Fibrous metal-organic framework materials, methods of making and using the same, composite solid electrolyte membranes, and lithium metal batteries

Abstract

This invention relates to the field of battery technology, disclosing a fibrous metal-organic framework material, its preparation method and applications, a composite solid electrolyte membrane, and a lithium metal battery. The preparation method employed in this invention is low-cost, simple in process, and has a wide range of applications, effectively reducing the cost for industries using this material and making it suitable for mass production. The metal-organic framework material obtained by this invention possesses advantages such as high mechanical strength, high flame retardancy, abundant pore structure, and excellent electrochemical stability. It can be applied to lithium batteries and other secondary batteries, and can be directly added as a filler to a polymer matrix as a composite solid electrolyte, added to positive and negative electrodes as a transport channel, used as an electrolyte additive and separator, etc., and applied to various components of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a fibrous metal-organic framework material, its preparation method and application, a composite solid electrolyte membrane, and a lithium metal battery. Background Technology

[0002] With the increasing prevalence of portable electronic products such as mobile phones, tablets, and laptops, as well as electric vehicles in daily life, enormous challenges are being posed to global energy storage equipment.

[0003] Lithium-ion batteries are widely used in aerospace, military equipment, and large-scale energy storage grids due to their excellent performance. As the application scope of lithium-ion batteries expands, the requirements for battery safety performance are also increasing. Battery spontaneous combustion is now commonplace. Ultimately, the main reason for battery safety issues is that existing lithium-ion battery systems contain flammable and leak-prone organic electrolytes. These electrolytes are chemically unstable, have low flash points, and are highly flammable.

[0004] To address the aforementioned safety issues, researchers have adopted measures such as adding flame-retardant additives, using heat-resistant membranes, constructing stable SEI membranes through pre-lithiation of the negative electrode, and using solid electrolytes to replace traditional membranes and electrolytes. Among these measures, the method of using solid electrolytes to replace traditional membranes and electrolytes has the greatest potential for application, as it eliminates the risk of electrolyte leakage and can also inhibit the growth of lithium dendrites to a certain extent.

[0005] In recent years, a new class of open structures has emerged, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and porous organic cages (POCs). These open structures feature large surface areas, high porosity, adjustable pore sizes, and easily functionalized pore surfaces. These materials can be added to polymer matrices as novel fillers to form organic-inorganic composite solid electrolyte membranes.

[0006] Currently, there is an urgent need in this field to develop a metal-organic framework material with high specific surface area and high aspect ratio to improve its application in the battery field. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems existing in the prior art and provide a fibrous metal-organic framework material, its preparation method and application, a composite solid electrolyte membrane and a lithium metal battery.

[0008] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a fibrous metal-organic framework material, wherein the method includes: subjecting a soluble metal salt and an organic ligand to a hydrothermal reaction in the presence of a solvent and under alkaline conditions to obtain the fibrous metal-organic framework material; The soluble metal salt has a nickel ion as its metal cation; the organic ligand contains a hydroxyl functional group; and the hydrothermal reaction takes 2-24 hours.

[0009] A second aspect of the present invention provides a fibrous metal-organic framework material obtained by the preparation method described in the first aspect.

[0010] The third aspect of the present invention provides the use of the fibrous metal-organic framework material according to the second aspect as a separator, solid electrolyte, binder, positive and negative electrode material, and other modified material in the preparation of metal batteries, secondary ion batteries, flexible batteries, capacitors, or hybrid energy storage devices.

[0011] The fourth aspect of the present invention provides a composite solid electrolyte membrane made of the fibrous metal-organic framework material described in the second aspect.

[0012] The fifth aspect of the present invention provides a lithium metal battery comprising the composite solid electrolyte membrane described in the fourth aspect.

[0013] The beneficial technical effects achieved by the present invention through the above technical solution are as follows: (1) The nanofiber structure with ultra-high aspect ratio synthesized by the hydrothermal method in this invention can greatly improve the specific surface area, and at the same time have high mechanical strength and high flame retardancy, which can effectively suppress safety issues such as lithium dendrite growth and thermal runaway. When used as a solid electrolyte, it has a high electrochemical window and high room temperature ionic conductivity under optimal conditions. The assembled symmetric battery can cycle stably for up to 2000h, and the overpotential is stable below 60mV, indicating that the solid electrolyte has excellent ion transport capability. The assembled full battery has high specific capacity, excellent cycle stability and rate performance.

[0014] (2) The fibrous metal-organic framework material prepared in this invention is further processed into a composite solid electrolyte material. Nickel ions carry a positive charge inside the material and will spontaneously attract the anions in the lithium salt to promote the dissociation of the lithium salt. The hydroxyl-containing organic ligands also further promote the dissociation of the lithium salt and promote the configurational transformation of the polymer molecular chain, which greatly shortens the migration path of lithium ions in the solid electrolyte and realizes the high-speed transfer of lithium ions.

[0015] (3) The fibrous metal-organic framework material provided by the present invention can be applied to lithium batteries and other secondary batteries, and can be used as composite solid electrolyte filler, positive and negative electrode material, electrolyte additive and separator, etc. in various components of the battery.

[0016] (4) The preparation method of the present invention is simple and controllable, environmentally friendly and inexpensive, and provides a new idea for the large-scale preparation and application of low-cost, renewable and high-performance fibrous MOF materials. Attached Figure Description

[0017] Figure 1 This is a scanning electron microscope image of the fibrous MOF material prepared in Example 1 of the present invention; Figure 2 This is a transmission electron microscope image of the fibrous MOF material prepared in Example 1 of the present invention; Figure 3 These are scanning electron microscope (SEM) images of fibrous MOF materials prepared at different reaction times according to Examples 1-4 of this invention; wherein (a1)-(a3) are Example 2; (b1)-(b3) are Example 3; (c1)-(c3) are Example 1; and (d1)-(d3) are Example 4. Figure 4 This is a scanning electron microscope image of the sheet-like MOF material prepared in Comparative Example 1 of this invention; Figure 5 This is the N2 adsorption-desorption isotherm of the fibrous MOF material prepared in Example 1 of the present invention (inset: pore size distribution diagram). Figure 6 This is a stress-strain curve of the MOF-based composite solid electrolyte membrane prepared in Application Example 1 of the present invention; Figure 7 This is a linear scanning voltammetry curve of the MOF-based composite solid electrolyte membrane prepared in Example 1 of this invention; Figure 8 This is the Arrhenius curve of the MOF-based composite solid electrolyte membrane prepared in Application Example 1 of this invention; Figure 9 This is a cycle performance diagram of a symmetrical battery assembled with the MOF-based composite solid electrolyte membrane prepared in Example 1 of this invention; Figure 10 This is a rate performance graph of a full cell assembled with the MOF-based composite solid electrolyte membrane prepared in Example 1 of this invention under stepped currents of 0.1, 0.2, 0.3, 0.4, 0.5, 1C, 3C, and 5C. Figure 11 This is a graph showing the cycling performance of a full cell assembled from the MOF-based composite solid electrolyte membrane prepared in Example 1 of this invention at a current density of 0.5C. Detailed Implementation

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] The first aspect of the present invention provides a method for preparing a fibrous metal-organic framework material, wherein the method comprises: subjecting a soluble metal salt and an organic ligand to a hydrothermal reaction in the presence of a solvent and under alkaline conditions to obtain the fibrous metal-organic framework material; The soluble metal salt has a nickel ion as its metal cation; the organic ligand contains a hydroxyl functional group; and the hydrothermal reaction takes 2-24 hours.

[0020] Metal-organic framework materials are generally crystalline materials with a periodic network structure formed by the self-assembly of inorganic metal centers and organic ligands. They are characterized by being porous, having a large specific surface area, multiple metal sites, excellent mechanical properties, and ion exchange capacity.

[0021] This invention, by selecting specific metal cation types and organic ligands with strongly interacting functional groups, and combining this with a specific reaction time, prepares fibrous metal-organic framework materials with high aspect ratio and high specific surface area. These materials also exhibit excellent flame retardant properties and electrochemical stability, thus improving material safety. Fibrous materials cannot be obtained by changing these conditions. The fibrous metal-organic framework materials prepared by this invention can be applied to lithium batteries and other secondary batteries. The assembled batteries exhibit high specific capacity, good cycle stability, and rate performance. Furthermore, they can be added as active fillers to polymer matrices as composite solid electrolytes, positive and negative electrode materials, electrolyte additives, separators, and other components of batteries.

[0022] This fibrous metal-organic framework material utilizes the coordination interaction between metal salt cations and organic ligands to interconnect them. Furthermore, due to the strongly interacting functional groups in the organic ligands, when used to prepare composite solid electrolyte membranes, they intersect between polymer molecular chains, promoting polymer crystal configuration transformation, shortening the lithium-ion transport path, reducing the lithium-ion desolvation energy, and significantly improving room-temperature ionic conductivity. The addition of the fibrous filler structure also enhances the mechanical properties of the solid electrolyte membrane.

[0023] In some embodiments of the present invention, the soluble metal salt is selected from at least one of sulfates, nitrates, halide salts, acetates and carbonates, such as at least one of nickel sulfate, nickel nitrate, nickel chloride, nickel acetate and nickel carbonate.

[0024] In some embodiments of the present invention, the soluble metal salt is nickel nitrate hexahydrate.

[0025] In some embodiments of the present invention, the organic ligand is 2-hydroxyterephthalic acid.

[0026] In some embodiments of the present invention, the solvent is N,N-dimethylformamide.

[0027] In some embodiments of the present invention, the alkaline conditions are formed using an alkaline substance, which is preferably selected from at least one of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0028] In some embodiments of the present invention, the amount of the soluble metal salt used is 0.096-0.288 g relative to 20-60 mL of solvent.

[0029] In some embodiments of the present invention, the amount of the organic ligand used is 0.182-0.546 g relative to 20-60 mL of solvent.

[0030] In some embodiments of the present invention, the molar ratio of the metal cation of the soluble metal salt to the organic ligand is 0.1-10:1, preferably 0.3-5:1, and more preferably 0.33:1.

[0031] In some embodiments of the present invention, the temperature of the hydrothermal reaction is 50-500°C, preferably 100-200°C, and more preferably 110°C.

[0032] In this invention, the hydrothermal reaction can be carried out in a conventional reactor (conventional hydrothermal method) or a microwave reactor (microwave hydrothermal method).

[0033] In some embodiments of the present invention, the hydrothermal reaction time is 6-24 hours, for example 6 hours, 12 hours, 18 hours, 24 hours, or any value within the range of any two of the above values, preferably 18 hours. This reaction time is required when carried out in a conventional reactor.

[0034] In some embodiments of the present invention, the hydrothermal reaction is carried out under microwave conditions. Under microwave conditions, the reaction temperature can be increased (200°C), at which point a shorter reaction time is required, for example, 2 hours.

[0035] In some embodiments of the present invention, the conventional hydrothermal method includes the following steps: (1) The soluble metal salt, organic ligand and solvent are first mixed (e.g., stirred) to obtain a mixed solution; (2) Then, the prepared 0.4M NaOH aqueous solution was added dropwise, and the mixture was stirred again to carry out a second mixing to obtain the precursor solution; (3) The precursor solution is subjected to a hydrothermal reaction, and the reaction product is cooled and washed multiple times; (4) The product obtained in step (3) is dried to obtain the fibrous metal-organic framework material.

[0036] In some embodiments of the present invention, in the conventional hydrothermal method, the time for the first mixing and the second mixing are independently 30 min to 4 h, preferably 30 to 120 min, and more preferably 45 min.

[0037] In some embodiments of the present invention, the microwave hydrothermal method includes the following steps: (1') The inorganic metal salt, organic ligand and solvent are first mixed (e.g., stirred) to obtain a mixed solution; (2') Then, the prepared 0.4M NaOH aqueous solution was added dropwise and stirred again to obtain the precursor solution; (3') The precursor solution is subjected to a microwave hydrothermal reaction, and the reaction product is cooled and washed multiple times; (4') The product obtained in step (3') is dried to obtain the fibrous MOF material.

[0038] In some embodiments of the present invention, in the microwave hydrothermal method, the time for the first mixing and the second mixing is independently 1-6 h, preferably 1-2 h, and more preferably 80 min.

[0039] In some embodiments of the present invention, the conditions for microwave hydrothermal reaction include: a reaction temperature of 60-400°C, preferably 80-200°C; and a reaction time of 2-24 hours, preferably 2-12 hours.

[0040] The washing process can be either DMF washing or ethanol washing, and can be performed by centrifugation.

[0041] In some embodiments of the present invention, the washing and centrifugation time is 5-15 min, preferably 8-12 min.

[0042] In some embodiments of the present invention, the washing and centrifugation speed is 3000-6000 rad / min, preferably 4000-5000 rad / min.

[0043] In some embodiments of the present invention, the drying conditions include: a temperature of 20-100°C, preferably 40-80°C; and a time of 2-24 hours, preferably 5-18 hours.

[0044] A second aspect of the present invention provides a fibrous metal-organic framework material obtained by the preparation method described in the first aspect.

[0045] In some embodiments of the present invention, the aspect ratio of the fibrous metal-organic framework material is 10-50000:1, preferably 40000-50000:1, and more preferably 48500:1.

[0046] In some embodiments of the present invention, the specific surface area of ​​the fibrous metal-organic framework material is 10-1000 m². 2 g -1 Preferably 150-235m 2 g -1 The optimal value is 233.57m. 2 g -1 .

[0047] The third aspect of the present invention provides the use of the fibrous metal-organic framework material according to the second aspect as a separator, solid electrolyte, binder, positive and negative electrode material, and other modified material in the preparation of metal batteries, secondary ion batteries, flexible batteries, capacitors, or hybrid energy storage devices.

[0048] The fourth aspect of the present invention provides a composite solid electrolyte membrane made of the fibrous metal-organic framework material described in the second aspect.

[0049] In some embodiments of the present invention, the thickness of the composite solid electrolyte membrane is 1-500 μm, preferably 200 μm.

[0050] In some embodiments of the present invention, the room temperature ionic conductivity of the composite solid electrolyte membrane is 1×10⁻⁶. -7 -1×10 -3 S cm -1 The preferred value is 2.21×10 -4 S cm -1 .

[0051] In some embodiments of the present invention, the tensile strength of the composite solid electrolyte membrane is 0.5-100 MPa, preferably 20-100 MPa, and more preferably 90 MPa.

[0052] The fifth aspect of the present invention provides a lithium metal battery comprising the composite solid electrolyte membrane described in the fourth aspect.

[0053] Batteries assembled with solid electrolyte membranes exhibit high specific capacity, excellent cycle stability, and rate performance.

[0054] The present invention will be described in detail below through embodiments.

[0055] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0056] Example 1 This embodiment illustrates the preparation of fibrous metal-organic framework materials via a hydrothermal method.

[0057] Weigh out 0.096 g (3.3 × 10⁻⁶) of nickel nitrate hexahydrate. -4 0.182 g (1 × 10 mol) and 2-hydroxyterephthalic acid 0.182 g (1 × 10 mol) - 3 0.032 g of sodium hydroxide was dissolved in 20 mL of DMF and stirred until dissolved. Then, 0.032 g of sodium hydroxide was dissolved in 2 mL of deionized water and added dropwise to the above mixed solution. After stirring for 1 h, a precursor solution was obtained. The precursor solution was placed in a hydrothermal reactor and kept at 110°C for 18 h. The reaction product was cooled to room temperature, washed with DMF and ethanol, dispersed in ethanol, and dried at 60°C for 2 h to obtain MOF-OH material.

[0058] Example 2 Fibrous metal-organic framework materials were prepared according to the method in Example 1, except that the reaction time was 6 hours.

[0059] Example 3 Fibrous metal-organic framework materials were prepared according to the method in Example 1, except that the reaction time was 12 h.

[0060] Example 4 Fibrous metal-organic framework materials were prepared according to the method in Example 1, except that the reaction time was 24 hours.

[0061] Example 5 The fibrous metal-organic framework material was prepared according to the method of Example 1, except that it was carried out in a microwave hydrothermal reactor at a temperature of 200°C for a reaction time of 2 hours.

[0062] Comparative Example 1 Weigh out 0.096 g (3.3 × 10⁻⁶) of nickel nitrate hexahydrate. -4 mol) and 0.166g (1×10) terephthalic acid -3 Dissolve 0.032 g of sodium hydroxide in 20 mL of DMF and stir until dissolved; then dissolve 0.032 g of sodium hydroxide in 2 mL of deionized water and add it dropwise to the above mixed solution. After stirring for 1 h, a precursor solution is obtained; the precursor solution is placed in a hydrothermal reactor and kept at 110ºC for 18 h. The reaction product is then cooled to room temperature, washed with DMF and ethanol, dispersed in ethanol, and dried at 60ºC for 2 h to obtain sheet-like MOF material.

[0063] Comparative Example 2 Weigh out 0.096 g (3.3 × 10⁻⁶) of nickel nitrate hexahydrate. -4 0.182 g (1 × 10 mol) and 2-hydroxyterephthalic acid 0.182 g (1 × 10 mol) - 30.032 g of sodium hydroxide was dissolved in 20 mL of DMF and stirred until dissolved. Then, 0.032 g of sodium hydroxide was dissolved in 2 mL of deionized water and added dropwise to the above mixed solution. After stirring for 1 h, a precursor solution was obtained. The precursor solution was placed in a hydrothermal reactor and kept at 100ºC for 3 h. The reaction product was cooled to room temperature, washed with DMF and ethanol, dispersed in ethanol, and dried at 60ºC for 2 h to obtain nanosphere MOF-OH material.

[0064] Comparative Example 3 Weigh out 0.069g (1×10) of lithium nitrate. -3 0.182 g (1 × 10 mol) and 2-hydroxyterephthalic acid 0.182 g (1 × 10 mol) -3 0.096 g of sodium hydroxide was dissolved in 20 mL of DMF and stirred until dissolved. Then, 0.096 g of sodium hydroxide was dissolved in 2 mL of deionized water and added dropwise to the above mixed solution. After stirring for 1 h, a precursor solution was obtained. The precursor solution was placed in a hydrothermal reactor and kept at 130ºC for 3 h. The reaction product was cooled to room temperature, washed with DMF and ethanol, dispersed in ethanol, and dried at 60ºC for 2 h to obtain sheet-like MOF-OH material.

[0065] Test Example 1 The scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the MOF-OH material prepared in Example 1 are shown below. Figure 1 and Figure 2 As shown, the material has a nanofiber-like structure with an ultra-high aspect ratio.

[0066] Scanning electron microscope (SEM) images of the fibrous metal-organic framework materials prepared in Examples 1-4 are shown below. Figure 3 As shown, the morphology of the fibrous MOF undergoes a systematic evolution with the extension of hydrothermal reaction time: at 6 h, it mainly consists of short and thick fibrous rudimentary crystal nuclei with limited exposed surface area; at 12 h, the fibers are significantly elongated, the diameter becomes thinner, and the specific surface area increases; at 18 h, the fibers reach their finest length and uniformity, with a smooth surface, the largest specific surface area, and the best dispersibility; while at 24 h, the fibers further lengthen but become thicker, the surface becomes rough, some break or entangle and agglomerate, and the specific surface area decreases.

[0067] Figure 4 A scanning electron microscope image of the sheet-like MOF material prepared in Comparative Example 1 is shown.

[0068] In addition, the specific surface area and major-to-minor axis of the metal-organic framework materials prepared in Examples 1-5 and Comparative Examples 1-3 are shown in Table 1. The N2 adsorption-desorption isotherm of the fibrous MOF material prepared in Example 1 is shown in Table 1. Figure 5 As shown.

[0069] Table 1

[0070] As shown in Table 1, in Examples 1-4, the specific surface area and aspect ratio of the fibrous materials first increased and then decreased with increasing reaction time, reaching their maximum values ​​at a reaction time of 18 h. In Example 5, a microwave hydrothermal method was used. After increasing the reaction temperature and significantly shortening the reaction time, the surface of the resulting fibrous material became rougher, leading to a decrease in specific surface area and aspect ratio. The specific surface areas of other morphological materials prepared in Comparative Examples 1-3 were all much lower than those of the fibrous materials. These results indicate that the fibrous network structure helps to obtain a higher specific surface area. A larger specific surface area means that more active sites can be provided for the electrolyte membrane, enabling it to interact with the electrolyte matrix to the maximum extent, thereby improving the Li... + The migration.

[0071] Application Examples 1-5 0.2g of PVDF-HFP and 0.02g of MOF material prepared in Examples 1-5 were weighed and dispersed in DMF. The mixture was stirred at room temperature for 6 hours. Then, 0.13g of LiTFSI was added and the mixture was stirred for another 3 hours. The thickness of the solid electrolyte was controlled by coating and vacuum dried at 120ºC to obtain a composite solid electrolyte membrane with a thickness of 200μm.

[0072] Application Comparative Examples 1-3 0.2 g of PVDF-HFP and 0.02 g of MOF material prepared in Comparative Examples 1-3 were weighed and dispersed in DMF. The mixture was stirred at room temperature for 6 h. Then, 0.13 g of LiTFSI was added and the mixture was stirred for another 3 h. The thickness of the solid electrolyte was controlled by coating and vacuum dried at 120ºC to obtain a composite solid electrolyte membrane with a thickness of 200 μm.

[0073] Test Example 2 The tensile strength, electrochemical window, and room temperature ionic conductivity of the composite solid electrolyte membranes prepared in Application Examples 1-5 and Comparative Examples 1-3 were tested.

[0074] Tensile strength test method: The tensile speed is 60 mm / min. The sample is cut into dumbbell-shaped strips, clamped between fixtures, and the thickness, width and length of the working area of ​​the strip are input to perform the tensile strength test.

[0075] Electrochemical window testing method: Assemble the composite solid electrolyte membrane into a battery with stainless steel as the blocking electrode, connect it to an electrochemical workstation for linear scan voltammetry testing, scan from the open circuit potential to a high potential (2.0V to 5.5V), and set the scan rate to 0.1-1mV / s.

[0076] Room temperature ionic conductivity test method: The solid electrolyte membrane is sandwiched between two stainless steel gaskets and connected to an electrochemical workstation for impedance testing at a frequency of 1MHz-0.1Hz.

[0077] The results are shown in Table 2. The stress-strain curve of the composite solid electrolyte membrane prepared in Example 1 is shown in Table 2. Figure 6 As shown, the linear sweep voltammetry curve is as follows: Figure 7 As shown, the Arrhenius curve is as follows: Figure 8 As shown.

[0078] Table 2

[0079] As shown in Table 2, in Application Examples 1-5, the tensile strength of the solid electrolyte membrane prepared with fibrous materials is 66-90 MPa, while the tensile strength of the solid electrolyte membrane prepared with other morphological materials in Comparative Examples 1-3 is 54-60 MPa. During battery cycling, the solid electrolyte may be subjected to different external forces. The greater the tensile strength, the better the electrolyte can resist external forces, avoid battery failure, and ensure the stable and reliable operation of the battery.

[0080] In Application Examples 1-5, the electrochemical window of the solid electrolyte prepared from the fibrous material is 4.2-4.8 V, while the electrochemical window of the solid electrolyte prepared from the other morphological materials in Comparative Examples 1-3 is 4.0-4.1 V. This broadened electrochemical window allows the solid electrolyte membrane to remain stable at higher potentials, avoiding side reactions caused by excessively high potentials. The solid electrolytes prepared in Examples 1-5 have a room temperature ionic conductivity of 5.64 × 10⁻⁶. -5 - 2.21×10 -4 Scm -1 In Comparative Examples 1-3, the room-temperature ionic conductivity of solid electrolytes prepared from other morphological materials was 3.75 × 10⁻⁶. -5 -4.81×10 -5 S cm -1 High ionic conductivity means less resistance to lithium ion migration in the electrolyte, allowing the battery to maintain high capacity and stability even under rapid charge and discharge conditions.

[0081] Test Example 3 The prepared composite solid electrolyte membrane was assembled into symmetrical cells and full cells for electrochemical performance testing and analysis.

[0082] The entire battery assembly process must be carried out in an argon-filled glove box. The assembly process for a symmetrical battery is as follows: the negative electrode shell, lithium sheet, composite solid electrolyte membrane, lithium sheet, and positive electrode shell are placed in sequence, and then placed in a packaging machine and pressurized to 50 MPa; the assembly process for a full battery is as follows: the negative electrode shell, lithium sheet, composite solid electrolyte membrane, lithium iron phosphate, and positive electrode shell are placed in sequence, and then placed in a packaging machine and pressurized to 50 MPa.

[0083] (1) Symmetrical cell test: at 0.1 mA cm -2 At the specified current density, the cells were charged for 1 hour, discharged for 1 hour, and then cycled. The test results are shown in Table 3. The cycle performance of the symmetric battery assembled using the composite solid electrolyte membrane prepared in Example 1 is shown in the figure below. Figure 9 As shown.

[0084] Table 3

[0085] As shown in Table 3, the stable cycle time of the symmetric batteries assembled using the composite solid electrolyte membranes prepared in Examples 1-5 was 1100-2000 h, with an overpotential of 50-60 mV. In contrast, the stable cycle time of the symmetric batteries assembled using the composite solid electrolyte membranes prepared in Comparative Examples 1-3 was 800-890 h, with an overpotential of 61-65 mV. High overpotentials lead to severe internal polarization of the battery, accelerate interfacial side reactions, induce dendrite growth, ultimately cause short circuits, and decrease cycle stability.

[0086] (2) Full battery test: Rate performance testing: The full battery was subjected to constant current charge and discharge tests under stepped current density conditions, with the voltage range being 2.5-4V.

[0087] Reversible specific capacity and cycle performance testing: Constant current charge-discharge testing and analysis were performed on the full battery. Test conditions: voltage range 2.5-4V.

[0088] Application Example 1: At stepped current densities of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 1C, 3C, and 5C, the reversible specific capacities were 151.2, 150.3, 149.2, 147.5, 143.2, 141.5, 116.4, and 108.9 mAh g, respectively. -1 Furthermore, the specific capacity can be recovered when returning to a low current density of 0.5C. Figure 10 ).

[0089] It can cycle stably for 500 cycles at a current density of 0.5C, with a capacity retention of 83.4%. Figure 11 ).

[0090] Application Example 2: At stepped current densities of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 1C, 3C, and 5C, the reversible specific capacities were 130.9, 127.3, 120.1, 116.4, 109.7, 101.5, 97.4, and 89.6 mAh g, respectively. -1 Furthermore, the specific capacity can be recovered when the current density returns to 0.5C.

[0091] It can cycle stably for 400 cycles at a current density of 0.5C with a capacity retention of 79.7%.

[0092] Application Example 3: At stepped current densities of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 1C, 3C, and 5C, the reversible specific capacities were 131.4, 129.1, 121.6, 119.8, 111.3, 105.7, 100.8, and 92.1 mAh g, respectively. -1 Furthermore, the specific capacity can be recovered when the current density returns to 0.5C.

[0093] It can cycle stably for 400 cycles at a current density of 0.5C with a capacity retention of 78.4%.

[0094] Application Example 4: At stepped current densities of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 1C, 3C, and 5C, the reversible specific capacities were 140.2, 137.4, 131.8, 128.5, 122.1, 117.2, 110.5, and 97.7 mAh g, respectively. -1 Furthermore, the specific capacity can be recovered when the current density returns to 0.5C.

[0095] It can cycle stably for 450 cycles at a current density of 0.5C with a capacity retention of 80.6%.

[0096] Application Example 5: At stepped current densities of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 1C, 3C, and 5C, the reversible specific capacities were 143.2, 140.7, 138.2, 135.5, 131.7, 128.5, 113.8, and 99.2 mAh g, respectively. -1 Furthermore, the specific capacity can be recovered when the current density returns to 0.5C.

[0097] It can cycle stably for 450 cycles at a current density of 0.5C with a capacity retention of 81.4%.

[0098] Application Comparative Example 1: At stepped current densities of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 1C, 3C, and 5C, the reversible specific capacities were 124.5, 121.1, 117.7, 113.9, 110.5, 108.9, 105.6, 96.2, and 79.3 mAh g, respectively. -1 Furthermore, the specific capacity can be recovered when the current density returns to 0.5C.

[0099] It can only cycle stably for 200 cycles at a current density of 0.5C, with a capacity retention of 56.4%. Application Comparative Example 2 At stepped current densities of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 1C, 3C, and 5C, the reversible specific capacities were 120.3, 118.7, 115.5, 111.9, 108.2, 104.6, 101.5, 91.8, and 72.1 mAh g, respectively. -1 .

[0100] It can only cycle stably for 180 cycles at a current density of 0.5C, with a capacity retention of 50.4%.

[0101] Application Comparative Example 3 At stepped current densities of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 1C, 3C, and 5C, the reversible specific capacities were 121.7, 119.1, 115.9, 112.5, 110.2, 107.9, 103.2, 98.6, and 79.4 mAh g, respectively. -1 .

[0102] It can only cycle stably for 200 cycles at a current density of 0.5C, with a capacity retention of 60.5%.

[0103] The results above show that the rate performance and cycle stability at 0.5C current density of the full cells assembled using the composite solid electrolyte membranes prepared in Examples 1-5 are superior to those of the full cells assembled using the composite solid electrolyte membranes prepared in Comparative Examples 1-3. This indicates that the full cells assembled using the composite solid electrolyte membranes prepared with fibrous materials have a longer service life, reducing the frequency of replacement; they also exhibit good stability, with the capacity fully recovering from a high rate to a low rate, demonstrating the robustness and reversibility of the material structure.

[0104] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a fibrous metal-organic framework material, characterized in that, The method includes: subjecting a soluble metal salt and an organic ligand to a hydrothermal reaction in the presence of a solvent and under alkaline conditions to obtain the fibrous metal-organic framework material; The soluble metal salt has a nickel ion as its metal cation; the organic ligand contains a hydroxyl functional group; and the hydrothermal reaction takes 2-24 hours.

2. The preparation method according to claim 1, wherein, The soluble metal salt is selected from at least one of sulfates, nitrates, halogenated salts, acetates, and carbonates; Preferably, the soluble metal salt is nickel nitrate hexahydrate; Preferably, the organic ligand is 2-hydroxyterephthalic acid; Preferably, the solvent is N,N-dimethylformamide; Preferably, the alkaline conditions are formed using an alkaline substance, which is preferably selected from at least one of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

3. The preparation method according to claim 1 or 2, wherein, The amount of the soluble metal salt used is 0.096-0.288 g relative to 20-60 mL of solvent; Preferably, the amount of the organic ligand used is 0.182-0.546 g relative to 20-60 mL of solvent; Preferably, the molar ratio of the metal cation to the organic ligand of the soluble metal salt is 0.1-10:1, more preferably 0.3-5:1, and even more preferably 0.33:

1.

4. The preparation method according to any one of claims 1-3, wherein, The temperature of the hydrothermal reaction is 50-500℃, preferably 100-200℃, and more preferably 110℃; Preferably, the hydrothermal reaction time is 6-24 hours, more preferably 18 hours; Preferably, the hydrothermal reaction is carried out under microwave conditions.

5. The fibrous metal-organic framework material obtained by the preparation method according to any one of claims 1-4.

6. The fibrous metal-organic framework material according to claim 5, wherein, The aspect ratio of the fibrous metal-organic framework material is 10-50000:1, preferably 40000-50000:1, and more preferably 48500:1; Preferably, the specific surface area of ​​the fibrous metal-organic framework material is 10-1000 m². 2 g -1 Preferably 150-235m 2 g -1 The optimal value is 233.57m. 2 g -1 .

7. The application of the fibrous metal-organic framework material according to claim 5 or 6 as a separator, solid electrolyte, binder, positive and negative electrode material, and other modified material in the preparation of metal batteries, secondary ion batteries, flexible batteries, capacitors, or hybrid energy storage devices.

8. A composite solid electrolyte membrane made from the fibrous metal-organic framework material as described in claim 5 or 6.

9. The composite solid electrolyte membrane according to claim 8, wherein, The thickness of the composite solid electrolyte membrane is 1-500 μm, preferably 200 μm; Preferably, the room temperature ionic conductivity of the composite solid electrolyte membrane is 1×10⁻⁶. -7 -1×10 -3 S cm -1 The preferred value is 2.21×10 -4 S cm -1 ; Preferably, the tensile strength of the composite solid electrolyte membrane is 0.5-100 MPa, more preferably 20-100 MPa, and even more preferably 90 MPa.

10. A lithium metal battery comprising the composite solid electrolyte membrane of claim 8 or 9.

Images