A Mo-Mn bimetallic single-atom cluster catalyst, its preparation method and its application in lithium-sulfur battery separators

Abstract

This invention relates to the field of lithium-sulfur battery technology, disclosing a Mo-Mn bimetallic single-atom cluster catalyst, its preparation method, and its application in lithium-sulfur battery separators. The method involves the self-assembly of metal ions and organic ligands to form a precursor, followed by sintering the organic material under heating conditions through a pyrolysis process to obtain a nitrogen-rich carbon support. After natural cooling, the successful synthesis of the Mo-Mn bimetallic single-atom cluster catalyst is confirmed by X-ray diffraction and transmission electron microscopy. The resulting target sample is then filtered through a Celgard separator to fabricate a functional separator for lithium-sulfur batteries. This invention effectively improves the problem of low active sulfur utilization in lithium-sulfur battery cycling, promotes the conversion and decomposition of polysulfides, thereby improving the cycle performance of lithium-sulfur batteries and providing guidance for the further design and development of novel high-efficiency electrocatalysts for lithium-sulfur batteries.

Description

Technical Field

[0001] This invention relates to the field of lithium-sulfur battery technology, and in particular to a Mo-Mn bimetallic single-atom cluster catalyst, its preparation method, and its application in lithium-sulfur battery separators. Background Technology

[0002] Because lithium-sulfur batteries have an extremely high theoretical specific capacity (1675 mAh g). -1 Lithium-sulfur batteries are considered a key development direction for next-generation high-energy-density rechargeable batteries due to their excellent long-cycle stability, sustainability, cost-effectiveness, and the environmental friendliness and abundance of sulfur resources. However, practical lithium-sulfur batteries still face significant challenges: the insulation properties of elemental sulfur and its discharge product, lithium sulfide, the dendrite growth of lithium metal anodes, volumetric strain during cycling, the slow reaction kinetics during sulfur redox reactions, and the shuttling of soluble lithium polysulfides all lead to low utilization of active sulfur, severe capacity decay, and ultimately, compromised battery life. To address the issues of lithium polysulfide shuttling and sluggish sulfur redox reaction kinetics during lithium-sulfur battery cycling, highly active electrocatalysts can be introduced to accelerate the rapid conversion of polysulfide species.

[0003] Single-atom catalysts have the characteristics of high atom utilization, well-defined local coordination structure and high intrinsic catalytic activity. They can efficiently catalyze the conversion of lithium polysulfides while adsorbing soluble lithium polysulfides, thereby suppressing the shuttle effect, reducing capacity decay and improving the cycle life of lithium-sulfur batteries.

[0004] However, the overall catalytic activity of single-atom catalysts is typically limited by low metal site concentrations (generally not exceeding 10%). To address this issue, cluster catalysts are introduced into single-atom catalysts. These catalysts can increase the concentration of active sites, thereby enhancing the overall intrinsic electrocatalytic activity. Therefore, the combination of single-atom and cluster catalysts holds promise for significantly improving the catalytic conversion capacity of lithium polysulfides in lithium-sulfur batteries, suppressing the shuttle effect, increasing the utilization rate of active sulfur, and thus accelerating the practical application of lithium-sulfur batteries. Summary of the Invention

[0005] To address the shortcomings in existing research on the aforementioned issues, this invention provides a Mo-Mn bimetallic single-atom cluster catalyst material for modifying the Celgard separator of lithium-sulfur batteries, thereby achieving high capacity, high rate capability, and long cycle life in lithium-sulfur batteries.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing a Mo-Mn bimetallic single-atom cluster catalyst includes the following steps:

[0008] Step 1: Preparation of precursors

[0009] (1) Manganese nitrate and molybdenum acetylacetonate were used as manganese source and molybdenum source, respectively. They were mixed with zinc nitrate hexahydrate in a certain proportion and stirred with methanol as solvent. Then, 2-methylimidazole / methanol dispersion was added to the above mixture and stirred rapidly at room temperature until uniformly mixed.

[0010] (2) After the solution obtained in (1) is stirred, it is washed by centrifugation with methanol and dried overnight in a vacuum drying oven to obtain the desired precursor.

[0011] Step 2: Preparation of Mo-Mn bimetallic single-atom cluster catalyst

[0012] (1) After the precursor in step one is subjected to high-temperature pyrolysis in an inert gas atmosphere with a program-controlled heating rate, a black powder of Mo-Mn bimetallic single-atom cluster catalyst can be obtained.

[0013] (2) The powder obtained in (1) is dispersed by adding a binder and a dispersion liquid, and then ultrasonically dispersed. After dispersion, it is attached to the Celgard membrane by vacuum filtration to obtain a Mo-Mn bimetallic single-atom cluster functional membrane.

[0014] Furthermore, the manganese source and molybdenum source used in step (1) are one or both of the following: a 50% manganese nitrate solution and molybdenum acetylacetonate, with masses of 1-3g and 0.05-0.15g respectively.

[0015] Furthermore, in step (2) of step one, the methanol is centrifuged 3 to 5 times, and the drying temperature is 50 to 60°C, and the drying time is 24 hours.

[0016] Furthermore, the heating atmosphere used in step two (1) is argon or nitrogen.

[0017] Furthermore, in step two (1), the heating rate is 2~3℃ / min, the pyrolysis temperature is 800~950℃, and the holding time is 3~5h.

[0018] Furthermore, the adhesive used in step two (2) is an acrylonitrile copolymer (5% by mass).

[0019] Furthermore, in step two (2), the dispersion is 70-80 mL of isopropanol and 20-30 mL of deionized water, and the sonication time is 30-60 min.

[0020] Furthermore, in step two (2), the filtration volume is 30 mL to 60 mL.

[0021] This invention also provides the application of a Mo-Mn bimetallic single-atom cluster catalyst in lithium-sulfur battery separators.

[0022] Compared with the prior art, the technical advantages of the present invention are:

[0023] (1) The method for preparing a Mo-Mn bimetallic single-atom cluster catalyst provided by this invention uses zeolite imidazole ester framework material as the basis and manganese nitrate and molybdenum acetylacetonate as the metal center source to obtain the MoMn-ZIF-8 precursor after sufficient stirring and centrifugation. The subsequent catalyst powder is prepared by cracking and calcining the precursor. The preparation process is simple, the process is simple, the yield is sufficient, and the reproducibility is good, which is conducive to efficient mass production.

[0024] (2) The Mo-Mn bimetallic single-atom cluster catalyst provided by the present invention is a manganese and molybdenum bimetallic nitrogen-rich carbon material with a large specific surface area and stable structure, and has significant advantages in both local atomic structure and microstructure.

[0025] (3) Using the Mo-Mn bimetallic single-atom cluster catalyst provided by this invention, this invention can be used to fabricate functional separators for lithium-sulfur batteries to improve the redox reaction kinetics of the sulfur electrode. The improved separator of this invention was used to assemble lithium-sulfur batteries, achieving a discharge rate of 0.2C (1C=1675 mAg). -1 Under these conditions, the first discharge capacity reaches as high as 1434mAhg. -1 After 100 cycles, it still has 1014mAh g. -1 To test extreme cycling conditions, after 1000 cycles at a 3C charge / discharge rate, the reversible discharge capacity still remained at 510 mAh / g. -1 (At this point, the battery without a catalyst-modified separator, used as a comparison, failed after 700 cycles), demonstrating high battery capacity and excellent cycle stability. Simultaneously, the functional separator fabricated using this invention increases the sulfur cathode loading of the lithium-sulfur battery to 7.07 mg / cm³. -2 It retains 5.5 mAh cm⁻¹ after 70 cycles. -2 Its discharge surface capacity suggests potential for commercial application as a lithium-sulfur battery separator. Attached Figure Description

[0026] Figure 1 The X-ray diffraction (XRD) patterns of the precursors obtained in Examples 1, 2, and 3 of this invention are shown.

[0027] Figure 2 The X-ray diffraction (XRD) patterns of the catalysts prepared in Examples 1, 2, and 3 of this invention are shown.

[0028] Figure 3 The images show the specific surface area adsorption-desorption curves of the catalysts prepared in Examples 1, 2, and 3 of this invention.

[0029] Figure 4These are images of the lithium polysulfide catalysts prepared in Examples 1, 2, and 3 of this invention, respectively, showing their adsorption experiments.

[0030] Figure 5 This is an experimental image of the H-type electrolytic cell of the catalyst functional membrane prepared in Example 1 of the present invention.

[0031] Figure 6 This is a field emission scanning electron microscope image of the cross-section of the catalyst functional membrane prepared in Example 1 of the present invention.

[0032] Figure 7 These are experimental contact angle images of the catalyst functional membranes prepared in Examples 1, 2, and 3 of this invention.

[0033] Figure 8 This is a field emission scanning electron microscope image of the catalyst prepared in Example 1 of the present invention.

[0034] Figure 9 This is a high-resolution transmission electron microscope image of the catalyst prepared in Example 1 of the present invention.

[0035] Figure 10 The long-cycle curves and coulombic efficiency diagrams of the functional separators prepared in Examples 1, 2 and 3 of this invention and assembled into coin-type lithium-sulfur batteries are shown.

[0036] Figure 11 The image shows the long-cycle curves and coulombic efficiency diagrams of the coin-type lithium-sulfur battery assembled with the catalyst functional membrane and high sulfur loading cathode prepared in Example 1 of this invention at a rate of 0.1C.

[0037] Figure 12 This is a comparison chart of the electrochemical performance of Example 1 of the present invention and a series of catalyst functional membranes for lithium-sulfur batteries reported in the literature. Detailed Implementation

[0038] The following will describe in conjunction with embodiments 1-4 of the present invention and the appendix. Figures 1-12 The technical solutions of the present invention will be described in detail below. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0039] Example 1:

[0040] A method for preparing a Mo-Mn bimetallic single-atom cluster catalyst includes the following steps:

[0041] Step 1: Preparation of precursors

[0042] (1) 0.0663g manganese nitrate and 0.0604g molybdenum acetylacetonate were added to a beaker as manganese source and molybdenum source, respectively, along with 1.3772g zinc nitrate hexahydrate. 100mL methanol was used as solvent and stirred. 3.245g 2-methylimidazole was completely dissolved in 100mL methanol and then added to the above mixture. The mixture was stirred rapidly at room temperature until it was uniformly mixed.

[0043] (2) After stirring the solution obtained in (1), wash it five times by centrifugation with methanol, and then dry it overnight at 60°C in a vacuum drying oven to obtain the desired precursor. The X-ray diffraction pattern of the precursor is shown below. Figure 1 As shown in the figure (Example 1 is represented as MoMn-NC).

[0044] Step 2: Preparation of Mo-Mn bimetallic single-atom cluster catalyst

[0045] (1) The precursor from step one was heated to 950℃ under an inert gas with a programmed heating rate of 2℃ / min and held for 3h. After pyrolysis, it was allowed to cool naturally, thus obtaining a black powder of the Mo-Mn bimetallic single-atom cluster catalyst. The X-ray diffraction pattern and field emission electron microscope image of the product are shown below. Figure 2 , Figure 8 As shown in the figure (Example 1 is represented as MoMn-NC).

[0046] A 50mg sample was taken for specific surface area testing, and the results are as follows: Figure 3 As shown, the specific surface area of ​​this product is 926 m². 2 g -1 A larger specific surface area is beneficial for the adsorption of polysulfides. 50 mg of the product was then placed at the bottom of a glass bottle, and an electrolyte containing Li₂S₆ was added for a visualization adsorption experiment. The supernatant after adsorption was then subjected to X-ray photoelectron spectroscopy (XPS) analysis. The results are as follows: Figure 4 As shown (Example 1 is represented as MoMn-NC in the figure), the supernatant S6 in the MoMn-NC group - The lowest signal indicates that it has the best adsorption effect on polysulfides.

[0047] The powder was dispersed in ethanol and characterized by high-resolution transmission electron microscopy. The results are as follows: Figure 9 As shown, no crystal structure was observed, which is consistent with the structure of the X-ray diffraction pattern.

[0048] (2) The powder obtained in (1) was dispersed by adding 480 μL of acrylonitrile multi-element copolymer (mass fraction of 5%) binder, 75 mL of isopropanol and 25 mL of deionized water, and then sonicated for 60 min. After dispersion, 40 mL of the dispersion was vacuum filtered and attached to a blank Celgard membrane to obtain a membrane with Mo-Mn bimetallic single-atom cluster catalyst.

[0049] Conduct H-type electrolytic cell experiments: such as Figure 5 As shown in the figure (Example 1 is represented as MoMn-NC), the prepared diaphragm was sandwiched between the connecting parts of the left and right glass containers of the H-type electrolytic cell. An electrolyte containing polysulfides was added to the left side of the container, and an electrolyte without polysulfides was added to the right side to simulate the diffusion of polysulfides. The results showed that, compared with the blank diaphragm, the prepared catalyst diaphragm had an inhibitory effect on the diffusion of polysulfides.

[0050] The prepared catalyst membrane was cut in half after rapid cooling with liquid nitrogen, and the cross-section of the membrane was characterized by field emission scanning electron microscopy. Figure 6 As shown, this demonstrates that the catalyst material can be uniformly attached to the membrane with an average cross-sectional width of 16 μm.

[0051] The contact angle of the prepared catalyst membrane was tested by adding 1 μL of electrolyte to the membrane surface and then photographing the image using a high frame rate camera. The results are as follows. Figure 7 As shown (Example 1 corresponds to MoMn-NC in the attached figure), the contact angle of this catalyst is 15.068°, indicating that it has good contact properties with the electrolyte.

[0052] The performance of batteries assembled with catalyst-functionalized separators and normal-load sulfur cathodes was tested. Figure 10 (Example 1 corresponds to MoMn-NC in the attached figure).

[0053] The performance of batteries assembled with catalyst-functional separators and high-capacity sulfur cathodes was tested. Figure 11 At a positive electrode loading of 7.07 mg / cm³ -1 It still maintained high cycle performance even under certain conditions.

[0054] The performance of the lithium-sulfur battery assembled with the catalyst membrane prepared in this embodiment is compared with the performance of existing membrane studies. The structure is as follows: Figure 12 As shown, lithium-sulfur batteries with Mo-Mn bimetallic single-atom cluster catalyst membranes exhibit advantages such as high rate cycling stability, long cycle life, and high discharge specific capacity.

[0055] Example 2:

[0056] A method for preparing a Mo-Mn bimetallic single-atom cluster catalyst includes the following steps:

[0057] Step 1: Preparation of precursors

[0058] (1) Add 0.1208g of molybdenum acetylacetonate and 1.3772g of zinc nitrate hexahydrate to a beaker, stir with 100mL of methanol as solvent, and then add 3.245g of 2-methylimidazole completely dissolved in 100mL of methanol to the above mixture. Stir rapidly at room temperature until uniformly mixed.

[0059] (2) After stirring the solution obtained in (1), wash it five times by centrifugation with methanol, and then dry it overnight at 60°C in a vacuum drying oven to obtain the desired precursor. The X-ray diffraction pattern of the precursor is shown below. Figure 1 As shown (Example 2 is represented as Mo-NC in the figure).

[0060] Step 2: Preparation of Mo-Mn bimetallic single-atom cluster catalyst

[0061] (1) The precursor from step one was heated to 950℃ under an inert gas with a programmed heating rate of 2℃ / min and held for 3h. After pyrolysis, it was allowed to cool naturally, thus obtaining a black powder of the Mo-Mn bimetallic single-atom cluster catalyst. The X-ray diffraction pattern and field emission electron microscope image of the product are shown below. Figure 2 , Figure 8 As shown (Example 2 is represented as Mo-NC in the figure).

[0062] A 50mg sample was taken for specific surface area testing, and the results are as follows: Figure 3 As shown, the specific surface area of ​​this product is 661 m². 2 g -1 Then, 50 mg of the product was placed at the bottom of a glass bottle, and an electrolyte containing Li₂S₆ was added for a visual adsorption experiment. The supernatant after adsorption was then subjected to X-ray photoelectron spectroscopy (XPS) analysis. The results are as follows: Figure 4 As shown (Example 2 is represented as Mo-NC in the figure).

[0063] (2) The powder obtained in (1) was dispersed by adding 480 μL of acrylonitrile multi-element copolymer (mass fraction of 5%) binder, 75 mL of isopropanol and 25 mL of deionized water, and then sonicated for 60 min. After dispersion, 40 mL of the dispersion was vacuum filtered and attached to a blank Celgard membrane to obtain a membrane with Mo-Mn bimetallic single-atom cluster catalyst function.

[0064] The contact angle of the prepared catalyst membrane was tested by adding 1 μL of electrolyte to the membrane surface and then photographing the image using a high frame rate camera. The results are as follows. Figure 7As shown (Example 2 corresponds to Mo-NC in the attached figure), the contact angle of this catalyst is 15.578°.

[0065] The performance of a battery assembled with a catalyst functional membrane and a sulfur cathode is as follows: Figure 10 (Example 2 corresponds to Mo-NC in the attached figure).

[0066] Example 3:

[0067] A method for preparing a Mo-Mn bimetallic single-atom cluster catalyst includes the following steps:

[0068] Step 1: Preparation of precursors

[0069] (1) Add 0.1326g of manganese nitrate solution and 1.3772g of zinc nitrate hexahydrate to a beaker, stir with 100mL of methanol as solvent, and then add 3.245g of 2-methylimidazole completely dissolved in 100mL of methanol to the above mixture. Stir rapidly at room temperature until uniformly mixed.

[0070] (2) After stirring the solution obtained in (1), wash it five times by centrifugation with methanol, and then dry it overnight at 60°C in a vacuum drying oven to obtain the desired precursor. The X-ray diffraction pattern of the precursor is shown below. Figure 1 As shown (Example 3 is represented as Mn-NC in the figure).

[0071] Step 2: Preparation of Mo-Mn bimetallic single-atom cluster catalyst

[0072] (1) The precursor from step one was heated to 950℃ under an inert gas with a programmed heating rate of 2℃ / min and held for 3h. After pyrolysis, it was allowed to cool naturally, thus obtaining a black powder of the Mo-Mn bimetallic single-atom cluster catalyst. The X-ray diffraction pattern and field emission electron microscope image of the product are shown below. Figure 2 , Figure 8 As shown (Example 3 is represented as Mn-NC in the figure).

[0073] A 50mg sample was taken for specific surface area testing, and the results are as follows: Figure 3 As shown, the specific surface area of ​​this product is 1167 m². 2 g -1 Then, 50 mg of the product was placed at the bottom of a glass bottle, and an electrolyte containing Li₂S₆ was added for a visual adsorption experiment. The supernatant after adsorption was then subjected to X-ray photoelectron spectroscopy (XPS) analysis. The results are as follows: Figure 4 As shown (Example 3 is represented as Mn-NC in the figure).

[0074] (2) The powder obtained in (1) was dispersed by adding 480 μL of acrylonitrile multi-element copolymer (mass fraction of 5%) binder, 75 mL of isopropanol and 25 mL of deionized water, and then sonicated for 60 min. After dispersion, 40 mL of the dispersion was vacuum filtered and attached to a blank Celgard membrane to obtain a membrane with Mo-Mn bimetallic single-atom cluster catalyst function.

[0075] The contact angle of the prepared catalyst membrane was tested by adding 1 μL of electrolyte to the membrane surface and then photographing the image using a high frame rate camera. The results are as follows. Figure 7 As shown (Example 3 corresponds to Mn-NC in the attached figure), the contact angle of this catalyst is 16.346°.

[0076] The performance of a battery assembled with a catalyst functional membrane and a sulfur cathode is as follows: Figure 10 (Example 3 corresponds to Mn-NC in the attached figure).

[0077] Example 4:

[0078] A method for preparing a Mo-Mn bimetallic single-atom cluster catalyst includes the following steps:

[0079] Step 1: Preparation of precursors

[0080] (1) Add 0.0663g of manganese nitrate, 0.0604g of molybdenum acetylacetonate and 1.3772g of zinc nitrate hexahydrate to a beaker and stir with 100mL of methanol as solvent. Then, dissolve 3.245g of 2-methylimidazole completely in 100mL of methanol and add it to the above mixture. Stir rapidly at room temperature until uniformly mixed.

[0081] (2) After the solution obtained in (1) is stirred, it is washed 5 times by centrifugation with methanol and dried overnight at 60°C in a vacuum drying oven to obtain the desired precursor.

[0082] Step 2: Preparation of Mo-Mn bimetallic single-atom cluster catalyst

[0083] (1) The precursor in step one is heated to 950°C under an inert gas with a heating rate of 2°C / min and kept at that temperature for 3 hours. After the pyrolysis is completed, it is cooled naturally to obtain a black powder of Mo-Mn bimetallic single-atom cluster catalyst.

[0084] (2) The powder obtained in (1) was dispersed by adding 480 μL of acrylonitrile multi-element copolymer (mass fraction of 5%) binder, 75 mL of ethanol and 25 mL of deionized water, and then sonicated for 60 min. After dispersion, 50 mL of the dispersion was vacuum filtered and attached to a blank Celgard membrane to obtain a membrane with Mo-Mn bimetallic single-atom cluster catalyst function.

[0085] Example 5:

[0086] A method for preparing a Mo-Mn bimetallic single-atom cluster catalyst includes the following steps:

[0087] Step 1: Preparation of precursors

[0088] (1) Add 0.0663g of manganese nitrate, 0.0604g of molybdenum acetylacetonate and 1.3772g of zinc nitrate to a beaker, stir with 100mL of methanol as solvent, and then add 3.245g of 2-methylimidazole completely dissolved in 100mL of methanol to the above mixture. Stir rapidly at room temperature until uniformly mixed.

[0089] (2) After the solution obtained in (1) is stirred, it is washed 5 times by centrifugation with methanol and dried overnight at 80°C in a vacuum drying oven to obtain the desired precursor.

[0090] Step 2: Preparation of Mo-Mn bimetallic single-atom cluster catalyst

[0091] (1) The precursor in step one is heated to 800°C under an inert gas with a heating rate of 2°C / min and kept at that temperature for 3 hours. After the pyrolysis is completed, it is cooled naturally to obtain a black powder of Mo-Mn bimetallic single-atom cluster catalyst.

[0092] (2) The powder obtained in (1) was dispersed by adding 360 μL of acrylonitrile multi-element copolymer (mass fraction of 5%) binder, 75 mL of ethanol and 25 mL of deionized water, and then sonicated for 30 min. After dispersion, 50 mL of the dispersion was vacuum filtered and attached to a blank Celgard membrane to obtain a membrane with Mo-Mn bimetallic single-atom cluster catalyst function.

[0093] Example 6:

[0094] A method for preparing a Mo-Mn bimetallic single-atom cluster catalyst includes the following steps:

[0095] Step 1: Preparation of precursors

[0096] (1) Add 0.0663g of manganese nitrate, 0.0604g of molybdenum acetylacetonate and 1.02g of zinc nitrate hexahydrate to a beaker, stir with 50mL of methanol as solvent, and then add 1.12g of 2-methylimidazole completely dissolved in 50mL of methanol to the above mixture. Stir rapidly at room temperature until uniformly mixed.

[0097] (2) After the solution obtained in (1) is stirred, it is washed 5 times by centrifugation with methanol and dried overnight at 60°C in a vacuum drying oven to obtain the desired precursor.

[0098] Step 2: Preparation of Mo-Mn bimetallic single-atom cluster catalyst

[0099] (1) The precursor in step one is heated to 950°C under an inert gas with a heating rate of 2°C / min and kept at that temperature for 3 hours. After the pyrolysis is completed, it is cooled naturally to obtain a black powder of Mo-Mn bimetallic single-atom cluster catalyst.

[0100] (2) The powder obtained in (1) was dispersed by adding 480 μL of acrylonitrile multi-element copolymer (mass fraction of 5%) binder, 75 mL of ethanol and 25 mL of deionized water, and then sonicated for 30 min. After dispersion, 50 mL of the dispersion was vacuum filtered and attached to a blank Celgard membrane to obtain a membrane with Mo-Mn bimetallic single-atom cluster catalyst function.

Claims

1. A method for preparing a Mo-Mn bimetallic single-atom cluster catalyst, comprising the following steps: Step 1: Preparation of precursors (1) Manganese nitrate and molybdenum acetylacetonate were used as manganese source and molybdenum source, respectively. They were mixed with zinc nitrate hexahydrate in a certain proportion and stirred with methanol as solvent to obtain a mixture. Then, 2-methylimidazole / methanol dispersion was added to the above mixture and stirred rapidly at room temperature until uniformly mixed. (2) After the solution obtained in (1) is stirred, it is washed by centrifugation with methanol and dried overnight in a vacuum drying oven to obtain the desired precursor. Step 2: Preparation of Mo-Mn bimetallic single-atom cluster catalyst (1) After the precursor in step one is subjected to high-temperature pyrolysis in an inert gas atmosphere with a programmed heating rate, a black powder of Mo-Mn bimetallic single-atom cluster catalyst can be obtained. (2) The powder obtained in (1) is dispersed by adding binder and dispersion liquid, and then ultrasonically dispersed. After dispersion, it is attached to Celgard membrane by vacuum filtration to obtain Mo-Mn bimetallic single-atom cluster functional membrane. The manganese source and molybdenum source used in step (1) are a 50% manganese nitrate solution and molybdenum acetylacetonate, respectively, with a mass of 1-3g and 0.05-0.15g, respectively. In step 2(1), the heating rate is 2-3℃ / min, the pyrolysis temperature is 800-950℃, and the holding time is 3-5h. In step 2 (2), the dispersion is 70-80 mL of isopropanol and 20-30 mL of deionized water, and the sonication time is 30-60 min.

2. The method for preparing a Mo-Mn bimetallic single-atom cluster catalyst according to claim 1, characterized in that: In step (2) of step one, the methanol is centrifuged 3 to 5 times, the drying temperature is 50 to 60°C, and the drying time is 24 hours.

3. The method for preparing a Mo-Mn bimetallic single-atom cluster catalyst according to claim 1, characterized in that: The heating atmosphere used in step two (1) is argon or nitrogen.

4. The method for preparing a Mo-Mn bimetallic single-atom cluster catalyst according to claim 1, characterized in that: The adhesive used in step two (2) is an acrylonitrile copolymer.

5. The method for preparing a Mo-Mn bimetallic single-atom cluster catalyst according to claim 1, characterized in that: In step 2 (2), the filtration volume is 30 mL to 60 mL.

6. A Mo-Mn bimetallic single-atom cluster catalyst prepared by the method according to any one of claims 1 to 5.

7. The application of the Mo-Mn bimetallic single-atom cluster catalyst of claim 6 in lithium-sulfur battery separators.

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