Sulfur atom-doped coal pitch-based carbon aerogel, preparation method and application

Abstract

The application discloses a kind of sulfur atom doped coal pitch-based carbon aerogel, preparation method and application, preparation method includes: coal pitch is dissolved in solvent, crosslinking agent and catalyst are added, after being mixed uniformly, pitch mixed solution is obtained, the coal pitch-based aerogel microspheres are obtained after washing and drying by heating reaction of pitch mixed solution;Coal pitch-based aerogel microspheres are mixed uniformly with sulfur-containing material according to mass ratio (0.1~5):1, to obtain carbonization precursor;Carbonization pyrolysis treatment is carried out to carbonization precursor in oxygen-free atmosphere, to obtain sulfur atom doped coal pitch-based carbon aerogel microspheres.The material prepared is applied in electromagnetic wave absorption field.The application provides an innovative technical path for preparing materials with excellent electromagnetic wave attenuation performance by combining sulfur atom doping with sulfur-containing material dosage control.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electromagnetic wave absorbing materials, and particularly relates to a sulfur atom doped coal pitch-based carbon aerogel, a preparation method and application thereof. BACKGROUND

[0002] With the progress of modern science and technology, electronic and electrical equipment is widely used in society, but the electromagnetic radiation and interference generated in the running process of electronic and electrical equipment has become the fourth major environmental pollution problem after air pollution, water pollution and noise pollution, which has caused serious influence on people's production and life, especially in the medical field of precision electronic instruments, the communication system in the field of aerospace, and the security of key information in network communication. Among the common wave-absorbing materials, carbon materials (such as carbon fibers, carbon nanotubes, carbon aerogels, etc.) have important research value and application value in the field of electromagnetic wave absorption due to their excellent electromagnetic wave absorption performance and light weight and high strength characteristics.

[0003] At present, pure carbon aerogel materials prepared by taking coal tar pitch as a carbon source can effectively promote the multiple emission and attenuation of electromagnetic waves in the material interior due to its extremely low density and extremely large specific surface area, thereby significantly enhancing the attenuation effect on electromagnetic waves, and have the possibility of becoming electromagnetic absorbing materials. However, the high electrical conductivity of pure carbon aerogel may cause impedance mismatching imbalance, and cannot be directly used for preparing electromagnetic absorbing materials. The present application dopes sulfur atoms on the basis of coal pitch-based carbon aerogel, so as to realize the impedance matching and optimization of the electromagnetic wave absorption performance of the carbon aerogel material. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to provide a sulfur atom doped coal pitch-based carbon aerogel, a preparation method and application thereof, which provides an innovative technical path for preparing materials with excellent electromagnetic wave attenuation performance by combining sulfur-containing material dosage control and sulfur atom doping.

[0005] To achieve the above-mentioned purpose of the application, the technical solutions adopted by the present application are as follows:

[0006] In the first aspect of the present application, the present application proposes a preparation method of a sulfur atom doped coal pitch-based carbon aerogel, as follows:

[0007] (1) Dissolve coal pitch in a solvent, add a crosslinking agent and a catalyst, mix uniformly to obtain a pitch mixed solution, heat the pitch mixed solution for crosslinking reaction, and wash and dry to obtain coal pitch-based aerogel microspheres;

[0008] (2) Mix the coal pitch-based aerogel microspheres with a sulfur-containing material uniformly to obtain a carbonized precursor;

[0009] The mass ratio of the sulfur-containing material to the coal-tar-based aerogel microspheres is (0.1-5):1.

[0010] (3) carbonizing and pyrolyzing the carbonized precursor in an oxygen-free atmosphere to obtain sulfur atom-doped coal-tar-based carbon aerogel microspheres.

[0011] Preferably, in step (1), the solvent comprises one or more of toluene, acetic acid, carbon disulfide, carbon tetrachloride and cyclohexane.

[0012] Preferably, the volume ratio of the solvent to the mass of the coal tar is 1-15 mL / g.

[0013] Preferably, the cross-linking agent comprises one or more of glyoxal, p-xylylene glycol, p-xylylene glycol and furfural.

[0014] Preferably, the volume ratio of the cross-linking agent to the mass of the coal tar is 5-15 mL / g.

[0015] Preferably, the catalyst comprises one or more of concentrated sulfuric acid, anhydrous aluminum chloride, anhydrous zinc chloride and sodium methoxide.

[0016] Preferably, the mass ratio of the catalyst to the coal tar is 0.005-0.08, i.e. the mass of the catalyst accounts for 0.5-8% of the mass of the coal tar.

[0017] Preferably, in step (1), the temperature of the cross-linking reaction is 50-80°C and the reaction time is 24-216 h.

[0018] Preferably, in step (1), the washing reagent comprises one or both of water and ethanol; the drying temperature is 50-160°C and the drying time is 3-32 h.

[0019] Preferably, in step (2), the sulfur-containing material comprises one or more of elemental sulfur, sulfite and organic sulfur compounds.

[0020] More preferably, the sulfur-containing material comprises one or more of sublimed sulfur, sodium sulfite, thioacetamide and thiourea.

[0021] Preferably, in step (3), the temperature of the carbonization and pyrolysis is 800-1600°C and the carbonization and pyrolysis time is 60-180 min.

[0022] More preferably, in step (3), the heating rate of the carbonization and pyrolysis process is controlled, and the heating rate is 2-5°C / min.

[0023] In the second aspect of the present application, the present application provides a sulfur atom-doped coal-tar-based carbon aerogel prepared by the above preparation method.

[0024] In the third aspect of the present application, the present application provides an application of the sulfur atom doped coal pitch based carbon aerogel, the prepared sulfur atom doped coal pitch based carbon aerogel is made into an electromagnetic wave absorbing material, and is used in the field of electromagnetic wave absorption.

[0025] Beneficial effects:

[0026] The sulfur atom doped coal pitch based carbon aerogel microsphere material has a large specific surface area, a small tap density, a suitable impedance matching, and realizes the characteristics of "wide, strong, light and thin" of the electromagnetic wave absorbing material, and the present application provides an innovative technical path for preparing a material with excellent electromagnetic wave attenuation performance by combining the content regulation of the sulfuration reagent and the sulfur atom doping method. BRIEF DESCRIPTION OF DRAWINGS

[0027] Fig. 1-2 It is an SEM diagram of the sulfur atom doped coal pitch based carbon aerogel microsphere prepared in Example 1.

[0028] Fig. 3 It is an FT-IR diagram of the sulfur atom doped coal pitch based carbon aerogel microsphere prepared in Example 1.

[0029] Fig. 4 It is an XRD diagram of the sulfur atom doped coal pitch based carbon aerogel microsphere prepared in Example 1.

[0030] Fig. 5 It is an S2p orbital XPS diagram of the sulfur atom doped coal pitch based carbon aerogel microsphere prepared in Example 1.

[0031] Fig. 6 It is a nitrogen adsorption / desorption curve of the sulfur atom doped coal pitch based carbon aerogel microsphere prepared in Example 1.

[0032] Fig. 7 It is a 2D reflection loss diagram of the sulfur atom doped coal pitch based carbon aerogel microsphere prepared in Example 1.

[0033] Fig. 8 It is a matching thickness and frequency relationship and impedance matching relationship diagram of the sulfur atom doped coal pitch based carbon aerogel microsphere prepared in Example 1 calculated by the lambda / 4 model. DETAILED DESCRIPTION

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the specific embodiments of the present application will be described below with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0035] The present application notes that doping sulfur atoms in carbon aerogel can form a large number of C-S / C=S functional groups inside the material, which act as dipole centers, enhancing the dipole polarization of the carbon aerogel, while increasing the defect concentration and strengthening the interface polarization, thereby further improving the polarization loss of the material to electromagnetic waves.

[0036] The present application provides a preparation method of sulfur atom doped coal pitch based carbon aerogel, as follows:

[0037] (1) Dissolve coal pitch (i.e. coal tar pitch) in a solvent, add a crosslinking agent and a catalyst, mix uniformly to obtain a pitch mixed solution, heat the pitch mixed solution in an oil bath for reaction, and wash and dry to obtain coal pitch based aerogel microspheres.

[0038] Preferably, the solvent is one or more of toluene, acetic acid, carbon disulfide, carbon tetrachloride and cyclohexane, which have strong solubility for coal pitch. Preferably, the volume ratio of the solvent to the mass of coal pitch is 1-15 mL / g.

[0039] Preferably, the crosslinking agent is one or more of glyoxal, p-xylylene glycol, p-xylylene glycol and furfuryl formaldehyde. Preferably, the volume ratio of the crosslinking agent to the mass of coal pitch is 5-15 mL / g.

[0040] Preferably, the catalyst is one or more of concentrated sulfuric acid, anhydrous aluminum chloride, anhydrous zinc chloride and sodium methoxide. Preferably, the mass ratio of the catalyst to the coal pitch is 0.5-8%.

[0041] In step (1), the oil bath heating reaction temperature is 50-80℃, and the reaction time is 24-216h.

[0042] In step (1), the washing reagent is one or both of water and ethanol; the drying temperature is 50-160℃, and the drying time is 3-32h.

[0043] (2) Mix the coal pitch based aerogel microspheres with sulfur-containing materials uniformly to obtain a carbonization precursor.

[0044] Preferably, the sulfur-containing material is one or more of elemental sulfur, sulfite and organic sulfur compounds, specifically one or more of sublimed sulfur, sodium sulfite, thioacetamide and thiourea. The mass ratio of the sulfur-containing material to the coal pitch based aerogel microspheres is (0.1-5):1.

[0045] (3) Carbonize and pyrolyze the carbonization precursor to obtain sulfur atom doped coal pitch based carbon aerogel microspheres with a size of 50-100nm.

[0046] In step (3), the carbonization pyrolysis temperature is 800-1600℃; the carbonization pyrolysis time is 60-180 min.

[0047] In step (3), the carbonization pyrolysis process is carried out in an oxygen-free atmosphere, preferably, the carbonization pyrolysis atmosphere comprises one or more of nitrogen atmosphere, argon atmosphere and carbon dioxide atmosphere.

[0048] More preferably, in step (3), the heating rate of the carbonization pyrolysis process is also controlled, specifically, the heating rate is 2-5℃ / min.

[0049] In the present application, the coal pitch species is not limited. The present application effectively removes part of the impurities in the material by high-temperature carbonization pyrolysis treatment of the carbonization precursor, and also enhances the movement ability of the polymeric molecular chain links in the carbonization precursor, protects the 3D structure of the network macromolecules generated by crosslinking, thereby enhancing the structural stability of the coal pitch-based carbon aerogel. More importantly, the material obtained by the carbonization pyrolysis temperature treatment has a low degree of graphitization, which helps to control the electrical conductivity of the sulfur atom-doped coal pitch-based carbon aerogel, avoids the dramatic increase in electrical conductivity due to the high degree of graphitization, prevents impedance mismatch imbalance, and ensures the stability and reliability of the material in the electromagnetic wave attenuation application.

[0050] The present application notes that by sulfur atom doping, a large number of C-S / C=S functional groups can be formed in the coal pitch-based carbon aerogel, which act as dipole centers, enhance the dipole polarization, and are conducive to increasing the defect concentration and strengthening the interface polarization, thereby further improving the polarization loss of the coal pitch-based carbon aerogel to electromagnetic waves. However, the amount of sulfur atom doping needs to be accurately controlled, for example, when the amount of sulfur atom doping is too high, it may reduce the overall electrical conductivity of the material, thereby reducing the electrical conductivity consumption. The present application precisely regulates the content of sulfur-containing material, moderately reduces the overall electrical conductivity of the material, to reduce its electrical conductivity, while maintaining the necessary electrical conductivity loss, to optimize the impedance matching and electromagnetic wave absorption performance. In addition, sulfur atom doping is also conducive to inducing larger pores in the network structure, thereby significantly increasing the specific surface area of the material (≥500m 2 / g). In the carbonization pyrolysis process, the melting of the sulfur-containing material can act as a flow template to further promote the increase of the specific surface area.

[0051] The advantage of sulfur atom doping is not only to optimize the pore structure of the material, but also to enhance the multiple reflection and interface polarization of electromagnetic waves in the material, effectively improving the attenuation ability of the material to electromagnetic waves. The minimum reflection loss of the sulfur atom-doped coal pitch-based carbon aerogel material prepared by the present application is-69.52dB, the effective absorption bandwidth is greater than 4GHz, and the maximum frequency bandwidth is 5.44GHz.

[0052] The technical solutions of the present application will be described in detail in the following specific embodiments.

[0053] Example 1

[0054] 5g of coal tar pitch, 50mL of crosslinking agent furanaldehyde, 10mL of solvent (by volume ratio, toluene:acetic acid = 1:1), and 1mL of catalyst concentrated sulfuric acid were mixed in a three-necked flask. The flask was placed in a 70℃ water bath for 96 hours to allow it to fully gel, thus obtaining coal tar pitch-based aerogel microspheres. After cooling the obtained coal tar pitch-based aerogel microspheres to room temperature, they were placed in an oven at 100℃ and dried for 5 hours.

[0055] 1g of coal tar pitch-based aerogel microspheres and 0.5g of sublimed sulfur were thoroughly mixed in an agate mortar and transferred to a ceramic boat. The mixture was then placed in a tube furnace and calcined. Under a nitrogen atmosphere, the temperature was increased to 900℃ at a rate of 5℃ / min and held for 2 hours to obtain the final product, sulfur atom-doped coal tar pitch-based carbon aerogel microspheres.

[0056] The prepared sulfur-doped coal tar pitch-based carbon aerogel microspheres were thoroughly mixed with sliced ​​paraffin at a mass ratio of 2:8 after heating to obtain concentric rings with an outer diameter of 7 mm and an inner diameter of 3.04 mm. Electromagnetic parameters were measured using a vector network analyzer in the frequency range of 2-18 GHz. Calculations of the measured complex permittivity and complex permeability revealed a minimum reflection loss RLmin of -69.52 dB at a thickness of 1.48 mm and a maximum effective bandwidth of 5.12 GHz.

[0057] Fig. 1-2 This is a SEM image of sulfur-doped coal tar pitch-based carbon aerogel microspheres prepared in Example 1.

[0058] Fig. 3 This is the FT-IR image of sulfur-doped coal tar pitch-based carbon aerogel microspheres prepared in Example 1, with a wavenumber range of 500-3500 cm⁻¹. -1 ,Depend on Fig. 1 As can be seen, after the cross-linking reaction, the stretching vibration peak of the C=O bond of furfural (furan carbaldehyde) molecule gradually disappeared in the infrared spectrum of the obtained carbon aerogel, but the characteristic vibrational absorption peak of the heteropentacyclic ring was still retained, indicating that the coal tar pitch and furfural underwent a cross-linking reaction, and the reaction was carried out according to the experimental design.

[0059] Fig. 4 This is the XRD pattern of the sulfur-doped coal tar pitch-based carbon aerogel microspheres prepared in Example 1. Fig. 2 It can be seen that only one set of peaks appeared in the XRD, which are diffraction peaks of amorphous carbon.

[0060] Fig. 5 XPS images of the S2p orbitals of sulfur-doped coal tar pitch-based carbon aerogel microspheres effectively demonstrate that sulfur atoms have been successfully doped into the interior of the material.

[0061] Fig. 6 is the nitrogen adsorption / desorption curve of the sulfur atom doped coal pitch based carbon aerogel microspheres prepared in Example 1, and the figure is a clear type I isotherm, and the BET specific surface area is calculated to be 995 m 2 / g.

[0062] Fig. 7 is the 2D reflection loss of the sulfur atom doped coal pitch based carbon aerogel microspheres prepared in Example 1, specifically, the strongest reflection absorption is-65.92 dB at 15.25 GHz when the thickness is 1.48 mm, and it can be seen that the above-mentioned material has good wave absorbing performance.

[0063] Fig. 8 is the matching thickness and frequency relationship and impedance matching relationship diagram of the sulfur atom doped coal pitch based carbon aerogel microspheres prepared in Example 1 calculated by the λ / 4 model, and the value of Z0 / Z in is 1 at 15.42 GHz, that is, the impedance of the free space and the impedance of the material are well adapted, so that the electromagnetic wave fully enters the material inside to realize multiple reflection and attenuation; and the λ / 4 model basically agrees with the actual result, indicating that the sulfur atom doped coal pitch based carbon aerogel microspheres are effective materials for electromagnetic wave absorption.

[0064] In summary, the sulfur atom doped coal pitch based carbon aerogel microspheres prepared in the embodiment have high electromagnetic wave absorption performance and good stability, so the sulfur atom doped coal pitch based carbon aerogel microspheres of the present application have a relatively ideal development prospect in the field of electromagnetic wave absorption.

[0065] Example 2

[0066] Put 5g of coal pitch, 50mL of crosslinking agent p-toluene diol, 5mL of solvent (calculated by volume ratio, toluene:acetic acid = 1:1), and 0.4g of catalyst anhydrous aluminum chloride into a three-necked flask, mix, put the flask into a 80℃ water bath kettle, and react for 216h to make it fully gel, obtain coal pitch based aerogel microspheres, and then put the obtained coal pitch based aerogel microspheres into an oven after cooling to room temperature, and dry at 160℃ for 32h.

[0067] Mix 1g of coal pitch based aerogel microspheres and 5g of sublimed sulfur in an agate mortar, transfer into a porcelain boat, and put into a tube furnace, and calcine under the atmosphere of nitrogen, and increase to 1600℃ at a temperature increasing speed of 5℃ / min, and keep for 3h to obtain the final product.

[0068] The prepared sulfur atom doped coal pitch based carbon aerogel microspheres and paraffin wax were heated and mixed thoroughly at a mass ratio of 2:8 to obtain a concentric ring with an outer diameter of 7 mm and an inner diameter of 3.04 mm. The electromagnetic parameters were measured by a vector network analyzer at a frequency of 2-18 GHz. The minimum reflection loss RLmin of-57.66 dB was obtained at a thickness of 1.98 mm, and the maximum effective frequency bandwidth was 4.12 GHz.

[0069] Example 3

[0070] Coal pitch 5 g, crosslinking agent furfural 50 mL, solvent 5 mL (calculated by volume ratio, toluene:acetic acid = 1:1), catalyst concentrated sulfuric acid 0.5 mL were put into a three-necked flask for mixing. The flask was placed in a 50°C water bath for 24 h to make it fully gelated, and coal pitch based aerogel microspheres were obtained. After the coal pitch based aerogel microspheres were cooled to room temperature, they were placed in an oven at 50°C for 3 h of drying.

[0071] 1 g of coal pitch based aerogel microspheres and 0.1 g of sulfur were mixed thoroughly in a agate mortar and transferred to a porcelain boat, which was placed in a tube furnace. The temperature was raised to 800°C at a rate of 2°C / min under a nitrogen atmosphere, and maintained for 1 h to obtain the final product.

[0072] The prepared sulfur atom doped coal pitch based carbon aerogel microspheres and paraffin wax were heated and mixed thoroughly at a mass ratio of 2:8 to obtain a concentric ring with an outer diameter of 7 mm and an inner diameter of 3.04 mm. The electromagnetic parameters were measured by a vector network analyzer at a frequency of 2-18 GHz. The minimum reflection loss RLmin of-57.66 dB was obtained at a thickness of 1.98 mm, and the maximum effective frequency bandwidth was 4.12 GHz.

[0073] Example 4

[0074] Coal pitch 5 g, crosslinking agent furfural 50 mL, solvent 10 mL (calculated by volume ratio, toluene:acetic acid = 1:1), catalyst concentrated sulfuric acid 1 mL were put into a three-necked flask for mixing. The flask was placed in a 70°C water bath for 96 h to make it fully gelated, and coal pitch based aerogel microspheres were obtained. After the coal pitch based aerogel microspheres were cooled to room temperature, they were placed in an oven at 100°C for 5 h of drying.

[0075] 1 g of coal pitch based aerogel microspheres and 1.5 g of thioacetamide were mixed thoroughly in a agate mortar and transferred to a porcelain boat, which was placed in a tube furnace. The temperature was raised to 900°C at a rate of 5°C / min under a nitrogen atmosphere, and maintained for 2 h to obtain the final product, i.e., sulfur atom doped coal pitch based carbon aerogel microspheres.

[0076] The prepared sulfur atom doped coal pitch based carbon aerogel microspheres and the sliced paraffin were mixed at a mass ratio of 2:8 after heating, to obtain a concentric ring with an outer diameter of 7 mm and an inner diameter of 3.04 mm. The electromagnetic parameters were measured by a vector network analyzer at a frequency of 2-18 GHz. The measured complex permittivity and complex permeability were calculated to obtain a minimum reflection loss RLmin of -47.54 dB at a thickness of 2.77 mm, and a maximum effective frequency bandwidth of 4.29 GHz.

[0077] Comparative Example 1

[0078] Coal pitch 5 g, crosslinking agent furfural 50 mL, solvent 10 mL (calculated by volume ratio, toluene:acetic acid = 1:1), catalyst concentrated sulfuric acid 1 mL were put into a three-necked flask for mixing. The flask was placed in a 70°C water bath for 96 h of reaction to make it fully gelated. Coal pitch based aerogel microspheres were obtained. After the obtained coal pitch based aerogel microspheres were cooled to room temperature, they were placed in an oven at 100°C for 5 h of drying. 1 g of coal pitch based aerogel microspheres was placed in a tube furnace for calcination. Under the protection of nitrogen, the temperature was raised to 900°C at a rate of 5°C / min and maintained for 2 h to obtain the final product, coal pitch based carbon aerogel microspheres.

[0079] The coal pitch based carbon aerogel microspheres prepared in the comparative example were mixed with sliced paraffin at a mass ratio of 2:8 after heating to obtain a concentric ring with an outer diameter of 7 mm and an inner diameter of 3.04 mm. The electromagnetic parameters were measured by a vector network analyzer at a frequency of 2-18 GHz. The measured complex permittivity and complex permeability were calculated to obtain a minimum reflection loss RLmin of -7.27 dB at a thickness of 3.75 mm, and no effective frequency bandwidth.

[0080] Comparative Example 2

[0081] Compared with Example 2, the amount of sulfur atom doping in this comparative example was excessive, i.e. the amount of sublimed sulfur was 6 g (the mass ratio of sublimed sulfur to coal pitch based aerogel was 6:1), and the other conditions were the same as in Example 1.

[0082] The material prepared in Comparative Example 2 was measured for electromagnetic parameters in the manner described in Example 1. The measured complex permittivity and complex permeability were calculated to obtain a minimum reflection loss RLmin of -30.25 dB at a thickness of 4.54 mm, and no effective frequency bandwidth. Excessive sulfur atom doping can cause a sharp drop in electrical conductivity, which in turn affects the impedance matching between the material inside and the free space, and the conductive network is destroyed, weakening the conductance loss.

[0083] The above has carried out the detailed elaboration to the example provided by the application. The principle and implementation mode of the application are described by applying specific examples in this paper, and the above example description is only used to help understand the core idea of the application. It should be pointed out that for ordinary skilled person in the art, without departing from the principle of the application, the application can be improved and modified, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A method for preparing a sulfur atom-doped coal pitch-based carbon aerogel, characterized by, The method comprises the following steps: (1) dissolving coal tar pitch in a solvent, adding a cross-linking agent and a catalyst, mixing uniformly to obtain a mixed solution of coal tar pitch, heating the mixed solution of coal tar pitch to react, and washing and drying to obtain coal tar pitch-based aerogel microspheres; (2) uniformly mixing the coal tar pitch-based aerogel microspheres with a sulfur-containing material to obtain a carbonization precursor; The sulfur-containing material comprises one or more of elemental sulfur, sulfite and organic sulfur compounds, and the mass ratio of the sulfur-containing material to the coal tar pitch-based aerogel microspheres is (0.1-5):1; (3) performing carbonization pyrolysis treatment on the carbonization precursor in an oxygen-free atmosphere, the carbonization pyrolysis temperature is 800-1600 ℃, and sulfur atom-doped coal tar pitch-based carbon aerogel microspheres are obtained.

2. The method of claim 1, wherein the sulfur atom-doped coal pitch-based carbon aerogel is prepared by the steps of: In step (2), the sulfur-containing material comprises one or more of sublimed sulfur, sodium sulfite, thioacetamide and thiourea.

3. The method of claim 1, wherein the sulfur atom-doped coal pitch-based carbon aerogel is prepared by the steps of: In step (3), the carbonization pyrolysis time is 60-180 min.

4. The method of claim 3, wherein the sulfur atom-doped coal pitch-based carbon aerogel is prepared by the steps of: In step (3), the heating rate of the carbonization pyrolysis process is controlled, and the heating rate is 2-5 ℃ / min.

5. The method of producing a sulfur atom-doped coal pitch-based carbon aerogel according to any one of claims 1 to 4, characterized by, In step (1), the solvent comprises one or more of toluene, acetic acid, carbon disulfide, carbon tetrachloride and cyclohexane; The volume ratio of the solvent to the mass of the coal tar pitch is 1-15 mL / g.

6. The method of producing a sulfur atom-doped coal pitch-based carbon aerogel according to any one of claims 1 to 4, characterized by, The cross-linking agent comprises one or more of glyoxal, p-xylylene glycol, p-xylylene alcohol and furfural; The volume ratio of the cross-linking agent to the mass of the coal tar pitch is 5-15 mL / g.

7. The method of producing a sulfur atom-doped coal pitch-based carbon aerogel according to any one of claims 1 to 4, characterized by, The catalyst comprises one or more of concentrated sulfuric acid, anhydrous aluminum chloride, anhydrous zinc chloride and sodium methoxide; The mass ratio of the catalyst to the coal tar pitch is 0.005-0.

08.

8. The method of claim 1-4 for the preparation of sulfur atom doped coal pitch based carbon aerogels, characterized in that, In step (1), the heating reaction temperature is 50-80 ℃, the reaction time is 24-216 h, the drying temperature is 50-160 ℃, and the drying time is 3-32 h.

9. A sulfur atom-doped coal pitch-based carbon aerogel, characterized by, The sulfur atom-doped coal tar pitch-based carbon aerogel is prepared by the method according to any one of claims 1-8.

10. Use of a sulfur atom-doped coal-tar pitch-based carbon aerogel, characterized in that, The sulfur atom-doped coal tar pitch-based carbon aerogel prepared by the method according to any one of claims 1-8 is used to prepare an electromagnetic wave absorbing material, which is used in the field of electromagnetic wave absorption.

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