Zero-dimensional Zn-Mo bimetallic HZIF modified diaphragm and preparation method thereof

Abstract

The invention discloses a zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm and a preparation method thereof.The preparation method comprises the following steps that zinc citrate dihydrate, molybdic acid and 2-isopropyl imidazole are prepared into an HZIF material through a solvothermal method; a double-sided asymmetric quasi-solid gel diaphragm with a positive electrode side adsorption catalyst layer and a negative electrode side lithium dendrite inhibition layer is constructed, positive electrode adsorption LiPS and high catalytic activity sites accelerate the kinetics of an oxidation-reduction reaction, the shuttle effect is remarkably inhibited, and the reaction is promoted; the negative electrode side realizes uniform conduction of lithium ions, induces compact deposition of lithium metal, and inhibits dendritic crystal growth. The modified diaphragm shows excellent Li2S deposition capacity of 32.68 mAh g <-1 > in a constant potential discharge experiment, and electroplating stripping of a Li / Li symmetric battery assembled by the Zn-Mo bimetallic HZIF material modified diaphragm can stably circulate for more than 1600 hours under the current density of 1 mA cm <-2 >.

Description

Technical Field

[0001] This invention belongs to the field of lithium-sulfur battery technology, specifically relating to the preparation method and application of zero-dimensional Zn-Mo bimetallic HZIF material modified separator, and also relating to zero-dimensional Zn-Mo bimetallic HZIF material modified separator. Background Technology

[0002] Lithium-sulfur (LSB) batteries have shown great promise for applications in electric vehicles and large-scale energy storage due to their advantages such as high theoretical energy density, low cost, and environmental friendliness. However, their industrialization process still faces key challenges such as the polysulfide "shuttle effect," lithium dendrite growth, liquid electrolyte leakage, and high interfacial impedance. Traditional polypropylene / polyethylene (PP / PE) separators have a single function, only achieving physical isolation, and are difficult to effectively suppress polysulfide migration or regulate interfacial reactions; while conventional coated separators generally suffer from problems such as easy coating peeling, functional limitations, and inability to meet the differentiated needs of the positive and negative electrode interfaces. Although quasi-solid-state / gel-state separators have some potential in improving safety and reducing leakage risk, they are still limited by bottlenecks such as low ionic conductivity, weak polysulfide suppression ability, and insufficient mechanical properties.

[0003] In recent years, functionalized membrane modification has become an important strategy for suppressing the shuttle effect due to its strong structural designability and controllable cost. Among them, hybrid zeolite imidazole frameworks (HZIFs), as a novel type of metal-organic framework material, integrate zeolite-like inorganic tetrahedral metal oxometalate (TO4) units with zeolite-type metal imidazole frameworks to form a hybrid crystalline zero-dimensional network that combines the structural tunability of ZIFs with the thermal / chemical stability of inorganic zeolites. Its high specific surface area, ordered channels, abundant polar sites, and metal centers can efficiently adsorb and catalyze the conversion of polysulfides, while achieving selective retention through size sieving effect. However, existing HZIF-based membranes mostly adopt a single-sided coating structure, making it difficult to achieve synergistic regulation of shuttle suppression on the positive electrode side and dendrite suppression on the negative electrode side.

[0004] Therefore, developing bifacial asymmetric quasi-solid gel membranes with original structure, novel process, and synergistic function has significant scientific and engineering value. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm, so as to solve the problems of existing diaphragms having single function and high interfacial impedance.

[0006] Another objective of this invention is to provide a zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm.

[0007] Another objective of this invention is to provide applications for zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragms.

[0008] The first technical solution adopted in this invention is a method for preparing a zero-dimensional Zn-Mo bimetallic HZIF material modified separator. This method employs an integrated quasi-solid-state gel structure, abandoning the traditional PP / PE substrate, significantly improving safety and reducing interfacial impedance. In terms of functional design, an innovative process of bilayer stepwise casting-thermally induced phase separation is used to construct a significantly different bifacial functional layer: the positive electrode side is enriched with Zn-Mo bimetallic HZIF, utilizing its strong adsorption and catalytic activity to efficiently suppress polysulfide shuttle; the negative electrode side is designed as a lithium-rich salt and rigid phase structure without HZIF to achieve uniform lithium conduction and effectively suppress lithium dendrite growth. Thus, through structural innovation and process optimization, synergistic regulation of the positive and negative electrode interfaces and overall improvement of battery performance are achieved. The specific operation steps are as follows:

[0009] Step 1: Weigh a certain amount of zinc citrate dihydrate, molybdic acid, and 2-isopropylimidazolium and dissolve them in DMF solution, stirring thoroughly to obtain solution A; Step 2: Transfer solution A obtained in Step 1 to a stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven with a programmed cooling function. Adjust the temperature to 140-180℃ for 60-80 hours. After the reactor has slowly cooled to room temperature, remove it and separate the product by filtration and washing. The product is a blue-black block B. Step 3: Dissolve the gel polymer, B obtained in Step 2 and lithium salt in a mixed solution of acetone and DMF, and stir until a uniform positive electrode side coating solution C with a certain viscosity is formed; Step 4: Dissolve the gel polymer, lithium salt, and rigid inorganic filler in a mixed solution of acetone and DMF, and stir until homogeneous to obtain the negative electrode side coating solution D; Step 5: Use a double-layer step casting method: First, use a scraper to apply the negative electrode side precursor liquid D to the glass plate. After semi-gelling, apply the positive electrode side precursor liquid C to the positive electrode side to form a double-layer asymmetric wet film. Step 6: After thermally induced phase separation and vacuum drying, a self-supporting, double-sided asymmetric quasi-solid gel membrane E without a PP / PE substrate is obtained.

[0010] Furthermore, in step 1 above, the molar ratio of zinc citrate dihydrate to molybdic acid and 2-isopropylimidazole is 1:11:6.

[0011] Furthermore, in step 1 above, the ratio of the total mass of zinc citrate dihydrate, molybdic acid, and 2-isopropylimidazole to DMF is 0.55-0.7 g: 5-8 mL, and 0.1-0.125 g of zinc citrate dihydrate, 0.31-0.44 g of molybdic acid, and 0.105-0.135 g of 2-isopropylimidazole are weighed out.

[0012] Furthermore, in step 1 above, DMF can be replaced with N,N-dimethylacetamide (DMA).

[0013] Furthermore, in step 1 above, the stirring time is 20-60 minutes.

[0014] Furthermore, in step 1 above, the temperature setting range of the oven is 140-180℃, and the time range is 60-80h.

[0015] Furthermore, in step 2 above, the heating rate of the oven is 3-5℃ / min. In the absence of a programmed cooling oven, a regular oven can be used instead; during cooling, simply turn off the oven power and allow it to naturally reach room temperature.

[0016] Furthermore, in step 2 above, ultrasonic treatment can be performed before filtration and washing to remove the precipitates adhering to the crystal surface.

[0017] Furthermore, in step 2 above, a DMF solution is used for vacuum filtration and washing.

[0018] Furthermore, in step 3 above, the mass ratio of gel polymer, Zn-Mo bimetallic HZIF material and lithium salt is 8-10:2-3:1.5-3, and the stirring time is 9-15 h.

[0019] Furthermore, the gel polymer in steps 3 and 4 above is PVDF-HFP, PEO, PAN or PMMA; the lithium salt is LiTFSI, LiPF6, LiClO4 or LiBF4; the amount of acetone is 4-6 mL; the amount of DMF is 1-2 mL; DMF can be replaced by DMA; and the stirring time is 48-72 h.

[0020] Furthermore, in step 4 above, the mass ratio of gel polymer, lithium salt, and rigid inorganic filler is 16-20:0.9-1:3-4.

[0021] Furthermore, in step 5 above, the negative electrode is coated first, followed by the positive electrode, with a coating thickness of 500-1000 μm.

[0022] Furthermore, in step 6 above, the vacuum drying temperature is 60-100℃, and the time is 2-12 h.

[0023] Furthermore, the Zn-Mo bimetallic HZIF material modified diaphragm prepared by the above method.

[0024] The beneficial effects of this invention are: (1) The material synthesis process is simple and has the potential for large-scale application: Zero-dimensional Zn-Mo bimetallic HZIF materials can be prepared by one-step solvothermal method. The reaction conditions are mild, the process is simple and the cost is low, making it easy to achieve large-scale production, which lays a solid foundation for the industrial application of high-performance lithium-sulfur battery materials.

[0025] (2) Bimetallic synergistic catalysis, efficient suppression of shuttle effect: In Zn-Mo bimetallic HZIF material, Mo has excellent catalytic activity for LiPS, which can efficiently promote its adsorption and liquid-solid phase conversion; Zn optimizes the activity of the catalytic center by regulating the local electronic structure. The two work together to significantly capture and rapidly convert shuttled LiPS, effectively suppressing its diffusion to the negative electrode, thereby reducing side reactions, reducing the loss of active materials, and greatly improving the cycle stability, coulombic efficiency and rate performance of the battery.

[0026] (3) Innovative membrane structure to achieve synergistic regulation of positive and negative electrode interfaces: The integrated quasi-solid gel structure is adopted, which abandons the traditional PP / PE substrate, significantly improves battery safety and reduces interface impedance; through the double-layer step casting-thermal induced phase separation process, a double-sided asymmetric functional layer is constructed: the positive electrode side is enriched with Zn-Mo bimetallic HZIF to achieve strong adsorption and catalytic conversion of polysulfides and suppress the shuttle effect; the negative electrode side is a lithium-rich salt and rigid phase structure without HZIF, which can uniformly guide lithium ion conduction and effectively suppress lithium dendrite growth. This solves the technical bottleneck of the existing membrane having a single function and being unable to meet the requirements of the positive and negative electrode interfaces, and achieves a breakthrough improvement in the overall performance of the battery. Attached Figure Description

[0027] Figure 1 This is a flowchart of the preparation process in Example 1; Figure 2 This is a characterization diagram of the flexibility of the Zn-Mo bimetallic HZIF material modified diaphragm prepared in Example 1. Figure 3 This is a graph showing the relationship between current density and potential (symmetric CV) of the symmetrical cell prepared in Example 1. Figure 4 This is a graph showing the Li2S deposition performance of the lithium-sulfur battery prepared in Example 1; Figure 5 This is a shuttle current performance diagram of the lithium-sulfur battery prepared in Example 1; Figure 6 This is a graph showing the electroplating stripping performance of the Li / / Li symmetric cell prepared in Case 1. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0029] Example 1: See Figure 1The preparation method of Zn-Mo bimetallic HZIF material modified diaphragm includes the following steps: Step 1: Weigh 0.122 g (0.2 mmol) of zinc citrate dihydrate, 0.38 g (2.117 mmol) of molybdic acid and 0.129 g (1.1692 mmol) of 2-isopropylimidazolium, dissolve them in 7 mL of DMF solution, and stir thoroughly to obtain solution A; Step 2: Transfer solution A obtained in Step 1 to a stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven with a programmed cooling function. Adjust the temperature to 160℃ for 72 hours. After the reactor has slowly cooled to room temperature, remove it and separate the product by filtration and washing. The product is a blue-black block B. Step 3: Dissolve PVDF-HFP (0.40 g), Zn-Mo bimetallic HZIF material (0.12 g) and LiTFSI (0.08 g) in a mixed solution of 4 mL acetone and 1 mL DMF, and stir for 48 h to obtain a positive electrode side coating solution C with a certain viscosity. Step 4: Dissolve PVDF-HFP (0.40 g), PEO (0.05 g), LiTFSI (0.08 g), and SiO2 (0.02 g) in a mixed solution of 4 mL acetone and 1 mL DMF, and stir for 48 h to obtain the negative electrode side coating solution D; Step 5: Use a two-layer step casting method: First, use a 500 μm scraper to coat the negative electrode precursor liquid D onto the glass plate. After semi-gelling, coat the positive electrode precursor liquid C onto the positive electrode side to form a two-layer asymmetric wet film.

[0030] Step 6: Transfer the membrane to a vacuum drying oven and dry it at 60°C for 12 h to obtain a self-supporting, double-sided asymmetric quasi-solid gel membrane E without PP / PE substrate.

[0031] Example 2: A method for preparing a Zn-Mo bimetallic HZIF material modified diaphragm, comprising the following steps: Step 1: Weigh 0.125 g (0.205 mmol) of zinc citrate dihydrate, 0.405 g (2.26 mmol) of molybdic acid and 0.137 g (1.24 mmol) of 2-isopropylimidazolium, dissolve them in 8 mL of DMA solution, and stir thoroughly to obtain solution A; Step 2: Transfer solution A obtained in Step 1 to a stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven with a programmed cooling function. Adjust the temperature to 170°C for 72 hours. After the reactor has slowly cooled to room temperature, remove it and separate the product by filtration and washing. The product is a blue-black block B. Step 3: Dissolve PAN (0.35 g), Zn-Mo bimetallic HZIF material (0.13 g) and LiPF6 (0.09 g) in a mixed solution of 4 mL acetone and 1 mL DMA, and stir for 50 h to obtain a positive electrode side coating solution C with a certain viscosity. Step 4: Dissolve PAN (0.320 g), PEO (0.04 g), LiPF6 (0.02 g), and SiO2 (0.024 g) in a mixed solution of 4 mL acetone and 1 mL DMA, and stir for 50 h to obtain the negative electrode side coating solution D; Step 5: Use a double-layer step casting method: First, use a 600 μm scraper to coat the negative electrode side precursor liquid D onto the glass plate. After semi-gelling, coat the positive electrode side precursor liquid C onto the positive electrode side to form a double-layer asymmetric wet film. Step 6: Transfer the membrane to a vacuum drying oven and dry it at 70°C for 10 h to obtain a self-supporting, double-sided asymmetric quasi-solid gel membrane E without PP / PE substrate.

[0032] Example 3: A method for preparing a Zn-Mo bimetallic HZIF material modified diaphragm, comprising the following steps: Step 1: Weigh 0.113 g (0.185 mmol) of zinc citrate dihydrate, 0.365 g (2.04 mmol) of molybdic acid and 0.124 g (1.12 mmol) of 2-isopropylimidazolium, dissolve them in 7 mL of DMF solution, and stir thoroughly to obtain solution A; Step 2: Transfer solution A obtained in Step 1 to a stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven with a programmed cooling function. Adjust the temperature to 160℃ for 60 hours. After the reactor has slowly cooled to room temperature, remove it and separate the product by filtration and washing. The product is a blue-black block. Step 3: Dissolve PMMA (0.40 g), Zn-Mo bimetallic HZIF material (0.12 g) and LiPF6 (0.08 g) in a mixed solution of 5 mL acetone and 1 mL DMF, and stir for 60 h to obtain a positive electrode side coating solution C with a certain viscosity. Step 4: Dissolve PMMA (0.256 g), PEO (0.032 g), LiPF6 (0.08 g), and SiO2 (0.02 g) in a mixed solution of 5 mL acetone and 1 mL DMF, and stir for 60 h to obtain the negative electrode side coating solution D; Step 5: Use a double-layer step casting method: First, use a 700 μm scraper to scrape the negative electrode side precursor liquid D onto the glass plate. After semi-gelling, scrape the positive electrode side precursor liquid C onto the positive electrode side to form a double-layer asymmetric wet film. Step 6: Transfer the membrane to a vacuum drying oven and dry it at 80°C for 8 hours to obtain a self-supporting, double-sided asymmetric quasi-solid gel membrane E without a PP / PE substrate.

[0033] Example 4: A method for preparing a Zn-Mo bimetallic HZIF material modified diaphragm, comprising the following steps: Step 1: Weigh 0.105 g (0.172 mmol) of zinc citrate dihydrate, 0.34 g (1.90 mmol) of molybdic acid and 0.115 g (1.04 mmol) of 2-isopropylimidazolium, dissolve them in 6 mL of DMF solution, and stir thoroughly to obtain solution A; Step 2: Transfer solution A obtained in Step 1 to a stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven with a programmed cooling function. Adjust the temperature to 160℃ for 72 hours. After the reactor has slowly cooled to room temperature, remove it and separate the product by vacuum filtration and washing. The product is a blue-black block. Step 3: Dissolve PMMA (0.40 g), Zn-Mo bimetallic HZIF material (0.12 g) and LiClO4 (0.08 g) in a mixed solution of 6 mL acetone and 2 mL DMF, and stir for 65 h to obtain a positive electrode side coating solution C with a certain viscosity. Step 4: Dissolve PMMA (0.256 g), PEO (0.032 g), LiClO4 (0.016 g), and Al2O3 (0.013 g) in a mixed solution of 6 mL acetone and 2 mL DMF, and stir for 65 h to obtain the negative electrode side coating solution D; Step 5: Use a double-layer step casting method: First, use an 800 μm scraper to coat the negative electrode side precursor liquid D onto the glass plate. After semi-gelling, coat the positive electrode side precursor liquid C onto the positive electrode side to form a double-layer asymmetric wet film. Step 6: Transfer the membrane to a vacuum drying oven and dry it at 90°C for 7 h to obtain a self-supporting, double-sided asymmetric quasi-solid gel membrane E without PP / PE substrate.

[0034] Example 5: A method for preparing a Zn-Mo bimetallic HZIF material modified diaphragm, comprising the following steps: Step 1: Weigh 0.100 g (0.164 mmol) of zinc citrate dihydrate, 0.323 g (1.80 mmol) of molybdic acid and 0.109 g (0.98 mmol) of 2-isopropylimidazolium, dissolve them in 5 mL of DMF solution, and stir thoroughly to obtain solution A; Step 2: Transfer solution A obtained in Step 1 to a stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven with a programmed cooling function. Adjust the temperature to 160℃ for 80 hours. After the reactor has slowly cooled to room temperature, remove it and separate the product by vacuum filtration and washing. The product is a blue-black block. Step 3: Dissolve PMMA (0.35 g), Zn-Mo bimetallic HZIF material (0.10 g) and LiBF4 (0.07 g) in a mixed solution of 6 mL acetone and 2 mL DMF, and stir for 70 h to obtain a positive electrode side coating solution C with a certain viscosity. Step 4: Dissolve PMMA (0.40 g), PEO (0.05 g), LiBF4 (0.08 g), and TiO2 (0.02 g) in a mixed solution of 6 mL acetone and 2 mL DMF, and stir for 70 h to obtain the negative electrode side coating solution D; Step 5: Use a double-layer step casting method: First, use a 900 μm scraper to scrape the negative electrode side precursor liquid D onto the glass plate. After semi-gelling, scrape the positive electrode side precursor liquid C onto the positive electrode side to form a double-layer asymmetric wet film. Step 6: Transfer the membrane to a vacuum drying oven and dry it at 120°C for 4 hours to obtain a self-supporting, double-sided asymmetric quasi-solid gel membrane E without a PP / PE substrate.

[0035] Example 6: A method for preparing a Zn-Mo bimetallic HZIF material modified diaphragm, comprising the following steps: Step 1: Weigh 0.119 g (0.195 mmol) of zinc citrate dihydrate, 0.385 g (2.15 mmol) of molybdic acid and 0.131 g (1.18 mmol) of 2-isopropylimidazolium, dissolve them in 7 mL of DMF solution, and stir thoroughly to obtain solution A; Step 2: Transfer solution A obtained in Step 1 to a stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven with a programmed cooling function. Adjust the temperature to 160℃ for 72 hours. After the reactor has slowly cooled to room temperature, remove it and separate the product (Zn-Mo bimetallic HZIF material) by vacuum filtration and washing. The product is in the form of blue-black lumps. Step 3: Dissolve PAN (0.40 g), Zn-Mo bimetallic HZIF material (0.12 g) and LiPF6 (0.08 g) in a mixed solution of 6 mL acetone and 2 mL DMF, and stir for 65 h to obtain a positive electrode side coating solution C with a certain viscosity. Step 4: Dissolve PAN (0.40 g), PEO (0.05 g), LiPF6 (0.08 g), and Al2O3 (0.02 g) in a mixed solution of 6 mL acetone and 2 mL DMF, and stir for 65 h to obtain the negative electrode side coating solution D; Step 5: Use a double-layer step casting method: First, use an 800 μm scraper to coat the negative electrode side precursor liquid D onto the glass plate. After semi-gelling, coat the positive electrode side precursor liquid C onto the positive electrode side to form a double-layer asymmetric wet film. Step 6: Transfer the membrane to a vacuum drying oven and dry it at 90°C for 7 h to obtain a self-supporting, double-sided asymmetric quasi-solid gel membrane E without PP / PE substrate.

[0036] The modified separators obtained in Examples 1-5 above were taken out and cut into circles with a diameter of 18 mm using a punch to obtain modified battery separators. The battery separators were then combined with sulfur-loaded graphene composite positive electrode material and lithium sheet negative electrode material, and assembled into lithium-sulfur batteries with springs and gaskets in an argon-filled glove box. The shuttle current, Li2S deposition, symmetric CV (1 V to -1 V, scan rate of 50 mV / s), electroplating stripping and other properties were tested under different currents.

[0037] See Figure 2 The Zn-Mo bimetallic HZIF membrane material obtained in Example 1 has a polygonal morphology.

[0038] like Figure 3 As shown in the figure, the symmetric cell assembled with the Zn-Mo bimetallic HZIF material modified separator exhibits the relationship between current density and potential at 50 mV / s. The Zn-Mo bimetallic HZIF material shows a highly reversible redox pair with low overpotential and high current response, which fully demonstrates the strong catalytic effect of this material on the redox kinetics of adsorbed LiPSs species.

[0039] like Figure 4 The figure shows the Li2S deposition performance of a lithium-sulfur battery assembled with a Zn-Mo bimetallic HZIF material-modified separator according to the present invention. To evaluate the electrocatalytic performance of the Zn-Mo bimetallic HZIF material for short-chain Li2S, the reduction and deposition behavior of Li2S was studied through a constant potential discharge experiment. First, the battery was discharged at 2.10 V to completely consume long-chain lithium polysulfides (Li2S). n (n=4-8), followed by polarization at 2.05 V to promote Li2S nucleation / growth until the current drops below 10⁻⁵ A. The results show that the modified separator prepared from the Zn-Mo bimetallic HZIF material achieves a current of 32.68 mAh g⁻¹. -1 Li2S deposition capacity.

[0040] like Figure 5 The figure shows the shuttle current performance of a lithium-sulfur battery assembled with a Zn-Mo bimetallic HZIF material-modified separator according to the present invention. To verify the effectiveness of the Zn-Mo bimetallic HZIF material in suppressing the LiPSs shuttle effect, a shuttle current test was conducted at 2.38 V after three battery cycles. The results show that the lithium-sulfur battery with the Zn-Mo bimetallic HZIF material-modified separator exhibits a lower shuttle current, indicating that the Zn-Mo bimetallic HZIF material can effectively suppress LiPSs diffusion, thereby improving sulfur utilization and slowing down capacity decay. The strong confinement effect of polysulfides also helps to achieve uniform Li... + Deposition and inhibition of lithium dendrite formation.

[0041] like Figure 6 The image shows the electroplating peeling performance of a Li / / Li symmetric battery assembled with a Zn-Mo bimetallic HZIF material-modified separator according to the present invention. The battery using the Zn-Mo bimetallic HZIF material-modified separator exhibits excellent performance at 1 mA cm⁻¹. -2 The membrane can be stably cycled for more than 1500 h at current density, and the polarization voltage remains at a low level, indicating that the Zn-Mo bimetallic HZIF material modified membrane can effectively regulate the uniform deposition / stripping behavior of lithium and significantly suppress the formation of lithium dendrites.

[0042] In summary, Example 1 is the best example.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm, characterized in that, Zn-Mo bimetallic HZIF material was prepared by solvothermal method using zinc citrate dihydrate, molybdic acid and 2-isopropylimidazolium; then, a double-sided asymmetric integrated quasi-solid-state gel membrane with a positive electrode side adsorption catalytic layer and a negative electrode side lithium dendrite suppression layer was constructed respectively.

2. The method for preparing the zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm according to claim 1, characterized in that, Specifically as follows: Step 1: Weigh zinc citrate dihydrate, molybdic acid and 2-isopropylimidazolium and dissolve them in N,N-dimethylformamide (DMF). Stir for 20-60 min to obtain solution A. Step 2: Transfer the solution A obtained in Step 1 to a stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven with a programmed cooling function. Heat the oven to 140-180℃ and keep it at that temperature for 60-80 hours. After the reactor has slowly cooled to room temperature, remove it and separate the product B by filtration and washing. Step 3: Dissolve the gel polymer, product B obtained in step 2, and lithium salt in a mixed solution of acetone and DMF, and stir until a uniform positive electrode side coating solution C with a certain viscosity is formed. Step 4: Dissolve the gel polymer, lithium salt, and rigid inorganic filler in a mixed solution of acetone and DMF, and stir until homogeneous to obtain the negative electrode side coating solution D; Step 5: Use a double-layer step casting method: First, use a scraper to apply the negative electrode side coating solution D to the glass plate. After semi-gelling, apply the positive electrode side coating solution C to form a double-layer asymmetric wet film. Step 6: The bilayer asymmetric wet membrane is subjected to thermally induced phase separation and vacuum drying to obtain a self-supporting bilayer asymmetric quasi-solid gel membrane E without PP / PE substrate.

3. The method for preparing the zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm according to claim 2, characterized in that, The molar ratio of zinc citrate dihydrate, molybdic acid, and 2-isopropylimidazole in step 1 is 1:11:

6.

4. The method for preparing the zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm according to claim 2, characterized in that, In step 2, the heating rate of the oven is 3-5℃ / min.

5. The method for preparing the zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm according to claim 2, characterized in that, In step 2, a DMF solution is used for vacuum filtration and washing. Before vacuum filtration and washing, ultrasonic treatment is performed to remove the precipitate adhering to the crystal surface.

6. The method for preparing the zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm according to claim 2, characterized in that, In step 3, the mass fraction of Zn-Mo bimetallic HZIF in the positive electrode coating solution C is 10%-30%; in step 3, the mass ratio of gel polymer, Zn-Mo bimetallic HZIF material and lithium salt is 8-10:2-3:1.5-3.

7. The method for preparing a zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm according to claim 2, characterized in that, The gel polymer in steps 3 and 4 is at least one of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyethylene oxide (PEO), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA); the lithium salt is at least one of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), and lithium tetrafluoroborate (LiBF4), and the stirring time is 48-72 h.

8. The method for preparing the zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm according to claim 2, characterized in that, In step 4, the rigid inorganic filler in the negative electrode side coating solution D is at least one of SiO2, Al2O3, and TiO2, with a mass fraction of 1%-5%; the mass ratio of gel polymer, lithium salt, and rigid inorganic filler in step 4 is 16-20:0.9-1:3-4. In step 5, the double-layer step casting sequence is: first the negative electrode side, then the positive electrode side, with a coating thickness of 500-1000 μm; In step 6, the induced phase separation temperature is 60-100℃, and the time is 2-12 h.

9. A zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragm, characterized in that, The membrane was prepared using the method described in any one of claims 1-8 for modifying the zero-dimensional Zn-Mo bimetallic HZIF material.

10. Application of zero-dimensional Zn-Mo bimetallic HZIF material modified diaphragms, characterized in that, The modified separator is used in lithium-sulfur batteries.

Images