Sulfide solid electrolyte with MOF structure, and preparation method and application thereof

Abstract

The invention provides a sulfide solid electrolyte with an MOF structure, and a preparation method and application thereof, the process is designed from a molecular level, and lithium ions and sulfur elements are used as basic components for constructing an MOF skeleton through in-situ combination of excellent ion conduction capability of the sulfide electrolyte and structural advantages of an MOF material; the bulk sulfide electrolyte with a regular three-dimensional multi-channel crystalline MOF structure is directly synthesized and constructed by taking a sulfur element as an inherent component of an MOF skeleton in a breakthrough manner, so that the intrinsic design of the sulfide MOF skeleton electrolyte is realized, and the problems of interface bonding, performance stability and ion transmission path are fundamentally solved; a sulfur element in the electrolyte is derived from sulfur atoms (such as-SH and-S-) of a ligand and participates in construction of an MOF skeleton, the electrolyte has the advantages of good interface stability, regular ion transmission channels, adjustable mechanical properties and the like, and the problems of poor interface stability, irregular ion transmission paths and the like of a sulfide electrolyte in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery materials technology, and in particular to a sulfide solid electrolyte with a MOF structure, its preparation method and application. Background Technology

[0002] Sulfide solid electrolytes (such as Li) 10 GeP2S 12 Li6PS5Cl) has extremely high lithium-ion conductivity (up to 10 at room temperature). -3 ~10 -2 Solid electrolytes (S / cm) are considered ideal electrolytes for next-generation high-energy-density batteries. However, these materials face significant technical bottlenecks. First, they readily react with water in the air, requiring the preparation of solid electrolytes to be carried out under anhydrous and oxygen-free conditions. Second, they are incompatible with the lithium metal anode interface, leading to the growth of local lithium dendrites and side reactions. Furthermore, the solid-solid interface contact between them and the positive and negative electrodes is difficult to control.

[0003] To improve interfacial properties, existing technologies typically employ a strategy of physically blending sulfide electrolytes with polymers (such as PEO), oxide fillers, or second-phase MOF materials (such as UIO-66). For example, US Patent 20200052330A discloses a sulfide solid electrolyte containing a metal-organic framework, which improves air stability and suppresses hydrogen sulfide generation by physically mixing MOFs with sulfide electrolytes (such as Li2S-P2S5). Another approach is to use conductive MOFs (such as Cu-BHT, Ni3(HITP)2) to combine with sulfide electrolytes, forming an electron-ion hybrid conductor, which is used in the positive electrode to reduce interfacial impedance.

[0004] Chinese patent CN202011299428.2 discloses a functionalized metal-organic framework material, its preparation method, and its application. This invention utilizes a thiol-containing organic ligand and a metal salt to first prepare a metal at a relatively low reaction temperature. Organic framework materials are then subjected to oxidation treatment to obtain functionalized metals. Organic framework materials, functionalized metals Organic framework materials exhibit good crystallinity, uniform structure, and small size, making them suitable for preparing solid-state electrolyte membranes. When these solid-state electrolyte membranes are used to assemble solid-state lithium metal batteries, the resulting batteries demonstrate stable cycle performance and good rate capability. However, while this patent uses sulfur-containing ligands, its purpose is to perform post-synthesis oxidation to obtain sulfonic acid groups; the final product is a proton (H). + The lithium conduction mechanism and chemical environment of the conductor or lithium ions after lithiation are fundamentally different from the sulfide skeleton of this application.

[0005] Existing technical solutions employ a physical composite strategy, using MOFs as fillers. Their role is primarily localized modification and improvement. The unique regular channels and active sites of MOF materials are not fully utilized for intrinsic ion transport processes, making it difficult to achieve uniform mixing at the molecular level and resulting in high interfacial impedance. Summary of the Invention

[0006] One of the objectives of this invention is to address the shortcomings of existing technologies by directly constructing a solid lithium-ion conductor with sulfur as the coordinating atom, and providing a sulfide solid electrolyte with a MOF structure. The sulfur element in this electrolyte originates from the sulfur atoms of the ligand itself (such as -SH, -S-) and participates in the construction of the MOF framework, exhibiting advantages such as good interface stability, regular ion transport channels, and adjustable mechanical properties.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A sulfide solid electrolyte with a MOF structure has the general chemical formula Lix[My(L)z]·nS, where M is Li or a mixture of Li and auxiliary metals (such as Zn, Cu), and L is a sulfur-containing organic ligand. The sulfur element serves as the constituent atom of the MOF framework and coordinates with metal nodes to form a three-dimensional porous MOF structure.

[0008] As an improvement, a metal ion node is included, wherein the metal ion node contains lithium ions (Li). + ) and optionally include zinc ions (Zn 2+ ), copper ions (Cu) 2+ ) or iron ions (Fe 2+ / Fe 3+ At least one of the following can be used to form a mixed metal ion node.

[0009] As an improvement, the MOF structure has a one-dimensional linear, two-dimensional planar, or three-dimensional intersecting channel shape, with the pore size adjustable in the range of 0.5~5nm, and an ionic conductivity of 10 at room temperature. -5 -10 -4 S / cm, capacity retention >96%, lithium-ion transference number >0.8, and stable with the cross-section of metallic lithium anode.

[0010] As an improvement, the chemical environment of the pore surface is mainly hydrophobic, which is determined by the functional groups of sulfur-containing organic ligands.

[0011] The second objective of this invention is to provide a method for preparing a sulfide solid electrolyte with a MOF structure. Designed at the molecular level, this method combines the excellent ion-conducting ability of sulfide electrolytes with the structural advantages of MOF materials in situ. Lithium ions and sulfur are used as basic building blocks of the MOF framework. This breakthrough method uses sulfur as an inherent component of the MOF framework, directly synthesizing a sulfide MOF framework electrolyte with a regular three-dimensional porous crystalline MOF structure. This achieves intrinsic design of the sulfide electrolyte, fundamentally solving the problems of interface bonding and performance stability, optimizing ion transport paths, and addressing the issues of poor interface stability and irregular ion transport paths present in existing sulfide electrolytes.

[0012] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a sulfide solid electrolyte with a MOF structure, employing a direct solvothermal method, includes the following steps: S1, under the protection of an inert atmosphere, lithium salt, sulfur-containing organic ligand and optional auxiliary metal salt are dissolved in an organic solvent to form a precursor solution; S2, the precursor solution is subjected to a one-step solvothermal reaction at a reaction temperature of 100~220℃ and a reaction time of 12~72h to directly synthesize a sulfur-containing electrolyte material with a MOF framework, in which sulfur element serves as a basic component of the framework and forms a regular ion transport channel. S3, cooling, washing and drying, to obtain MOF-structured sulfide solid electrolyte powder.

[0013] As an improvement, the auxiliary metal salt is selected from zinc acetate, copper acetate, etc.

[0014] A method for preparing a sulfide solid electrolyte with a MOF structure, employing an ion exchange-sulfidation method, includes the following steps: S1, synthesized with zinc (Zn) 2+ ) or copper (Cu 2+ ) is a MOF precursor for metal nodes; S2, the MOF precursor is contacted with a lithium salt solution, and lithium ions (Li) are exchanged through ion exchange. + Introduce the MOF framework; S3. Under an inert or reducing atmosphere, the ion-exchanged material is subjected to sulfurization treatment at a temperature of 200-500℃ for 1-10 hours, so that sulfur atoms partially or completely replace heteroatoms in the framework, thereby obtaining a MOF structure that retains the crystal structure.

[0015] As an improvement, the sulfur-containing organic ligand is selected from at least one of 2,5-dimercaptoterephthalic acid (DMTTA), 1,4-benzenedithiol, 2,3-dimercaptosuccinic acid, or their thio derivatives.

[0016] As an improvement, the pore size of the MOF structure is 0.5~5nm, which can be controlled by selecting sulfur-containing organic ligands with different lengths and functional groups.

[0017] As an improvement, the lithium salt is lithium acetate, lithium nitrate, or lithium chloride; and the organic solvent is N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), or a mixture thereof.

[0018] As an improvement, the MOF precursor is MOF-5, ZIF-8, or HKUST-1; the sulfur source for the sulfidation treatment is elemental sulfur, hydrogen sulfide, or thiourea.

[0019] The core concept of both the direct solvothermal method and the ion exchange-sulfidation method in this invention lies in using sulfur and lithium ions as intrinsic components for constructing the MOF framework, rather than introducing them through post-modification or physical mixing, thereby directly preparing bulk sulfide solid electrolyte materials with atomically ordered ion channels. The direct solvothermal method is a 'one-step synthesis', while the ion exchange-sulfidation method involves 'constructing the framework first, then converting the function'. Both ultimately aim to achieve the 'intrinsicization' design of sulfide electrolytes. The term 'intrinsicization' design refers to embedding the target function (such as the ion-conducting ability of sulfides) into the basic chemical structure and crystal framework of a material through molecular design, making it an inherent property of the material. 'Bulk' materials refer to materials that inherently possess complete solid-state electrolyte functions, rather than being a physical composite of two or more materials with different functions. Their ion transport channels are atomically ordered channels determined by the crystal structure itself (as opposed to the random migration paths in amorphous or crystalline materials). Unlike the existing technology that uses pre-made, single-function MOFs as fillers to physically blend with pre-made sulfide electrolytes, the "intrinsicization" design proposed in this invention aims to directly prepare a novel substance through molecular synthesis. This substance possesses both the regular channels of MOFs and the intrinsic ionic conductivity of sulfides.

[0020] A third objective of this invention is to provide an application of a sulfide solid electrolyte with a MOF structure. To achieve the above objective, this invention provides the following technical solution: An electrode sheet includes an electrode active material, a conductive agent, and a sulfide solid electrolyte having a MOF structure as described above.

[0021] A solid-state battery includes a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive electrode and the negative electrode. The solid electrolyte layer includes a sulfide solid electrolyte with a MOF structure as described above. The positive electrode and the negative electrode are both electrode sheets as described above.

[0022] Preferably, at a current density of 0.2 mA / cm², the lithium symmetric battery can cycle stably for more than 1000 hours with a capacity retention of >96%, exhibiting good interface compatibility and stability.

[0023] The beneficial effects of this invention are as follows: (1) In the solid electrolyte of the present invention, the sulfur element originates from the sulfur atoms of the ligand itself (such as -SH, -S-) and participates in the construction of the MOF framework, rather than being filled as a guest in the channels of the pre-synthesized MOF (such as ZIF-8, UIO-66 or MIL-125-NH2). It is the first bulk material that combines the advantages of MOF crystal structure and the function of sulfide electrolyte. The ion transport channel is an atomically regular three-dimensional channel with a high lithium ion transference number. It has advantages such as good interface compatibility and stability, regular ion transport channel, and adjustable mechanical properties. The invented solid electrolyte product exhibits excellent performance, with an ionic conductivity of 10 at room temperature. -5 -10 -4 S / cm, excellent cycling stability (capacity retention >96%); the organic components in the MOF act as a natural buffer layer, significantly improving the interfacial compatibility with the electrode and inhibiting lithium dendrite growth. (2) In terms of process, this invention is designed at the molecular level. By combining the excellent ion conduction ability of sulfide electrolyte with the structural advantages of MOF material in situ, lithium ions and sulfur elements are used as basic components to construct the MOF skeleton. It breaks through by using sulfur elements as an inherent component of the MOF skeleton (instead of introducing it after modification, which is fundamentally different from the existing technology of using pre-made MOF as a filler to physically combine with sulfide electrolyte). It directly synthesizes and constructs a bulk sulfide electrolyte with a regular three-dimensional porous crystalline MOF structure, realizes the intrinsic design of sulfide electrolyte, fundamentally solves the problems of interface bonding and performance stability, and optimizes the ion transport path. Among them, the direct solvothermal method constructs the target sulfide MOF electrolyte bulk through a one-step solvothermal reaction of sulfur-containing ligands; while the ion exchange-sulfidation method integrates ion exchange and sulfidation to form a complete process, ensuring the Li... + Introduction and structural stability; this method differs from the modification strategy of simply grafting -SO3Li groups onto UIO-66, using a classic MOF as a precursor and introducing Li through ion exchange. + By introducing a framework and then performing gas-phase or liquid-phase sulfidation treatment, the O, N and other atoms in the framework are partially or completely replaced with S atoms, thereby transforming it into a sulfide electrolyte with a MOF structure. Furthermore, the process of this invention offers high designability, enabling further enhancement of room-temperature ionic conductivity through ligand design and metal node modulation. This includes precisely controlling the pore size, pore shape, and surface chemical environment of the MOF by selecting sulfur-containing organic ligands of different lengths (e.g., from rigid 1,4-benzenedithiols to flexible long-chain dithiols) and functional groups (e.g., ligands containing both -SH and -COOH). Additionally, the introduction of Zn²⁺ further enhances the MOF's ionic conductivity. + Cu² + Equal to Li + By forming hybrid nodes and utilizing the coordination preferences and bond strengths of different metal ions, the stability of the framework and its affinity for lithium ions are optimized, thereby achieving control over ion transport and interface properties. Compared with using MOFs with fixed structures (such as MIL-125-NH2) as fillers in existing technologies, this invention is more flexible and can prepare electrolyte materials with specific ionic conductivity, interface stability and mechanical strength to meet the needs of different positive and negative electrode materials. (3) In this invention, since sulfur atoms exist in the MOF framework in a stable coordinate bond form, compared with traditional sulfide glass ceramic electrolytes such as Li2S-P2S5 which are extremely sensitive to moisture, the electrolyte of this invention has significantly reduced reactivity with moisture in the air, thereby improving air stability; the organic ligand part in the MOF framework can serve as a flexible buffer layer with the electrode material, effectively relieving the volume change stress during charging and discharging. At the same time, the regular pore structure can guide the uniform deposition of lithium ions, thereby effectively inhibiting the growth of lithium dendrites and improving the interface compatibility with the lithium metal anode; by controlling the mechanical properties of the MOF material, such as by changing the rigidity and flexibility of the ligand to adjust the modulus, it can undergo moderate deformation under battery assembly pressure, forming a closer contact with the positive and negative electrode active particles and reducing the interface impedance; Specifically, regarding ligand design, choosing rigid 1,4-phenyl disulfide tends to result in smaller pore sizes and higher moduli, suitable for systems requiring strong mechanical support; while choosing longer-chain, flexible dithiols can create larger pore sizes, and the increased flexibility of the material itself facilitates better interface adhesion with electrodes; regarding metal node control, for example, the introduction of Zn²⁺… + It can form stronger metal-sulfur bonds, improving framework stability, while the introduction of Cu²⁺ + This provides a certain level of electron conduction capability, making it suitable for positive electrode composite materials.

[0024] In summary, the preparation method of the present invention is simple, mild, and the material synthesis process is controllable, making it easy to scale up production. It is especially suitable for the preparation of high-performance solid-state battery systems such as lithium batteries and lithium-sulfur batteries. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the crystal structure of the Li-Zn-S-MOF (ZIF-8) sulfide solid electrolyte prepared in Example 1 of the present invention; Figure 3 This is a process flow diagram of Embodiment 2 of the present invention; Figure 4 This is a graph showing the cycling performance of the sulfide solid electrolyte with MOF structure in a symmetrical battery according to the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1: Preparation of Li-Zn-S-MOF electrolyte by direct solvothermal method A method for preparing a sulfide solid electrolyte with a MOF structure, such as... Figure 1 As shown, the direct solvothermal method includes the following steps: Raw material preparation: In a glove box filled with argon (H2O, O2<0.1ppm), weigh 0.5mmol of lithium acetate (CH3COOLi), 1.0mmol of 2,5-dimercaptoterephthalic acid (DMTTA) and 0.5mmol of zinc acetate dihydrate (Zn(CH3COO)2·2H2O); Precursor solution preparation: Dissolve the above raw materials together in 30 mL of a mixed solvent consisting of N,N-dimethylformamide (DMF) and anhydrous ethanol in a volume ratio of 2:1, and sonicate for 30 min to ensure complete dissolution and mixing; Solvothermal reaction: The mixed solution was transferred to a 50 mL polytetrafluoroethylene-lined high-pressure reactor, sealed, and placed in an oven at 150 °C for 48 h. Post-processing: After the reaction is complete, the product is allowed to cool naturally to room temperature. The product is then removed from the glove box and washed three times with anhydrous ethanol by centrifugation to remove unreacted raw materials and solvent molecules. Finally, the product is vacuum dried at 70°C for 12 hours to obtain a pale yellow microcrystalline powder, which is the target product.

[0028] In the solvothermal reaction step of this method, the selection of reaction temperature and time is crucial. If the temperature is too low or the time is too short, the reaction will be incomplete, resulting in poor crystallinity. If the temperature is too high, the ligand will decompose or the framework will collapse. The process conditions have been optimized to ensure that the thiol group (-SH) on the DMTTA ligand is completely deprotonated and fully coordinated with the metal ions to form a MOF structure with high crystallinity and uniform pore size. This is the basis for obtaining high ionic conductivity.

[0029] Performance testing: The obtained powder was pressed into discs with a diameter of 10 mm under 10 MPa. Electrochemical impedance spectroscopy (EIS) was used to determine its room temperature ionic conductivity, which was approximately 8.7 × 10⁻⁶. -5 S / cm; the lithium-ion transference number t was obtained by combining DC polarization and AC impedance methods (Bruce-Vincent method). Li + The modulus was 0.82; a Li|electrolyte|Li symmetric cell was assembled and subjected to constant current cycling test. At a current density of 0.2 mA / cm², it could cycle stably for more than 1000 hours without short circuit; the Young's modulus was tested by nanoindentation technology. The Young's modulus of the electrolyte sheet after pressing was about 5 GPa, which showed moderate rigidity to ensure electronic insulation, while having a certain degree of flexibility to improve interface contact.

[0030] See Figure 2 This diagram illustrates a specific embodiment of the general formula Lix[My(L)z]·nS—a crystal structure diagram of a Li-Zn-S-MOF electrolyte. The diagram visually demonstrates that sulfur atoms, as coordinating atoms, directly participate in constructing the regular channel structure of the MOF. Yellow spheres represent macropores, blue polyhedra represent nodes where zinc (Zn) or lithium (Li) binds to sulfur, and gray frames represent connecting units composed of organic ligands (DMTTA). Three-dimensional channels are formed between zinc (Zn), lithium (Li), and the ligands, allowing lithium ions to migrate rapidly within them.

[0031] Example 2: Preparation of sulfide electrolytes with MOF structure by ion exchange-sulfidation method A method for preparing a sulfide solid electrolyte with a MOF structure, such as... Figure 3 As shown, the ion exchange-sulfurization method includes the following steps: Precursor synthesis: Zinc-based MOF-5 (using terephthalic acid as a ligand) was synthesized according to existing technical methods. Lithium-ion exchange: 1 g of MOF-5 powder was soaked in 20 mL of LiCl methanol solution (0.5 M) and stirred at 60 °C for 24 h to allow Li to ionize. + Zn2 in partially swapped MOF backbone +After exchange, the mixture was washed several times with methanol to obtain the Li / Zn-MOF intermediate. Gas-phase sulfidation: The above Li / Zn-MOF intermediate and excess sulfur powder (mass ratio 1:3) were placed in the upstream and downstream regions of a tube furnace, respectively. Under argon protection, the temperature was increased to 350°C at a rate of 5°C / min and maintained at this temperature for 2 hours. The sulfur vapor generated by the sublimation of the sulfur powder reacted with the oxygen atoms in the MOF framework to achieve sulfidation, resulting in a black sulfide electrolyte with a MOF structure.

[0032] In the gas-phase sulfidation step of this method, the sulfidation temperature is a key process parameter. The temperature needs to be high enough to allow sulfur atoms to undergo a displacement reaction with oxygen / nitrogen atoms in the framework, but it must be much lower than the temperature at which the MOF framework decomposes (e.g., MOF-5 decomposes at about 500℃) to ensure that the crystal framework of the parent MOF is preserved during sulfidation. Mild sulfidation conditions are a key parameter for maintaining the MOF structure.

[0033] Performance testing: The obtained powder was pressed into discs with a diameter of 10 mm under 10 MPa. Electrochemical impedance spectroscopy (EIS) was used to determine its room temperature ionic conductivity, which was approximately 8.6 × 10⁻⁶. -5 S / cm; the lithium-ion transference number t was obtained by combining DC polarization and AC impedance methods (Bruce-Vincent method). Li + The modulus was 0.81; a Li|electrolyte|Li symmetric cell was assembled and subjected to constant current cycling test. At a current density of 0.2 mA / cm², it could cycle stably for more than 1000 h without short circuit; the Young's modulus was tested by nanoindentation technology, and the Young's modulus of the electrolyte sheet after pressing was approximately 5.1 GPa.

[0034] Example 3: Solid-state battery assembly and performance testing Battery assembly: The Li-Zn-S-MOF electrolyte powder prepared in Example 1 was mixed with lithium iron phosphate (LiFePO4) and conductive carbon black in an agate mortar at a mass ratio of 70:25:5 to prepare a positive electrode sheet. The positive electrode was then assembled into a CR2032 type button cell with lithium metal as the negative electrode.

[0035] Performance testing: Charge-discharge tests were conducted at 0.1C rate and room temperature. The initial discharge specific capacity reached 157mAh / g, and the capacity retention rate after 50 cycles was 96.5%, demonstrating excellent cycle stability.

[0036] Comparative Example 1: Physically Composite MOF Packing Material Prepared according to the method of patent CNUS20200052330A, the pre-synthesized ZIF-8MOF filler was mixed with Li 10 GeP2S12 (LGPS) sulfide electrolytes were physically mixed at a mass ratio of 5:95.

[0037] Tests showed that the composite electrolyte had poor interfacial stability with lithium metal, and the assembled lithium symmetric battery exhibited a performance of 0.2 mA / cm². 2 Short circuits occurred in less than 200 hours of cycling at the current density, and the ionic conductivity decreased with the placement time. This proves that the physical mixing strategy cannot achieve uniform composite at the molecular level and is difficult to solve the interface problem. Compared with Comparative Example 1, the superiority of the "intrinsicization" design of this invention is fully demonstrated.

[0038] Comparative Example 2: Direct sulfurization of the MOF precursor (700℃) according to the method described in patent CN201910728106.6 resulted in structural collapse.

[0039] The comparative results show that the electrolyte of Example 1 of the present invention did not exhibit short circuits after 50 cycles (2800 h) in a lithium symmetric battery (e.g., Figure 4 As shown in the figure, it is significantly better than the comparative example.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sulfide solid electrolyte with a MOF structure, characterized in that, Its general chemical formula is Lix[My(L)z]·nS, where M is Li or a mixture of Li and auxiliary metals, and L is a sulfur-containing organic ligand. Sulfur acts as a constituent atom of the MOF framework and coordinates with metal nodes to form a three-dimensional porous MOF structure.

2. The sulfide solid electrolyte with MOF structure according to claim 1, characterized in that, It includes metal ion nodes, which contain lithium ions and at least one of zinc ions, copper ions or iron ions to form a mixed metal ion node.

3. A sulfide solid electrolyte with a MOF structure according to claim 1, characterized in that, The MOF structure has one-dimensional linear, two-dimensional planar, or three-dimensional intersecting channel shapes, with pore sizes adjustable in the range of 0.5~5nm, and an ionic conductivity of up to 10 at room temperature. -5 -10 -4 S / cm, capacity retention >96%, lithium-ion transference number >0.8, and stable with the cross-section of metallic lithium anode.

4. A method for preparing a sulfide solid electrolyte with a MOF structure as described in any one of claims 1-3, characterized in that, Includes the following steps: S1, lithium salt and sulfur-containing organic ligands are dissolved in an organic solvent to form a precursor solution; S2, the precursor solution is subjected to a one-step solvothermal reaction at a reaction temperature of 100~220℃ and a reaction time of 12~72h to directly synthesize a sulfur-containing electrolyte material with a MOF framework, in which sulfur element serves as a basic component of the framework and forms a regular ion transport channel. S3, cooling, washing and drying, yields a sulfide solid electrolyte with a MOF structure.

5. A method for preparing a sulfide solid electrolyte with a MOF structure as described in any one of claims 1-3, characterized in that, Includes the following steps: S1, synthesize MOF precursors with zinc or copper as metal nodes; S2, the MOF precursor is brought into contact with a lithium salt solution, and lithium ions are introduced into the MOF framework through ion exchange; S3. Under an inert or reducing atmosphere, the ion-exchanged material is subjected to sulfurization treatment at a temperature of 200-500℃ for 1-10 hours, so that sulfur atoms partially or completely replace heteroatoms in the framework, thereby obtaining a MOF structure that retains the crystal structure.

6. The method for preparing a sulfide solid electrolyte with a MOF structure according to claim 4, characterized in that, The sulfur-containing organic ligand is selected from at least one of 2,5-dimercaptoterephthalic acid, 1,4-benzenedithiol, 2,3-dimercaptosuccinic acid, or their thio derivatives; the organic solvent is N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), or a mixture thereof. By selecting sulfur-containing organic ligands of different lengths and functional groups, the pore size, channel shape, and surface chemical environment of MOF structures can be controlled.

7. A method for preparing a sulfide solid electrolyte with a MOF structure according to claim 4 or 5, characterized in that, The lithium salt is lithium acetate, lithium nitrate, or lithium chloride.

8. The method for preparing a sulfide solid electrolyte with a MOF structure according to claim 5, characterized in that, The MOF precursor is MOF-5, ZIF-8, or HKUST-1; the sulfur source for the sulfidation treatment is elemental sulfur, hydrogen sulfide, or thiourea.

9. An electrode sheet, characterized in that, It includes electrode active materials, conductive agents, and sulfide solid electrolytes with MOF structures as described in any one of claims 1-3.

10. A solid-state battery, comprising a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive and negative electrodes, characterized in that, The solid electrolyte layer includes a sulfide solid electrolyte with a MOF structure as described in any one of claims 1-3, and the positive and negative electrodes are both electrode sheets as described in claim 9. At a current density of 0.2 mA / cm², the lithium symmetric battery can cycle stably for more than 1000 hours with a capacity retention rate of >96%, exhibiting good interface compatibility and stability.

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