Zinc metal organic framework material as well as preparation method and application thereof

Abstract

The invention discloses a zinc metal organic framework material as well as a preparation method and application thereof, and relates to the technical field of energy materials. The invention provides a preparation method of a zinc metal organic framework material, which takes soluble zinc salt as a zinc source and dimethylimidazole and pentaamino tetrazole as ligands, and is prepared by liquid phase reaction. The coating material based on the zinc metal organic framework material can realize the protection of the zinc negative electrode of the zinc ion battery, can reduce the irreversible consumption of the zinc negative electrode and electrolyte in the cycle process of the battery, and obviously delays the performance degradation of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of energy materials, and in particular to a zinc metal organic framework material and a preparation method and application thereof. Background Art

[0002] With the continued surge in global demand for energy storage, the lithium-ion battery industry has experienced explosive growth, but the shortage of lithium resources it faces has become increasingly prominent, directly leading to rising raw material costs. Against this backdrop, new battery technologies have become a hot topic in industry research. Among them, aqueous zinc-ion batteries (ZIBs) have attracted much attention from all walks of life due to their significant advantages such as high safety, low cost, and environmental friendliness. However, problems such as corrosion, gas production, and dendrite growth of the zinc negative electrode in this battery system have seriously restricted the battery's cycle stability and service life, causing it to face bottlenecks in the actual industrialization process.

[0003] Currently, strategies to suppress zinc dendrites and side reactions primarily focus on electrolyte modification and anode coating modification. Anode coating technology, by comparison, has become a research priority due to its low cost, simple process, and environmental friendliness. However, conventional coating materials commonly suffer from defects such as low ionic conductivity and severe interfacial polarization, significantly impacting battery performance and necessitating technological breakthroughs. Summary of the Invention

[0004] The present invention aims to provide a zinc metal organic framework material, its preparation method, and its application to address the problems of the prior art. The zinc metal organic framework nanosheet material (ZMF) provided by the present invention is a two-dimensional metal organic framework material. A coating material based on this ZMF can protect the zinc negative electrode of a zinc ion battery, effectively isolating the zinc negative electrode from direct contact with the electrolyte, inhibiting the occurrence of side reactions, and regulating the uniform deposition of zinc ions to inhibit dendrite growth, thereby improving the overall performance of the battery.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is to provide a method for preparing a zinc metal organic framework material, comprising the following steps:

[0007] The zinc metal organic framework nanosheet material (ZMF) is obtained by using a soluble zinc salt as a zinc source, dimethylimidazole and pentaaminotetrazole as ligands through a liquid phase reaction.

[0008] As a further preferred embodiment of the present invention, the molar ratio of dimethylimidazole (DMI) to pentaaminotetrazole (PAT) is (8-10):1; and the molar ratio of zinc in the zinc source to the ligand is 1:(0.8-4).

[0009] The present invention utilizes a competitive coordination strategy to partially replace dimethylimidazole with pentaaminotetrazole to achieve regulation of MOF morphology, optimize the coordination concentration of the two ligands, and thus obtain zinc metal organic framework nanosheet materials (ZMF).

[0010] As a further preferred embodiment of the present invention, ZMF can be prepared by the following steps:

[0011] (1) Dissolve DMI and PAT ligand in methanol, stir and sonicate to completely dissolve them to obtain solution A;

[0012] (2) dissolving a soluble zinc salt in methanol, stirring and ultrasonicating the solution to completely dissolve the solution, to obtain solution B;

[0013] (3) Solution A and Solution B are mixed and stirred thoroughly, and then a liquid phase reaction is carried out in a water bath;

[0014] (4) The reaction system obtained in step (3) is filtered, cleaned, and dried to obtain ZMF.

[0015] As a further preferred embodiment of the present invention, the temperature of the liquid phase reaction is 60-80° C. and the reaction time is 3-12 hours.

[0016] As a further preferred embodiment of the present invention, the soluble zinc salt is zinc acetate and / or zinc nitrate.

[0017] As a further preferred embodiment of the present invention, when the liquid phase reaction is carried out, the concentration of the soluble zinc salt in the reaction system is 0.01 to 0.1 mol / L.

[0018] As a further preference of the present invention, the solvent used in the liquid phase reaction is methanol and / or ethanol.

[0019] The second technical solution of the present invention: provides a zinc metal organic framework material prepared by the above preparation method.

[0020] The third technical solution of the present invention is to provide the application of the above-mentioned zinc metal organic framework material in the preparation of zinc negative electrode protective coating material for zinc ion batteries.

[0021] The fourth technical solution of the present invention is to provide a zinc negative electrode protective coating material for a zinc ion battery, which contains the above-mentioned zinc metal organic framework material.

[0022] As a further preferred embodiment of the present invention, the zinc negative electrode protective coating material for zinc ion batteries further includes a binder.

[0023] The fifth technical solution of the present invention is to provide a method for protecting the zinc negative electrode of a zinc ion battery, wherein the zinc negative electrode of the zinc ion battery is coated with the above-mentioned zinc negative electrode protective coating material, and a protective coating is obtained after drying and curing to protect the zinc negative electrode of the zinc ion battery.

[0024] Furthermore, the coating of the present invention is prepared by mixing ZMF and a binder and dispersing them in a solvent to form a uniform slurry, and then coating the slurry on one side of the surface of the zinc negative electrode of the zinc ion battery. After drying and curing, the zinc negative electrode protective coating of the zinc ion battery is obtained.

[0025] As a further preferred embodiment of the present invention, the binder is one or more of PVDF, CMC and PVA.

[0026] As a further preferred embodiment of the present invention, the mass ratio of ZMF to binder is (20-5):1.

[0027] As a further preferred embodiment of the present invention, the coating is performed by spin coating, scraping coating or spraying.

[0028] As a further preferred embodiment of the present invention, the zinc negative electrode of the zinc ion battery is washed multiple times with ethanol, acetone and pure water before slurry coating.

[0029] As a further preferred embodiment of the present invention, the drying is performed by vacuum drying; the temperature of the vacuum drying is 60-80° C., and the time is 6-12 hours.

[0030] As a further preferred embodiment of the present invention, the thickness of the protective coating obtained after drying and curing is 10-60 μm.

[0031] The present invention discloses the following technical effects:

[0032] 1. The present invention utilizes a competitive coordination strategy and a liquid phase method to synthesize a zinc metal organic framework material (ZMF). The preparation method is simple and efficient and can be prepared on a large scale.

[0033] 2. The coating material based on the zinc metal organic framework material of the present invention can protect the zinc negative electrode of the zinc ion battery. On the one hand, it can effectively isolate the direct contact between the zinc metal and the electrolyte. On the other hand, the abundant pores and active sites can provide channels for the rapid transmission of Zn2+, reduce the energy barrier of ion migration, thereby guiding and promoting the uniform deposition of Zn2+ and inhibiting the growth of dendrites and the occurrence of side reactions.

[0034] 3. After the zinc negative electrode of the zinc ion battery is coated with ZMF coating material, the irreversible consumption of the zinc negative electrode and electrolyte can be reduced during the battery cycle, significantly delaying the battery performance degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is the SEM image of the ZMF prepared in Example 1 of the present invention.

[0037] Figure 2 This is a cross-sectional SEM image of the ZMF@Zn negative electrode based on the ZMF in Example 1 of the present invention.

[0038] Figure 3 This is an SEM image of the zinc substrate disassembled after 50 cycles of the ZMF@Zn||ZMF@Zn symmetric battery based on the ZMF in Example 1 of the present invention.

[0039] Figure 4 This is a comparison chart of the cycle tests of the ZMF@Zn||ZMF@Zn symmetric battery prepared based on ZMF in Example 1 of the present invention and the symmetric battery assembled with bare zinc. DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0042] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0043] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0044] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0045] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0046] Unless otherwise specified, the room temperature mentioned in the present invention is 25±5°C.

[0047] Example 1 Preparation of ZMF

[0048] 7.1837g (0.07483mol) of dimethylimidazole and 1.063g (0.00748mol) of pentaaminotetrazole were weighed and dissolved in 250ml of methanol. Ultrasonication was performed for 5min to fully dissolve them. Then, 4.587g of zinc acetate (0.02091mol) was weighed and added to 250ml of methanol. Ultrasonication was performed for 5min to fully dissolve them. The total concentration of the ligands in the mixed solution system was 0.1646mol / L, the molar ratio of dimethylimidazole to pentaaminotetrazole was 10:1, and the zinc ion concentration was 0.0414mol / L. The mixture was then mixed in a conical flask and sealed. The mixture was heated in a water bath at 60°C for 3h, then washed three times with methanol and dried in a vacuum oven at 60°C for 24h to obtain pure ZMF.

[0049] Figure 1 This is the SEM image of the ZMF prepared in Example 1 of the present invention.

[0050] Preparation of the ZMF@Zn anode: 200 mg of the ZMF prepared in Example 1 and 20 mg of a binder (PVDF) were added to 6 ml of nitrogen-methylpyrrolidone and stirred at room temperature for 12 hours. The resulting slurry was coated on a metallic zinc substrate by doctor blade coating. The metallic zinc substrate was washed sequentially with ethanol, acetone, and pure water. The zinc substrate coated with the ZMF slurry was then placed in a vacuum oven and dried at 60°C for 12 hours to obtain a ZMF@Zn anode (coating thickness: 20 μm). Figure 2 This is the cross-sectional SEM image of the prepared ZMF@Zn negative electrode.

[0051] Battery assembly: Two ZMF@Zn negative electrodes were used as the positive and negative electrodes of the battery, respectively, with a glass fiber filter membrane as the separator and a 2.0 M ZnSO4 solution as the electrolyte to assemble into a CR2025 button cell (ZMF@Zn||ZMF@Zn symmetrical battery).

[0052] Symmetrical battery performance test: at 25°C at 1 mA / cm 2 The surface current density is 1 mAh / cm 2 The capacity of the battery was cycled and the room temperature cycle performance test was performed. After 50 cycles, the battery was disassembled for characterization and analysis. The SEM image of the zinc negative electrode surface after 50 cycles is shown in Figure 2. Figure 3 shown.

[0053] Figure 4 The figure is a comparison of the cycle test of the ZMF@Zn||ZMF@Zn symmetrical battery (marked as ZMF) prepared based on ZMF in Example 1 of the present invention and the symmetrical battery assembled with bare zinc (BareZn). Figure 4 It can be seen from the symmetrical battery cycling performance that the ZMF@Zn||ZMF@Zn symmetrical battery prepared based on the ZMF in Example 1 of the present invention can stably cycle for more than 3000 hours, while the unprotected zinc symmetrical battery has a short circuit in less than 100 hours, proving that the ZMF protective coating has a good protective effect on the zinc negative electrode.

[0054] Example 2

[0055] ZMF was prepared by a liquid phase method according to the method of Example 1. 200 mg of ZMF and 10 mg of a binder (PVDF) were taken, 20 ml of nitrogen methyl pyrrolidone was added, and the mixture was stirred at room temperature for 12 h. The obtained slurry was applied to a metal zinc substrate by spin coating, and the zinc substrate coated with the ZMF slurry was then placed in a vacuum drying oven and dried at 60 ° C for 12 h to obtain a ZMF@Zn negative electrode with a thinner coating thickness of about 10 μm. Two pieces of ZMF@Zn negative electrodes were used as the positive and negative electrodes of the battery, respectively, with a glass fiber filter membrane as a separator and a 2.0 M ZnSO4 solution as the electrolyte. A CR2025 button cell was assembled and the obtained electrodes were assembled into a battery for testing. The electrodes coated with ZMF showed more stable charge and discharge performance and had a longer cycle life.

[0056] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a zinc metal organic framework material, characterized in that: The following steps are involved: The zinc metal organic framework material is obtained by taking a soluble zinc salt as a zinc source, dimethylimidazole and pentaaminotetrazole as ligands through liquid phase reaction.

2. The preparation method according to claim 1, characterized in that The molar ratio of the dimethylimidazole to pentaaminotetrazole is (8-10):1; the molar ratio of the zinc in the zinc source to the ligand is 1:(0.8-4).

3. The preparation method according to claim 1, characterized in that The temperature of the liquid phase reaction is 60-80° C., and the reaction time is 3-12 hours.

4. The preparation method according to claim 1, characterized in that The soluble zinc salt is zinc acetate and / or zinc nitrate.

5. The preparation method according to claim 1, characterized in that When the liquid phase reaction is carried out, the concentration of the soluble zinc salt in the reaction system is 0.01 to 0.1 mol / L.

6. The preparation method according to claim 1, characterized in that The solvent used in the liquid phase reaction is methanol and / or ethanol.

7. The zinc metal organic framework material prepared by the preparation method according to claims 1-6.

8. Use of the zinc metal organic framework material as claimed in claim 7 in preparing a zinc negative electrode protective coating material for zinc ion batteries.

9. A zinc negative electrode protective coating material for a zinc ion battery, characterized in that: Contains the zinc metal organic framework material according to claim 7.

10. A zinc negative electrode protection method for a zinc ion battery, characterized in that: The zinc negative electrode protective coating material for a zinc ion battery according to claim 9 is used to coat the zinc negative electrode of the zinc ion battery, and a protective coating is obtained after drying and curing to protect the zinc negative electrode of the zinc ion battery.

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