A zinc metal organic framework material, a preparation method and application thereof

Abstract

The application discloses a zinc metal organic framework material and a preparation method and application thereof, and relates to the technical field of energy materials.The application provides a preparation method of a zinc metal organic framework material, wherein a soluble zinc salt is used as a zinc source, dimethyl imidazole and pentaamino tetrazole are used as ligands, and a liquid phase reaction is performed to obtain the zinc metal organic framework material.A coating material based on the zinc metal organic framework material can protect a zinc negative electrode of a zinc ion battery, and can reduce irreversible consumption of the zinc negative electrode and electrolyte during battery cycle, thereby significantly delaying battery performance degradation.

Description

Technical Field

[0001] This invention relates to the field of energy materials technology, and in particular to a zinc metal-organic framework material, its preparation method, and its application. Background Technology

[0002] With the continued surge in global energy storage demand, the lithium-ion battery industry has experienced explosive growth, but the shortage of lithium resources is becoming increasingly prominent, directly leading to a continuous rise in raw material costs. Against this backdrop, new battery technologies have become a hot research topic in the industry. Among them, aqueous zinc-ion batteries (ZIBs) have attracted much attention due to their significant advantages such as high safety, low cost, and environmental friendliness. However, problems such as corrosion, gas generation, and dendrite growth in the zinc anode of this battery system severely restrict the cycle stability and lifespan of the battery, posing a bottleneck to its actual industrialization process.

[0003] Currently, strategies for suppressing zinc dendrites and side reactions mainly focus on two major directions: electrolyte modification and negative electrode coating modification. Comparatively, negative electrode coating technology has become a research focus due to its low cost, simple process, and environmental friendliness. However, traditional coating materials generally suffer from defects such as low ionic conductivity and severe interfacial polarization, which greatly affect the actual performance of batteries, necessitating technological breakthroughs. Summary of the Invention

[0004] The purpose of this invention is to provide a zinc metal-organic framework material, its preparation method, and its applications to solve the problems existing in the prior art. The zinc metal-organic framework nanosheet material (ZMF) provided by this invention is a two-dimensional metal-organic framework material. Coating materials based on this ZMF can protect the zinc anode of zinc-ion batteries, effectively isolating the zinc anode from direct contact with the electrolyte, suppressing side reactions, and simultaneously regulating the uniform deposition of zinc ions and inhibiting dendrite growth, thereby improving the overall performance of the battery.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] One of the technical solutions of this 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) was obtained by liquid-phase reaction using soluble zinc salt as the zinc source and dimethylimidazolium and pentaminetetrazole as ligands.

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

[0009] This invention utilizes a competitive coordination strategy to partially substitute dimethylimidazole with pentaaminotetrazole to regulate the morphology of MOFs, optimize the coordination concentration of the two ligands, and thus obtain zinc metal-organic framework nanosheets (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 ligands in methanol, stir and sonicate to completely dissolve them to obtain solution A;

[0012] (2) Dissolve the soluble zinc salt in methanol, stir and sonicate to completely dissolve it, and obtain solution B;

[0013] (3) Mix solution A and solution B and stir thoroughly, then carry out the liquid phase reaction under water bath conditions;

[0014] (4) The reaction system obtained in step (3) is filtered, washed, 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 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 preferred embodiment 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 this invention provides the application of the above-mentioned zinc metal-organic framework material in the preparation of zinc anode protective coating material for zinc-ion batteries.

[0021] The fourth technical solution of the present invention provides a zinc negative electrode protective coating material for zinc-ion batteries, comprising the above-mentioned zinc metal-organic framework material.

[0022] As a further preferred embodiment of the present invention, the zinc anode protective coating material of the zinc-ion battery also includes an adhesive.

[0023] The fifth technical solution of the present invention provides a method for protecting the zinc negative electrode of a zinc-ion battery. The zinc negative electrode of the zinc-ion battery is coated with the above-mentioned zinc negative electrode protective coating material, and after drying and curing, a protective coating is obtained 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 binder and dispersing them in a solvent to form a uniform slurry. The slurry is then coated on one side of the zinc anode surface of a zinc-ion battery. After drying and curing, the zinc anode protective coating of the zinc-ion battery is obtained.

[0025] As a further preferred embodiment of the present invention, the adhesive 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 anode of the zinc-ion battery is cleaned multiple times with ethanol, acetone and pure water before being coated with slurry.

[0029] As a further preferred embodiment of the present invention, the drying is performed using vacuum drying; the temperature of the vacuum drying is 60-80℃, and the time is 6-12h.

[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. This invention utilizes a competitive coordination strategy to synthesize a zinc metal-organic framework (ZMF) material using a liquid-phase method. The preparation method is simple, efficient, and can be scaled up.

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

[0034] 3. By using ZMF coating material to protect the zinc anode of zinc-ion batteries, the irreversible consumption of zinc anode and electrolyte can be reduced during battery cycling, significantly delaying battery performance degradation. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

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

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

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

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of 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 terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0042] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0043] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

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

[0045] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0046] Unless otherwise specified, the ambient temperature involved in this invention is 25±5℃.

[0047] Example 1: Preparation of ZMF

[0048] Weigh 7.1837 g (0.07483 mol) of dimethylimidazole and 1.063 g (0.00748 mol) of pentaaminotetrazole, and dissolve them in 250 ml of methanol. Sonicate for 5 min to ensure complete dissolution. Then weigh 4.587 g of zinc acetate (0.02091 mol) into 250 ml of methanol and sonicate for 5 min to ensure complete dissolution. The total concentration of ligands in the mixed solution is 0.1646 mol / L, with a molar ratio of dimethylimidazole to pentaaminotetrazole of 10:1 and a zinc ion concentration of 0.0414 mol / L. Mix the solutions in an Erlenmeyer flask, seal the flask, and heat in a water bath at 60 °C for 3 h. Wash the flask three times with methanol, and then dry it in a vacuum drying oven at 60 °C for 24 h to obtain pure ZMF.

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

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

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

[0052] Symmetrical battery performance test: at 25℃ with 1mA / cm 2 Surface current density, 1 mAh / cm 2 The battery was cycled at its capacity for room temperature performance testing. After 50 cycles, the battery was disassembled for characterization and analysis. The SEM image of the zinc anode surface after 50 cycles is shown below. Figure 3 As shown.

[0053] Figure 4 This is a comparison chart of cycle tests between the ZMF@Zn||ZMF@Zn symmetric cell (labeled ZMF) prepared based on ZMF in Example 1 of this invention and a symmetric cell assembled with bare zinc (BareZn). Figure 4 The cycling performance of the symmetric cells shows that the ZMF@Zn||ZMF@Zn symmetric cell prepared based on ZMF in Example 1 of this invention can cycle stably for more than 3000 hours, while the unprotected zinc symmetric cell has already short-circuited in less than 100 hours, proving that the ZMF protective coating has a good protective effect on the zinc anode.

[0054] Example 2

[0055] ZMF was prepared by liquid-phase method according to the method in Example 1. 200 mg of ZMF and 10 mg of binder (PVDF) were added to 20 ml of N-methylpyrrolidone and stirred at room temperature for 12 h. The resulting slurry was then spin-coated onto a zinc substrate. The zinc substrate coated with ZMF slurry was then dried in a vacuum drying oven at 60 °C for 12 h to obtain a ZMF@Zn negative electrode with a thinner coating of approximately 10 μm. Two ZMF@Zn negative electrodes were used as the positive and negative electrodes of the battery, respectively. A glass fiber filter membrane was used as the separator, and 2.0 M ZnSO4 solution was used as the electrolyte to assemble a CR2025 coin cell. The resulting electrode assembly was tested. The electrode using the ZMF coating exhibited more stable charge-discharge performance and a longer cycle life.

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

Claims

1. A method for preparing a zinc metal-organic framework material, characterized in that, Includes the following steps: The zinc metal-organic framework material was obtained by liquid-phase reaction using soluble zinc salt as the zinc source and dimethylimidazole and pentaminetetrazole as ligands. The molar ratio of dimethylimidazolium to pentaminotetrazole is (8-10):1; the molar ratio of zinc in the zinc source to the ligand is 1:(0.8~4); The liquid phase reaction is carried out at a temperature of 60-80℃ for 3-12 hours.

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

3. 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 0.01~0.1 mol / L.

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

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

6. The application of the zinc metal-organic framework material as described in claim 5 in the preparation of zinc anode protective coating materials for zinc-ion batteries.

7. A protective coating material for the zinc negative electrode of a zinc-ion battery, characterized in that, Contains the zinc metal-organic framework material as described in claim 5.

8. A method for protecting the zinc negative electrode of a zinc-ion battery, characterized in that, The zinc anode of a zinc-ion battery is coated with the zinc anode protective coating material of claim 7. After drying and curing, a protective coating is obtained, thereby protecting the zinc anode of the zinc-ion battery.

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