An intercalated expanded-layer molybdenum disulfide nanosheet composite, one-step solvothermal preparation method and application thereof

Abstract

The application discloses an intercalated and expanded molybdenum disulfide nanosheet composite material and a one-step solvothermal preparation method and application thereof. The preparation method comprises the following steps: dissolving a sulfur source and a molybdenum source in a mixed solvent to obtain a precursor solution; wherein the mixed solvent comprises an amine compound and ethanol; the amine compound comprises at least one of butylamine, ethylenediamine or octylamine; and the carbon base is placed in the precursor solution, and a solvothermal reaction is carried out at 200-240 DEG C for 8-12 hours. When the composite material prepared by the method is used as a functional interlayer of a lithium-sulfur battery, excellent performance is exhibited in inhibiting the shuttle effect and improving the cycle stability.

Description

Technical Field

[0001] This invention relates to the fields of new energy materials and electrochemical energy storage technology, specifically to an intercalated and expanded molybdenum disulfide nanosheet composite material and its one-step solvothermal preparation method and application. Background Technology

[0002] Lithium-sulfur batteries boast a capacity of up to 1675 mAh g. -1 Theoretical specific capacity and 2600 Wh kg -1 With its high energy density, coupled with the advantages of abundant sulfur resources, low cost, and environmental friendliness, lithium-sulfur batteries are considered one of the most promising next-generation high-energy-density energy storage systems. However, the practical application of lithium-sulfur batteries still faces many challenges: First, the intermediate products of charging and discharging, lithium polysulfides (Li2S), are problematic. x (4≤x≤8) is easily soluble in electrolyte and migrates back and forth between positive and negative electrodes, causing a serious "shuttle effect," resulting in irreversible loss of active material, low coulombic efficiency, and reduced cycle life; secondly, the sulfur source and its discharge end products (Li2S2 / Li2S) have electronic insulation, which restricts the utilization rate of active material; thirdly, about 80% of the volume expansion can easily lead to the destruction of electrode structure during repeated charge and discharge.

[0003] To suppress the shuttle effect, introducing a functional interlayer between the sulfur cathode and the separator is an effective solution. An ideal interlayer material needs to possess high conductivity, abundant polysulfide adsorption sites, and the ability to catalyze the rapid conversion of polysulfides. Two-dimensional layered transition metal sulfides (such as MoS2), with their unique layered structure and highly polar surface, exhibit strong chemisorption of polysulfides, and their edge sites can catalyze polysulfide conversion. However, the small interlayer spacing of conventional MoS2 (approximately 0.62 nm) severely restricts the interlayer diffusion of lithium ions and polysulfides, and also hinders the full exposure of active sites.

[0004] Therefore, developing a new molybdenum disulfide nanosheet composite material is of great significance. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a one-step solvothermal preparation method for intercalated and expanded molybdenum disulfide nanosheet composite materials. When the composite material prepared by this method is used as a functional interlayer in lithium-sulfur batteries, it exhibits excellent performance in suppressing the shuttle effect and improving cycle stability.

[0006] The present invention also proposes a composite material prepared by the above method.

[0007] The present invention also proposes applications of the above-mentioned materials.

[0008] According to one aspect of the present invention, a one-step solvothermal preparation method for intercalated and extended molybdenum disulfide nanosheet composite materials is provided, comprising the following steps: A sulfur source and a molybdenum source are dissolved in a mixed solvent to obtain a precursor solution; wherein the mixed solvent includes an amine compound and ethanol; the amine compound includes at least one of butylamine, ethylenediamine, or octylamine. The carbon substrate is placed in the precursor solution and subjected to a solvothermal reaction at 200-240°C for 8-12 hours to obtain the product.

[0009] According to some embodiments of the present invention, the preparation method further includes the following steps: after a solvothermal reaction, the product is cooled and then washed and dried to obtain the final product.

[0010] According to some embodiments of the invention, the cooling is achieved by natural cooling to room temperature.

[0011] According to some embodiments of the present invention, the room temperature is 25±5℃.

[0012] According to some embodiments of the present invention, the solvent used for washing includes water and ethanol. Washing is performed repeatedly with water and ethanol.

[0013] According to some embodiments of the present invention, the drying is performed using vacuum drying.

[0014] According to some embodiments of the present invention, the organic amine compound in the amine compound is a straight-chain organic amine compound, such as n-(long)octylamine.

[0015] According to some embodiments of the present invention, the drying temperature is 60-90°C, more preferably overnight in an oven at 80°C.

[0016] According to some embodiments of the present invention, the sulfur source and the molar source have a sulfur to molybdenum molar ratio of 1 to 4:1.

[0017] According to some embodiments of the present invention, the molar ratio of sulfur to molybdenum is 1.5 to 2.5:1, such as 2:1.

[0018] According to some embodiments of the present invention, the molybdenum source comprises at least one of hexavalent molybdenum or trivalent molybdenum.

[0019] According to some embodiments of the present invention, the molybdenum source includes at least one of ammonium molybdate, sodium molybdate, ammonium thiomolybdate, or molybdenum acetylacetonate.

[0020] According to some embodiments of the present invention, the sulfur source includes at least one of thiourea, L-cysteine, glutathione, thioacetamide, or elemental sulfur.

[0021] According to some embodiments of the present invention, the volume ratio of amine compound to ethanol in the mixed solvent is 2 to 4:10, such as 3:10.

[0022] According to some embodiments of the present invention, the preparation method further includes the step of placing the carbon substrate in the precursor solution and then sonicating it for 10 to 60 minutes.

[0023] According to some embodiments of the present invention, the ultrasound duration is 20-40 minutes, such as 30 minutes.

[0024] According to some embodiments of the present invention, the solvothermal reaction is carried out in a high-pressure reactor, and the reaction system is transferred to the high-pressure reactor under stirring.

[0025] According to some embodiments of the present invention, the stirring time is 10 to 60 minutes, such as 15 minutes.

[0026] According to some embodiments of the present invention, the stirring speed is 200~1500 rpm.

[0027] According to some embodiments of the present invention, the stirring speed is 500~600 rpm.

[0028] According to some embodiments of the present invention, the preparation method further includes ultrasonic dispersion treatment during the preparation of the precursor solution. A uniformly dispersed precursor solution is obtained through ultrasonic dispersion.

[0029] According to some embodiments of the present invention, the carbon substrate is a pretreated carbon substrate, the pretreatment including cleaning to remove surface oil and impurities, and drying.

[0030] According to some embodiments of the present invention, the carbon substrate comprises a conductive carbon material.

[0031] According to some embodiments of the present invention, the carbon substrate includes at least one of carbon nanotubes, graphene, or carbon cloth.

[0032] According to some embodiments of the present invention, the cleaning is performed using ultrasonic cleaning with ethanol and water.

[0033] According to some embodiments of the present invention, the carbon substrate is cut to the required size and then cleaned.

[0034] According to some embodiments of the present invention, the carbon substrate comprises commercial hydrophobic carbon cloth or other carbon cloth that has been acid-treated or plasma-treated.

[0035] According to some embodiments of the present invention, the preparation method includes the following steps: dissolving elemental sulfur and molybdenum acetylacetonate in a mixed solution of octylamine and ethanol to obtain a precursor solution; arranging carbon in the above solution and transferring it to a high-pressure reactor under stirring for a solvothermal reaction to obtain the precursor.

[0036] Some embodiments of this invention provide a one-step solvothermal preparation method for intercalated extended molybdenum disulfide nanosheet composite material (OA-MoS2 / CC). This method uses molybdenum acetylacetonate as the molybdenum source, elemental sulfur as the sulfur source, octylamine as both the intercalating agent and solvent, and ethanol as an auxiliary solvent. Octylamine-intercalated extended MoS2 nanosheets are directly grown on the surface of pretreated carbon cloth through a one-step solvothermal reaction. This method is simple and efficient, requiring no subsequent high-temperature annealing or separate intercalation steps. The resulting sandwich can be directly used in lithium-sulfur batteries, enabling the battery to achieve high-rate performance. This overcomes the problems of small MoS2 interlayer spacing, complex preparation process, and the need for additional binders in traditional molybdenum disulfide functional sandwiches.

[0037] According to another aspect of the present invention, an intercalated molybdenum disulfide nanosheet composite material prepared by the above method is provided.

[0038] According to another aspect of the present invention, the application of the above-described composite material in the preparation of lithium-sulfur batteries is proposed.

[0039] According to another aspect of the present invention, a lithium-sulfur battery is provided, comprising a sulfur cathode, a functional interlayer, and a separator arranged in sequence, wherein the raw material for preparing the functional interlayer includes the aforementioned composite material.

[0040] This functional interlayer is placed directly between the sulfur cathode and the separator, requiring no adhesives or conductive additives. The intercalation of amine compounds such as octylamine in the functional interlayer expands the MoS2 interlayer spacing (up to ~0.86 nm), providing a rapid diffusion channel for lithium ions and polysulfides. Simultaneously, the abundant Mo-S edge sites and intercalated amino functional groups synergistically chemisorb polysulfides and catalyze their conversion, effectively suppressing the shuttle effect and achieving high-rate performance lithium-sulfur batteries.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This invention simultaneously achieves the nucleation and growth of MoS2 and the in-situ intercalation and layer expansion of amine compounds in a solvothermal reaction, eliminating the need for subsequent high-temperature annealing or separate intercalation treatment, thus significantly simplifying the preparation process and reducing energy consumption. The amine compounds act as both reaction solvents and intercalating agents, as well as reducing agents and structure-directing agents, effectively expanding the interlayer spacing of MoS2 (from 0.62 nm to 0.86 nm). Simultaneously, their long carbon chain hydrophobic ends contribute to improving the structural stability of the interlayer in the electrolyte.

[0042] 2. This invention employs a one-step solvothermal reaction method, which is simple, environmentally friendly, and requires no complex post-processing. Using carbon substrates such as carbon cloth as a three-dimensional conductive framework, MoS2 nanosheets are uniformly grown on the carbon fiber surface, forming a binder-free, self-supporting interlayer that can be directly used in battery assembly. This interlayer significantly inhibits polysulfide shuttle, exhibiting high specific capacity, excellent rate performance, and long cycle stability in lithium-sulfur batteries. The raw materials used are inexpensive and readily available, the reaction conditions are mild, the carbon cloth can be pre-cut to electrode size, and the resulting product has a stable structure and good catalytic activity, making it suitable for large-scale production and possessing great application potential.

[0043] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0044] Figure 1 This is a scanning electron microscope (SEM) image of the octylamine intercalated MoS2 / carbon cloth prepared in Example 1 of this invention.

[0045] Figure 2 yes Figure 1 The corresponding material is a magnified high-magnification scanning electron microscope (SEM) image of a local area.

[0046] Figure 3 This is an image showing the elemental distribution of octylamine intercalated MoS2 / carbon cloth obtained in Example 1 of this invention.

[0047] Figure 4 The images shown are high-resolution transmission electron microscope (HRTEM) images (A) and lattice analysis (B) of the octylamine intercalated MoS2 prepared in Example 1 of this invention.

[0048] Figure 5 This is a comparison chart of the cycle performance of lithium-sulfur batteries assembled in Example 1 of the present invention and Comparative Examples 1, 2, and 3 at a 1C rate.

[0049] Figure 6 This is a degradation graph of the lithium-sulfur battery assembled in Example 1 of the present invention during the first 100 cycles at a current density of 1C for the OA-MoS2 / CC battery. Detailed Implementation

[0050] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available. Unless otherwise specified, the same parameter value is the same in all embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0051] In the description of this invention, references to terms such as "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] Organic amine molecules (such as octylamine, butylamine, and ethylenediamine) possess suitable carbon chain lengths and terminal amino groups, allowing them to intercalate into the MoS2 interlayer via intercalation reactions. This significantly expands the interlayer spacing, thereby enhancing ion transport capabilities and exposing more catalytically active edges. Simultaneously, directly loading extended MoS2 onto three-dimensional porous carbon cloth creates a self-supporting, highly conductive, and flexible multifunctional sandwich layer, avoiding the use of binders in traditional slurry coating processes. In this invention, octylamine is preferably used as both an intercalating agent and a solvent, and octylamine-intercalated extended MoS2 is directly grown on carbon cloth via a one-step solvothermal method, serving as a multifunctional sandwich layer for lithium-sulfur batteries.

[0053] Example 1 This example provides a method for preparing an octylamine intercalated extended MoS2 / carbon cloth multifunctional sandwich, the specific operation of which is as follows: Commercial carbon cloth (WOS1009, Taiwan Carbon Energy) was cut into 12 mm diameter discs, ultrasonically cleaned in ethanol and deionized water for 30 minutes each, and dried in a 60°C oven for later use.

[0054] Weigh 0.04 g of elemental sulfur and 0.16 g of molybdenum acetylacetonate, dissolve them in a mixed solution of 6 mL of n-octylamine and 20 mL of ethanol, and sonicate for 15 minutes until completely dissolved to obtain a clear orange-yellow precursor solution.

[0055] The pretreated carbon cloth discs were immersed in the above solution and sonicated for 30 minutes, followed by magnetic stirring for several minutes to ensure full impregnation of the carbon cloth. The mixture was then transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, heated to 220°C, and maintained at that temperature for 10 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature.

[0056] The carbon cloth was removed and washed three times each with ethanol and deionized water to remove unreacted species and physically adsorbed octylamine from the surface. The washed carbon cloth was then dried overnight in a vacuum drying oven at 80°C to obtain an octylamine intercalated and expanded MoS2 / carbon cloth multifunctional sandwich, denoted as OA-MoS2 / CC.

[0057] The structure of the prepared OA-MoS2 / CC material was characterized, and the results are as follows: Figure 1-4 As shown. From Figure 1 As can be seen, MoS2 nanosheets are uniformly covered on the surface of the carbon fibers. Figure 2 As can be seen, MoS2 nanosheets are uniformly covered on the surface of carbon fibers and are accompanied by many pores. Figure 3 This further corroborates the fact that Mo and S elements are uniformly coated on the carbon fiber surface. From Figure 4 As can be seen, the material of this invention exhibits a clear extended layer structure. Due to the intercalation of octylamine, the interlayer spacing is increased to 0.86 nm, while the conventional MoS2 interlayer spacing is 0.62 nm, indicating that octylamine intercalation was successful. In summary, the OA-MoS2 / CC prepared in Example 1 of this invention has MoS2 nanosheets uniformly covering carbon cloth, with the interlayer spacing increased to 0.86 nm.

[0058] Preparation of sulfur electrode: The sulfur cathode was prepared using a traditional slurry coating method. First, a sulfur cathode slurry was prepared by adding 70% sulfur, 20% conductive agent (Ketjen Black), and 10% polyvinylidene fluoride (PVDF) binder to N-methyl-2-pyrrolidone (NMP). The mixture was then ground for 20 minutes to form a uniform paste. Finally, the slurry was coated onto aluminum foil, dried in a vacuum oven at 60°C for 12 hours, and then rolled and cut into circular electrodes with a diameter of 12 mm.

[0059] The steps for assembling the multifunctional sandwich layer of a lithium-sulfur battery are as follows: The lithium-sulfur battery mainly consists of a lithium anode, an OA-MoS2 / carbon cloth multifunctional sandwich layer, a polypropylene membrane, a catalyst cathode (i.e., the sulfur cathode obtained in the aforementioned operation), and an electrolyte. The obtained OA-MoS2 / CC multifunctional sandwich layer is sequentially placed between the sulfur cathode and the separator for assembly. Before electrochemical testing, the assembled battery is allowed to stand for 12 hours. Constant current discharge / charge tests are performed using a multichannel battery testing system (LAND CT2001A) at room temperature (25°C), with discharge and charge conducted at a current density of 1C and a voltage window of 1.7V - 2.8V.

[0060] Example 2 This example provides a method for preparing an octylamine intercalated and expanded MoS2 / carbon cloth multifunctional sandwich, which is basically the same as that in Example 1, except that: acid treatment is used during carbon cloth pretreatment (concentrated sulfuric acid and concentrated nitric acid are mixed in a mass ratio of 3:1 and then soaked); the solvothermal reaction time is extended to 12 hours.

[0061] Example 3 This example provides a method for preparing an octylamine intercalated and expanded MoS2 / carbon cloth multifunctional sandwich, which is basically the same as that in Example 1, except that the mass ratio of elemental sulfur to molybdenum acetylacetonate is adjusted to 0.08 g : 0.16 g.

[0062] Comparative Example 1 This example provides a method for preparing a MoS2 / carbon cloth multifunctional sandwich layer, which is basically the same as in Example 1, except that octylamine is not added, and only ethanol is used as the solvent. The other steps are the same, resulting in a conventional unintercalated MoS2 / carbon cloth sandwich layer, denoted as MoS2 / CC. 0.04 g of elemental sulfur and 0.16 g of molybdenum acetylacetonate were weighed and dissolved in 20 mL of ethanol. The solution was sonicated for 15 minutes until completely dissolved, yielding a clear precursor solution. The pretreated carbon cloth discs were immersed in the above solution and sonicated for another 30 minutes, followed by magnetic stirring for several minutes to ensure thorough wetting. The mixture was then transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene (PTFE), heated to 220°C, and reacted for 10 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The carbon cloth was removed and washed three times each with ethanol and deionized water to remove unreacted species from the surface. The washed carbon cloth was dried overnight in a vacuum drying oven at 80°C to obtain the MoS2 / carbon cloth multifunctional sandwich layer, denoted as MoS2 / CC.

[0063] Preparation of sulfur electrode: The sulfur cathode was prepared using a traditional slurry coating method. First, 80% sulfur, 10% conductive agent (Ketjen Black), and 10% polyvinylidene fluoride (PVDF) binder were added to an N-methyl-2-pyrrolidone (NMP) solution to prepare a sulfur cathode slurry. The mixture was then ground for 20 minutes to form a uniform paste. Finally, the slurry was coated onto aluminum foil, dried in a vacuum oven at 60°C for 12 hours, and then rolled and cut into circular electrodes with a diameter of 12 mm.

[0064] The steps for assembling the multifunctional sandwich layer of a lithium-sulfur battery are as follows: The lithium-sulfur battery mainly consists of a lithium anode, a MoS2 / carbon cloth multifunctional sandwich layer (referred to as MoS2 / CC), a polypropylene membrane, a catalyst cathode (i.e., the sulfur cathode obtained in the aforementioned operation), and an electrolyte. The obtained MoS2 / CC sandwich layer is sequentially placed between the sulfur cathode and the separator for assembly. Before conducting electrochemical tests, the assembled battery is allowed to stand for 12 hours. The test conditions are exactly the same as in Example 1.

[0065] Comparative Example 2 It is basically the same as Example 1, except that only untreated blank carbon cloth CC is added as a multifunctional interlayer (referred to as CC).

[0066] Preparation of sulfur electrode: The sulfur cathode was prepared using a traditional slurry coating method. First, 80% sulfur, 10% conductive agent (Ketjen Black), and 10% polyvinylidene fluoride (PVDF) binder were added to an N-methyl-2-pyrrolidone (NMP) solution to prepare a sulfur cathode slurry. The mixture was then ground for 20 minutes to form a uniform paste. Finally, the slurry was coated onto aluminum foil, dried in a vacuum oven at 60°C for 12 hours, and then rolled and cut into circular electrodes with a diameter of 12 mm.

[0067] The steps for assembling the multifunctional sandwich layer of a lithium-sulfur battery are as follows: The lithium-sulfur battery mainly consists of a lithium anode, blank carbon cloth (CC), a polypropylene membrane, a catalyst cathode (i.e., the sulfur cathode obtained in the aforementioned operation), and an electrolyte. The obtained CC sandwich layer is sequentially placed between the sulfur cathode and the separator. Before conducting electrochemical tests, the assembled battery is left to stand for 12 hours. The test conditions are exactly the same as in Example 1.

[0068] Comparative Example 3 It is basically the same as Example 1, except that no interlayer is used, only a polypropylene membrane (PP) is used as the membrane, and no additional carbon cloth interlayer is added.

[0069] Preparation of sulfur electrode: The sulfur cathode was prepared using a traditional slurry coating method. First, 80% sulfur, 10% conductive agent (Ketjen Black), and 10% polyvinylidene fluoride (PVDF) binder were added to an N-methyl-2-pyrrolidone (NMP) solution to prepare a sulfur cathode slurry. The mixture was then ground for 20 minutes to form a uniform paste. Finally, the slurry was coated onto aluminum foil, dried in a vacuum oven at 60°C for 12 hours, and then rolled and cut into circular electrodes with a diameter of 12 mm.

[0070] The steps for assembling the multifunctional sandwich layer of a lithium-sulfur battery are as follows: The lithium-sulfur battery mainly consists of a lithium anode, a polypropylene separator, a catalyst cathode (i.e., the sulfur cathode obtained in the aforementioned operation), and an electrolyte. Before conducting electrochemical tests, the assembled battery was left to stand for 12 hours. Constant current discharge / charge tests were performed using a multi-channel battery testing system (LAND CT 2001A) at room temperature, with discharge and charge conducted at a current density of 1C. The test conditions were completely consistent with those in Example 1.

[0071] The comparison graph of the cycle performance of the lithium-sulfur batteries assembled in Example 1 of this invention with those in Comparative Examples 1, 2, and 3 at 1C rate is shown in the figure below. Figure 5 As shown in the figure, the specific capacity is still 719.5 mAh / g after 500 cycles.

[0072] The degradation graph of the lithium-sulfur battery assembled in Example 1 of this invention at 1C current density for the first 100 cycles of OA-MoS2 / CC is shown in the figure. Figure 6 As shown, after 100 cycles, the capacity decay rate is 0.13% per cycle.

[0073] In summary, this invention discloses a one-step solvothermal preparation method for intercalated extended MoS2 / carbon cloth multifunctional interlayers and its application in lithium-sulfur batteries. Using molybdenum acetylacetonate as the molybdenum source, elemental sulfur as the sulfur source, octylamine as both the intercalating agent and solvent, and ethanol as an auxiliary solvent, octylamine-intercalated extended MoS2 nanosheets are grown in situ on the surface of pretreated carbon cloth using a one-step solvothermal method. This method is simple and efficient, requiring no subsequent high-temperature annealing or separate intercalation steps, and the resulting self-supporting interlayer can be directly used in lithium-sulfur batteries. Octylamine intercalation increases the interlayer spacing of MoS2 from 0.62 nm to 0.86 nm, providing rapid ion transport channels and abundant active edge sites. Combined with the three-dimensional conductive network of the carbon cloth, it achieves efficient physical barrier, chemical adsorption, and catalytic conversion of polysulfides. Lithium-sulfur batteries using this interlayer still exhibit a specific capacity of 719.5 mAh / g after 500 cycles at 1C, demonstrating excellent cycle performance. The present invention has a simple preparation process, low cost, and can be scaled up, and has broad application prospects in the field of next-generation high-energy-density lithium-sulfur batteries.

[0074] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A one-step solvothermal preparation method for intercalated and extended molybdenum disulfide nanosheet composite materials, characterized in that: Includes the following steps: A sulfur source and a molybdenum source are dissolved in a mixed solvent to obtain a precursor solution; wherein the mixed solvent includes an amine compound and ethanol; the amine compound includes at least one of butylamine, ethylenediamine, or octylamine. The carbon substrate is placed in the precursor solution and subjected to a solvothermal reaction at 200-240°C for 8-12 hours to obtain the product.

2. The one-step solvothermal preparation method of the intercalated and extended molybdenum disulfide nanosheet composite material according to claim 1, characterized in that: The sulfur source and molybdenum source have a sulfur to molybdenum molar ratio of 1 to 4:

1.

3. The one-step solvothermal preparation method of the intercalated and extended molybdenum disulfide nanosheet composite material according to claim 1, characterized in that: The molybdenum source includes at least one of ammonium molybdate, sodium molybdate, ammonium thiomolybdate, or molybdenum acetylacetonate; and / or the sulfur source includes at least one of thiourea, L-cysteine, glutathione, thioacetamide, or elemental sulfur.

4. The one-step solvothermal preparation method of the intercalated and extended molybdenum disulfide nanosheet composite material according to claim 1, characterized in that: The volume ratio of amine compounds to ethanol in the mixed solvent is 2~4:

10.

5. The one-step solvothermal preparation method of the intercalated and extended molybdenum disulfide nanosheet composite material according to claim 1, characterized in that: The solvothermal reaction is carried out in a high-pressure reactor. The reaction system is transferred to the high-pressure reactor with stirring at a speed of 200-1500 rpm.

6. The one-step solvothermal preparation method of the intercalated and extended molybdenum disulfide nanosheet composite material according to claim 1, characterized in that: The carbon substrate includes at least one of carbon nanotubes, graphene, or carbon cloth.

7. A one-step solvothermal preparation method of the intercalated and extended molybdenum disulfide nanosheet composite material according to any one of claims 1 to 6, characterized in that: The preparation method includes the following steps: dissolving elemental sulfur and molybdenum acetylacetonate in a mixed solution of octylamine and ethanol to obtain a precursor solution; arranging carbon in the above solution and transferring it to a high-pressure reactor under stirring for a solvothermal reaction to obtain the precursor.

8. The intercalated molybdenum disulfide nanosheet composite material prepared by the method according to any one of claims 1 to 7.

9. The application of the composite material according to claim 8 in the preparation of lithium-sulfur batteries.

10. A lithium-sulfur battery, characterized in that: It includes a sulfur cathode, a functional interlayer, and a separator stacked sequentially, wherein the raw material for preparing the functional interlayer includes the composite material according to claim 8.

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