Zinc negative electrode based on MOF material modification and preparation and application thereof

Abstract

The invention belongs to the technical field of zinc ion batteries, and provides a zinc negative electrode based on MOF material modification as well as preparation and application. According to the preparation method of the zinc negative electrode based on MOF material modification, provided by the invention, an MOF interface layer with a three-dimensional porous structure can be formed on the surface of the zinc substrate, so that the zinc negative electrode has high specific surface area, porosity and higher chemical stability. The zinc negative electrode MOF interface layer Zn-BTC structure prepared by the method comprises three carboxyl groups, oxygen atoms in the carboxyl groups have high electronegativity and can generate a remarkable electrostatic attraction effect with zinc ions with positive charges, and the electrostatic attraction effect can guide the zinc ions to perform ordered deposition, so that the growth of zinc dendrites is effectively inhibited, and the service life of the zinc negative electrode is prolonged. And the cycling stability of the zinc negative electrode battery is obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of zinc ion batteries, and in particular to a zinc negative electrode modified based on MOF materials and its preparation and application. Background Art

[0002] At present, various types of aqueous metal ion batteries have been developed, such as zinc ion batteries, sodium ion batteries, potassium ion batteries, aluminum ion batteries, etc. Compared with other active metals, zinc metal has a suitable redox potential (-0.76V) and excellent Zn / Zn 2+ The reversibility of the Zn anode makes it possible to directly use it as the negative electrode. In addition, compared with other active metals, Zn metal has good tolerance to oxygen and humid atmosphere. At the same time, the Zn negative electrode also has a high theoretical capacity (820 mAh g -1 and 5854mAhcm -3 ) inherent advantages. Zinc's high natural abundance (about 300 times that of lithium) and good tolerance make zinc cheap to purchase and process, which also makes the prospect of zinc-ion batteries for industrial production satisfying. Although aqueous zinc batteries based on metallic zinc anodes have the advantages of high theoretical energy density, intrinsic safety and low cost, there are still problems that need to be solved in aqueous zinc-ion batteries.

[0003] First, similar to lithium metal, Zn 2+ There is also the problem of uneven ion flux during the deposition and dissolution process, and dendrites are easily formed during the cycle. The growth of dendrites may cause battery performance degradation or even pierce the separator and cause battery short circuit. Secondly, since metallic zinc is thermodynamically active in aqueous electrolytes, side reactions will occur at the interface between zinc and electrolytes, which manifests as zinc corrosion and hydrogen evolution reaction in slightly acidic electrolytes. Although the high overpotential of zinc anode for hydrogen evolution reaction can inhibit H 2 However, the low-rate hydrogen evolution reaction still consumes the negative electrode. 2 The precipitation of OH in the electrolyte will - The concentration changes and byproducts are generated on the surface of the zinc negative electrode. The continuous side reactions not only damage the electrode surface and promote the growth of dendrites, but also consume the electrolyte. The growth of zinc dendrites increases the surface area of ​​contact between the electrode and the electrolyte and also accelerates the occurrence of side reactions. These are key issues that affect the performance of the zinc negative electrode and hinder the further development of zinc-ion batteries.

[0004] In recent years, solutions to the zinc metal anode problem have emerged, such as constructing an interface protection layer, electrode structure design, electrolyte regulation, and diaphragm optimization. For example, Yang et al. studied the effect of the interface modification layer of the Mg-Al layered double hydroxide zinc anode on the electrochemical performance of zinc ion batteries (Yang, et al. Redistributing Zn-ion flux by interlayer ion channels in Mg-Al layered double hydroxide-based artificial solid electrolyte interface for ultra-stable and dendrite-free Zn metalanodes. Energy Storage Materials 41 (2021): 230-239.). The test results showed that the prepared symmetric battery had a current density of 1 mA cm -2 , with a capacity of 1 mAh cm -2 Under the conditions, its cycle time is 400h, which can effectively improve the cycle stability of the battery. The Mg-Al layered double hydroxide layer constructed by this invention can effectively weaken the side reactions between zinc metal and electrolyte, and realize the high reversibility of zinc negative electrode, but there are still problems such as high internal resistance, slow ion migration rate and low cycle life. For example, the bimetallic ZnTi-MOF as the interface modification layer of zinc metal negative electrode can reduce polarization and hydrogen evolution corrosion side reactions, thereby improving the utilization rate and cycle life of the battery. However, the synthesis complexity of bimetallic doped MOF materials as zinc negative electrodes is relatively high, and the ratio and distribution of the two metals need to be precisely controlled. The synthesis process is more complicated and the cost is increased; at the same time, the two metals may be unevenly distributed, affecting the structural stability and performance consistency. In the short term, the performance of bimetallic doped MOF materials as zinc negative electrodes is excellent, but from the perspective of long-term stability, as the number of cycles increases, metal migration or dissolution may cause structural stability to be destroyed, and the battery life is not stable.

[0005] Therefore, it is urgent to develop a zinc negative electrode with a new interface modification layer to promote the efficient migration of zinc ions, provide abundant active sites, and optimize the stability and cycle performance of zinc negative electrode batteries. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a zinc negative electrode modified based on MOF material and its preparation and application.

[0007] The present invention provides a method for preparing a zinc negative electrode based on MOF material modification, comprising:

[0008] Solution A was prepared by dissolving zinc nitrate hexahydrate in ethanol;

[0009] Dissolve trimesic acid in N,N-dimethylformamide to prepare solution B;

[0010] Solutions A and B were subjected to hydrothermal treatment, washed, and first vacuum dried to obtain Zn-BTC powder;

[0011] Mixing a binder, Zn-BTC and N-methylpyrrolidone to obtain a slurry;

[0012] The slurry is coated on the surface of the zinc substrate, and after a second vacuum drying, a zinc negative electrode with a MOF interface layer on the surface is obtained.

[0013] Preferably, the mass ratio of the zinc nitrate hexahydrate to trimesic acid is 0.5-2:0.5-1.

[0014] Preferably, the hydrothermal treatment temperature is 80-120° C., and the hydrothermal treatment time is 5-12 hours.

[0015] Preferably, the washing reagent is ethanol, the washing times are 1 to 3 times; the first vacuum drying temperature is 60 to 100° C., and the first vacuum drying time is 8 to 16 hours.

[0016] Preferably, the mass concentration of Zn-BTC in the slurry is in the range of 120 to 200 mg / mL. -1 .

[0017] Preferably, the mass ratio of the binder to Zn-BTC is 1:4 to 1:9.

[0018] Preferably, the binder comprises polyvinylidene fluoride and / or polytetrafluoroethylene.

[0019] Preferably, the second vacuum drying temperature is 60-100° C., and the second vacuum drying time is 8-16 hours.

[0020] The present invention provides a zinc negative electrode, which is prepared by the above method and comprises a zinc negative electrode and a MOF interface layer coated on the surface, wherein the MOF interface layer is composed of Zn-BTC.

[0021] The present invention also provides the use of the zinc negative electrode prepared by the above method in an aqueous zinc ion battery.

[0022] Beneficial effects:

[0023] The present invention provides a method for preparing a zinc negative electrode based on MOF material modification. By selecting trimesic acid as a ligand, under hydrothermal conditions, zinc ions react with the carboxylic acid groups of trimesic acid to form coordination bonds, and gradually generate Zn-BTC three-dimensional organic framework crystals. After vacuum drying, Zn-BTC powder is obtained, which is coated on the surface of a zinc substrate to form a MOF interface layer with a three-dimensional porous structure, so that the zinc negative electrode has a high specific surface area, porosity and higher chemical stability.

[0024] The present invention adopts a coating method to construct a MOF interface layer on the surface of the zinc substrate. The MOF interface layer is composed of Zn-BTC, which can directly block the direct contact between the zinc negative electrode and the electrolyte in the application of the zinc negative electrode battery, significantly reduce corrosion and the generation of by-products, and can effectively inhibit the hydrogen evolution reaction, alleviate the problem of rapid attenuation of the battery capacity, and improve the stability of the zinc negative electrode battery.

[0025] The present invention also proposes a zinc negative electrode, comprising a zinc negative electrode and a MOF interface layer coated on the surface, wherein the MOF interface layer is composed of Zn-BTC; the "Zn-BTC" structure in the MOF interface layer of the present invention contains three carboxyl groups, and the oxygen atoms in these carboxyl groups have high electronegativity and can produce significant electrostatic attraction with positively charged zinc ions. This electrostatic attraction can guide the zinc ions to deposit in an orderly manner, thereby effectively inhibiting the growth of zinc dendrites and significantly improving the cycle stability of the zinc negative electrode battery.

[0026] The zinc negative electrode prepared by the method of the present invention is assembled into a symmetrical battery and has a high conductivity at 1 mA cm -2 The current density and 0.5 mAh cm -2 Under the condition of surface capacity, it can achieve a cycle time of more than 800 hours, showing excellent stability and cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The symmetrical battery assembled with Zn-BTC@Zn obtained in Example 1 as electrode at 1 mA cm -2 、0.5mAhcm -2 Cycle performance under .

[0028] Figure 2 The symmetrical cell assembled with MOF-5@Zn obtained in Comparative Example 1 as electrode at 1 mA cm -2 、0.5mAhcm -2 Cycle performance under .

[0029] Figure 3 The symmetrical cell assembled with MOF-74@Zn obtained in Comparative Example 2 as electrode at 1 mA cm -2、0.5mAhcm -2 Cycle performance under .

[0030] Figure 4 The symmetrical battery assembled with the bare Zn electrode obtained in Comparative Example 3 at 1 mA cm -2 , 0.5mAh cm -2 Cycle performance under . DETAILED DESCRIPTION

[0031] The present invention provides a method for preparing a zinc negative electrode based on MOF material modification, comprising:

[0032] Solution A was prepared by dissolving zinc nitrate hexahydrate in ethanol;

[0033] Dissolve trimesic acid in N,N-dimethylformamide to prepare solution B;

[0034] Solutions A and B were subjected to hydrothermal treatment, washed, and first vacuum dried to obtain Zn-BTC powder;

[0035] The Zn-BTC powder, the binder and N-methylpyrrolidone are mixed to obtain a slurry;

[0036] The slurry is coated on the surface of the zinc substrate, and after a second vacuum drying, a zinc negative electrode with a MOF interface layer on the surface is obtained.

[0037] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0038] In the present invention, zinc nitrate hexahydrate is dissolved in ethanol to prepare solution A; trimesic acid is dissolved in N,N-dimethylformamide to prepare solution B; in the present invention, the solution is prepared by mixing and dissolving in a stirring manner;

[0039] In the present invention, the mass ratio of zinc nitrate hexahydrate to ethanol volume in the solution A is 0.5-2 g:10-30 ml, preferably 1-2 g:20-30 ml, and more preferably 1.19 g:25 ml.

[0040] In the present invention, the mass of trimesic acid in the solution B and the volume ratio of N,N-dimethylformamide are 0.5-2g:10-50ml, preferably 0.5-1g:10-30ml, and more preferably 0.84g:25ml. The present invention selects trimesic acid (BTC) with three carboxylic acid groups, which can form multi-dentate coordination with metal ions to construct a more complex three-dimensional framework structure. Its symmetry and multi-dentate coordination ability make the preparation of MOF layer have higher structural complexity and chemical stability. At the same time, the Zn-BTC formed by the multi-dentate coordination of trimesic acid has a high specific surface area, increases the storage sites of zinc ions, and improves the battery capacity and cycle performance.

[0041] In the present invention, solutions A and B are subjected to hydrothermal treatment, washed, and first vacuum dried to obtain Zn-BTC powder. The present invention has no special requirements for the preparation order and addition order of solution A and solution B.

[0042] In the present invention, the hydrothermal reaction is preferably carried out in a reactor, which can provide a high-pressure environment; in the present invention, the hydrothermal treatment temperature is preferably 80-120°C, more preferably 80°C, 100°C or 120°C; in the present invention, the hydrothermal treatment time is preferably 5-12h, more preferably 6h, 8h, 10h or 12h. The hydrothermal treatment of the present invention can provide a high-temperature and high-pressure environment, which helps to promote the coordination reaction between metal ions and organic ligands. The zinc ion (Zn 2+ ) and trimesic acid (BTC) ligands gradually generate Zn-BTC crystals through coordination bonds under hydrothermal conditions. Zn-BTC crystals are a kind of MOF material with a three-dimensional metal framework structure. The instability defects of the MOF material structure can be eliminated during the Zn-BTC crystallization process, thereby improving the chemical stability of the MOF material.

[0043] In the present invention, the mass ratio of zinc nitrate hexahydrate in the solution A to trimesic acid in the solution B is 0.5-2:0.5-1, more preferably 1-2:0.5-1, and in a specific embodiment preferably 1.19:0.84.

[0044] In the present invention, the washing agent is preferably ethanol, and the washing times are preferably 1 to 3 times.

[0045] In the present invention, the temperature of the first vacuum drying is preferably 60 to 100° C., more preferably 80° C., and the time of the first vacuum drying is preferably 8 to 16 hours, more preferably 10 to 14 hours.

[0046] After obtaining the Zn-BTC powder, the present invention mixes the Zn-BTC powder, a binder and N-methylpyrrolidone to obtain a slurry;

[0047] In the present invention, the mixing and stirring can be carried out in a conventional manner, and the mixing and stirring time is preferably 8 to 16 hours; in the present invention, the mass concentration of Zn-BTC in the slurry is preferably 120 to 200 mg / mL -1 , more preferably 140 to 180 mg / mL -1 , preferably 150 mg / mL in the embodiment -1 .

[0048] In the present invention, the mass ratio of the binder to Zn-BTC in the slurry is preferably 1:4 to 1:9. A reasonable ratio of the binder to Zn-BTC can make the electrode material particles bond and firmly adhere to the surface of the zinc substrate to form a stable electrode structure. A too high ratio will over-cover the active sites and reduce the utilization rate; a too low ratio will make the structure loose and easy to fall off, affecting the battery cycle stability.

[0049] In the present invention, the binder preferably includes polyvinylidene fluoride and / or polytetrafluoroethylene; in the present invention, polyvinylidene fluoride and polytetrafluoroethylene are both used as binders to fix the MOF layer on the surface of the zinc substrate, but specifically polyvinylidene fluoride (PVDF) focuses on enhancing the conductivity and mechanical strength of the electrode, and polytetrafluoroethylene (PTFE) focuses on improving the chemical stability of the electrode.

[0050] After obtaining the slurry, the present invention coats the slurry on the surface of the zinc substrate, and after a second vacuum drying, obtains a zinc negative electrode having a MOF interface layer on the surface.

[0051] In the present invention, the temperature of the second vacuum drying is preferably 60 to 100°C, more preferably 80°C, and the time of the first vacuum drying is preferably 8 to 16 hours, more preferably 10 to 14 hours. The present invention constructs a dense and tough MOF interface protective layer on the zinc substrate interface through a simple process of coating and vacuum drying.

[0052] In the present invention, the zinc substrate can be any zinc material substrate as the negative electrode material, preferably zinc foil or zinc rod, and the thickness of the zinc foil is preferably 20 to 200 um, and more preferably 30 to 100 um.

[0053] The present invention also provides a zinc negative electrode, which is prepared by the above method, including a zinc negative electrode and a MOF interface layer coated on the surface, wherein the MOF interface layer is composed of Zn-BTC. In the present invention, the Zn-BTC is a three-dimensional metal organic framework, and the three-dimensional framework porous structure of Zn-BTC reduces the volume expansion and contraction of the zinc negative electrode during the charging and discharging process, further extending the battery life and life stability. Compared with other MOF materials, "Zn-BTC" contains a richer number of carboxyl groups in the ligand, and its structure contains three carboxyl groups. The oxygen atoms in these carboxyl groups have a higher electronegativity and can produce significant electrostatic attraction with positively charged zinc ions. This electrostatic attraction can guide the zinc ions to deposit in an orderly manner, thereby effectively inhibiting the growth of zinc dendrites, and thus significantly improving the cycle stability of the battery.

[0054] In the present invention, the thickness ratio of the MOF interface layer to the zinc negative electrode is preferably 50-100:20-200, and more preferably 100:30.

[0055] The present invention also provides the use of a zinc negative electrode prepared by the above-mentioned method for preparing a zinc negative electrode based on MOF material modification in an aqueous zinc ion battery.

[0056] In an embodiment of the present invention, the aqueous zinc ion battery is preferably a symmetrical battery, which comprises a negative electrode, an electrolyte (ZnSO 4 ), separator (glass fiber), battery shell (CR2016) and the negative electrode is the zinc negative electrode prepared by the above scheme.

[0057] The zinc negative electrode modified based on MOF material provided by the present invention and its preparation and application are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0058] Example 1

[0059] Preparation of zinc negative electrode based on MOF (Zn-BTC) modification:

[0060] 1) Dissolve zinc nitrate hexahydrate (1.19 g) in ethanol (25 mL) and stir well to prepare solution A;

[0061] 2) Dissolve trimesic acid (0.84 g) in N,N-dimethylformamide (25 mL) and stir until completely dissolved to form solution B;

[0062] 3) Mix solutions A and B together and continue stirring until the mixture is uniform. After stirring, put them into a reactor for hydrothermal treatment at a temperature of 100°C for 12 hours. After hydrothermal treatment, wash with ethanol three times, and then dry at 60°C under vacuum for 12 hours to obtain Zn-BTC powder.

[0063] 4) Dissolve polyvinylidene fluoride (40 mg) and Zn-BTC (160 mg) in N-methylpyrrolidone (1 mL), and stir the mixed solution to obtain a uniform mixture.

[0064] 5) The uniformly stirred slurry was coated on the surface of a zinc foil with a thickness of 30 μm using a four-sided preparation device, and the coating thickness was 100 μm; after vacuum drying at 60° C. for 12 h, an aqueous zinc ion battery negative electrode having a MOF interface layer on the surface was obtained.

[0065] After the materials prepared in this example are assembled into a symmetrical battery, the cycle performance is as follows: Figure 1 As shown, at 1 mA cm -2 At a current density of 0.5 mAh cm -2 In this case, the cycle time can reach 800h.

[0066] Example 2

[0067] Preparation of zinc negative electrode based on MOF (Zn-BTC) modification:

[0068] 1) Dissolve zinc nitrate hexahydrate (0.5 g) in ethanol (10 mL) and stir well to prepare solution A;

[0069] 2) Dissolve trimesic acid (0.5 g) in N,N-dimethylformamide (10 mL) and stir until completely dissolved to form solution B;

[0070] 3) Mix solutions A and B together and continue stirring until the mixture is uniform. After stirring, put them into a reactor for hydrothermal treatment at a temperature of 80°C for 12 hours. After hydrothermal treatment, wash with ethanol three times, and then dry under vacuum at 100°C for 8 hours to obtain Zn-BTC powder.

[0071] 4) Dissolve polyvinylidene fluoride (20 mg) and Zn-BTC (180 mg) in N-methylpyrrolidone (1 mL), and stir the mixed solution to obtain a uniform mixture.

[0072] 5) The stirred slurry was coated on the surface of a zinc foil with a thickness of 50 μm using a four-sided preparation device, and the coating thickness was 100 μm. After vacuum drying at 100° C. for 8 h, an aqueous zinc ion battery negative electrode with a MOF interface layer on the surface was obtained.

[0073] Example 3

[0074] Preparation of zinc negative electrode based on MOF (Zn-BTC) modification:

[0075] 1) Dissolve zinc nitrate hexahydrate (1.5 g) in ethanol (30 mL) and stir well to prepare solution A;

[0076] 2) Dissolve trimesic acid (2 g) in N,N-dimethylformamide (30 mL) and stir until completely dissolved to form solution B;

[0077] 3) Mix solutions A and B together and continue stirring until the mixture is uniform. After stirring, put them into a reactor for hydrothermal treatment at a temperature of 100°C for 10 hours. After hydrothermal treatment, wash twice with ethanol and then dry under vacuum at 80°C for 10 hours to obtain Zn-BTC powder.

[0078] 4) Dissolve polyvinylidene fluoride (30 mg) and Zn-BTC (150 mg) in N-methylpyrrolidone (1 mL), and stir the mixed solution to obtain a uniform mixture.

[0079] 5) The uniformly stirred slurry was coated on the surface of a zinc foil with a thickness of 200 μm using a four-sided preparation device, and the coating thickness was 100 μm; after vacuum drying at 80° C. for 10 h, an aqueous zinc ion battery negative electrode having a MOF interface layer on the surface was obtained.

[0080] Comparative Example 1

[0081] Preparation of zinc negative electrode based on MOF (MOF-5) modification:

[0082] First, 16.99 g of zinc acetate dihydrate was dissolved in 500 ml of N, N-dimethylformamide, and the mixture was stirred at a stirring rate of 500 rpm for 10 min under magnetic stirring to be uniformly mixed, and this solution was referred to as solution A; 5.065 g of terephthalic acid was dissolved in 400 ml of N, N-dimethylformamide, and the mixture was stirred at a stirring rate of 500 rpm for 10 min under magnetic stirring to be uniformly mixed, and this solution was referred to as solution B; 8.5 ml of triethylamine was slowly added to solution B, and the mixture was stirred at room temperature for 10 min to be uniformly mixed, and this solution was referred to as solution C;

[0083] Under stirring conditions, solution A was slowly added to solution C, and then stirring was continued for 12 hours at a speed of 500 rpm. The above solution was centrifuged and washed three times in a centrifuge at a speed of 9000 rpm, wherein the washing solvent was a mixed solution of N, N-dimethylformamide and methanol in a volume ratio of 1:1, and then dried in an oven at 80°C for 12 hours to obtain MOF-5 powder.

[0084] Polyvinylidene fluoride (40 mg) and MOF-5 (160 mg) were dissolved in N-methylpyrrolidone (1 mL), and the mixed solution was stirred evenly.

[0085] The evenly stirred slurry was coated on the surface of a zinc foil with a thickness of 30 μm using a four-sided preparation apparatus. The coating thickness was 100 μm. After vacuum drying at 60°C for 12 h, an aqueous zinc ion battery negative electrode with a MOF interface layer on the surface was obtained.

[0086] After the materials prepared in this comparative example are assembled into a symmetrical battery, the cycle performance is as follows Figure 2 As shown, at 1 mA cm -2 At a current density of 0.5 mAh cm -2 In this case, the cycle time can reach 290h.

[0087] Comparative Example 2

[0088] Preparation of zinc negative electrode based on MOF (MOF-74) modification:

[0089] A mixture of 2,5-dihydroxyterephthalic acid (1.0 g) and zinc nitrate hexahydrate (4.52 g) was dissolved in 100 mL of DMF. Then, 5 mL of water was added and the sealed solution was placed in an oven at 110 ° C for 24 hours. After cooling to room temperature, the solid was centrifuged, washed three times with DMF, and then washed twice with methanol. The solid product was soaked in methanol for 6 days. During this period, new solvent (methanol) was added three times after pouring out the old solvent. Finally, the methanol was removed for 1 hour under high vacuum conditions at a temperature of 150 ° C to obtain MOF-74 powder.

[0090] Polyvinylidene fluoride (40 mg) and MOF-74 (160 mg) were dissolved in N-methylpyrrolidone (1 mL), and the mixed solution was stirred evenly.

[0091] The stirred slurry was coated on the surface of a zinc foil with a thickness of 30 μm using a four-sided preparation device, and the coating thickness was 100 μm. After vacuum drying at 60°C for 12 hours, an aqueous zinc ion battery negative electrode with a MOF interface layer on the surface was obtained.

[0092] After the materials prepared in this comparative example are assembled into a symmetrical battery, the cycle performance is as follows Figure 3 As shown, at 1 mA cm -2 At a current density of 0.5 mAh cm -2 In this case, the cycle time can reach 200h.

[0093] Comparative Example 3

[0094] Symmetrical cells were assembled with 30 μm zinc foil and the electrolyte was 2 M ZnSO 4 The diaphragm is glass fiber. The cycling performance of pure zinc symmetric battery is as follows Figure 4 The current density is 1 mA cm -2 , with a capacity of 0.5 mAh cm -2 When the battery is used, the cycle life is only 140h.

[0095] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a zinc negative electrode based on MOF material modification, comprising: Solution A was prepared by dissolving zinc nitrate hexahydrate in ethanol; Dissolve trimesic acid in N,N-dimethylformamide to prepare solution B; Solutions A and B were subjected to hydrothermal treatment, washed, and first vacuum dried to obtain Zn-BTC powder; Mixing a binder, Zn-BTC and N-methylpyrrolidone to obtain a slurry; The slurry is coated on the surface of the zinc substrate, and after a second vacuum drying, a zinc negative electrode with a MOF interface layer on the surface is obtained.

2. The method for preparing a zinc negative electrode based on MOF material modification according to claim 1, characterized in that: The mass ratio of the zinc nitrate hexahydrate to trimesic acid is 0.5-2:0.5-1.

3. The method for preparing a zinc negative electrode based on MOF material modification according to claim 1, characterized in that: The hydrothermal treatment temperature is 80-120° C., and the hydrothermal treatment time is 5-12 hours.

4. The method for preparing a zinc negative electrode based on MOF material modification according to claim 1, characterized in that: The washing reagent is ethanol, the washing times are 1 to 3 times; the first vacuum drying temperature is 60 to 100° C., and the first vacuum drying time is 8 to 16 hours.

5. The method for preparing a zinc negative electrode based on MOF material modification according to claim 1, characterized in that: The mass concentration of Zn-BTC in the slurry is in the range of 120 to 200 mg / mL. -1 .

6. The method for preparing a zinc negative electrode based on MOF material modification according to claim 1, characterized in that: The mass ratio of the binder to Zn-BTC is 1:4 to 1:

9.

7. The method for preparing a zinc negative electrode based on MOF material modification according to claim 1, characterized in that: The binder includes polyvinylidene fluoride and / or polytetrafluoroethylene.

8. The method for preparing a zinc negative electrode based on MOF material modification according to claim 1, characterized in that: The second vacuum drying temperature is 60-100° C., and the second vacuum drying time is 8-16 hours.

9. A zinc negative electrode prepared by the method according to any one of claims 1 to 8, comprising a zinc negative electrode and a MOF interface layer coated on the surface, wherein the MOF interface layer is composed of Zn-BTC.

10. Use of the zinc negative electrode prepared by the method according to any one of claims 1 to 8 or the zinc negative electrode according to claim 9 in an aqueous zinc ion battery.

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