A cathode material for lithium sulfide batteries and a preparation method thereof

Abstract

The present invention discloses a cathode material for a lithium sulfide battery and a preparation method thereof. The cathode material for the lithium sulfide battery is composed of active sulfur, aerogel microspheres used for carrying lithium sulfide, and porous MXene microgels coating the cathode material. The preparation method includes: S31, dissolving active sulfur in an organic solvent to form a homogeneous solution of active sulfur; S32, completely immersing the aerogel microspheres in the homogeneous solution of active sulfur prepared in S31, and performing ultrasonic stirring until the organic solvent completely volatilizes, thereby obtaining a cathode precursor material adsorbed with active sulfur; S33, uniformly coating the cellulose-supported porous MXene microgels on the surface of the cathode precursor prepared in S32, and performing vacuum drying to obtain the cathode material for the lithium sulfide battery.

Description

Technical Field

[0001] The present application relates to the technical field of material preparation, and particularly to a cathode material for a lithium-sulfide battery and a preparation method thereof. Background Art

[0002] Problems such as the relatively low specific energy density, insufficient service life, and environmental pollution of the currently widely used lithium iron phosphate / C and ternary material / C systems of lithium-ion batteries have severely restricted the in-depth application and development of lithium-ion batteries.

[0003] Lithium-sulfur batteries have high specific capacity and energy density. At the same time, sulfur has a rich storage capacity and is environmentally friendly with little pollution to the environment. Therefore, lithium-sulfur batteries are considered to be a very promising type of lithium battery. However, lithium-sulfur batteries have certain problems and disadvantages, such as the shuttle effect of polysulfide compounds, the low electrical conductivity of sulfur elements, and volume expansion during the cycling process. At the same time, lithium metal generates lithium dendrites during the cycling process, which can cause the diaphragm to be pierced, resulting in battery short-circuit and triggering battery safety problems, thus restricting the practical application of the lithium-sulfur battery system. Lithium sulfide (Li2S), as the lithiated product of sulfur, is used as the cathode material for lithium-ion batteries. It can provide lithium ions by itself, avoiding the use of metallic lithium as the anode, thereby effectively eliminating potential safety hazards. Moreover, for lithium sulfide-based materials, charging is carried out first and then discharging, so the destruction of the material structure caused by volume expansion can be avoided, and better electrochemical performance can be obtained. It is a lithium-ion battery cathode material with great development potential. However, lithium sulfide has active chemical properties and easily reacts with moisture in the air to generate toxic gas H2S. Moreover, lithium sulfide exhibits electron and ion insulation, so the electrochemical activity of the lithium-sulfide battery cathode material is relatively low. At the same time, during the charge and discharge process, the dissolution, diffusion, and shuttle effect of polysulfide ions still exist, and the battery will still show serious capacity attenuation. Summary of the Invention

[0004] In view of the above deficiencies, the embodiments of the present application provide a cathode material for a lithium-sulfide battery and a preparation method thereof. The cathode material for the lithium-sulfide battery uses a multi-component composite aerogel microsphere material of graphene, carbon nanotubes, and porous MXene as the carrier of the cathode active substance. A layer of porous MXene microgel is also coated outside the cathode material to act as a diaphragm, avoiding the reaction of lithium sulfide with moisture in the external air to generate toxic gas H2S. This preparation method can not only effectively improve the electronic conductivity, loading amount, and utilization rate of the sulfur-lithium cathode active substance, but also alleviate the dissolution problem of intermediate polysulfide ions, improve the battery cycle stability, and make it possible to obtain high-performance lithium-sulfur batteries.

[0005] According to an embodiment of the present application, a cathode material for a lithium sulfide battery is provided. The cathode material for the lithium sulfide battery is composed of active sulfur, aerogel microspheres used for carrying lithium sulfide, and porous MXene microgels coating the cathode material.

[0006] Preferably, the active sulfur is at least one or several of Li2S8, Li2S6, Li2S4, Li2S2, and Li2S, and the weight percentage of the active sulfur in the cathode material for the lithium sulfide battery is 60–80 wt.%.

[0007] The preparation method of the above-mentioned cathode material for a lithium sulfide battery includes the following steps:

[0008] S31: Dissolve the active sulfur in an organic solvent to form a homogeneous solution of active sulfur.

[0009] S32: Immerse the aerogel microspheres completely into the homogeneous solution of active sulfur prepared in S31, and stir ultrasonically until the organic solvent completely volatilizes, thus obtaining a cathode precursor material adsorbed with active sulfur.

[0010] S33: Uniformly coat the cellulose-supported porous MXene microgels on the surface of the cathode precursor prepared in S32, and dry it under vacuum to obtain the cathode material for the lithium sulfide battery.

[0011] Preferably, the method for preparing the aerogel microsphere material used for carrying lithium sulfide includes:

[0012] S11: Take MXene nanosheets, stir and disperse them into a hydrogen peroxide solution, stir and etch, and then centrifuge and wash the reacted solution, and disperse it ultrasonically to obtain a porous MXene nanosheet solution.

[0013] S12: Add a nitrogen source, a boron source, and a phosphorus source to a dispersant, and stir well to make them evenly dispersed to obtain a heteroatom dispersion.

[0014] S13: Add the porous MXene nanosheet solution prepared in S11 to the heteroatom dispersion prepared in S12, stir well until they are evenly mixed, and then centrifuge and dry the mixture to obtain a precursor material.

[0015] S14: Put the precursor material into a corundum crucible, transfer it to a tubular furnace, in a protective atmosphere, heat it to a predetermined temperature, keep it warm, and then naturally cool it to room temperature. Heat it to 200–500 °C at a heating rate of 3–6 °C / min; keep it warm for 1-5 hours and then naturally cool it to room temperature, and collect the solid in the corundum crucible to obtain a heteroatom-doped porous MXene material.

[0016] S15: Take ferrocene and the heteroatom-doped porous MXene material prepared in S14 and place them in a mortar, add an organic dispersant, grind until they are fully mixed, and then dry to obtain a mixture.

[0017] S16. Place the mixture prepared in S15 in a corundum crucible, evenly spread an ignition agent on the top, put the crucible into a microwave device, collect the product after microwave radiation, and thus obtain a porous MXene material with in-situ grown carbon nanotubes and heteroatom doping.

[0018] S17. Dissolve the porous MXene material with in-situ grown carbon nanotubes and heteroatom doping prepared in S16 in deionized water, ultrasonically dissolve it thoroughly, then add graphene oxide (GO), and ultrasonically dissolve it thoroughly to obtain a composite dispersion of porous MXene and graphene oxide.

[0019] S18. Atomize the dispersion prepared in S17 into droplet microspheres by spray method, and form composite ice microspheres of porous MXene and graphene oxide in a cooling bath receiving liquid. Subsequently, freeze-dry the ice microspheres to obtain an aerogel microsphere material for carrying lithium sulfide.

[0020] Preferably, the porous MXene nanosheets are ceramic materials with a porous two-dimensional sheet structure, preferably Ti3C2T x 。

[0021] Preferably, the heteroatom is one or more of N, B, and P, and the molar ratio of heteroatom to MXene is (1:10) to (1:1), where the molar ratio of B:N:P is approximately (0 to 1):(0 to 4):(0 to 4), preferably 1:2:3.

[0022] Preferably, the mass ratio of MXene nanosheets to the H2O2 solution is 0.1 to 1, and the mass concentration of the H2O2 solution is 0.01% to 0.1%.

[0023] Preferably, the etching temperature is 20 to 80 °C, and the etching time is 10 to 100 min.

[0024] Preferably, the boron source is selected from one or more of sodium borohydride, boric acid, and B2H6; the phosphorus source is selected from one or more of phosphoric acid, sodium hypophosphite, hexafluorophosphoric acid, and ammonium dihydrogen phosphate; the nitrogen source is selected from one or more of ammonium sulfate, nitric acid, urea, and 1-butyl-3-methylimidazolium tetrafluoroborate (BMI-TFB).

[0025] Preferably, the dispersant is selected from one or more of deionized water and ethanol; the protective atmosphere is any one or two of argon and nitrogen.

[0026] Preferably, the ferrocene is bis(cyclopentadienyl)iron (chemical formula: Fe(C5H5)2), and the mass ratio of ferrocene to heteroatom-doped porous MXene is (0.5:1) to (1.5:1), preferably 1:1.

[0027] Preferably, the organic dispersant is one or more of toluene, acetone, and dimethyl sulfoxide (DMSO), preferably acetone; the mass ratio of the amount of the organic dispersant to the total amount of ferrocene and heteroatom-doped porous MXene is (1:100) to (1:20).

[0028] Preferably, the ignition agent is selected from one or two of carbon powder or carbon fiber, preferably carbon fiber, and the mass ratio of the ignition agent to the mixture is (1:300) to (1:100).

[0029] Preferably, in S14, it is heated to 200 - 500 °C at a heating rate of 3 - 6 °C / min; after holding for 1 - 5 hours, it is naturally cooled to room temperature; the power of the microwave equipment is 400 - 1500 W, preferably 900 W; the microwave radiation time for each time is 20 s - 80 s, preferably 40 s; the number of microwave radiation times is 1 - 5 times, preferably 3 times.

[0030] Preferably, the concentration of the composite dispersion liquid of the porous MXene and graphene oxide is 1% - 3%.

[0031] Preferably, the method for preparing the cellulose-supported porous Mxene microgel material includes:

[0032] S21. Take MXene nanosheets, stir and disperse them in a hydrogen peroxide (H2O2) solution, stir and etch, and then centrifuge and wash the reacted solution, and ultrasonically disperse it to obtain a porous MXene nanosheet solution;

[0033] S22. Add the cellulose raw material to deionized water, break and stir it to make it fully dispersed and uniform to obtain a cellulose dispersion;

[0034] S23. Add the porous MXene nanosheet solution to the cellulose dispersion and stir well to obtain the cellulose-supported porous MXene microgel material.

[0035] Preferably, the cellulose includes various celluloses such as bacterial cellulose, nanofibrillated cellulose, microcrystalline cellulose, and oxidized cellulose at the micron and nanometer levels, preferably bacterial cellulose; the mass ratio of cellulose to MXene nanosheets is 1:1 to 1:20.

[0036] Preferably, the organic solvent is one or more of anhydrous ethanol, diethylene glycol dimethyl ether (DME), and 1,3-dioxolane (DOL), preferably anhydrous ethanol.

[0037] The technical solutions provided by the embodiments of the present application may include the following beneficial effects:

[0038] As can be seen from the above embodiments, the carbon nanotube / graphene oxide adopted in the present application has the advantages of good chemical stability, large elastic modulus and high mechanical strength, and forms an interlaced network structure in the electrode, which can provide a buffer for the volume expansion of the positive electrode during the cycling process, effectively reducing the stress generated by the volume expansion of the electrode material during the charge and discharge process of the lithium-sulfur battery; the prepared lithium sulfide has rich pores, which is beneficial to increasing the specific surface area to adsorb a large amount of lithium sulfide active substances and improving the loading rate. At the same time, it has good physical barrier and chemical adsorption effects on the polysulfides generated during the charge and discharge process, thereby reducing the occurrence of the shuttle effect. The intercalation and connection of porous MXene / graphene oxide / carbon nanotubes will form a multi-layer network structure, which is beneficial to electron transfer, thereby improving the reaction kinetic activity of the lithium-sulfur battery. Using a multi-component composite aerogel microsphere material of graphene, carbon nanotubes and porous MXene as the carrier of the positive electrode active substance, a layer of porous MXene microgel is coated outside the positive electrode material to act as a separator, avoiding the reaction of lithium sulfide with moisture in the external air to generate toxic gas H2S. This preparation method can not only effectively improve the electronic conductivity, loading amount and utilization rate of the sulfur-lithium positive electrode active substance, but also alleviate the dissolution problem of intermediate polysulfide ions, improve the battery cycle stability, and make high-performance lithium-sulfur batteries possible. At the same time, the preparation method of the present invention has simple production process, easy control, low cost, and is green and pollution-free from raw material use to the preparation process, which is conducive to large-scale industrial production.

[0039] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. Detailed Description of the Invention

[0040] Here, the exemplary embodiments will be described in detail.

[0041] Example 1

[0042] S1. Prepare an aerogel microsphere material for carrying lithium sulfide, and the steps are as follows:

[0043] S11. Preparation of a porous MXene nanosheet solution: Take 30 parts by weight of Ti3C2T x Nanosheets are stirred and dispersed into 300 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.01%, stirred and etched at 20°C for 10 minutes, and then the reaction solution is centrifuged and washed, and ultrasonically dispersed to obtain a porous MXene nanosheet solution.

[0044] S12. Preparation of heteroatom dispersion: Take 100 parts by weight of boric acid with a concentration of 1%. The boron source can be replaced with sodium borohydride or B2H6; 100 parts by weight of phosphoric acid with a concentration of 1%. The phosphorus source can be replaced with sodium hypophosphite, hexafluorophosphoric acid, or ammonium dihydrogen phosphate; 100 parts by weight of nitric acid with a concentration of 1%. The nitrogen source can be replaced with ammonium sulfate, urea, or 1-butyl-3-methylimidazolium tetrafluoroborate; Add 300 parts by weight of deionized water and stir well to obtain a heteroatom dispersion.

[0045] S13. Preparation of precursor material: Add the porous MXene nanosheet solution prepared in S11 to the heteroatom dispersion prepared in S12. After stirring well until evenly mixed, centrifuge and dry the mixture to obtain a precursor material.

[0046] S14. Preparation of heteroatom-doped porous MXene material: Put the precursor material into a corundum crucible, then transfer it to a tube furnace. In a protective atmosphere of argon and nitrogen in a ratio of 1:1, heat it to 200 °C at a heating rate of 3 °C / min. After holding for 1 hour, naturally cool it to room temperature, and collect the solid in the corundum crucible to obtain a heteroatom-doped porous MXene material.

[0047] S15. Preparation of ferrocene and porous MXene mixture: Take 10 parts by weight of ferrocene and 20 parts by weight of the heteroatom-doped porous MXene material prepared in S14 and place them in a mortar. Add 0.3 parts by weight of acetone, which can be replaced with toluene or dimethyl sulfoxide (DMSO); Grind for 5 minutes until fully mixed, and then dry to obtain a ferrocene and porous MXene mixture;

[0048] S16. Preparation of in-situ grown carbon nanotube composite heteroatom-doped porous MXene material: Place the mixture prepared in S15 in a corundum crucible, evenly spread 0.1 parts by weight of carbon fiber on the top. Put the crucible into a microwave device, set the power to 400 W and the time to 20 s. After 1 microwave irradiation, collect the product to obtain an in-situ grown carbon nanotube composite heteroatom-doped porous MXene material.

[0049] S17. Preparation of porous MXene and graphene oxide composite dispersion: Take 1 part by weight of the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material prepared in S16 and dissolve it in 200 parts by weight of deionized water. Ultrasonicate it to dissolve it fully, and then add 1 part by weight of graphene oxide (GO) and ultrasonicate it to dissolve it fully to obtain a porous MXene and graphene oxide composite dispersion;

[0050] S18. Preparation of aerogel microsphere material for carrying lithium sulfide: The dispersion liquid prepared in S17 is atomized into droplet microspheres by a spraying method, and porous MXene and graphene oxide composite ice microspheres are formed in a cooling bath receiving liquid. Subsequently, the ice microspheres are freeze-dried under the conditions of a temperature lower than -50 °C and a pressure lower than 50 Pa, and the composite aerogel microspheres of porous MXene and graphene oxide for carrying lithium sulfide can be obtained.

[0051] S2. Preparation of a cellulose-supported porous Mxene microgel material, the steps are as follows:

[0052] S21. Preparation of porous MXene nanosheet solution: Take 20 parts by weight of Ti3C2T x nanosheets and stir and disperse them into 200 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.01%, stir and etch at 20 °C for 10 minutes, and then centrifuge and wash the reaction solution and ultrasonically disperse it to obtain a porous MXene nanosheet solution.

[0053] S22. Preparation of cellulose dispersion liquid: Add 1 part by weight of bacterial cellulose raw material (here, various cellulose with micron and nanometer scales such as nanocellulose, microcrystalline cellulose, and oxidized cellulose can be used for replacement) to 200 parts by weight of deionized water, and use a high-speed stirrer to break and stir at a rotation speed of 15000 rpm to make it fully dispersed and uniform, and obtain a bacterial cellulose dispersion liquid.

[0054] S23. Preparation of cellulose-supported porous MXene: Add the porous MXene nanosheet solution prepared in S21 to the bacterial cellulose dispersion liquid prepared in S22, and stir well to obtain a bacterial cellulose-supported porous MXene microgel material.

[0055] S3. Preparation of the positive electrode material for a lithium sulfide battery, the specific steps are as follows:

[0056] S31. Preparation of homogeneous solution of active sulfur: Dissolve 6 g of Li2S8 in 600 ml of absolute ethanol to form a homogeneous solution with a concentration of 10 mg / ml;

[0057] S32. Preparation of positive electrode precursor material adsorbed with active sulfur: Completely immerse the aerogel microspheres prepared in S1 in the homogeneous solution of active sulfur prepared in S31, and ultrasonically stir until the organic solvent completely volatilizes, and obtain the positive electrode precursor material adsorbed with active sulfur;

[0058] S33. Uniformly coat the cellulose-supported porous MXene microgel prepared in S2 on the surface of the positive electrode precursor prepared in S32, and vacuum dry to obtain the positive electrode material for a lithium sulfide battery.

[0059] Example 2

[0060] S1. Preparation of aerogel microspheres loaded with lithium sulfide, specifically including the following steps:

[0061] S11. Preparation of porous MXene nanosheet solution: Take 30 parts by weight of Ti3C2T x nanosheets and stir and disperse them into 60 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.05%. Stir and etch at 50 °C for 50 minutes, and then centrifuge and wash the reacted solution, and ultrasonically disperse it to obtain a porous MXene nanosheet solution.

[0062] S12. Preparation of heteroatom dispersion: Take 100 parts by weight of boric acid with a concentration of 1%. The boron source can be replaced by one or more of sodium borohydride and B2H6. Add 100 parts by weight of deionized water and stir well to obtain a heteroatom dispersion.

[0063] S13. Preparation of precursor material: Add the porous MXene nanosheet solution prepared in S11 to the heteroatom dispersion prepared in S12. After stirring well until evenly mixed, centrifuge and dry the mixture to obtain a precursor material.

[0064] S14. Preparation of heteroatom-doped porous MXene material: After placing the precursor material in a corundum crucible, transfer it to a tubular furnace. In a nitrogen protection atmosphere, heat it to 400 °C at a heating rate of 5 °C / min. After holding for 3 hours, naturally cool it to room temperature, and collect the solid in the corundum crucible to obtain a heteroatom-doped porous MXene material.

[0065] S15. Preparation of ferrocene and porous MXene mixture: Take 10 parts by weight of ferrocene and 10 parts by weight of the heteroatom-doped porous MXene material prepared in S14 and place them in a mortar. Add 0.4 parts by weight of acetone, which can be replaced by toluene or dimethyl sulfoxide (dmso);, grind for 8 minutes until fully mixed, and then dry to obtain a ferrocene and porous MXene mixture;

[0066] S16. Preparation of in-situ grown carbon nanotube composite heteroatom-doped porous MXene material: Place the mixture prepared in S15 in a corundum crucible, evenly spread 0.1 parts by weight of carbon fiber on the top, place the crucible in a microwave device, set the power to 900 W and the time to 40 s, and collect the product after 3 times of microwave radiation to obtain an in-situ grown carbon nanotube composite heteroatom-doped porous MXene material.

[0067] S17. Preparation of the composite dispersion of porous MXene and graphene oxide: Take 10 parts by weight of the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material prepared in S16 and dissolve it in 500 parts by weight of deionized water. Ultrasonically dissolve it until it is completely dissolved, then add 1 part by weight of graphene oxide (GO), and ultrasonically dissolve it to obtain the composite dispersion of porous MXene and graphene oxide;

[0068] S18. Preparation of the aerogel microsphere material for loading lithium sulfide: Atomize the dispersion prepared in S17 into droplet microspheres by spray method, and form the composite ice microspheres of porous MXene and graphene oxide in the cooling bath receiving liquid. Subsequently, freeze-dry the ice microspheres in an environment with a temperature below -50°C and a pressure below 50 Pa to obtain the composite aerogel microspheres of porous MXene and graphene oxide for loading lithium sulfide.

[0069] S2. Preparation of a cellulose-supported porous Mxene microgel material, the steps are as follows:

[0070] S21. Preparation of the porous MXene nanosheet solution: Take 10 parts by weight of Ti3C2T x nanosheets and stir and disperse them into 20 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.05%. Stir and etch at 50°C for 50 minutes, then centrifuge and wash the reaction solution, and ultrasonically disperse it to obtain the porous MXene nanosheet solution.

[0071] S22. Preparation of the cellulose dispersion: Add 1 part by weight of nanocellulose (here, various cellulose materials such as bacterial cellulose, microcrystalline cellulose, and oxidized cellulose with micron or nanometer scale can be used for replacement) raw material to 50 parts by weight of deionized water, and use a high-speed stirrer to break and stir at a speed of 20000 rpm to make it fully dispersed and uniform, obtaining the nanocellulose dispersion.

[0072] S23. Preparation of the cellulose-supported porous MXene: Add the porous MXene nanosheet solution prepared in S21 to the nanocellulose dispersion prepared in S22, and stir well to obtain the nanocellulose-supported porous MXene microgel material.

[0073] S3. Preparation of the positive electrode material for lithium sulfide batteries, the specific steps are as follows:

[0074] S31. Preparation of the active sulfur homogeneous solution: Dissolve 7 g of Li2S8 in 350 ml of absolute ethanol to form a homogeneous solution with a concentration of 20 mg / ml;

[0075] S32. Preparation of the cathode precursor material for adsorbing active sulfur: Immerse 3 g of the aerogel microspheres obtained in S1 completely into the homogeneous solution of active sulfur prepared in S31, and stir ultrasonically until the organic solvent completely volatilizes, thus obtaining the cathode precursor material for adsorbing active sulfur;

[0076] S33. Uniformly coat the cellulose-supported porous MXene microgel prepared in S2 on the surface of the cathode precursor prepared in S32, and dry it under vacuum to obtain the cathode material for lithium sulfide batteries.

[0077] Example 3

[0078] S1. Preparation of the aerogel microsphere material used for carrying lithium sulfide, which specifically includes the following steps:

[0079] S11. Preparation of the porous MXene nanosheet solution: Take 9 parts by weight of Ti3C2T x nanosheets and stir and disperse them into 9 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.1%. Stir and etch at 80 °C for 100 minutes, and then centrifuge and wash the reaction solution and disperse it ultrasonically to obtain the porous MXene nanosheet solution.

[0080] S12. Preparation of the heteroatom dispersion: Take 100 parts by weight of nitric acid with a concentration of 1%. The nitrogen source can be replaced with ammonium sulfate, nitric acid, urea, 1-butyl-3-methylimidazolium tetrafluoroborate, add 100 parts by weight of deionized water, and stir well to obtain the heteroatom dispersion.

[0081] S13. Preparation of the precursor material: Add the porous MXene nanosheet solution prepared in S11 to the heteroatom dispersion prepared in S12, stir well until evenly mixed, then centrifuge and dry the mixture to obtain the precursor material.

[0082] S14. Preparation of the heteroatom-doped porous MXene material: Put the precursor material into a corundum crucible, then transfer it to a tubular furnace, and heat it to 500 °C at a heating rate of 6 °C / min under a nitrogen protection atmosphere. After keeping it warm for 5 hours, naturally cool it to room temperature, and collect the solid in the corundum crucible to obtain the heteroatom-doped porous MXene material.

[0083] S15. Preparation of the ferrocene and porous MXene mixture: Take 10 parts by weight of ferrocene and 5 parts by weight of the heteroatom-doped porous MXene material prepared in S14 and place them in a mortar, add 0.75 parts by weight of acetone, which can be replaced with toluene or dimethyl sulfoxide (DMSO), grind for 10 minutes until fully mixed, and then dry to obtain the ferrocene and porous MXene mixture;

[0084] S16. Preparation of in-situ grown carbon nanotube composite heteroatom-doped porous MXene material: Place the mixture prepared in S15 above in a corundum crucible, evenly lay 0.15 parts by weight of carbon fiber on the top, put the crucible into a microwave device, set the power to 1500 W and the time to 80 s, collect the product after 5 times of microwave radiation, and thus obtain the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material.

[0085] S17. Preparation of porous MXene and graphene oxide composite dispersion: Take 20 parts by weight of the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material prepared in S16 and dissolve it in 150 parts by weight of deionized water, ultrasonically dissolve it thoroughly, then add 1 part by weight of graphene oxide (GO), and ultrasonically dissolve it thoroughly to obtain the porous MXene and graphene oxide composite dispersion;

[0086] S18. Preparation of aerogel microsphere material for loading lithium sulfide: Atomize the dispersion prepared in S17 into droplet microspheres by spray method, and form porous MXene and graphene oxide composite ice microspheres in the cooling bath receiving liquid. Subsequently, freeze-dry the ice microspheres in an environment with a temperature below -50 °C and a pressure below 50 Pa to obtain the porous MXene and graphene oxide composite aerogel microspheres for loading lithium sulfide.

[0087] S2. Preparation of a cellulose-supported porous Mxene microgel material, the steps are as follows:

[0088] S21. Preparation of porous MXene nanosheet solution: Take 1 part by weight of Ti3C2T x Nanosheets are stirred and dispersed into 1 part by weight of hydrogen peroxide (H2O2) solution with a mass concentration of 0.1%, stirred and etched at 80 °C for 100 minutes, and then the reaction solution is centrifuged and washed, and ultrasonically dispersed to obtain the porous MXene nanosheet solution.

[0089] S22. Preparation of cellulose dispersion: Dilute 1 part by weight of microcrystalline cellulose (here, various cellulose such as nanocellulose, microcrystalline cellulose, and oxidized cellulose at the micron and nanometer levels can be used for replacement) raw material with 25 parts by weight of water, and use a high-speed stirrer to break and stir at a speed of 30000 rpm to make it fully dispersed and uniform, and obtain the microcrystalline cellulose dispersion.

[0090] S23. Preparation of cellulose-supported porous MXene: Add the porous MXene nanosheet solution prepared in S21 to the microcrystalline cellulose dispersion prepared in S22, and stir thoroughly to obtain the microcrystalline cellulose-supported porous MXene microgel material.

[0091] S3. Preparation of the positive electrode material for lithium sulfide battery, the specific steps are as follows:

[0092] S31. Preparation of homogeneous solution of active sulfur: Dissolve 8 g of Li2S8 in 200 ml of absolute ethanol to form a homogeneous solution with a concentration of 40 mg / ml;

[0093] S32. Preparation of cathode precursor material adsorbed with active sulfur: Immerse 2 g of the aerogel microspheres prepared in S1 completely into the homogeneous solution of active sulfur prepared in S31, and stir ultrasonically until the organic solvent completely volatilizes, then the cathode precursor material adsorbed with active sulfur is obtained;

[0094] S33. Uniformly coat the cellulose-supported porous MXene microgel prepared in S2 on the surface of the cathode precursor prepared in S32, and vacuum dry to obtain the cathode material for lithium-sulfide battery.

[0095] Example 4

[0096] S1. Preparation of aerogel microsphere material used for carrying lithium sulfide, which specifically includes the following steps:

[0097] S11. Preparation of porous MXene nanosheet solution: Take 20 parts by weight of Ti3C2T x nanosheets and stir and disperse them into 200 parts by weight of hydrogen peroxide (H2O2) solution with a mass concentration of 0.01%, stir and etch at 20 °C for 10 minutes, then centrifuge and wash the reaction solution, and ultrasonically disperse to obtain a porous MXene nanosheet solution.

[0098] S12. Preparation of heteroatom dispersion: Take 100 parts by weight of phosphoric acid with a concentration of 1%, and the phosphorus source can be replaced with sodium hypophosphite, hexafluorophosphoric acid, or ammonium dihydrogen phosphate. Add 100 parts by weight of deionized water, and stir well to obtain a heteroatom dispersion. S13. Preparation of precursor material: Add the porous MXene nanosheet solution prepared in S11 to the heteroatom dispersion prepared in S12, stir well until evenly mixed, then centrifuge and dry the mixture to obtain a precursor material.

[0099] S14. Preparation of heteroatom-doped porous MXene material: Put the precursor material into a corundum crucible, then transfer it to a tubular furnace, and heat it to 200 °C at a heating rate of 3 °C / min in an argon protective atmosphere. After keeping it at this temperature for 1 hour, naturally cool it to room temperature, and collect the solid in the corundum crucible to obtain the heteroatom-doped porous MXene material.

[0100] S15. Preparation of ferrocene and porous MXene mixture: Take 10 parts by weight of ferrocene and 20 parts by weight of the heteroatom-doped porous MXene material prepared in S14 and place them in a mortar. Add 0.3 parts by weight of acetone, which can be replaced with toluene or dimethyl sulfoxide (DMSO), and grind for 5 minutes until fully mixed, then dry to obtain a ferrocene and porous MXene mixture;

[0101] S16. Preparation of Porous MXene Material Composited with In-situ Grown Carbon Nanotubes and Doped with Heteroatoms: Place the mixture prepared in S15 in a corundum crucible, evenly spread 0.1 part by weight of carbon fiber on the top, put the crucible into a microwave device, set the power to 400 W and the time to 20 s, collect the product after 1-time microwave radiation, and thus obtain the porous MXene material composited with in-situ grown carbon nanotubes and doped with heteroatoms.

[0102] S17. Preparation of Composite Dispersion of Porous MXene and Graphene Oxide: Dissolve 1 part by weight of the porous MXene material composited with in-situ grown carbon nanotubes and doped with heteroatoms prepared in S16 in 200 parts by weight of deionized water, ultrasonically dissolve it thoroughly, then add 1 part by weight of graphene oxide (GO), and ultrasonically dissolve it thoroughly to obtain the composite dispersion of porous MXene and graphene oxide;

[0103] S18. Preparation of Aerogel Microsphere Material for Loading Lithium Sulfide: Atomize the dispersion prepared in S17 into droplet microspheres by spray method, and form composite ice microspheres of porous MXene and graphene oxide in a cooling bath receiving liquid. Subsequently, freeze-dry the ice microspheres in an environment with a temperature below -50 °C and a pressure below 50 Pa to obtain the composite aerogel microspheres of porous MXene and graphene oxide for loading lithium sulfide.

[0104] S2. Preparation of a Cellulose-Supported Porous Mxene Microgel Material, the steps are as follows:

[0105] S21. Preparation of Porous MXene Nanosheet Solution: Take 20 parts by weight of Ti3C2T x nanosheets and stir and disperse them into 200 parts by weight of hydrogen peroxide (H2O2) solution with a mass concentration of 0.01%, stir and etch at 20 °C for 10 minutes, then centrifuge and wash the reacted solution, and ultrasonically disperse it to obtain the porous MXene nanosheet solution.

[0106] S22. Preparation of Cellulose Dispersion: Add 1 part by weight of oxidized cellulose raw material (here, various cellulose materials such as bacterial cellulose, microcrystalline cellulose, and nanofibrillated cellulose with micron-level and nanometer-level sizes can be used for replacement) to 200 parts by weight of deionized water, use a high-speed stirrer to break and stir at a rotation speed of 15000 rpm to make it fully dispersed and uniform, and obtain the oxidized cellulose dispersion.

[0107] S23. Preparation of Cellulose-Supported Porous MXene: Add the porous MXene nanosheet solution prepared in S21 to the oxidized cellulose dispersion prepared in S22, and stir thoroughly to obtain the oxidized cellulose-supported porous MXene microgel material.

[0108] S3. Preparation of the Cathode Material for Lithium Sulfide Battery, the specific steps are as follows:

[0109] S31. Preparation of homogeneous solution of active sulfur: Dissolve 6 g of Li2S8 in 600 ml of absolute ethanol to form a homogeneous solution with a concentration of 10 mg / ml.

[0110] S32. Preparation of cathode precursor material adsorbed with active sulfur: Immerse 4 g of the aerogel microspheres prepared in S1 completely into the homogeneous solution of active sulfur prepared in S31, and stir ultrasonically until the organic solvent completely volatilizes, then the cathode precursor material adsorbed with active sulfur is obtained.

[0111] S33. Uniformly coat the cellulose-supported porous MXene microgel prepared in S2 on the surface of the cathode precursor prepared in S32, and dry it under vacuum to obtain the cathode material for lithium-sulfide battery.

[0112] Example 5

[0113] S1. Preparation of aerogel microsphere material used for carrying lithium sulfide, specifically including the following steps:

[0114] S11. Preparation of porous MXene nanosheet solution: Take 20 parts by weight of Ti3C2T x nanosheets and stir and disperse them into 40 parts by weight of hydrogen peroxide (H2O2) solution with a mass concentration of 0.05%, stir and etch at 50 °C for 50 minutes, and then centrifuge and wash the reacted solution, and disperse it ultrasonically to obtain a porous MXene nanosheet solution.

[0115] S12. Preparation of heteroatom dispersion: Take 100 parts by weight of boric acid with a concentration of 1%, and the boron source can be replaced with sodium borohydride, B2H6; 100 parts by weight of phosphoric acid with a concentration of 1%, and the phosphorus source can be replaced with sodium hypophosphite, hexafluorophosphoric acid, ammonium dihydrogen phosphate; add 200 parts by weight of deionized water, and stir evenly to obtain a heteroatom dispersion.

[0116] S13. Preparation of precursor material: Add the porous MXene nanosheet solution prepared in S11 to the heteroatom dispersion prepared in S12, stir evenly until mixed, then centrifuge and dry the mixture to obtain a precursor material.

[0117] S14. Preparation of heteroatom-doped porous MXene material: Put the precursor material into a corundum crucible, then transfer it to a tubular furnace, and heat it to 400 °C at a heating rate of 5 °C / min under an argon protection atmosphere. After holding for 3 hours, cool it naturally to room temperature, and collect the solid in the corundum crucible to obtain the heteroatom-doped porous MXene material.

[0118] S15. Preparation of ferrocene and porous MXene mixture: Take 10 parts by weight of ferrocene and 10 parts by weight of heteroatom-doped porous MXene material prepared in S14 and place them in a mortar. Add 0.4 parts by weight of dimethyl sulfoxide, which can be replaced by acetone or toluene. Grind for 8 minutes until fully mixed, and then dry to obtain the ferrocene and porous MXene mixture.

[0119] S16. Preparation of in-situ grown carbon nanotube composite heteroatom-doped porous MXene material: Place the mixture prepared in S15 in a corundum crucible, evenly spread 0.1 parts by weight of carbon fiber on the top, put the crucible into a microwave device, set the power to 900 W and the time to 40 s, and collect the product after 3 times of microwave radiation to obtain the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material.

[0120] S17. Preparation of porous MXene and graphene oxide composite dispersion: Take 10 parts by weight of the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material prepared in S16 and dissolve it in 500 parts by weight of deionized water. Ultrasonically dissolve it until fully dissolved, and then add 1 part by weight of graphene oxide (GO) and ultrasonically dissolve it to obtain the porous MXene and graphene oxide composite dispersion.

[0121] S18. Preparation of aerogel microsphere material for loading lithium sulfide: Atomize the dispersion prepared in S17 into droplet microspheres by spray method and form porous MXene and graphene oxide composite ice microspheres in a cooling bath receiving liquid. Subsequently, freeze-dry the ice microspheres in an environment with a temperature below -50 °C and a pressure below 50 Pa to obtain the composite aerogel microspheres of porous MXene and graphene oxide for loading lithium sulfide.

[0122] S2. Preparation of a cellulose-supported porous Mxene microgel material, the steps are as follows:

[0123] S21. Preparation of porous MXene nanosheet solution: Take 10 parts by weight of Ti3C2T x Nanosheets are stirred and dispersed into 20 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.05%, stirred and etched at 50 °C for 50 minutes, and then the reaction solution is centrifuged and washed, and ultrasonically dispersed to obtain the porous MXene nanosheet solution.

[0124] S22. Preparation of cellulose dispersion: Add 1 part by weight of bacterial cellulose raw material (here, various cellulose materials such as nanocellulose, microcrystalline cellulose, and oxidized cellulose with micron-level and nanometer-level sizes can be used to replace) to 50 parts by weight of deionized water, and use a high-speed stirrer to break and stir at a speed of 20000 rpm to make it fully dispersed and uniform, obtaining the bacterial cellulose dispersion.

[0125] S23. Preparation of cellulose-supported porous MXene: Add the porous MXene nanosheet solution prepared in S21 to the bacterial cellulose dispersion prepared in S22, and stir well to obtain the bacterial cellulose-supported porous MXene microgel material.

[0126] S3. Preparation of the cathode material for a lithium sulfide battery, and the specific steps are as follows:

[0127] S31. Preparation of a homogeneous solution of active sulfur: Dissolve 7 g of Li2S8 in 350 ml of absolute ethanol to form a homogeneous solution with a concentration of 20 mg / ml.

[0128] S32. Preparation of the cathode precursor material adsorbed with active sulfur: Completely immerse the aerogel microspheres prepared in S1 in the homogeneous solution of active sulfur prepared in S31, and perform ultrasonic stirring until the organic solvent completely evaporates, to obtain the cathode precursor material adsorbed with active sulfur.

[0129] S33. Uniformly coat the cellulose-supported porous MXene microgel prepared in S2 on the surface of the cathode precursor prepared in S32, and perform vacuum drying to obtain the cathode material for a lithium sulfide battery.

[0130] Example 6

[0131] S1. Preparation of the aerogel microsphere material used for carrying lithium sulfide, and the specific steps include the following:

[0132] S11. Preparation of the porous MXene nanosheet solution: Take 5 parts by weight of Ti3C2T x nanosheets, stir and disperse them into 5 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.1%, stir and etch at 80 °C for 100 minutes, and then centrifuge and wash the reacted solution, and perform ultrasonic dispersion to obtain the porous MXene nanosheet solution.

[0133] S12. Preparation of the heteroatom dispersion: Take 100 parts by weight of phosphoric acid with a concentration of 1%, and the phosphorus source can be replaced with sodium hypophosphite, hexafluorophosphoric acid, or ammonium dihydrogen phosphate; 100 parts by weight of nitric acid with a concentration of 1%, and the nitrogen source can be replaced with ammonium sulfate, urea, or 1-butyl-3-methylimidazolium tetrafluoroborate; add 200 parts by weight of deionized water, and stir well to obtain the heteroatom dispersion.

[0134] S13. Preparation of the precursor material: Add the porous MXene nanosheet solution prepared in S11 to the heteroatom dispersion prepared in S12, stir well until evenly mixed, and then centrifuge and dry the mixture to obtain the precursor material.

[0135] S14. Preparation of heteroatom-doped porous MXene material: After putting the precursor material into a corundum crucible, transfer it to a tube furnace. In a nitrogen-protected atmosphere, heat it to 500 °C at a heating rate of 6 °C / min. After holding for 5 hours, cool it naturally to room temperature, and collect the solid in the corundum crucible to obtain the heteroatom-doped porous MXene material.

[0136] S15. Preparation of ferrocene and porous MXene mixture: Take 10 parts by weight of ferrocene and 5 parts by weight of the heteroatom-doped porous MXene material prepared in S14 and place them in a mortar. Add 0.75 parts by weight of toluene, which can be replaced by acetone or dimethyl sulfoxide;, grind for 10 minutes until fully mixed, and then dry to obtain the ferrocene and porous MXene mixture;

[0137] S16. Preparation of in-situ grown carbon nanotube composite heteroatom-doped porous MXene material: Place the mixture prepared in S15 above in a corundum crucible, and evenly spread 0.15 parts by weight of carbon fiber on the top. Put the crucible into a microwave device, set the power to 1500 W and the time to 80 s, and collect the product after 5 times of microwave radiation to obtain the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material.

[0138] S17. Preparation of porous MXene and graphene oxide composite dispersion: Take 20 parts by weight of the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material prepared in S16 and dissolve it in 150 parts by weight of deionized water. Ultrasonically dissolve it until fully dissolved, and then add 1 part by weight of graphene oxide (GO), and ultrasonically dissolve it to obtain the porous MXene and graphene oxide composite dispersion;

[0139] S18. Preparation of aerogel microsphere material for loading lithium sulfide: Atomize the dispersion prepared in S17 into droplet microspheres by spray method, and form porous MXene and graphene oxide composite ice microspheres in the cooling bath receiving liquid. Subsequently, freeze-dry the ice microspheres in an environment with a temperature below -50 °C and a pressure below 50 Pa to obtain the porous MXene and graphene oxide composite aerogel microspheres for loading lithium sulfide.

[0140] S2. Preparation of a cellulose-supported porous Mxene microgel material, the steps are as follows:

[0141] S21. Preparation of porous MXene nanosheet solution: Take 1 part by weight of Ti3C2T x Nanosheets are stirred and dispersed into 1 part by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.1%, stirred and etched at 80 °C for 100 minutes, and then the reaction solution is centrifuged and washed, and ultrasonically dispersed to obtain the porous MXene nanosheet solution.

[0142] S22. Preparation of cellulose dispersion: Dilute 1 part by weight of bacterial cellulose raw material (which can be replaced by various cellulose materials such as nanocellulose, microcrystalline cellulose, and oxidized cellulose at the micron and nanometer levels) with 25 parts by weight of water, and use a high-speed blender to break and stir at a speed of 30,000 rpm to make it fully dispersed and uniform, obtaining a bacterial cellulose dispersion.

[0143] S23. Preparation of cellulose-supported porous MXene: Add the porous MXene nanosheet solution prepared in S21 to the bacterial cellulose dispersion prepared in S22, and stir well to obtain a cellulose-supported porous MXene microgel material.

[0144] S3. Preparation of the positive electrode material for a lithium-sulfide battery, and the specific steps are as follows:

[0145] S31. Preparation of a homogeneous solution of active sulfur: Dissolve 8 g of Li2S8 in 200 ml of absolute ethanol to form a homogeneous solution with a concentration of 40 mg / ml.

[0146] S32. Preparation of the positive electrode precursor material adsorbed with active sulfur: Immerse 2 g of the aerogel microspheres prepared in S1 completely into the homogeneous solution of active sulfur prepared in S31, and stir ultrasonically until the organic solvent completely evaporates, obtaining the positive electrode precursor material adsorbed with active sulfur.

[0147] S33. Uniformly coat the cellulose-supported porous MXene microgel prepared in S2 on the surface of the positive electrode precursor prepared in S32, and dry it under vacuum to obtain the positive electrode material for a lithium-sulfide battery.

[0148] Example 7

[0149] S1. Preparation of an aerogel microsphere material used for carrying lithium sulfide, and the specific steps include the following:

[0150] S11. Preparation of a porous MXene nanosheet solution: Take 10 parts by weight of Ti3C2T x Nanosheets are stirred and dispersed into 100 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.01%, etched by stirring at 20 °C for 10 minutes, and then the reaction solution is centrifuged and washed, and ultrasonically dispersed to obtain a porous MXene nanosheet solution.

[0151] S12. Preparation of a heteroatom dispersion:

[0152] Take 100 parts by weight of boric acid with a concentration of 1%, and the boron source can be replaced by sodium borohydride, B2H6; 100 parts by weight of nitric acid with a concentration of 1%, and the nitrogen source can be replaced by ammonium sulfate, urea, 1-butyl-3-methylimidazolium tetrafluoroborate; add 200 parts by weight of deionized water, and stir well to obtain a heteroatom dispersion.

[0153] S13. Preparation of precursor material: Add the porous MXene nanosheet solution obtained in S11 to the heteroatom dispersion obtained in S12, stir well until evenly mixed, then centrifuge and dry the mixture to obtain the precursor material.

[0154] S14. Preparation of heteroatom-doped porous MXene material: Place the precursor material in a corundum crucible, then transfer it to a tube furnace. Under an argon protection atmosphere, heat it to 200 °C at a heating rate of 3 °C / min. After holding for 1 hour, cool it naturally to room temperature, and collect the solid in the corundum crucible to obtain the heteroatom-doped porous MXene material.

[0155] S15. Preparation of ferrocene and porous MXene mixture: Take 10 parts by weight of ferrocene and 20 parts by weight of the heteroatom-doped porous MXene material prepared in S14 and place them in a mortar. Add 0.3 parts by weight of acetone, which can be replaced by toluene or dimethyl sulfoxide, and grind for 5 minutes until fully mixed, then dry to obtain the ferrocene and porous MXene mixture;

[0156] S16. Preparation of in-situ grown carbon nanotube composite heteroatom-doped porous MXene material: Place the mixture prepared in S15 in a corundum crucible, evenly spread 0.1 part by weight of carbon fiber on the top, put the crucible into a microwave device, set the power to 400 W and the time to 20 s, and collect the product after 1 microwave irradiation to obtain the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material.

[0157] S17. Preparation of porous MXene and graphene oxide composite dispersion: Take 1 part by weight of the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material prepared in S16 and dissolve it in 200 parts by weight of deionized water, sonicate it to dissolve it fully, and then add 1 part by weight of graphene oxide (GO), sonicate it to dissolve it fully to obtain the porous MXene and graphene oxide composite dispersion;

[0158] S18. Preparation of aerogel microsphere material for loading lithium sulfide: Atomize the dispersion prepared in S17 into droplet microspheres by spray method, and form porous MXene and graphene oxide composite ice microspheres in a cooling bath receiving liquid. Subsequently, freeze-dry the ice microspheres under the conditions of a temperature lower than -50 °C and a pressure lower than 50 Pa to obtain the composite aerogel microspheres of porous MXene and graphene oxide for loading lithium sulfide.

[0159] S2. Preparation of a cellulose-supported porous Mxene microgel material, the steps are as follows:

[0160] S21. Preparation of porous MXene nanosheet solution: Take 20 parts by weight of Ti3C2T xThe nanosheets were stirred and dispersed in 200 parts by weight of a hydrogen peroxide (H2O2) solution with a mass concentration of 0.01%, stirred and etched at 20°C for 10 minutes, and then the reacted solution was centrifuged and washed, and ultrasonically dispersed to obtain a porous MXene nanosheet solution.

[0161] S22. Preparation of cellulose dispersion: Add 200 parts by weight of deionized water to 1 part by weight of bacterial cellulose raw material (which can be replaced by nanocellulose, micronized cellulose, oxidized cellulose and other micron- and nano-sized cellulose) and use a high-speed stirrer to crush and stir at a speed of 15000 pm to fully disperse it to obtain a bacterial cellulose dispersion.

[0162] S23. Preparation of cellulose-supported porous MXene: Add the porous MXene nanosheet solution prepared in S21 to the bacterial cellulose dispersion prepared in S22, and stir thoroughly to obtain a porous MXene microgel material supported by bacterial cellulose.

[0163] S3, preparing the positive electrode material of lithium sulfide battery, the specific steps are as follows:

[0164] S31, preparation of active sulfur homogeneous solution: dissolve 6g Li2S8 in 600ml anhydrous ethanol to form a homogeneous solution with a concentration of 10mg / ml;

[0165] S32, preparation of a positive electrode precursor material for adsorbing active sulfur: completely immerse 4g of the aerogel microspheres prepared by S1 in the active sulfur homogeneous solution prepared by S31, and stir by ultrasonication until the organic solvent is completely volatilized, thereby obtaining a positive electrode precursor material for adsorbing active sulfur;

[0166] S33. The cellulose-supported porous MXene microgel prepared in S2 is uniformly coated on the surface of the positive electrode precursor prepared in S32, and vacuum dried to obtain the positive electrode material of the lithium sulfide battery.

[0167] Those skilled in the art will readily appreciate other embodiments of the present application after considering the description and practicing the contents disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The description and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the claims.

[0168] It should be understood that the present application is not limited to the precise structure that has been described above, and that various modifications and changes may be made without departing from its scope. The scope of the present application is limited only by the appended claims.

Claims

1. A cathode material for a lithium sulfide battery, characterized in that: The positive electrode material of the lithium sulfide battery is composed of active sulfur, aerogel microspheres used for carrying lithium sulfide, and porous MXene microgels coating the positive electrode material; The preparation method of the positive electrode material of the lithium sulfide battery includes the following steps: S31. Dissolve active sulfur in an organic solvent to form a homogeneous solution of active sulfur; S32. Immerse the aerogel microspheres completely in the homogeneous solution of active sulfur prepared in S31, and stir ultrasonically until the organic solvent completely volatilizes, thus obtaining the positive electrode precursor material adsorbed with active sulfur; S33. Uniformly coat the cellulose-supported porous MXene microgel on the surface of the positive electrode precursor prepared in S32, and dry it under vacuum to obtain the positive electrode material of the lithium sulfide battery; The method for preparing the aerogel microsphere material used for carrying lithium sulfide includes: S11. Take MXene nanosheets and stir and disperse them into a hydrogen peroxide solution, stir and etch, and then centrifuge and wash the reacted solution, and disperse it ultrasonically to obtain a porous MXene nanosheet solution; S12. Add a nitrogen source, a boron source, and a phosphorus source to a dispersant, and stir well to make it uniformly dispersed to obtain a heteroatom dispersion; S13. Add the porous MXene nanosheet solution prepared in S11 to the heteroatom dispersion prepared in S12, stir well until evenly mixed, then centrifuge and dry the mixture to obtain a precursor material; S14. Put the precursor material into a corundum crucible, transfer it to a tubular furnace, in a protective atmosphere, heat it to a predetermined temperature, keep it warm, and then naturally cool it to room temperature, and collect the solid in the corundum crucible to obtain a heteroatom-doped porous MXene material; S15. Take ferrocene and the heteroatom-doped porous MXene material prepared in S14 and place them in a mortar, add an organic dispersant, grind until fully mixed, and then dry to obtain a mixed material; S16. Place the mixed material prepared in S15 in a corundum crucible, evenly spread an igniter on the top, put the crucible into a microwave device, and collect the product after microwave radiation to obtain an in-situ grown carbon nanotube composite heteroatom-doped porous MXene material; S17. Dissolve the in-situ grown carbon nanotube composite heteroatom-doped porous MXene material prepared in S16 in deionized water, ultrasonically dissolve it sufficiently, then add graphene oxide, and ultrasonically dissolve it sufficiently to obtain a porous MXene and graphene oxide composite dispersion; S18. Atomize the dispersion prepared in S17 into droplet microspheres by spraying method, and form porous MXene and graphene oxide composite ice microspheres in a cooling bath receiving solution, and then freeze-dry the ice microspheres to obtain the aerogel microsphere material used for carrying lithium sulfide; The method for preparing the cellulose-supported porous Mxene microgel material includes: S21. Take MXene nanosheets and stir and disperse them into a hydrogen peroxide (H2O2) solution, stir and etch, and then centrifuge and wash the reacted solution, and disperse it ultrasonically to obtain a porous MXene nanosheet solution; S22. Add cellulose raw materials to deionized water, break and stir to make it fully and uniformly dispersed to obtain a cellulose dispersion; S23. Add the porous MXene nanosheet solution to the cellulose dispersion and stir well to obtain the cellulose-supported porous MXene microgel material.

2. The cathode material for a lithium sulfide battery according to claim 1, wherein: The active sulfur is one or more of Li2S8, Li2S6, Li2S4, Li2S2, and Li2S, and the weight percentage of the active sulfur in the cathode material of the lithium-sulfide battery is 60–80 wt.%.

3. The cathode material for a lithium sulfide battery according to claim 1, wherein: The porous MXene nanosheet is a ceramic material with a porous two-dimensional sheet structure.

4. The cathode material for a lithium sulfide battery according to claim 3, characterized in that: porous MXene nanosheets are Ti3C2T x 。 5. The preparation method according to claim 1, wherein: The heteroatom is N, B, or P, and the molar ratio of the heteroatom to MXene is (1:10) to (1:1), where the molar ratio of B:N:P is (0–1):(0–4):(0–4).

6. The preparation method according to claim 5, characterized in that: The molar ratio of B:N:P is 1:2:

3.

7. The cathode material for a lithium sulfide battery according to claim 1, wherein: The mass ratio of the MXene nanosheet to the H2O2 solution is 0.1–1, and the mass concentration of the H2O2 solution is 0.01%–0.1%.

8. The cathode material for a lithium sulfide battery according to claim 1, wherein: The etching temperature is 20–80 °C, and the etching time is 10–100 min.

9. The cathode material for a lithium sulfide battery according to claim 1, wherein: The boron source is selected from one or more of sodium borohydride, boric acid, and B2H6; the phosphorus source is selected from one or more of phosphoric acid, sodium hypophosphite, hexafluorophosphoric acid, and ammonium dihydrogen phosphate; the nitrogen source is selected from one or more of ammonium sulfate, nitric acid, urea, and 1-butyl-3-methylimidazolium tetrafluoroborate.

10. The cathode material for a lithium sulfide battery according to claim 1, characterized in that: The dispersant is selected from one or more of deionized water and ethanol; the protective atmosphere is any one or two of argon and nitrogen.

11. The cathode material for a lithium sulfide battery according to claim 1, wherein: The ferrocene is bis(cyclopentadienyl)iron, and the mass ratio of ferrocene to the heteroatom-doped porous MXene material is (0.5:1) to (1.5:1).

12. The cathode material for a lithium sulfide battery according to claim 11, characterized in that: The mass ratio of ferrocene to the heteroatom-doped porous MXene material is 1:

1.

13. The cathode material for a lithium sulfide battery according to claim 1, wherein: The organic dispersant is one or more of toluene, acetone, and dimethyl sulfoxide; the mass ratio of the amount of the organic dispersant to the total amount of ferrocene and the heteroatom-doped porous MXene is (1:100) to (1:20).

14. The cathode material for a lithium sulfide battery according to claim 1, wherein: The igniter is selected from one or two of carbon powder or carbon fiber, and the mass ratio of the igniter to the mixture is (1:300) to (1:100).

15. The cathode material for a lithium sulfide battery according to claim 1, characterized in that: In S14, after placing the precursor material in a corundum crucible, transfer it to a tube furnace, and heat it to 200–500 °C at a heating rate of 3–6 °C / min in a protective atmosphere; after holding for 1–5 hours, cool it naturally to room temperature; The power of the microwave device is 400–1500 W; the time of each microwave radiation is 20 s–80 s; the number of microwave radiation times is 1–5 times.

16. The cathode material for a lithium sulfide battery according to claim 15, characterized in that: The power of the microwave device is 900 W; the time of each microwave radiation is 40 s; the number of microwave radiation times is 3 times.

17. The cathode material for a lithium sulfide battery according to claim 1, characterized in that: The concentration of the composite dispersion of the porous MXene and graphene oxide is 1%–3%.

18. The cathode material for a lithium sulfide battery according to claim 1, characterized in that: The cellulose raw material includes bacterial cellulose, nanofibrillated cellulose, microcrystalline cellulose, or oxidized cellulose; the mass ratio of the cellulose raw material to the MXene nanosheet is 1:1 to 1:

20.

19. The cathode material for a lithium sulfide battery according to claim 18, characterized in that: The cellulose raw material is bacterial cellulose.