Manganese zinc ferrite / graphene composite aerogel material and preparation method thereof

Abstract

The invention relates to a manganese zinc ferrite / graphene composite aerogel material and a preparation method thereof. The manganese zinc ferrite / graphene composite aerogel material is prepared from the following raw materials: manganese zinc ferrite and graphene oxide, wherein the mass ratio of the manganese zinc ferrite to the graphene oxide is (0.06-0.18): 1, and the manganese zinc ferrite and the graphene oxide are subjected to hydrothermal reaction and freeze drying to obtain the composite aerogel material. According to the technical scheme, the method has the advantages that the impedance matching degree of the graphene aerogel is improved, the effective absorption bandwidth is widened, and the graphene aerogel is light and efficient.

Description

Technical Field

[0001] The present application relates to the technical field of composite materials, and in particular to a manganese zinc ferrite / graphene composite aerogel material and a preparation method thereof. Background Art

[0002] Graphene aerogel, a typical dielectric lossy absorber, retains the inherent physical and chemical properties of single-sheet graphene while also offering other advantages, including excellent mechanical properties; a porous structure that further increases specific surface area while also reducing its density; a three-dimensional structure that improves mass and electron transport; pores that provide a large number of adsorption sites; and excellent thermal stability and hydrophobicity. Furthermore, graphene aerogel's precursor is graphene oxide, which, after reduction, retains a large number of residual functional groups and defects. This reduces conductivity and improves impedance matching. Furthermore, these defects and functional groups act as polarization centers, contributing to polarization relaxation. Both contribute to electromagnetic wave attenuation, making graphene aerogel an ideal absorber. However, due to graphene's high electrical conductivity, graphene aerogel still suffers from poor impedance matching.

[0003] Because graphene aerogels have a unique three-dimensional porous network structure, they can be loaded with other substances. Combining graphene with other types of absorbing materials can produce composite materials with improved microwave absorption properties. Furthermore, by designing and manipulating the composite structure, not only can the material's intrinsic dipole polarization be enhanced, but interfacial polarization can also be generated, further enhancing its ability to attenuate electromagnetic waves.

[0004] Constructing composites of graphene aerogel and other different types of absorbing materials is an effective method for enhancing electromagnetic wave absorption. On the one hand, the increased polarization loss caused by the multiple interfaces of different components can improve dielectric loss capacity. On the other hand, the synergistic effect of different loss mechanisms can significantly improve impedance matching and broaden the effective bandwidth. The simultaneous addition of multiple additives with different loss mechanisms can further enhance absorption performance. However, many challenges remain: the microwave absorption mechanism of composite materials and the factors that broaden effective absorption are still not clearly understood; reflection loss values are still difficult to meet requirements; and the material preparation process is still relatively cumbersome, requiring further improvement in terms of cost reduction and environmental protection. Summary of the Invention

[0005] In response to the above-mentioned deficiencies in the prior art, the present application provides a method for improving the impedance matching of graphene aerogel and broadening the effective absorption bandwidth, and for obtaining a lightweight and efficient manganese zinc ferrite / graphene composite aerogel material.

[0006] In order to solve the above technical problems, the technical solution adopted in this application is: a manganese zinc ferrite / graphene composite aerogel material, the raw materials of which include: manganese zinc ferrite and graphene oxide; wherein the mass ratio of manganese zinc ferrite to graphene oxide is 0.06~0.18:1, and the manganese zinc ferrite and graphene oxide are hydrothermally reacted and freeze-dried to obtain a composite aerogel material.

[0007] Furthermore, the graphene oxide has a sheet diameter of 0.5 to 5 μm and a thickness of 0.8 to 1.2 nm.

[0008] Furthermore, the particle size of the manganese zinc ferrite is 60 to 80 μm.

[0009] Furthermore, the mass ratio of the manganese zinc ferrite to graphene oxide is 0.12-0.18:1.

[0010] The present application also provides the above-mentioned manganese zinc ferrite / graphene composite aerogel material and a preparation method thereof, the method comprising the steps of:

[0011] (1) preparing an aqueous graphene oxide dispersion: weighing graphene oxide powder and adding it to deionized water, ultrasonicating at room temperature until GO is completely dissolved, adjusting the pH to neutral, and mechanically exfoliating the graphene oxide using a high-speed disperser to obtain an aqueous graphene oxide dispersion;

[0012] (2) Preparation of manganese zinc ferrite / graphene composite aerogel material: adding manganese zinc ferrite to the aqueous dispersion of graphene oxide in step (1), and ultrasonicating at room temperature to fully disperse the manganese zinc ferrite in the aqueous dispersion of graphene oxide, then transferring it to a polytetrafluoroethylene liner, reacting it at 150-200°C in a reactor for 8-15h, cooling it to room temperature, transferring it to a freeze dryer, and freeze-drying it for 24-96h to obtain a manganese zinc ferrite / graphene composite aerogel material.

[0013] Furthermore, the rotation speed of the high-speed disperser in step (1) is 1000-2000 r / min, and the stripping time is 10-15 min.

[0014] Furthermore, the concentration of the graphene oxide in the dispersion in step (1) is in the range of 5 to 15 mg / ml.

[0015] Furthermore, the graphene oxide described in step (1) has a sheet diameter of 0.5 to 5 μm and a thickness of 0.8 to 1.2 nm.

[0016] Furthermore, the particle size of the manganese zinc ferrite described in step (2) is 60 to 80 μm.

[0017] Furthermore, the mass ratio of the manganese zinc ferrite to graphene oxide in step (2) is 0.06 to 0.18:1.

[0018] Furthermore, the mass ratio of the manganese zinc ferrite to graphene oxide in step (2) is 0.12 to 0.18:1.

[0019] Furthermore, the reaction in step (2) is carried out in a reactor at 170-185° C. for 10-12 hours.

[0020] Furthermore, the freeze-drying time in step (2) is 24-48 hours and the temperature is -55 to -60°C.

[0021] Advantages and benefits of this application:

[0022] 1. The composite aerogel material of the present application, wherein the manganese zinc ferrite has a high magnetic permeability but a low dielectric constant, and the graphene oxide has a high dielectric constant but a low magnetic permeability; based on the properties of the above two main raw materials, after the two are compounded through a hydrothermal reaction, the manganese zinc ferrite can be evenly distributed in the three-dimensional skeleton of the graphene oxide, and the electromagnetic parameters of the two can be complementary, thereby improving the impedance matching of the aerogel material, reducing the reflection of electromagnetic waves on the surface of the material, and increasing the amount of electromagnetic waves entering the interior of the material; the combination of the two not only improves the matching of electromagnetic parameters, but also enhances multiple loss mechanisms, so that the composite material exhibits excellent electromagnetic wave absorption ability in the X-band.

[0023] 2. The aerogel material of the present application, in which the electromagnetic parameters and impedance matching performance of the composite aerogel are regulated by regulating the ratio of manganese zinc ferrite to graphene oxide, thereby improving the loss of electromagnetic waves in the composite aerogel material, and the low density of the obtained graphene aerogel is also beneficial to improving the "heavy" problem of traditional absorbing materials; the manganese zinc ferrite embedded in the graphene aerogel skeleton can also avoid corrosion and oxidation of ferromagnetic materials during long-term use; the preparation raw materials of the present application mainly include manganese zinc ferrite and graphene oxide, and the obtained absorbing material can achieve absorbing performance in a wide frequency range of 8.2-12.4 GHz; while the prior art generally contains a variety of absorbing agents, such as aminated cellulose fiber, activated carbon powder, nano-titanium dioxide, graphene oxide-manganese zinc ferrite composite material, conductive micropowder, etc., there is interference between the multiphase materials, and the content of graphene oxide-manganese zinc ferrite composite material is low, so the obtained material only has absorbing performance in the low frequency band (such as 30 MHz to 1.5 GHz).

[0024] 3. The composite aerogel of the present application adopts a hydrothermal reaction and freeze-drying treatment process, thereby maintaining the unique porous structure of the aerogel material (the current existing technology uses a drying process at 80-90°C for 10-12 hours without involving freeze-drying. Therefore, this existing process will not retain the three-dimensional structure of the gel and cannot obtain the graphene aerogel with the porous structure of the present application). The pores and interfaces inside this unique porous structure can reflect the incident electromagnetic waves multiple times, extending the propagation path of the electromagnetic waves inside the material, thereby improving energy dissipation; the porous structure can also adjust the dielectric constant and magnetic permeability of the material to make it more compatible with the impedance of free space, thereby reducing the reflection of electromagnetic waves on the surface of the material and increasing the electromagnetic wave energy entering the material; and this preparation process can also optimize the porosity, reduce the reflectivity of the material surface, and allow more electromagnetic waves to enter the material and be absorbed; in addition, this porous structure significantly reduces the density of the material, so that it can achieve lightweight while maintaining excellent wave absorption performance, which is particularly suitable for aerospace, mobile equipment and other fields; as in the technical solution of the present application, the density of the manganese zinc ferrite alone is 5.2g / cm 3 , the density of graphene oxide alone is 2.2 g / cm 3 The density of the aerogel material obtained by combining the two through the above-mentioned treatment process - manganese zinc ferrite / graphene composite aerogel is only 0.02g / cm 3 about.

[0025] 4. In the process of preparing the aqueous dispersion of graphene oxide, the present application adopts a high-speed disperser for mechanical exfoliation. This is because the existence of van der Waals forces and hydrogen bonds between graphene oxide sheets makes them easily agglomerated, affecting their performance. The shear force of the high-speed disperser disperses them into a single layer or a few layers, ensuring uniform distribution. The dispersed graphene oxide has a larger specific surface area and more active sites, which is conducive to the uniform distribution of manganese zinc ferrite. The use of a high-speed disperser to disperse graphene oxide is a key step in ensuring its performance and application effect. The present application adopts a hydrothermal reactor to provide a high-temperature and high-pressure environment to promote the graphene oxide sheets to form a single layer through π-π interaction. The conditions in the hydrothermal reactor help the graphene sheets to form a stable cross-linked structure, thereby enhancing the mechanical strength and stability of the aerogel. Under high temperature and high pressure, some oxygen-containing functional groups of graphene oxide are removed, and the conjugated π bond structure is restored, the conductivity is improved, the dielectric constant and dielectric loss are increased, the interaction between the material and electromagnetic waves is enhanced, and the absorption performance is improved. The existing technology uses a crystallization method for preparation, and the subsequent filtration and drying methods will cause the aerogel structure to shrink and the overall density to increase. The density of the aerogel in this application is only 0.02g / cm 3 It can improve the problem of "heaviness" of traditional absorbing materials.

[0026] 5. The technical solution of the present application designs the structure of the absorbing material and regulates the electromagnetic parameters to prepare a flexible, lightweight material with high absorbing performance. However, the existing technology does not involve a freeze-drying process, but instead dries it at 80-90°C for 10-12 hours. This process cannot retain the three-dimensional structure of the gel, and it is impossible to obtain the graphene aerogel product with the specific porous structure of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 (such as Figure 1 -a) and the pure graphene oxide aerogel material prepared in Comparative Example 1 (as shown Figure 1 -b) SEM image.

[0028] Figure 2 This is a reflection loss curve of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 at different thicknesses within the X-band (8.2-12.4 GHz) frequency range.

[0029] Figure 3 This is a physical picture of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 1.

[0030] Figure 4 These are the actual pictures corresponding to the post-processing of composite aerogel materials using freeze-drying and drying methods respectively.

[0031] Figure 5 This is a curve showing the attenuation constant (α) of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 as a function of frequency within the X-band (8.2-12.4 GHz) frequency range.

[0032] Figure 6 This is a reflection loss curve of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 2 at different thicknesses in the frequency range of 2 to 18 GHz.

[0033] Figure 7 This is a reflection loss curve of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 3 at different thicknesses in the frequency range of 2 to 18 GHz.

[0034] Figure 8 The pure graphene oxide aerogel material prepared in Comparative Example 1 (such as Figure 8 -a), the manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 with an addition amount of 30 mg of manganese zinc ferrite (as shown in Figure 8 -b), the manganese zinc ferrite / graphene composite aerogel material prepared in Example 2 with an addition amount of 60 mg of manganese zinc ferrite (as shown in Figure 8-c), the manganese zinc ferrite / graphene composite aerogel material prepared in Example 3 with an addition amount of 90 mg of manganese zinc ferrite (as shown in Figure 8 -d) SEM images. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the embodiments and drawings. Obviously, the embodiments described are only preferred embodiments, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] Example 1:

[0037] A manganese zinc ferrite / graphene composite aerogel material and a preparation method thereof, the specific implementation steps are as follows:

[0038] (1) Preparation of an aqueous graphene oxide dispersion: 0.5 g of graphene oxide powder was weighed and added to 50 mL of deionized water. The mixture was ultrasonicated at room temperature for a period of time until the GO was completely dissolved. The pH was adjusted to neutral, and the mixture was mechanically exfoliated using a high-speed disperser (the speed of the high-speed disperser was 1200 rpm for 12 min) to obtain an aqueous graphene oxide dispersion.

[0039] (2) Preparation of manganese zinc ferrite / graphene composite aerogel material: 30 mg of manganese zinc ferrite was added to the aqueous dispersion of graphene oxide in step (1), and ultrasonicated at room temperature for 30 min to fully disperse the manganese zinc ferrite in the aqueous dispersion of graphene oxide. The material was then transferred to a polytetrafluoroethylene liner, reacted at 180° C. in a reactor for 12 h, cooled to room temperature, and then transferred to a freeze dryer and freeze-dried at -55 to -60° C. for 48 h to obtain a manganese zinc ferrite / graphene composite aerogel material.

[0040] Comparative Example 1

[0041] The difference between Comparative Example 1 and Example 1 is that in the preparation process of the composite aerogel in step (2), the magnetic material manganese zinc ferrite is not added, that is, only the aqueous dispersion of graphene oxide is subjected to hydrothermal reaction, and the rest of the process is exactly the same, that is, pure graphene oxide aerogel is obtained.

[0042] Figure 1 The manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 (such as Figure 1 -a) and the pure graphene oxide aerogel material prepared in Comparative Example 1 (as shown Figure 1 -b) SEM picture. Figure 1-a, it can be seen that the manganese zinc ferrite (the red box in the figure is manganese zinc ferrite, and the blue box is graphene aerogel) is evenly distributed in the three-dimensional structure of the graphene aerogel, indicating the successful preparation of the composite material.

[0043] The manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 was added to molten paraffin and molded into a cylinder and a cylindrical ring, which were used for conductivity testing and microwave absorption (MA) measurement, respectively.

[0044] Figure 2 This is a reflection loss curve of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 at different thicknesses within the X-band (8.2-12.4 GHz) frequency range. min ) is -46.8296dB, and can achieve a reflection loss of -16.1799dB at a low matching thickness of 3.2mm, showing excellent wave absorbing performance.

[0045] As attached Figure 3 As shown in FIG. 1 , a physical image of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 of the present application; the density of the manganese zinc ferrite in the present application is 5.2 g / cm 3 , the density of graphene oxide is 2.2g / cm 3 The density of the finally prepared manganese zinc ferrite / graphene composite aerogel is 0.02g / cm 3 .

[0046] As attached Figure 4 As shown, these are real pictures corresponding to the composite aerogel material after post-processing using freeze-drying and drying methods respectively. As can be seen from the pictures, the aerogel material treated by the freeze-drying process of the present application maintains a good structure and appearance, and the structure is more stable; while the aerogel material treated by the drying process undergoes structural deformation and collapse, and it cannot be guaranteed that the specific porous aerogel structure of the present application is obtained.

[0047] Figure 5 This is a curve showing the attenuation constant (α) of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 over the X-band (8.2-12.4 GHz) frequency range. The attenuation constant is the ability of an absorbing material to dissipate electromagnetic waves and is an important factor in determining the absorption characteristics of microwave absorbers. The manganese zinc ferrite / graphene composite aerogel material prepared using this method exhibits a gradually increasing attenuation constant as the frequency increases, reaching a maximum attenuation constant of 102.1697 Np / m at 9.439 GHz, demonstrating excellent electromagnetic wave dissipation performance.

[0048] Examples 2 and 3 discussed the effect of manganese zinc ferrite on the structure of graphene composite aerogel by adjusting the addition amount of manganese zinc ferrite.

[0049] Example 2:

[0050] A manganese zinc ferrite / graphene composite aerogel material and a preparation method thereof, the specific implementation steps are as follows:

[0051] (1) Preparation of an aqueous graphene oxide dispersion: 0.5 g of graphene oxide powder was weighed and added to 50 mL of deionized water. The mixture was ultrasonicated at room temperature for a period of time until the GO was completely dissolved. The pH was adjusted to neutral, and the mixture was mechanically exfoliated using a high-speed disperser to obtain an aqueous graphene oxide dispersion.

[0052] (2) Preparation of manganese zinc ferrite / graphene composite aerogel material: 60 mg of manganese zinc ferrite was added to the aqueous dispersion of graphene oxide in step (1), and ultrasonicated at room temperature for 30 min to fully disperse the manganese zinc ferrite in the aqueous dispersion of graphene oxide. The material was then transferred to a polytetrafluoroethylene liner, reacted at 180° C. in a reactor for 12 h, cooled to room temperature, and then transferred to a freeze dryer and freeze-dried for 48 h to obtain a manganese zinc ferrite / graphene composite aerogel material.

[0053] The manganese zinc ferrite / graphene composite aerogel material prepared in Example 2 was added to molten paraffin and molded into a cylinder and a cylindrical ring, which were used for conductivity testing and microwave absorption (MA) measurement, respectively.

[0054] Figure 6 This is a reflection loss curve of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 2 at different thicknesses in the frequency range of 2 to 18 GHz. min ) is -42.3423dB, and the matching thickness is only 1.7mm.

[0055] Example 3:

[0056] A manganese zinc ferrite / graphene composite aerogel material and a preparation method thereof, the specific implementation steps are as follows:

[0057] (1) Preparation of an aqueous graphene oxide dispersion: 0.5 g of graphene oxide powder was weighed and added to 50 mL of deionized water. The mixture was ultrasonicated at room temperature for a period of time until the GO was completely dissolved. The pH was adjusted to neutral, and the mixture was mechanically exfoliated using a high-speed disperser to obtain an aqueous graphene oxide dispersion.

[0058] (2) Preparation of manganese zinc ferrite / graphene composite aerogel material: 90 mg of manganese zinc ferrite was added to the aqueous dispersion of graphene oxide in step (1), and ultrasonicated at room temperature for 30 min to fully disperse the manganese zinc ferrite in the aqueous dispersion of graphene oxide. The material was then transferred to a polytetrafluoroethylene liner, reacted at 180° C. in a reactor for 12 h, cooled to room temperature, and then transferred to a freeze dryer and freeze-dried for 48 h to obtain a manganese zinc ferrite / graphene composite aerogel material.

[0059] The manganese zinc ferrite / graphene composite aerogel material prepared in Example 3 was added to molten paraffin and molded into a cylinder and a cylindrical ring, which were used for conductivity testing and microwave absorption (MA) measurement, respectively.

[0060] Figure 7 This is a reflection loss curve of the manganese zinc ferrite / graphene composite aerogel material prepared in Example 3 at different thicknesses in the frequency range of 2 to 18 GHz. min ) is -16.3096 dB, and the matching thickness is only 1.6 mm. Compared with Examples 1 and 2, the matching thickness of the manganese zinc ferrite / graphene composite aerogel absorber prepared in Example 3 is lower. However, due to the agglomeration of the manganese zinc ferrite, the synergistic effect between the two is reduced, and the loss capacity of the incident electromagnetic wave is greatly reduced.

[0061] Figure 8 The pure graphene oxide aerogel material prepared in Comparative Example 1 (such as Figure 8 -a), the manganese zinc ferrite / graphene composite aerogel material prepared in Example 1 with an addition amount of 30 mg of manganese zinc ferrite (as shown in Figure 8 -b), the manganese zinc ferrite / graphene composite aerogel material prepared in Example 2 with an addition amount of 60 mg of manganese zinc ferrite (as shown in Figure 8 -c), the manganese zinc ferrite / graphene composite aerogel material prepared in Example 3 with an addition amount of 90 mg of manganese zinc ferrite (as shown in Figure 8 The SEM image of the graphene composite aerogel (shown in Figure 1) is shown in Figure 2 (a). The red frame shows manganese zinc ferrite. As the manganese zinc ferrite content increases, the distribution of manganese zinc ferrite in the graphene composite aerogel becomes more uniform, which promotes the synergistic effect of the magnetic and dielectric materials and improves the composite's microwave absorption performance. However, when the manganese zinc ferrite addition amount is 90 mg, the manganese zinc ferrite shows a large degree of agglomeration in the graphene composite aerogel, which is not conducive to improving the impedance matching performance of the composite.

[0062] It can be seen from the above embodiments and comparative examples of the present application that the above technical solution of the present application uses manganese zinc ferrite and graphene oxide as the main raw materials, and then obtains an aerogel material through hydrothermal reaction and freeze-drying treatment, which can maintain a specific porous structure. The pores and interfaces inside the porous structure can reflect the incident electromagnetic waves multiple times, extend the propagation path of the electromagnetic waves inside the material, and thus improve energy dissipation; the porous structure can adjust the dielectric constant and magnetic permeability of the material to make it more compatible with the impedance of free space, thereby reducing the reflection of electromagnetic waves on the surface of the material and increasing the energy of electromagnetic waves entering the material; by optimizing the porosity, the reflectivity of the material surface can be reduced, allowing more electromagnetic waves to enter the material and be absorbed; the porous structure significantly reduces the density of the material, so that it can achieve lightweight while maintaining excellent absorbing performance, and is particularly suitable for aerospace, mobile equipment and other fields; due to the addition of zinc in the manganese zinc ferrite, the absorption band is wider, and manganese zinc ferrite is superior to manganese ferrite in absorption bandwidth and temperature stability, and is suitable for broadband applications.

Claims

1. A manganese zinc ferrite / graphene composite aerogel material, characterized by: The raw materials of the material include: manganese zinc ferrite and graphene oxide; the mass ratio of manganese zinc ferrite to graphene oxide is 0.06-0.18:1, and the manganese zinc ferrite and graphene oxide are subjected to hydrothermal reaction and freeze-drying treatment to obtain a composite aerogel material.

2. The manganese zinc ferrite / graphene composite aerogel material according to claim 1, characterized in that: The graphene oxide has a sheet diameter of 0.5 to 5 μm and a thickness of 0.8 to 1.2 nm.

3. The manganese zinc ferrite / graphene composite aerogel material according to claim 1, characterized in that: The particle size of the manganese-zinc ferrite is 60-80 μm.

4. The manganese zinc ferrite / graphene composite aerogel material according to claim 1, characterized in that: The mass ratio of the manganese zinc ferrite to graphene oxide is 0.12-0.18:

1.

5. A method for preparing the manganese zinc ferrite / graphene composite aerogel material according to any one of claims 1 to 4, characterized in that: The steps of the method include: (1) preparing an aqueous dispersion of graphene oxide: weighing graphene oxide powder and adding it to deionized water, ultrasonicating at room temperature until the graphene oxide is fully dispersed, adjusting the pH to neutral, and mechanically exfoliating the water using a high-speed disperser to obtain an aqueous dispersion of graphene oxide; (2) Preparation of manganese zinc ferrite / graphene composite aerogel material: adding manganese zinc ferrite to the aqueous dispersion of graphene oxide in step (1), and ultrasonicating at room temperature to fully disperse the manganese zinc ferrite in the aqueous dispersion of graphene oxide, then transferring it to a polytetrafluoroethylene liner, reacting it at 150-200°C in a reactor for 8-15h, cooling it to room temperature, transferring it to a freeze dryer, and freeze-drying it for 24-96h to obtain a manganese zinc ferrite / graphene composite aerogel material.

6. The method for preparing the manganese zinc ferrite / graphene composite aerogel material according to claim 5, characterized in that: The rotation speed of the high-speed disperser described in step (1) is 1000-2000 r / min, and the stripping time is 10-15 min.

7. The method for preparing the manganese zinc ferrite / graphene composite aerogel material according to claim 5, characterized in that: The concentration of the graphene oxide in the dispersion described in step (1) is in the range of 5 to 15 mg / ml.

8. The method for preparing the manganese zinc ferrite / graphene composite aerogel material according to claim 5, characterized in that: The graphene oxide described in step (1) has a sheet diameter of 0.5 to 5 μm and a thickness of 0.8 to 1.2 nm.

9. The method for preparing the manganese zinc ferrite / graphene composite aerogel material according to claim 5, characterized in that: The particle size of the manganese zinc ferrite described in step (2) is 60 to 80 μm; the mass ratio of the manganese zinc ferrite described in step (2) to graphene oxide is 0.06 to 0.18:

1.

10. The method for preparing the manganese zinc ferrite / graphene composite aerogel material according to claim 5, characterized in that: The reaction in step (2) is carried out in a reactor at 170-185° C. for 10-12 hours; the freeze-drying time in step (2) is 24-48 hours, and the temperature is -55 to -60° C.

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