A coordination polymer nanowire separator material, preparation method and application in the field of sodium ion batteries

Abstract

The present invention specifically relates to a coordination polymer nanowire separator material, a preparation method thereof, and an application in the field of sodium-ion batteries. Aiming at the problems of low porosity, poor wettability, insufficient thermal stability, and difficulty in degradation existing in traditional polyolefin and glass fiber separators, the present invention proposes a method for preparing a separator material by using a transition metal compound and nitrilotriacetic acid as raw materials through a hydrothermal reaction. The separator can effectively improve the transmission efficiency of sodium ions, optimize the electrochemical performance of the battery, and its characteristics such as high temperature resistance (250 °C), high voltage window (4.8 V), and excellent liquid absorption significantly improve the safety and cycle performance of the battery. It provides an efficient, low-cost, and environmentally friendly separator solution for sodium-ion batteries and has important industrial application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium-ion battery materials, and particularly relates to a coordination polymer nanowire separator material, a preparation method thereof, and an application in the field of sodium-ion batteries. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present invention, and it is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Lithium-ion batteries are widely used in consumer electronics, electric vehicles, and energy storage systems due to their advantages such as high energy density and long cycle life. However, the scarcity and uneven distribution of lithium resources are very likely to hinder the subsequent development of the lithium battery industry and the new energy industry. Sodium and lithium are in the same main group, with similar properties, and are rich in reserves, evenly distributed, and inexpensive. Based on these advantages, sodium-ion batteries are regarded as an ideal choice for the next-generation large-scale energy storage technology.

[0004] As a key component of sodium-ion batteries, the separator not only plays a role in preventing short circuits between the positive and negative electrodes but also provides a channel for the transmission of sodium ions. Its properties play a decisive role in battery performance and safety. Currently, polyolefin separators and glass fiber separators are widely used in sodium-ion batteries. Among them, polyolefin separators (such as polyethylene PE and polypropylene PP) have problems such as low porosity, poor wettability, and poor thermal stability, and their raw materials rely on petroleum-based materials, resulting in high production costs. Although glass fiber separators have good wettability and thermal stability, their large thickness leads to an increase in battery internal resistance and a decrease in battery performance. In addition, the processing performance of glass fiber separators is poor, which limits their large-scale application in sodium-ion batteries. More importantly, both types of separators are difficult to degrade under natural environmental conditions and are prone to causing environmental pollution after being discarded, which is contrary to the concept of green environmental protection. The defects of commercial separators in terms of performance and process, especially the problems of high cost and non-degradability, make it difficult for sodium-ion batteries to meet the actual needs of people for energy storage batteries. Therefore, developing a low-cost and green degradable separator material has become the focus of current research. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a separator material suitable for sodium-ion batteries, to overcome the problems of low porosity, poor wettability, and poor thermal stability of existing polyolefin separators and glass fiber separators, and at the same time reduce the production cost of the separator material.

[0006] To achieve the above technical objectives, the present invention provides a method for preparing a coordination polymer nanowire separator material, using inexpensive iron and manganese metal compounds and organic ligands as the raw material system. In particular, industrial waste (such as iron rust) and low-cost nitrilotriacetic acid can be utilized as the core raw materials, and the preparation is achieved through a simple hydrothermal process without the need to configure complex equipment or add precious metal catalysts. Firstly, the production cost is controlled, and the reuse of waste industrial raw materials is realized. In addition, the above separator material also has excellent electrochemical performance, wetting performance, and high-temperature resistance characteristics, perfectly overcoming the deficiencies of existing separator materials.

[0007] Based on the above technical effects, the present invention provides the following technical solutions:

[0008] In the first aspect of the present invention, a method for preparing a coordination polymer nanowire separator material is provided, including the following steps:

[0009] (1) Disperse a transition metal compound and nitrilotriacetic acid in a mixed solvent of an organic solvent and water, and obtain a reaction solution through a hydrothermal reaction;

[0010] (2) Filter the reaction solution to obtain a white solid, and dry it overnight to obtain a solid powder;

[0011] (3) After dissociating the solid powder, disperse it in water, and obtain the coordination polymer nanowire separator material through papermaking and drying.

[0012] In the above step (1), the metal element in the transition metal compound can be selected from the elements in Groups 3 to 12 of the periodic table, including scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and other lanthanide elements, etc. The valence of the transition metal element in the compound is mainly +2 and +3. Since the above preparation method has no strict restrictions on the type of metal element in the transition metal compound, considering economic factors, those skilled in the art can conventionally select transition metal elements with lower costs and easier access, such as chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), etc.

[0013] Further, the chemical forms of the transition metal compounds include oxides, sulfides, halides, organic acid salts, inorganic acid salts, inorganic base salts, or organic base salts of the above-mentioned transition metal elements. Therefore, feasible examples of the transition metal compounds include ferrous oxide, iron oxide, iron sulfide, iron chloride, ferrous chloride, iron sulfate, ferrous sulfate, iron nitrate, ferrous nitrate, iron hydroxide, chromium sesquioxide, potassium chromate, chromium chloride, chromium sulfate, manganese monoxide, manganese dioxide, manganese sesquioxide, cobalt oxide, cobalt hydroxide, copper sulfate, copper hydroxide, copper nitrate, copper oxide, copper sulfide, cuprous chloride, copper bromide, nickel monoxide, nickel oxide, nickel hydroxide, nickel sulfate, nickel chloride, nickel nitrate, etc. Those skilled in the art can make a conventional selection from the above compounds based on factors such as the convenience and safety of raw material acquisition. For cost considerations, industrial wastes mainly composed of the above compounds can even be selected, such as rust, waste batteries, mineral wastes containing metals, etc.

[0014] Further, the organic solvent is preferably an alcohol or other organic reagent that can be miscible with water in any proportion. Feasible examples include isopropyl alcohol, ethylene glycol, N,N-dimethylformamide, ethanol, or methanol. In the mixed solvent, the volume ratio of water to the organic solvent is 1:3 to 10.

[0015] Furthermore, in the above step (1), the mass-volume ratio of the transition metal compound, nitrilotriacetic acid, and the mixed solvent is 0.2 g:(0.1 - 2) g:(20 - 80) mL.

[0016] Further, the temperature of the hydrothermal reaction is 80 - 180°C, more preferably 100 - 160°C; the reaction time is 6 - 48 h, more preferably 12 - 48 h.

[0017] In the above step (2), the preferred drying temperature is 60 - 110°C, and the drying time is 12 - 48 h; feasible drying methods include but are not limited to negative pressure drying, heat radiation drying, etc.

[0018] In the above step (3), the preferred dispersion ratio of the solid powder to water is 0.4 - 2 g:0.5 L. The defibration and papermaking are common processes in the paper-making industry for making pulp into paper. Those skilled in the art can use a defibrator or a paper-making machine to achieve this; after papermaking, it is dried at 60 - 110°C for 1 - 30 min to obtain a self-supporting film, and the separator material is obtained by stamping with a mold, and the preferred thickness is 25 - 125 μm.

[0019] In the second aspect of the present invention, a coordination polymer nanowire separator material prepared by the method described in the first aspect is provided.

[0020] The present invention has investigated the heat resistance, degradation performance, wetting performance and electrochemical performance of the above-mentioned coordination polymer nanowire separator material. After verification, the above-mentioned separator material can withstand high temperatures, and the upper limit temperature for use can reach 250 °C; it has good biodegradability, and the degradation rate exceeds 90% within 15 days in the natural environment, significantly reducing the environmental burden after battery disposal; and the above-mentioned separator material can also significantly improve the wetting effect of the electrolyte to ensure the free transmission of sodium ions during charge and discharge; when applied to sodium-ion batteries, the above-mentioned separator material has a higher voltage window (4.8 V), and the assembled button battery has excellent electrochemical performance.

[0021] In the third aspect of the present invention, there is provided an application of the coordination polymer nanowire separator material described in the second aspect in a sodium-ion battery.

[0022] In the fourth aspect of the present invention, there is provided a sodium-ion button battery using the coordination polymer nanowire separator material described in the second aspect as the separator.

[0023] The positive electrode of the sodium-ion button battery is prepared as follows: Prussian blue, carbon black and polyvinylidene fluoride are mixed, and N-methylpyrrolidone is added to make a uniform slurry, which is then coated on aluminum foil and dried to obtain the positive electrode.

[0024] The negative electrode of the sodium-ion button battery is a sodium metal sheet.

[0025] The electrolyte of the sodium-ion button battery is a ethylene carbonate / polycarbonate solution of NaClO 4 where the concentration of NaClO 4 is 0.8 - 1.2 M, the volume ratio of ethylene carbonate / polycarbonate is 1:1, and the electrolyte also contains 4.5 - 5.5% of fluoroethylene carbonate (FEC) as an additive.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The preparation method of the coordination polymer nanowire separator material provided by the present invention has the advantages of simple operation and wide raw material sources. In particular, the iron-based compound raw material can be taken from industrial waste (such as rust), and combined with the low-energy-consuming hydrothermal process, the comprehensive production cost is greatly reduced, providing a significant economic advantage for large-scale application.

[0028] 2. The coordination polymer nanowire separator material provided by the present invention has relatively small and orderly nanoporous structures, and the nanowire surface is rich in functional groups. As a separator material for sodium-ion batteries, it can effectively improve the transmission efficiency of sodium ions and optimize the electrochemical performance of the battery.

[0029] 3. In addition, the above-mentioned separator material also has good biodegradability, with a degradation rate exceeding 90% within 15 days in the natural environment, significantly reducing the environmental burden after battery disposal and conforming to the development concept of green environmental protection. By using low-cost raw materials and a simple process, the present invention not only realizes the economical production of the separator material but also solves the environmental problem of non-degradability of traditional separators, providing a new solution for the sustainable development of sodium-ion batteries and having important application significance in the field of battery separator materials, especially in the field of sodium-ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0031] Figure 1 Scanning electron microscope image of the coordination polymer nanowire separator material prepared in Example 1;

[0032] Figure 2 Heat resistance test results of the coordination polymer nanowire separator material prepared in Example 1, commercial glass fiber separator, and commercial polyolefin separator;

[0033] Figure 3 Degradability test results of the coordination polymer nanowire separator material prepared in Example 1, commercial glass fiber separator, and commercial polyolefin separator;

[0034] Among them, Figure 3 A is the initial morphology (0 days) of the three separators in the standard soil environment;

[0035] Figure 3 B is the morphology comparison after being buried for 3 days (under the same soil depth / humidity conditions);

[0036] Figure 3 C is the morphology comparison after being buried for 15 days (under the same soil depth / humidity conditions);

[0037] Figure 4 Contact angle test results of the coordination polymer nanowire separator material prepared in Example 1;

[0038] Among them, Figure 4 A shows the test state before the droplet contacts the separator surface at the initial state (0 seconds);

[0039] Figure 4 B shows the infiltration state of the droplet 0.05 seconds after contacting the separator surface;

[0040] Figure 5Linear sweep voltammetry test results of the button cell assembled with the coordination polymer nanowire separator material prepared in Example 1 and a commercial glass fiber separator;

[0041] Figure 6 Performance results of the coin cell assembled with the coordination polymer nanowire separator material prepared in Example 1 and a commercial glass fiber separator at a charge-discharge rate of 1 C.

[0042] Figure 7 Performance results of the coin full cell assembled with the coordination polymer nanowire separator material prepared in Example 1 and a hard carbon negative electrode at a charge-discharge rate of 1 C. Detailed implementation manners

[0043] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0044] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0045] In order to enable those skilled in the art to more clearly understand the technical solutions of the present invention, the technical solutions of the present invention will be described in detail below in combination with specific examples and comparative examples.

[0046] Example 1

[0047] In this example, a coordination polymer nanowire separator material is provided, and the preparation method of the material is as follows:

[0048] (1) Weigh 0.2 g of iron(III) oxide and 0.5 g of nitrilotriacetic acid, add 40 mL of a 1:3 water / isopropanol mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 160 °C and keep warm for 24 h to obtain a reaction solution;

[0049] (2) Filter the reaction solution, continuously inject a water / ethanol mixed solution for washing during the filtration process to obtain a white solid, and place the solid in a vacuum drying oven to dry overnight at 110 °C to obtain a dry white powder;

[0050] (3) Take 0.5 g of the obtained white powder, transfer it to 0.5 L of pure water, and disperse it completely by disintegration. Then, make paper from the dispersion liquid through a Kayser sheet former. After drying at 100 °C for 5 min, peel the self-supporting film from the surface of the filter screen, and the coordination polymer nanowire separator material can be obtained after stamping with a mold, which can be used as a separator for sodium-ion batteries.

[0051] Example 2

[0052] In this example, another coordination polymer nanowire separator material and its preparation method are provided. The difference from Example 1 is that step (1) is as follows: Weigh 0.2 g of iron(III) oxide and 0.5 g of nitrilotriacetic acid, add 40 mL of a 1:10 water / isopropanol mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 160 °C and keep it warm for 24 h to obtain a reaction solution.

[0053] Example 3

[0054] In this example, another coordination polymer nanowire separator material and its preparation method are provided. The difference from Example 1 is that step (1) is as follows: Weigh 0.2 g of iron(III) oxide and 0.5 g of nitrilotriacetic acid, add 40 mL of a 1:3 water / ethylene glycol mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 100 °C and keep it warm for 48 h to obtain a reaction solution.

[0055] Example 4

[0056] In this example, another coordination polymer nanowire separator material and its preparation method are provided. The difference from Example 1 is that step (1) is as follows: Weigh 0.2 g of iron(III) oxide and 0.5 g of nitrilotriacetic acid, add 40 mL of a 1:3 water / N,N-dimethylformamide mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 120 °C and keep it warm for 48 h to obtain a reaction solution.

[0057] Example 5

[0058] In this example, another coordination polymer nanowire separator material and its preparation method are provided. The difference from Example 1 is that step (1) is as follows: Weigh 0.2 g of ferric chloride and 0.5 g of nitrilotriacetic acid, add 40 mL of a 1:3 water / isopropanol mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 160 °C and keep it warm for 12 h to obtain a reaction solution.

[0059] Example 6

[0060] In this example, another coordination polymer nanowire separator material and its preparation method are provided. The difference from Example 1 is that step (1) is as follows: Weigh 0.2 g of ferrous sulfate and 0.2 g of nitrilotriacetic acid, add 40 mL of a 1:3 water / isopropanol mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 160 °C and keep warm for 12 h to obtain a reaction solution.

[0061] Example 7

[0062] In this example, another coordination polymer nanowire separator material and its preparation method are provided. The difference from Example 1 is that step (1) is as follows: Weigh 0.2 g of ferrous chloride and 0.2 g of nitrilotriacetic acid, add 40 mL of a 1:3 water / isopropanol mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 160 °C and keep warm for 12 h to obtain a reaction solution.

[0063] Example 8

[0064] In this example, another coordination polymer nanowire separator material and its preparation method are provided. The difference from Example 1 is that step (1) is as follows: Weigh 0.2 g of manganese chloride and 0.2 g of nitrilotriacetic acid, add 40 mL of a 1:3 water / isopropanol mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 160 °C and keep warm for 12 h to obtain a reaction solution.

[0065] Example 9

[0066] In this example, another coordination polymer nanowire separator material is provided. The preparation method of the material is as follows:

[0067] (1) Weigh 0.2 g of ferric oxide and 0.1 g of nitrilotriacetic acid, add 20 mL of a 1:3 water / isopropanol mixed solvent, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 160 °C and keep warm for 24 h to obtain a reaction solution;

[0068] (2) Filter the reaction solution, continuously inject a water / ethanol mixed solution for washing during the filtration process to obtain a white solid. Put the solid into a vacuum drying oven and dry it at 60 °C for 48 h to obtain a dried white powder;

[0069] (3) Take 0.4 g of the obtained white powder, transfer it to 0.5 L of pure water, disperse it completely by deflocculation, pass the dispersion through a Kayser sheet former for papermaking, dry it at 60 °C for 30 min, then peel the self-supporting film from the surface of the filter screen, and after stamping with a mold, a separator for sodium-ion batteries can be prepared.

[0070] Example 10

[0071] In this example, another coordination polymer nanowire separator material is provided, and the preparation method of the material is as follows:

[0072] (1) Weigh 0.2 g of iron(III) oxide and 2 g of nitrilotriacetic acid, add 80 mL of a 1:3 mixed solvent of water / isopropanol, stir magnetically until a homogeneous solution is formed, transfer it to a polytetrafluoroethylene reaction kettle, heat to 160 °C and keep warm for 24 h to obtain a reaction solution;

[0073] (2) Filter the reaction solution, continuously inject a mixed solution of water / ethanol for washing during the filtration process to obtain a white solid, put the solid into a vacuum drying oven and dry it overnight at 110 °C to obtain a dry white powder;

[0074] (3) Take 2 g of the obtained white powder, transfer it to 0.5 L of pure water, disperse it completely by defibration, make the dispersion sheet paper through a Kajaani sheet former, peel the self-supporting film from the surface of the filter screen after drying at 110 °C for 1 min, and a separator for sodium-ion batteries can be prepared after stamping with a mold.

[0075] Comparative Example 1

[0076] The used comparative example is commercial Whatman glass fiber.

[0077] Performance Test

[0078] Cut the separators prepared in Examples 1-8 and Comparative Example 1 into circular pieces with a diameter of 19 mm, and use them as separators for sodium-ion batteries respectively. Mix Prussian blue, carbon black and polyvinylidene fluoride in a mass ratio of 7:2:1, add N-methylpyrrolidone and grind them in a mortar to make a uniform slurry, coat it on aluminum foil, and dry it in a vacuum drying oven at 110 °C. Cut the electrode sheet into circular pieces with a diameter of 12 mm as the positive electrode of the sodium-ion battery, use a sodium sheet as the negative electrode of the sodium-ion battery, and the electrolyte is prepared by dissolving 1 M of NaClO 4 in a mixed solvent of ethylene carbonate (EC) and polycarbonate (PC) (volume ratio 1:1), and add 5% of fluoroethylene carbonate (FEC) as an additive. For the full battery, use hard carbon as the negative electrode of the sodium-ion battery. Assemble the battery in a glove box filled with argon, with a moisture content lower than 0.01 ppm and an oxygen content lower than 0.01 ppm. After assembly, perform a performance test on the charge-discharge specific capacity of the battery.

[0079] Figure 1Scanning electron microscope image of the coordination polymer nanowire separator material prepared in Example 1. It can be seen that the separator material is a one-dimensional coordination polymer nanowire, formed by the stacking and crossing of numerous slender nanowires. Moreover, the surface of the nanowires has fine and ordered nanopore structures, and the length of the nanowires can reach 50 μm.

[0080] Figure 2 Results of the heat resistance test. Heat resistance test conditions: Polyolefin separator (PP), the coordination polymer nanowire separator (Fe-NTA) prepared in Example 1, and the commercial Whatman glass fiber (GF / D) in Comparative Example 1 were respectively placed on an infrared microcrystalline heating plate, and gradually heated from room temperature to 200 °C at intervals of 25 °C, and kept constant at each temperature point for 1 hour, and the deformation state was recorded with a grid background. Experiments show that: Fe-NTA has no visible deformation before 150 °C, which is better than the failure threshold of 125 °C of PP. At 200 °C, both Fe-NTA and GF / D maintain their complete morphology, but GF / D is an inorganic material (inherent heat resistance), while the organic coordination structure of Fe-NTA still remains stable at this temperature.

[0081] Figure 3 Results of the degradability test. Degradability test conditions: Fe-NTA, PP, and GF / D were respectively buried at the same depth in the flower pot soil, and the degradation of the above-mentioned separator materials was dug out and recorded at regular intervals. As Figure 3 shown, Fe-NTA can be degraded in the natural environment and has been completely degraded in 15 days.

[0082] Figure 4 Results of the contact angle test. Contact angle test conditions: Using a contact angle measuring instrument, with ethanol as the test liquid, and a high-speed imaging system to record the droplet contact process. Figure 4 A (0 s) is the initial state before droplet contact, showing the critical contact point of the complete hemispherical droplet and the separator surface; Figure 4 B (0.05 s) captures the wetting behavior immediately after droplet contact. The edge of the droplet spreads radially, and the contact angle drops sharply to 28°, proving that Fe-NTA can induce the droplet to achieve ultra-fast wetting on a millisecond time scale.

[0083] Figure 5 Results of the linear sweep voltammetry test of the button battery. Linear sweep voltammetry test conditions: Sodium metal negative electrode / stainless steel positive electrode symmetric battery structure, test voltage range 0 - 6 V, scan rate 0.001 V / s (Chenhua electrochemical workstation). The voltage window of GF / D is 4.6 V, while the voltage window of Fe-NTA reaches 4.8 V, indicating that the latter has a wider working voltage range.

[0084] Figure 6Charge-discharge specific capacities of sodium-ion batteries assembled with Fe-NTA and GF / D respectively at a current density of 1 C. The results show that after 500 cycles, the capacity retention rate of the sodium-ion battery assembled with Fe-NTA is 75.6%, while that of the sodium-ion battery assembled with GF / D is 60.9%. It indicates that the coordination polymer nanowire separator material provided by the present invention can effectively improve the service life of sodium-ion batteries as a separator material.

[0085] Figure 7 Performance results of a button-type full battery assembled with Fe-NTA and a hard carbon negative electrode (PBA||HC) charged and discharged at 1 C: The first-cycle discharge capacity of this battery is 67.1 mAh g −1 , and it still maintains 60.7 mAh g −1 after 100 cycles, and the capacity retention rate reaches 90.5%. It proves the optimization effect of the coordination polymer nanowire separator material provided by the present invention on the electrochemical performance in a complete battery system.

[0086] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a coordination polymer nanowire membrane material, characterized in that: The steps include: (1) dispersing a transition metal compound and nitrilotriacetic acid in a mixed solvent of an organic solvent and water, wherein the mass volume ratio of the transition metal compound, nitrilotriacetic acid, and the mixed solvent is 0.2 g: 0.1-2 g: 20-80 mL; and subjecting the mixture to a hydrothermal reaction to obtain a reaction solution; The transition metal compound is selected from one of ferric oxide, ferric chloride, ferrous sulfate, ferrous chloride, and manganese chloride. The temperature of the hydrothermal reaction is 100-160° C. and the reaction time is 12-48 hours. (2) filtering the reaction solution to obtain a white solid, and drying overnight to obtain a solid powder; (3) The solid powder is dispersed in water after being dispersed, and the coordination polymer nanowire membrane material is obtained by papermaking and drying.

2. The method for preparing the coordination polymer nanowire membrane material according to claim 1, characterized in that: In step (1), the organic solvent is selected from isopropanol, ethylene glycol, N,N-dimethylformamide, ethanol or methanol; in the mixed solvent, the volume ratio of water to the organic solvent is 1:3-10.

3. The method for preparing the coordination polymer nanowire membrane material according to claim 1, characterized in that: In step (2), the drying temperature is 60-110° C. and the drying time is 12-48 h.

4. The method for preparing the coordination polymer nanowire membrane material according to claim 1, characterized in that: In step (3), the dispersion ratio of the solid powder to water is 0.4-2 g:0.5 L.

5. The method for preparing the coordination polymer nanowire membrane material according to claim 1, characterized in that: In step (3), after papermaking is completed, the paper is dried at 60-110° C. for 1-30 min to obtain a self-supporting film, which is then punched through a mold to obtain the diaphragm material with a thickness of 25-125 μm.

6. The coordination polymer nanowire membrane material prepared by the method according to any one of claims 1 to 5.

7. Use of the coordination polymer nanowire diaphragm material according to claim 6 in sodium ion batteries.

8. A sodium ion button battery, characterized in that: The coordination polymer nanowire diaphragm material according to claim 6 is used as a diaphragm.

9. The sodium ion button battery according to claim 8, characterized in that: The positive electrode of the sodium ion button battery is prepared as follows: Prussian blue, carbon black and polyvinylidene fluoride are mixed, N-methylpyrrolidone is added to prepare a uniform slurry, which is coated on an aluminum foil and dried to obtain the positive electrode.

10. The sodium ion button battery according to claim 8, characterized in that: The negative electrode of the sodium ion button battery is a sodium metal sheet; The electrolyte of the sodium ion button battery is a NaClO4 ethylene carbonate / polycarbonate solution, wherein the concentration of NaClO4 is 0.8-1.2M, the volume ratio of ethylene carbonate / polycarbonate is 1:1, and the electrolyte also contains 4.5-5.5% fluoroethylene carbonate as an additive.

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