination to mix well. Mixing solution; Step c, raising the temperature and increasing the stirring speed to fully solidify the mixed solution to obtain a solidified product; Step d, performing high-temperature annealing treatment on the solidified product under the protection of an inert atmosphere to obtain a Zn-Fe-Mn oxide-hard carbon composite material; The metal organic complex of Zn is Zn(acac)2; the metal organic complex of Mn is Mn(acac)2; the metal organic complex of Fe is Fe(acac)3; The homemade solvent combination includes a carbon source, a curing agent, an organic solvent and a leavening agent; the carbon source includes at least one of phenolic resin and epoxy resin; the curing agent includes at least one of ethylenediamine and diethylenetriamine; the organic solvent includes at least one of anhydrous ethanol and acetone; and the leavening agent includes at least one of sodium bicarbonate and sodium carbonate.

2. The preparation method according to claim 1, characterized in that The mass ratio of the carbon source, the curing agent, the organic solvent and the leavening agent is (10-15): (0.1-1): (0.5-5): (0.5-4).

3. The preparation method according to claim 2, characterized in that The self-made solvent combination and the The mass ratio of the powder is (1-6): (1-6).

4. The preparation method according to any one of claims 1 to 3, characterized in that The stirring rate in step b is 0.1 rpm to 1.5 rpm, the heating temperature in step c is 60° C. to 90° C., and the stirring rate is 100 rpm to 300 rpm.

5. The preparation method according to claim 1, wherein the coprecipitation-calcination method in step a comprises the following steps: a-1: Dissolve the metal organic complex of Zn, the metal organic complex of Mn, the metal organic complex of Fe and NaHCO3 powder in sufficient amount of deionized water to obtain a single solution; a-2: All the single solutions obtained in a-1 are mixed to obtain a coprecipitate; a-3: Filter the precipitate, wash it with deionized water 3-5 times, and dry it; a-4: calcining the coprecipitate under the protection of inert gas and performing high temperature annealing to obtain powder.

6. The preparation method according to claim 5, characterized in that The mass ratio of the Zn metal organic complex: the Mn metal organic complex: the Fe metal organic complex: NaHCO3 is 44:100:(1-60):

107.

7. The preparation method according to claim 6, characterized in that In step a-3, the annealing temperature is 800° C. to 1000° C., the annealing time is 2-3 hours, and it is performed under vacuum conditions.

8. A Zn-Fe-Mn oxide-hard carbon composite material, characterized in that: The Zn-Fe-Mn oxide-hard carbon composite material is prepared by the preparation method of the Zn-Fe-Mn oxide-hard carbon composite material according to any one of claims 1 to 7.

9. Use of the Zn-Fe-Mn oxide-hard carbon composite material according to claim 8, characterized in that The composite material is used as an absorbing material in scenarios of aircraft stealth, electromagnetic absorption, electromagnetic protection or microwave darkroom.

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