Method for preparing amino-functionalized metal organic framework-clay mineral composite membrane material and lithium metal battery separator

Abstract

The application belongs to the technical field of batteries, and discloses a preparation method of an amino-functionalized metal organic framework-clay mineral composite membrane material and a lithium metal battery separator. The method adopts a one-step solvothermal method, and in-situ reaction is carried out on a reaction kettle with a titanium source and montmorillonite. The presence of the montmorillonite has a regulating effect on the growth morphology of NH2-MIL-125, and meanwhile, the highly ordered pore structure of the metal organic framework can be used to regulate the morphology and structure of the montmorillonite. The obtained composite material is uniformly coated on the surface of a polypropylene separator to form a stable functional coating. The prepared composite separator fully plays the synergistic effect of NH2-MIL-125 and the montmorillonite. On the one hand, the ordered pores and interlayer channels guide the uniform transmission of lithium ions, and on the other hand, the local current density is reduced, so as to effectively inhibit the growth of lithium dendrites. When the composite separator is applied to a lithium metal battery, the polarization voltage in the charging and discharging process of the battery can be reduced, and the cycle stability and safety of the battery can be improved.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage battery application technology, specifically relating to a method for preparing and applying an amino-functionalized metal-organic framework-clay mineral composite membrane material. Background Technology

[0002] Renewable energy sources, such as wind and solar power, are intermittent and require efficient energy storage systems for stable utilization. Lithium metal batteries, due to their extremely high energy density, are considered key to next-generation energy storage. However, they are prone to lithium dendrite formation during charging and discharging, which can puncture the separator and cause short circuits, seriously threatening battery safety and cycle life. Therefore, suppressing lithium dendrite growth has become a core technical challenge in developing safe and long-life lithium metal batteries.

[0003] Montmorillonite, a natural clay mineral, offers new possibilities for solving the lithium dendrite problem due to its advantages such as cation exchange capacity, tunable interlayer spacing, and low cost. However, its intrinsic ionic conductivity is low, limiting its rapid charge-discharge performance; and during long-term cycling, its layered structure is prone to collapse or peeling from the matrix, leading to a gradual decrease in its dendrite suppression effect. While there is considerable research on montmorillonite in batteries, systematic optimization of its ion transport pathways using metal-organic frameworks remains relatively lacking. Therefore, reducing the local current density of montmorillonite-based materials during long-term cycling through structural design is of great significance for improving the safety and application of lithium metal batteries.

[0004] This invention introduces an amino-functionalized metal-organic framework to construct an ion-sieving structure while regulating the ion transport pathway of montmorillonite. This structure promotes the orderly arrangement of ion diffusion channels, thereby significantly improving the ion transport rate. Furthermore, the uniformly distributed nano-coating on the membrane surface effectively homogenizes the lithium-ion flow, achieving long-term suppression of lithium dendrite growth and greatly improving the cycle stability of the battery. This method provides a practical and feasible technical approach to enhance the safety performance of lithium metal batteries. Summary of the Invention

[0005] In view of the above situation, this invention proposes a method for preparing an amino-functionalized metal-organic framework-clay mineral composite membrane material. Montmorillonite composite material is prepared by in-situ growth, exhibiting uniformly distributed nanosheets and good long-cycle performance and reduced interfacial polarization. When applied to lithium metal batteries, it can achieve excellent cycle performance.

[0006] The present invention adopts the following technical solution:

[0007] A method for preparing an amino-functionalized metal-organic framework-clay mineral composite membrane material includes the following preparation steps: Step 1: Dissolve a certain amount of clay minerals in an organic solvent, mix them evenly by ultrasonication, add ligands, mix them evenly by ultrasonication, add organic solvent to obtain a mixed solution; Step 2: Add a titanium source to the mixed solution described in Step 1, then sonicate. After the reaction, wash and dry to obtain the composite material, and collect the powder. Step 3, diaphragm modification: Grind the powder described in step 2, weigh a certain amount of composite material, acetylene black and polyvinylidene fluoride, grind them evenly, add a certain amount of N-methylpyrrolidone to obtain a slurry, coat it onto the diaphragm to form a uniform nano-coating, and dry it to obtain the diaphragm composite material.

[0008] The clay mineral includes at least one of calcium-based montmorillonite, hydrogen-based montmorillonite, lithium-based montmorillonite, magnesium-based montmorillonite, and sodium-based montmorillonite, with calcium-based montmorillonite being preferred.

[0009] The ligand comprises at least one of aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, terephthalic acid, azobenzene-4,4'-dicarboxylic acid, and tetrafluoroterephthalic acid, preferably aminoterephthalic acid.

[0010] The titanium source includes at least one of tetraisopropyl titanate, titanium tetrachloride, and tetraethyl titanate, preferably tetraisopropyl titanate.

[0011] The mass ratio of the clay mineral, ligand, and titanium source is 0.5–3:0.1–2:0.1–1.5; preferably 0.7:0.5:0.4.

[0012] The ultrasound time in steps 1 and 2 is 10 min to 60 min, preferably 30 min, and the ultrasound frequency is 20 Hz to 100 Hz, preferably 40 Hz.

[0013] The centrifugation time in step 2 is 3 to 5 minutes, preferably 5 minutes. The centrifugation speed is 8000 rpm to 11000 rpm, preferably 10000 rpm. The washing solvent is N,N-dimethylformamide and anhydrous methanol, with cross-washing performed 1 to 10 times, preferably 6 times. The drying temperature is 50°C to 80°C, preferably 60°C. The drying time is 12 h to 36 h, preferably 12 h.

[0014] In step 3, the mass ratio of the composite material, acetylene black, and polyvinylidene fluoride is 150–200: 25–75: 1–50, the coating thickness is 50 μm–250 μm, the drying temperature is 30 ℃–50 ℃, and the drying time is 8 h–14 h.

[0015] The diaphragm can be at least one of polypropylene diaphragm, polyethylene diaphragm, and polyimide diaphragm, preferably polypropylene diaphragm. The thickness of the nano-coating is 50 μm to 250 μm; the drying temperature is 30℃ to 80℃, and the drying time is 8h to 14h.

[0016] A lithium metal battery separator material is disclosed, wherein the separator composite material is an amino-functionalized metal-organic framework-clay mineral composite membrane material obtained by the aforementioned preparation method. This composite membrane material is attached as a functional coating to the surface of the lithium metal battery substrate membrane. The functional coating is a dense, nanoscale coating that can guide uniform lithium ion transport and inhibit lithium dendrite growth.

[0017] A lithium metal battery includes a lithium metal battery separator, a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode is a lithium metal negative electrode. The electrolyte is a 1 mol / L LiTFSI electrolyte, the solvent is a 1:1 volume ratio of DOL and DME, and 1% LiNO3 is added to the electrolyte.

[0018] Another technical solution of the present invention is the application of the amino-functionalized metal-organic framework-clay mineral composite membrane material in the preparation of lithium metal batteries. The characteristic of this invention is that, as a functional coating material for lithium metal battery separators, it is used to inhibit lithium dendrite growth, reduce the battery charge-discharge polarization voltage, and improve the battery cycle stability and safety.

[0019] This invention provides a method for preparing an amino-functionalized metal-organic framework-clay mineral composite membrane material, which has the following advantages: (1) This invention achieves stereolithography by combining NH2-MIL-125 with montmorillonite and utilizing organic ligands to regulate the ion transport of montmorillonite, significantly improving the structural integrity of the coating during battery cycling. The prepared composite coating is uniform and dense with a thickness at the nanometer level, and it constructs ordered ion channels, which can efficiently promote lithium-ion transport and effectively inhibit dendrite growth. This composite separator material exhibits excellent long-cycle performance, which helps to improve the safety and lifespan of the battery.

[0020] (2) In this invention, the above-mentioned NH2-MIL-125 and montmorillonite composite material is coated on the surface of a polypropylene separator to form a functionalized coating. This preparation method is simple, the raw materials are readily available and the cost is low, providing a new design idea for the application of montmorillonite in the field of battery separators, and is expected to be extended to other types of battery separator systems, with broad application prospects. Attached Figure Description

[0021] Figure 1 This is a SEM image of NH2-MIL-125 prepared in Example 3 of the present invention.

[0022] Figure 2 This is a SEM image of the calcium-based montmorillonite used in Example 2 of the present invention.

[0023] Figure 3 This is a scan image of the montmorillonite-NH2-MIL-125 composite material prepared in Example 4 of the present invention.

[0024] Figure 4 This is a mapping analysis diagram of the montmorillonite-NH2-MIL-125 composite material prepared in Example 4 of the present invention.

[0025] Figure 5 The images show the XRD patterns of the calcium-based montmorillonite, the prepared NH2-MIL-125, and the montmorillonite-NH2-MIL-125 membrane composite material used in Examples 2, 3, and 4 of this invention.

[0026] Figure 6 The images show the FT-IR spectra of calcium-based montmorillonite, the prepared NH2-MIL-125, and the montmorillonite-NH2-MIL-125 membrane composite material used in Examples 2, 3, and 4 of this invention.

[0027] Figure 7 The calcium-based montmorillonite, the prepared NH2-MIL-125, and the montmorillonite-NH2-MIL-125 membrane composite material used in Examples 1, 2, 3, and 4 of this invention were tested at 1 mA cm⁻¹. -2 - 1 mAh cm -2 Voltage polarization diagram under the given conditions.

[0028] Figure 8 The calcium-based montmorillonite, the prepared NH2-MIL-125, and the montmorillonite-NH2-MIL-125 membrane composite material used in Examples 1, 2, 3, and 4 of this invention were tested at 10 mA cm⁻¹. -2 - 10 mAh cm -2 Voltage polarization diagram under the given conditions.

[0029] Figure 9 This is a scale diagram showing the polypropylene, calcium-based montmorillonite, and the prepared NH2-MIL-125, montmorillonite-NH2-MIL-125, montmorillonite-NH2-MIL-125 (9:1), montmorillonite-NH2-MIL-125 (7:3), montmorillonite-NH2-MIL-125 (5:5), montmorillonite-MIL-H2ADB, and montmorillonite-MIL-H2tfBDC membrane composite materials used in Examples 1, 2, 3, 4, 5, 6, 7, 8, and 9 of the present invention.

[0030] Figure 10The nitrogen adsorption-desorption isotherms are shown in Examples 3 and 4 of this invention.

[0031] Figure 11 The pore size distribution diagrams are for the NH2-MIL-125 and montmorillonite-NH2-MIL-125 membrane composite materials prepared in Examples 3 and 4 of this invention. Detailed Implementation

[0032] To better understand the present invention, the following embodiments will further illustrate the content of the present invention. Unless otherwise specified, the experimental methods and detection methods described in the embodiments of the present invention are conventional methods; unless otherwise specified, the reagents and materials described are commercially available.

[0033] Example 1 (1) Polypropylene diaphragm Commercial polypropylene diaphragm slices were cut into 19 mm diameter discs, denoted as PP.

[0034] Example 2 (1) Diaphragm modification Weigh out 175 mg of calcium-based montmorillonite, 50 mg of acetylene black, and 25 mg of polyvinylidene fluoride. Add them to an agate mortar and grind for 20 min until homogeneous. Then add 2.2 mL of N-methylpyrrolidone and grind for another 25 min to obtain a homogeneous paste without stratification. Adhere the polypropylene diaphragm to a coating machine, clean it with anhydrous ethanol, and then coat it using a 200 μm coater. The coating machine temperature was 40 ℃. The drying time was 10 h, and the diaphragm slices were 19 mm in diameter rounds, denoted as MMT.

[0035] Example 3 (1) Preparation of NH2-MIL-125 Weigh out 0.504 g of aminoterephthalic acid and dissolve it in 63 mL of N,N-dimethylformamide. After ultrasonic mixing, transfer the suspension to a 100 mL reactor, add 7 mL of anhydrous methanol, and then add 415 μL of tetraisopropyl titanate. After ultrasonic dissolution, place the reactor in a forced-air drying oven, raise the temperature to 150 °C, and keep it at this temperature for 24 h.

[0036] (2) Washing After the reaction was completed, the reactor was allowed to cool naturally to room temperature. The reaction products were separated using a centrifuge, and the precipitate was collected by centrifugation. The collected precipitate was washed six times with N,N-dimethylformamide and anhydrous methanol alternately to remove residual reactants. Centrifugation time was 3 min, and centrifugation speed was 10,000 rpm. The precipitate was collected by centrifugation. Finally, the collected product was placed in a vacuum drying oven and dried at 60 °C for 12 h to obtain the NH2-MIL-125 material.

[0037] (3) Diaphragm modification Weigh out 175 mg of NH2-MIL-125 material, 50 mg of acetylene black, and 25 mg of polyvinylidene fluoride. Add them to an agate mortar and grind for 20 min until homogeneous. Then add 2.2 mL of N-methylpyrrolidone and grind for another 25 min to obtain a homogeneous paste without stratification. Adhere the polypropylene diaphragm to a coating machine, clean it with anhydrous ethanol, and then coat it using a 200 μm coater. The coating machine temperature is 40℃. The drying time is 10 h. The diaphragm slices are 19 mm diameter rounds, labeled NH2-MIL-125.

[0038] Example 4 (1) Preparation of montmorillonite-NH2-MIL-125 Weigh 0.7 g of calcium-based montmorillonite and dissolve it in 63 mL of N,N-dimethylformamide. After sonicating for 30 min to mix evenly, transfer the suspension to a 100 mL reactor. Add 0.504 g of aminoterephthalic acid and sonicate for 30 min to mix. Then add 7 mL of anhydrous methanol and 415 μL of tetraisopropyl titanate. After sonicating for 30 min to dissolve, place the reactor in a forced-air drying oven and raise the temperature to 150 °C. Maintain the reaction at this temperature for 24 h.

[0039] (2) Washing After the reaction was completed, the reactor was allowed to cool naturally to room temperature. The reaction products were separated using a centrifuge, and the precipitate was collected by centrifugation. The collected precipitate was washed six times with N,N-dimethylformamide and anhydrous methanol alternately to remove residual reactants. Centrifugation time was 3 min, and centrifugation speed was 10,000 rpm. The precipitate was collected by centrifugation. Finally, the collected product was placed in a vacuum drying oven and dried at 60 °C for 12 h to obtain the montmorillonite-NH2-MIL-125 membrane material.

[0040] (3) Diaphragm modification Weigh out 175 mg of montmorillonite-NH2-MIL-125 membrane material, 50 mg of acetylene black, and 25 mg of polyvinylidene fluoride. Add these to an agate mortar and grind for 20 min until homogeneous. Then add 2.2 mL of N-methylpyrrolidone and grind for another 25 min to obtain a homogeneous paste without stratification. Adhere the polypropylene membrane to a coating machine, clean it with anhydrous ethanol, and then coat it using a 200 μm coater. The coating machine temperature was 40 ℃. The drying time was 10 h. The membrane slices were 19 mm diameter rounds, designated MMT-NH2-MIL-125.

[0041] Example 5 (1) Preparation of montmorillonite-NH2-MIL-125(9:1) Weigh out calcium-based montmorillonite and tetraisopropyl titanate in a mass ratio of 9:1. All other steps are the same as in Implementation Case 4. This is denoted as MMT-NH2-MIL-125(9:1).

[0042] Example 6 (1) Preparation of montmorillonite-NH2-MIL-125(7:3) Weigh out calcium-based montmorillonite and tetraisopropyl titanate in a mass ratio of 7:3. All other steps are the same as in Implementation Case 4. This is denoted as MMT-NH2-MIL-125(7:3).

[0043] Example 7 (1) Preparation of montmorillonite-NH2-MIL-125(5:5) Weigh out calcium-based montmorillonite and tetraisopropyl titanate in a mass ratio of 5:5. All other steps are the same as in Implementation Case 4. This is denoted as MMT-NH2-MIL-125(5:5).

[0044] Example 8 (1) Preparation of montmorillonite-MIL-H2ADB Weigh 0.504 g of azobenzene-4,4'-dicarboxylic acid. All other steps are the same as in Implementation Case 4. This is denoted as MMT-MIL-H2ADB.

[0045] Example 9 (1) Preparation of montmorillonite-MIL-H2tfBDC Weigh out 0.504 g of tetrafluoroterephthalic acid. All other steps are the same as in Implementation Case 4. This is denoted as MMT-MIL-H2tfBDC.

[0046] The organic-intercalated clay-mineral composite membrane material prepared in this invention can be assembled into a lithium-ion battery using the same steps as conventional assembly methods. The prepared clay-mineral composite membrane materials were assembled into symmetrical batteries for charge-discharge testing: the electrolyte was 1 mol / L LiTFSI (DOL:DME = 1:1 with 1% LiNO3), and the electrodes were lithium sheets. CR2025 coin cells were assembled in an argon-filled glove box. Constant current charge-discharge experiments were conducted using a NEWARE battery testing system.

[0047] Appendix Figure 1 The NH2-MIL-125 prepared in Example 3 of this invention has a disc-shaped morphology. (See attached image.) Figure 2 The image shown is a scan of the calcium-based montmorillonite used in Example 2 of this invention. It displays tightly stacked montmorillonite lamellae, forming irregular large aggregates, with no peeling at the lamellae edges. Figure 3 The image shown is a scanning electron microscope (SEM) image of the montmorillonite-NH2-MIL-125 composite material prepared in Example 4 of this invention. No clearly isolated disk structures were observed in the composite system. The montmorillonite surface exhibits a peeled lamellar morphology, indicating that the presence of montmorillonite regulates the growth morphology of NH2-MIL-125. (See attached image.) Figure 4 To further confirm the loading of NH2-MIL-125, mapping analysis detected a uniform distribution of Ti elements, confirming the successful composite of NH2-MIL-125 with montmorillonite.

[0048] Appendix Figure 5 The crystal structures of the calcium-based montmorillonite used in Examples 2, 3, and 4 of this invention, the prepared NH2-MIL-125, and the montmorillonite-NH2-MIL-125 composite material are shown. The diffraction peaks of the composite montmorillonite match the standard card of MMT (PDF#13-0135), the layered structure remains intact, and there are no impurity peaks in the XRD scanning range of 5-80°. At the same time, the characteristic diffraction peaks of NH2-MIL-125 appear, proving that the two are successfully composited.

[0049] Appendix Figure 6 The following are the FT-IR spectra of the calcium-based montmorillonite used in Examples 2, 3, and 4 of this invention, the prepared NH2-MIL-125, and the montmorillonite-NH2-MIL-125 composite material. Compared with MMT, the montmorillonite-NH2-MIL-125 shows newly added peaks at 1380 and 1263 cm⁻¹. -1 The peak is a characteristic peak belonging to the CN group and is associated with the ligand of NH2-MIL-125, indicating that NH2-MIL-125 and MMT have successfully recombinated. The retention of the original peak of MMT indicates that the main structure of MMT has not been destroyed due to recombination.

[0050] Appendix Figure 7-8The voltage polarization diagrams of polypropylene, calcium-based montmorillonite, and the prepared NH2-MIL-125 and montmorillonite-NH2-MIL-125 membrane composite materials used in Examples 1, 2, 3 and 4 of this invention are shown under different conditions. Figure 7 It is at 1 mA cm -2 -1 mAh cm -2 Under cycling conditions, montmorillonite-NH2-MIL-125 has an overpotential of only 14.5 mV and a cycle life of up to 1100 h. Figure 8 It is at 10 mA cm -2 - 10 mAh cm -2 Under cycling conditions, montmorillonite-NH2-MIL-125 exhibits an overpotential of only 44.1 mV and a cycle life of up to 1000 h. (See attached image.) Figure 9 This is a scale-up diagram showing the polypropylene, calcium-based montmorillonite, and the prepared NH2-MIL-125, montmorillonite-NH2-MIL-125, montmorillonite-NH2-MIL-125, montmorillonite-NH2-MIL-125 (9:1), montmorillonite-NH2-MIL-125 (7:3), montmorillonite-NH2-MIL-125 (5:5), montmorillonite-MIL-H2ADB, and montmorillonite-MIL-H2tfBDC membrane composite materials used in Examples 1, 2, 3, 4, 5, 6, 7, 8, and 9 of this invention. Montmorillonite-NH2-MIL-125 exhibits relatively stable voltage at various current densities. When the current density increases from 1 mA cm⁻¹... -2 Increased to 10 mA cm -2 At that time, the overpotential of montmorillonite-NH2-MIL-125 remained stable at around 141 mV, the overpotential of montmorillonite-MIL-H2ADB was 131 mV, and the overpotential of montmorillonite-MIL-H2tfBDC was 123 mV. These composite materials collectively improved the interfacial stability and electrochemical reliability of the lithium metal anode, providing important experimental evidence for the development of high-performance lithium metal battery separator materials.

[0051] Appendix Figure 10 The figures show the nitrogen adsorption-desorption isotherms of the NH2-MIL-125 and montmorillonite-NH2-MIL-125 membrane composites prepared in Examples 3 and 4 of this invention. Figure 11 This is a pore size distribution diagram. The specific surface area of ​​NH2-MIL-125 is 667.28 m². 2 g -1 The pore size is 0.54 nm; while the specific surface area of ​​montmorillonite-NH2-MIL-125 is only 101.06 m². 2 g -1With a pore size of 1.01 nm, the composite sample's pore structure is conducive to the uniform dispersion of lithium-ion flux, avoiding excessively high local concentrations, thereby effectively inhibiting dendrite growth. At the same time, the introduction of montmorillonite may enhance interfacial stability. The synergistic effect of multiple factors improves the overall performance.

[0052] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention. Those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Equivalent substitutions or transformations made by those skilled in the art based on the present invention are all within the protection scope of the present invention. The protection scope of the present invention is defined by the claims.

Claims

1. A method for preparing an amino-functionalized metal-organic framework-clay mineral composite membrane material, characterized in that, Includes the following steps: Step 1: Disperse the clay minerals in an organic solvent, mix them by ultrasonication, add the ligand, mix them by ultrasonication again, add more organic solvent, and obtain a mixed solution. Step 2: Add titanium source to the mixed solution in Step 1, mix with ultrasonication, and then carry out a solvothermal reaction. The reaction product is washed and dried to obtain amino-functionalized metal-organic framework-clay mineral composite powder. Step 3: Mix and grind the composite material powder from Step 2 with conductive agent and binder, add N-methylpyrrolidone to prepare a slurry, coat the slurry onto the surface of the base film to form a nano-coating, and dry to obtain an amino-functionalized metal-organic framework-clay mineral composite membrane material.

2. The preparation method according to claim 1, characterized in that, In step 1, the clay mineral is a montmorillonite-based clay mineral, selected from one or more of calcium-based montmorillonite, hydrogen-based montmorillonite, lithium-based montmorillonite, magnesium-based montmorillonite, and sodium-based montmorillonite; the ligand is selected from one or more of aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, terephthalic acid, azobenzene-4,4'-dicarboxylic acid, and tetrafluoroterephthalic acid; the organic solvent is one or a combination of two of N,N-dimethylformamide and anhydrous methanol.

3. The preparation method according to claim 1, characterized in that, In step 2, the titanium source is selected from one or more of tetraisopropyl titanate, titanium tetrachloride, and tetraethyl titanate; the mass ratio of the clay mineral, ligand, and titanium source is (0.5-3):(0.1-2):(0.1-1.5), preferably, the mass ratio of the clay mineral, ligand, and titanium source is 0.7:0.5:0.

4.

4. The preparation method according to claim 1, characterized in that, In steps 1 and 2, the duration of a single ultrasound is 10 min to 60 min, and the ultrasound frequency is 20 Hz to 100 Hz; in step 2, the temperature of the solvothermal reaction is 120 ℃ to 180 ℃, and the reaction time is 18 h to 30 h.

5. The preparation method according to claim 1, characterized in that, In step 2, the washing is performed by alternating washing with N,N-dimethylformamide and anhydrous methanol, and the number of washing cycles is 1 to 10. Before washing, the reaction product is centrifuged for 3 to 5 minutes at a speed of 8000 to 11000 rpm. The drying temperature is 50°C to 80°C and the drying time is 12 to 36 hours.

6. The preparation method according to claim 1, characterized in that, In step 3, the conductive agent is acetylene black, and the binder is polyvinylidene fluoride; the mass ratio of the composite material powder, conductive agent, and binder is (150-200):(25-75):(1-50); the base film is selected from one or more of polypropylene membrane, polyethylene membrane, and polyimide membrane; the thickness of the nano-coating is 50μm-250μm; the drying temperature is 30℃-80℃, and the drying time is 8h-14h.

7. An amino-functionalized metal-organic framework-clay mineral composite membrane material, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.

8. A lithium metal battery separator, characterized in that, The invention comprises the amino-functionalized metal-organic framework-clay mineral composite membrane material as described in claim 7, wherein the composite membrane material is attached as a functional coating to the surface of a lithium metal battery substrate membrane.

9. A lithium metal battery, characterized in that, The battery includes the lithium metal battery separator of claim 8, and further includes a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode is a lithium metal negative electrode.

10. The application of the amino-functionalized metal-organic framework-clay mineral composite membrane material according to claim 7 in the preparation of lithium metal batteries, characterized in that, As a functional coating material for lithium metal battery separators, it is used to suppress lithium dendrite growth, reduce battery charge and discharge polarization voltage, and improve battery cycle stability and safety.

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