Applications of aloe vera peel biocarbon materials in the preparation of lithium-sulfur batteries

Abstract

This invention discloses the use of aloe vera peel biochar material in the preparation of lithium-sulfur batteries. The aloe vera peel biochar material serves as a raw material for both the positive electrode and the separator in lithium-sulfur batteries. The positive electrode material includes KOH@AVP / S positive electrode material, and the separator material includes Co@AVP separator modification material. This invention uses aloe vera peel biochar material as a precursor, and obtains a high specific surface area KOH@AVP / S positive electrode material by KOH etching. Simultaneously, Co metal nanoparticles are introduced through a simple hydrothermal reaction to prepare a Co@AVP separator modification material that can be used to modify the separator. The simultaneous application of these two materials in lithium-sulfur batteries allows them to exert a synergistic effect.

Description

Technical Field

[0001] This invention belongs to the field of lithium-sulfur battery material technology, specifically relating to the use of aloe vera peel biocarbon material in the preparation of lithium-sulfur batteries. Background Technology

[0002] With rapid societal development, the demand for energy has increased dramatically. The excessive consumption of traditional fossil fuels has led to increasingly serious environmental pollution and the greenhouse effect. Furthermore, due to the non-renewable nature of fossil fuels, they cannot sustainably meet human needs. Therefore, the development and utilization of clean and renewable energy has always been a research hotspot in the field of new energy. Rechargeable batteries, as efficient energy storage systems, play a crucial role in the storage of clean and renewable energy. Lithium-ion batteries (LIBs) have been widely used in people's production and daily lives since their invention. However, the energy density of lithium-ion batteries is limited by the specific capacity of the cathode material, making it difficult to achieve significant improvements.

[0003] Therefore, lithium-sulfur batteries have become a research hotspot in energy storage devices due to their abundant sulfur reserves, low price, and high theoretical specific capacity (1675 mAh / g) and theoretical energy density (2600 Wh / kg). However, some problems still exist in the research of lithium-sulfur batteries at present, which seriously limit their widespread application. For example, the shuttle effect of lithium polysulfides (long-chain polysulfides diffuse from the cathode to the anode and accumulate on the lithium sheet during battery operation, reducing conductivity), the low conductivity of sulfur, and the volume expansion during discharge lead to poor cycle stability, poor rate performance, low coulombic efficiency, and serious loss of active material, thus restricting the commercialization process of lithium-sulfur batteries.

[0004] To address these challenges, researchers have proposed various strategies, primarily including the functional design and synthesis of the cathode and intermediate layers to adsorb and block the shuttle effect, thereby promoting the redox reaction of lithium polysulfides (LiPSs). Other strategies include electrolyte optimization, such as the preparation of solid electrolytes to suppress the dissolution and dispersion of LiPSs. Currently, the use of multifunctional carbon materials to regulate the shuttle effect, modify membranes to promote LiPS catalytic reactions, and construct high-sulfur host materials have become mainstream research trends. However, the synthesis of these materials typically requires complex steps and long preparation times. Therefore, the large-scale synthesis of porous carbon materials using simple methods has become a research hotspot. Multifunctional carbon materials prepared using biomass have shown great and unique potential as energy storage materials in the field of electrochemical energy storage. Unfortunately, most modified materials can only achieve one or two excellent properties, making it difficult to simultaneously possess both high discharge specific capacity and the ability to effectively mitigate the redox kinetics of LiPSs. These issues still limit the commercial development of lithium-sulfur batteries. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide the use of aloe vera peel biocarbon material in the preparation of lithium-sulfur batteries.

[0006] Another object of the present invention is to provide a lithium-sulfur battery.

[0007] The technical solution of the present invention is as follows:

[0008] The use of aloe vera peel biochar material in the preparation of lithium-sulfur batteries, wherein the aloe vera peel biochar material is used as a raw material for preparing the positive electrode and separator of lithium-sulfur batteries.

[0009] The raw material for this positive electrode includes KOH@AVP / S positive electrode material. The preparation method of this KOH@AVP / S positive electrode material includes: using aloe vera peel powder as raw material, performing high-temperature annealing and carbonization at 500℃, KOH etching, high-temperature annealing at 700℃ and acid washing in sequence to obtain KOH@AVP, and then performing a sulfur melting reaction to obtain KOH@AVP / S positive electrode material.

[0010] The raw material for this membrane includes Co@AVP membrane modification material. The preparation method of this Co@AVP membrane modification material includes: using aloe vera peel powder, urea and cobalt nitrate hexahydrate as raw materials, carrying out a hydrothermal reaction, then adding pore-forming agents K2CO3 and CaCO3 and ball milling evenly, and then successively performing vacuum drying, high-temperature annealing at 500-700℃ in an argon atmosphere and acid washing to obtain the Co@AVP membrane modification material.

[0011] In a preferred embodiment of the present invention, the preparation method of the KOH@AVP / S cathode material includes: the 500°C high-temperature annealing carbonization is performed by heating the aloe vera peel powder to 500°C at a heating rate of 5°C / min and holding it at that temperature for 3 hours; the KOH etching is performed by mixing the material obtained from the 500°C high-temperature annealing carbonization with KOH and stirring at 110°C for 12 hours to remove excess moisture, followed by drying; the 700°C high-temperature annealing is performed by heating the material obtained from the KOH etching to 700°C at a heating rate of 2°C / min and holding it at that temperature for 1 hour to activate the KOH; the acid washing is performed by washing the material obtained from the 700°C high-temperature annealing with hydrochloric acid, then washing it thoroughly with deionized water, and then drying it thoroughly. The obtained KOH@AVP is then subjected to a sulfur melting reaction to obtain the KOH@AVP / S cathode material.

[0012] More preferably, the mass ratio of the material obtained by high-temperature annealing and carbonization at 500°C to KOH is 1:1-3.

[0013] In a preferred embodiment of the present invention, the preparation method of the Co@AVP membrane modified material includes: the high-temperature annealing at 500-700°C in an argon atmosphere as follows: the material obtained by vacuum drying is heated to 500°C in an argon atmosphere at a heating rate of 5°C / min, annealed for 1 hour and 30 minutes, then heated to 700°C at a heating rate of 2°C / min and held for 2 hours, and then cooled naturally; the acid washing is as follows: the material obtained by high-temperature annealing at 500-700°C in an argon atmosphere is acid washed with hydrochloric acid, then thoroughly washed with deionized water, and then thoroughly dried.

[0014] More preferably, the mass ratio of aloe vera peel powder, urea, and cobalt nitrate hexahydrate is 1:0.5-1:0.05-0.1; the hydrothermal reaction temperature is 80℃ and the time is 12h; the mass ratio of the material obtained from the hydrothermal reaction to the pore-forming agents K2CO3 and CaCO3 is 1:0.5-1:0.5-1.

[0015] A lithium-sulfur battery comprises a positive electrode and a separator. The positive electrode is prepared from KOH@AVP / S positive electrode material. The preparation method of the KOH@AVP / S positive electrode material includes: using aloe vera peel powder as raw material, performing high-temperature annealing and carbonization at 500°C, KOH etching, high-temperature annealing at 700°C, and acid washing to obtain KOH@AVP, and then performing a molten sulfur reaction to obtain the KOH@AVP / S positive electrode material. The separator is prepared from Co@AVP separator modified material. The preparation method of the Co@AVP separator modified material includes: using aloe vera peel powder, urea, and cobalt nitrate hexahydrate as raw materials, performing a hydrothermal reaction, then adding pore-forming agents K2CO3 and CaCO3 and ball milling uniformly, and then performing vacuum drying, high-temperature annealing at 500-700°C under argon atmosphere, and acid washing to obtain the Co@AVP separator modified material.

[0016] In a preferred embodiment of the present invention, the preparation method of the KOH@AVP / S cathode material includes: the 500°C high-temperature annealing carbonization is performed by heating the aloe vera peel powder to 500°C at a heating rate of 5°C / min and holding it at that temperature for 3 hours; the KOH etching is performed by mixing the material obtained from the 500°C high-temperature annealing carbonization with KOH and stirring at 110°C for 12 hours to remove excess moisture, followed by drying; the 700°C high-temperature annealing is performed by heating the material obtained from the KOH etching to 700°C at a heating rate of 2°C / min and holding it at that temperature for 1 hour to activate the KOH; the acid washing is performed by washing the material obtained from the 700°C high-temperature annealing with hydrochloric acid, then washing it thoroughly with deionized water, and then drying it thoroughly for 24 hours. The obtained KOH@AVP is then subjected to a sulfur melting reaction to obtain the KOH@AVP / S cathode material.

[0017] More preferably, the mass ratio of the material obtained by high-temperature annealing and carbonization at 500°C to KOH is 1:1-3.

[0018] In a preferred embodiment of the present invention, the preparation method of the Co@AVP membrane modified material includes: the high-temperature annealing at 500-700°C in an argon atmosphere as follows: the material obtained by vacuum drying is heated to 500°C in an argon atmosphere at a heating rate of 5°C / min, annealed for 1 hour and 30 minutes, then heated to 700°C at a heating rate of 2°C / min and held for 2 hours, and then cooled naturally; the acid washing is as follows: the material obtained by high-temperature annealing at 500-700°C in an argon atmosphere is acid washed with hydrochloric acid, then thoroughly washed with deionized water, and then thoroughly dried.

[0019] More preferably, the mass ratio of aloe vera peel powder, urea, and cobalt nitrate hexahydrate is 1:0.5-1:0.05-0.1; the hydrothermal reaction temperature is 80℃ and the time is 12h; the mass ratio of the material obtained from the hydrothermal reaction to the pore-forming agents K2CO3 and CaCO3 is 1:0.5-1:0.5-1.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention uses aloe vera peel biomass carbon material as a precursor, and obtains a high specific surface area KOH@AVP / S cathode material by KOH etching. Simultaneously, Co metal nanoparticles are introduced through a simple hydrothermal reaction to prepare a Co@AVP separator modifier material that can be used to modify the separator. The simultaneous application of these two materials in lithium-sulfur batteries demonstrates a synergistic effect.

[0022] 2. This invention applies aloe vera peel biomass carbon materials to the modification of both the cathode material and the separator in lithium-sulfur batteries. This design not only provides ample space for significant volume changes in the sulfur cathode during charge and discharge, but also allows the Co metal nanoparticles loaded on the carbon material to act as active sites, effectively catalyzing the conversion of polysulfides, suppressing the shuttle effect of polysulfides, and further accelerating reaction kinetics. Therefore, the assembled lithium-sulfur battery exhibits excellent cycle stability and rate performance. Attached Figure Description

[0023] Figure 1 The images show the XRD patterns of all materials prepared in Examples 1 and 2 of this invention.

[0024] Figure 2 This is a SEM image of the KOH@AVP cathode material obtained in Example 1 of the present invention.

[0025] Figure 3 This is a SEM image of the Co@AVP membrane modified material obtained in Example 2 of the present invention.

[0026] Figure 4 The BET specific surface area diagrams are for the KOH@AVP cathode material prepared in Example 1 and the Co@AVP membrane modified material prepared in Example 2 of this invention.

[0027] Figure 5 Physical images (right) of a commercially available separator (left) and a lithium-sulfur battery separator modified with the Co@AVP separator modification material prepared in Example 1 of this invention.

[0028] Figure 6 The graph shows the rate performance test results of a 2025-type coin cell lithium-sulfur battery assembled using the KOH@AVP / S cathode material prepared in Example 1 and the Co@AVP / / PP material prepared in Example 2.

[0029] Figure 7 The graph shows the cycle performance test results of a 2025-type coin cell lithium-sulfur battery assembled using the KOH@AVP / S cathode material prepared in Example 1 of this invention and the Co@AVP / / PP combined material prepared in Example 2. Detailed Implementation

[0030] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0031] Example 1: Preparation of KOH@AVP / S cathode

[0032] (1) 15g of aloe vera peel powder was heated to 500℃ at a heating rate of 5℃ / min and annealed for 3h to obtain aloe vera peel biomass carbon material.

[0033] (2) Take out the aloe vera peel biomass carbon material, mix it with KOH at a weight ratio of 1:3, add deionized water, stir at 110℃ for etching reaction for 12h, then remove excess water and transfer to tube furnace, heat to 700℃ at a heating rate of 2℃ / min and hold for annealing for 1h to activate KOH.

[0034] (3) Take out the material obtained in step (2) and wash it with 1M hydrochloric acid for 12 hours. Then rinse it repeatedly with deionized water to remove excess KOH and other impurities. Then dry it in a vacuum oven at 80°C for 12 hours to obtain KOH@AVP.

[0035] (4) KOH@AVP and elemental sulfur are ground in a mortar at a mass ratio of 2:3 for more than 30 minutes to make them uniformly mixed. Then, they are placed in a sealed vial filled with argon gas and heated at 155°C for 12 hours to carry out the sulfur melting reaction to obtain KOH@AVP / S cathode material.

[0036] (5) KOH@AVP / S cathode material, Ketjen black, and polyvinylidene fluoride (PVDF) were mixed uniformly in N-methylpyrrolidone (NMP) at a weight ratio of 7:2:1 to prepare an electrode slurry. This slurry was then manually coated onto aluminum foil and dried at 60°C to prepare the cathode electrode. The average sulfur loading of the manually cut cathode electrode sheet was 1.3 mg / cm³. 2 .

[0037] like Figure 1 The image shown is the XRD pattern of KOH@AVP in Example 1. Figure 1 It can be seen that the KOH@AVP(101) peak, characteristic of the amorphous structure, is slightly weaker than that of AVP, indicating that the graphitization degree of KOH-L HP is slightly lower. Figure 2 The image shown is a SEM image of KOH@AVP obtained in Example 1 of this study. From... Figure 2 It can be seen that KOH has a significant etching effect on aloe vera peel carbon material, revealing a porous structure. Figure 4 The specific surface area of ​​KOH@AVP was shown to be 1982.1 m². 2 / g. This further demonstrates that KOH@AVP provides space for the enormous volume of sulfur host before and after charge and discharge.

[0038] Example 2: Preparation of Co@AVP / / PP

[0039] (1) Add 2g of aloe vera peel powder, 1g of urea and 150mg of cobalt nitrate hexahydrate to 25mL of ethanol, stir evenly at room temperature, and then carry out hydrothermal reaction at 80℃ for 12h to remove ethanol.

[0040] (2) The material obtained in step (1) is ball-milled with pore-forming agents K2CO3 and CaCO3 in a mass ratio of 1:1:1.

[0041] (3) The material obtained in step (2) is heated to 500°C in an argon atmosphere at a heating rate of 5°C / min, annealed for 1 hour and 30 minutes, and then heated to 700°C at a heating rate of 2°C / min and held for 2 hours, and then cooled naturally.

[0042] (4) The material obtained in step (3) was acid-washed with 1M hydrochloric acid for 12h and washed with a large amount of deionized water 3 times. Then it was vacuum-dried at 80℃ for 24h to obtain Co@AVP membrane modified material.

[0043] (5) The above Co@AVP membrane modification material is mixed with polyvinylidene fluoride (PVDF) at a mass ratio of 4:1 and ultrasonically dispersed in N,N-dimethylformamide (DMF) for 2 hours to obtain a slurry. Then, the slurry is vacuum filtered and assembled on the surface of a commercial membrane made of PP and vacuum dried at 60°C for 12 hours to obtain the Co@AVP / / PP lithium-sulfur battery membrane.

[0044] like Figure 1 The image shown is the XRD pattern of the Co@AVP membrane modified material obtained in Example 2 of this study. Figure 1 It can be seen that the X-ray diffraction peaks of the membrane-modified material Co@AVP sample correspond to 44.2°, 51.5°, and 75.8° of the (111), (200), and (220) crystal planes of metallic Co, respectively (PDF#15-0806). A broad peak at 44.70° is also observed, corresponding to the graphitized carbon (101) plane, exhibiting an amorphous structure. The Co@AVP (101) peak is slightly weaker than that of AVP, indicating a slightly lower degree of graphitization in Co@AVP. This demonstrates that the Co metal nanoparticles were successfully loaded onto AVP, and the material was successfully prepared. Figure 3 The image shown is a SEM image of the Co@AVP membrane modified material obtained in Example 2 of this study. Figure 3 Co nanoparticles can be clearly seen embedded inside the material, proving that Co nanoparticles were successfully loaded into the aloe vera peel carbon material. Figure 4 The specific surface area of ​​the Co@AVP membrane modified material was shown to be 2078.4 m². 2 / g demonstrates that it can provide sufficient space and expose more catalytic centers to capture and promote the redox of LiPSs. Figure 5 The images show a commercial separator (left) and a lithium-sulfur battery separator modified with the Co@AVP separator modifier prepared in Example 2 (right), demonstrating that the Co@AVP separator modifier has been uniformly coated onto the surface of the commercial separator.

[0045] Example 3: Preparation of a conventional sulfur cathode

[0046] In this embodiment, the preparation process involves adding sulfur powder, acetylene black, PVDF, and other chemicals in a mass ratio of 6:3:1 to an agate container, followed by the addition of an appropriate amount of N-methylpyrrolidone (NMP). The mixture is then stirred in a ball mill at 250 rpm for 3 hours to obtain a slurry. The resulting slurry is coated onto aluminum foil and dried in a vacuum oven at 60°C for 12 hours, yielding a sulfur content of approximately 1.3 mg / cm³. -2 Ordinary sulfur cathode.

[0047] Example 4: Assembly of Lithium-Sulfur Batteries

[0048] In this embodiment, the KOH@AVP / S cathode material obtained in Example 1, along with a Co@AVP / / PP modified separator, commercial lithium-sulfur battery electrolyte, lithium metal sheets, gaskets, spring contacts, and the positive and negative electrode shells, are stacked and assembled to form a 2025-type coin cell. A standard sulfur cathode and an unmodified separator, commercial lithium-sulfur battery electrolyte, lithium metal sheets, gaskets, spring contacts, and the positive and negative electrode shells are also stacked and assembled to form a 2025-type coin cell as a control blank.

[0049] like Figure 6 The figure shown is a rate performance test graph of a 2025-type coin cell lithium-sulfur battery assembled with KOH@AVP / S cathode material and Co@AVP / / PP obtained in Example 4. From... Figure 6 It is evident that the rate performance of the lithium-sulfur battery assembled with KOH@AVP / S cathode material and Co@AVP / / PP is significantly higher than that of the blank battery. Furthermore, the lithium-sulfur battery assembled with KOH@AVP / S cathode material and Co@AVP / / PP maintains a high capacity of 891.58 mmAh / g at a high rate of 4C, demonstrating that this battery can maintain relatively low polarization at high rates. Figure 7 The figure shown is a cycle performance test graph of a 2025-type coin-type lithium-sulfur battery assembled with KOH@AVP / S cathode material and Co@AVP / / PP obtained in Example 4. From Figure 7 The results show that the lithium-sulfur battery still has a discharge specific capacity of 590.84 mAh / g after 800 cycles at 1C, which is significantly higher than the discharge specific capacity of the control battery (96.04 mA h / g), achieving high energy density. This demonstrates that the battery exhibits good cycle stability in long-term cycling experiments.

[0050] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. The use of aloe vera peel biocarbon material in the preparation of lithium-sulfur batteries, characterized in that: The aloe vera peel biocarbon material is used as a raw material for preparing the positive electrode and separator of lithium-sulfur batteries. The raw material for this positive electrode includes KOH@AVP / S positive electrode material. The preparation method of this KOH@AVP / S positive electrode material includes: using aloe vera peel powder as raw material, performing high-temperature annealing and carbonization at 500 ℃, KOH etching, high-temperature annealing at 700 ℃ and acid washing in sequence to obtain KOH@AVP, and then performing a sulfur melting reaction to obtain KOH@AVP / S positive electrode material; The raw material for this membrane includes Co@AVP membrane modification material. The preparation method of this Co@AVP membrane modification material includes: using aloe vera peel powder, urea and cobalt nitrate hexahydrate as raw materials, carrying out a hydrothermal reaction at a temperature of 80 ℃ for 12 h, then adding pore-forming agents K2CO3 and CaCO3 and ball milling evenly, followed by vacuum drying, high-temperature annealing at 500-700℃ under argon atmosphere and acid washing to obtain the Co@AVP membrane modification material.

2. The use as described in claim 1, characterized in that: The preparation method of the KOH@AVP / S cathode material includes: the 500℃ high-temperature annealing carbonization is performed by heating the aloe vera peel powder to 500℃ at a heating rate of 5℃ / min and holding it at that temperature for 3 hours; the KOH etching is performed by mixing the material obtained from the 500℃ high-temperature annealing carbonization with KOH and stirring at 110℃ for 12 hours to remove excess moisture, followed by drying; the 700℃ high-temperature annealing is performed by heating the material obtained from the KOH etching to 700℃ at a heating rate of 2℃ / min and holding it at that temperature for 1 hour to activate KOH; the acid washing is performed by washing the material obtained from the 700℃ high-temperature annealing with hydrochloric acid, then washing it thoroughly with deionized water, and then drying it thoroughly. The obtained KOH@AVP is then subjected to a sulfur melting reaction to obtain the KOH@AVP / S cathode material.

3. The use as described in claim 2, characterized in that: The mass ratio of the material obtained by high-temperature annealing and carbonization at 500 ℃ to KOH is 1:1-3.

4. The use as described in claim 1, characterized in that: In the preparation method of the Co@AVP membrane modified material: the high-temperature annealing at 500-700℃ in an argon atmosphere is as follows: the material obtained by vacuum drying is heated to 500℃ in an argon atmosphere at a heating rate of 5℃ / min, annealed for 1 h30 min, then heated to 700℃ at a heating rate of 2℃ / min and held for 2 h, and then cooled naturally; the acid washing is as follows: the material obtained by high-temperature annealing at 500-700℃ in an argon atmosphere is acid washed with hydrochloric acid, then thoroughly washed with deionized water, and then thoroughly dried.

5. The use as described in claim 4, characterized in that: The mass ratio of aloe vera peel powder, urea, and cobalt nitrate hexahydrate is 1:0.5-1:0.05-0.1; the mass ratio of the material obtained from the hydrothermal reaction to the pore-forming agents K2CO3 and CaCO3 is 1:0.5-1:0.5-1.

6. A lithium-sulfur battery having a positive electrode and a separator, characterized in that: The raw materials for the positive electrode include KOH@AVP / S positive electrode material. The preparation method of the KOH@AVP / S positive electrode material includes: using aloe vera peel powder as raw material, performing high-temperature annealing and carbonization at 500 ℃, KOH etching, high-temperature annealing at 700 ℃, and acid washing to obtain KOH@AVP, and then performing a sulfur melting reaction to obtain the KOH@AVP / S positive electrode material. The raw materials for the separator include Co@AVP separator modified material. The preparation method of the Co@AVP separator modified material includes: using aloe vera peel powder, urea, and cobalt nitrate hexahydrate as raw materials, performing a hydrothermal reaction at 80 ℃ for 12 h, then adding pore-forming agents K2CO3 and CaCO3 and ball milling uniformly, and then performing vacuum drying, high-temperature annealing at 500-700 ℃ under argon atmosphere, and acid washing to obtain the Co@AVP separator modified material.

7. A lithium-sulfur battery as described in claim 6, characterized in that: In the preparation method of the KOH@AVP / S cathode material: the 500 ℃ high-temperature annealing carbonization is as follows: the aloe vera peel powder is heated to 500 ℃ at a heating rate of 5 ℃ / min and held for 3 h; the KOH etching is as follows: the material obtained by 500 ℃ high-temperature annealing carbonization is mixed evenly with KOH and stirred at 110 ℃ for 12 h to remove excess water, and then dried; the 700 ℃ high-temperature annealing is as follows: the material obtained by KOH etching is heated to 700 ℃ at a heating rate of 2 ℃ / min and held for 1 h to activate KOH; the acid washing is as follows: the material obtained by 700 ℃ high-temperature annealing is acid washed with hydrochloric acid, then thoroughly washed with deionized water, and then thoroughly dried. The obtained KOH@AVP is then subjected to a sulfur melting reaction to obtain the KOH@AVP / S cathode material.

8. A lithium-sulfur battery as described in claim 7, characterized in that: The mass ratio of the material obtained by high-temperature annealing and carbonization at 500 ℃ to KOH is 1:1-3.

9. A lithium-sulfur battery as described in claim 6, characterized in that: In the preparation method of the Co@AVP membrane modified material: the high-temperature annealing at 500-700 ℃ in an argon atmosphere is as follows: the material obtained by vacuum drying is heated to 500 ℃ in an argon atmosphere at a heating rate of 5 ℃ / min, annealed for 1 h 30 min, then heated to 700 ℃ at a heating rate of 2 ℃ / min and held for 2 h, and then cooled naturally; the acid washing is as follows: the material obtained by high-temperature annealing at 500-700 ℃ in an argon atmosphere is acid washed with hydrochloric acid, then thoroughly washed with deionized water, and then thoroughly dried.

10. A lithium-sulfur battery as described in claim 9, characterized in that: The mass ratio of aloe vera peel powder, urea, and cobalt nitrate hexahydrate is 1:0.5-1:0.05-0.1; the mass ratio of the material obtained from the hydrothermal reaction to the pore-forming agents K2CO3 and CaCO3 is 1:0.5-1:0.5-1.

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