Preparation method of Zr-MOF nano material and application of Zr-MOF nano material in aqueous zinc-iodine battery

Abstract

The invention discloses a preparation method of a Zr-MOF nano material, which comprises the following steps: adding deionized water into a reaction mixture consisting of zircon salt, 4 ', 4', 4 ', 4'-(ethylene-1, 1, 2, 2-tetraalkyl) tetra ([1, 1 '-biphenyl]-4-carboxylic acid), an acid regulator and an organic solvent to form a mixed solution, heating and reacting in a high-pressure reaction kettle, and cooling to room temperature to obtain the Zr-MOF nano material. And centrifugally collecting and cleaning a product, and drying in a dark place to obtain the Zr-MOF nano material. According to the application of the Zr-MOF nano material in the water-based zinc-iodine battery, the Zr-MOF nano material and iodine are prepared into a composite material, then the composite material is prepared into electrode slurry, the surface of a stainless steel mesh is coated with the electrode slurry, and the electrode slurry is dried to serve as an electrode plate of the water-based zinc-iodine battery. The preparation process is simple, Zr-MOF nano-materials with different structures can be obtained by adjusting the deionized water content of the system, and the Zr-MOF nano-materials can be applied to an electrode plate of an aqueous zinc-iodine battery to improve the cycle performance of the battery.

Description

Technical Field

[0001] This invention relates to a method for preparing Zr-MOF and its application, belonging to the field of electrode material technology. Background Technology

[0002] Aqueous zinc-iodine batteries have shown great promise in large-scale energy storage due to their high theoretical capacity, environmental friendliness, and intrinsic safety. However, iodine cathodes suffer from slow reaction kinetics and the shuttle effect of polyiodide ions, resulting in poor rate performance and cycle stability. Traditional porous host materials (such as carbon-based materials) mainly rely on physical confinement to anchor polyiodides, but weak adsorption makes it difficult to achieve efficient and persistent fixation of iodine species and synergistic regulation of catalytic conversion, especially at high current densities where the kinetic bottleneck is particularly prominent.

[0003] Zirconium-based metal-organic frameworks (Zr-MOFs) are ideal host materials for iodine cathodes, but traditional Zr-MOF preparation relies on a multi-step solvothermal-acid etching process: first, high-temperature hydrothermal self-assembly forms Zr-MOF crystal materials with microporous structures, and then a second acid treatment etches out mesoporous or hollow structures. The process is cumbersome, generates a large amount of waste acid, and is costly. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a method for preparing Zr-MOF nanomaterials. The aim is to overcome the cumbersome steps and large amounts of waste acid associated with traditional methods for obtaining Zr-MOF nanomaterials with a hollow, defective framework. This invention also provides a method for using Zr-MOF nanomaterials as an iodine cathode host in aqueous zinc-iodine batteries to improve the battery's discharge specific capacity and cycle performance.

[0005] The technical solution of this invention is as follows: A method for preparing Zr-MOF nanomaterials, wherein deionized water is added to a reaction mixture consisting of zirconium salt, 4',4",4",4"-(ethylene-1,1,2,2-tetraalkyl)tetra([1,1'-biphenyl]-4-carboxylic acid), an acid modifier and an organic solvent to form a mixed solution, and the mixture is heated and reacted in a high-pressure reactor. The product is then collected by centrifugation, washed and dried in the dark to obtain Zr-MOF nanomaterials.

[0006] Further, the process includes the steps of dissolving zirconium salt and acid modifier in an organic solvent to form solution A, dissolving 4',4",4",4"-(ethylene-1,1,2,2-tetraalkyl)tetra([1,1'-biphenyl]-4-carboxylic acid) in an organic solvent to form organic ligand solution B, and mixing solution A and organic ligand solution B and stirring to obtain a reaction mixture.

[0007] Furthermore, when deionized water is added to the reaction mixture, the volume ratio of the amount of deionized water added to the volume of the organic solvent constituting the reaction mixture is (10-300):2000.

[0008] Furthermore, the molar concentration of zirconium in solution A is (4–7) × 10⁻⁶. -2 The organic ligand solution B contains 15–25 g / L of 4',4",4",4"-(ethylene-1,1,2,2-tetraalkyl)tetra([1,1'-biphenyl]-4-carboxylic acid).

[0009] Furthermore, the heating temperature during the reaction in the high-pressure reactor is 100–130 °C.

[0010] Further, the zirconium salt is ZrCl4, ZrOCl2·8H2O, ZrO(NO3)2· x H2O, one or more of the following: 1≤x≤5.

[0011] Furthermore, during the stirring reaction, the organic ligand solution B is added to the solution A while stirring, and the stirring speed is not less than 200 r / min.

[0012] Furthermore, the drying time in the dark is 4 to 48 hours.

[0013] Another technical solution of the present invention is as follows: an application of Zr-MOF nanomaterials in aqueous zinc-iodine batteries, wherein the Zr-MOF nanomaterials are made into an electrode slurry and coated on the surface of a stainless steel mesh, and after drying, it is used as an electrode sheet for aqueous zinc-iodine batteries.

[0014] Furthermore, the electrode slurry made from the Zr-MOF nanomaterials comprises electrode material and slurry solvent. The electrode material comprises 65% to 85% Zr-MOF nanomaterials by mass, 5% to 25% Ketjen black, and the remainder is binder.

[0015] Compared with the prior art, the advantages of the technical solution provided by the present invention are as follows: This invention involves adding deionized water to a reaction system consisting of the organic ligand 4',4",4",4"-(ethylene-1,1,2,2-tetraalkyl)tetra([1,1'-biphenyl]-4-carboxylic acid) (ETTC), zirconium salt, and an organic solvent. Water molecules participate in the coordination process, inducing the formation of a hollow-structured defect-framework Zr-MOF nanomaterial. This hollow structure effectively shortens ion migration paths and improves reactant transport efficiency. Simultaneously, the water introduction promotes the formation of zirconium clusters, which not only enhance framework stability but also allow for the chemical anchoring of I3 by its Lewis acidic vacancies. – / I5 –The presence of polyiodine intermediates significantly suppresses the shuttle effect and synergistically enhances the cycle stability and reaction kinetics of zinc-iodine batteries, making them more advantageous in applications such as energy storage and electrochemical catalysis. This invention is simple to operate, the reaction is easy to control, has good reproducibility and safety, and is suitable for continuous large-scale production. Zr-MOF nanomaterials prepared using this method, when applied to the electrodes of aqueous zinc-iodine batteries, can improve the discharge specific capacity and exhibit better cycle stability. Attached Figure Description

[0016] Figure 1 The image shows the XRD pattern of the Zr-MOF nanomaterials prepared in Example 1.

[0017] Figure 2 The image shows the FT-IR spectrum of the Zr-MOF nanomaterials prepared in Example 1.

[0018] Figure 3 SEM images of Zr-MOF nanomaterials prepared in Examples 1 and 7 using different proportions of deionized water based on Example 1.

[0019] Figure 4 The images are TEM images of Zr-MOF nanomaterials prepared in Examples 1 and 7 using different proportions of deionized water based on Example 1.

[0020] Figure 5 Cyclic stability spectra of the Zr-MOF nanomaterials obtained in Examples 1 and 7 after being fabricated into I2@Zr-MOF and used as iodine cathodes in aqueous zinc-iodine batteries.

[0021] Figure 6 The rate performance spectra of the Zr-MOF nanomaterials obtained in Examples 1 and 7 after being fabricated into I2@Zr-MOF and used as iodine cathodes in aqueous zinc-iodine batteries are shown. Detailed Implementation

[0022] The present invention will be further described below with reference to embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. After reading this description, any modifications of this description in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0023] Example 1

[0024] (1) Weigh 15 mg of ETTC into 1 mL of DMF solution to form organic ligand solution B.

[0025] (2) Weigh 10 mg of zirconium chloride (ZrCl4) and 300 μL of acetic acid and add them to 1 mL of DMF solution. Stir with a magnetic stirrer to obtain a colorless solution A.

[0026] (3) Add the organic ligand solution B obtained in step (1) to the solution A obtained in step (2) while stirring, and stir the mixture with a magnetic stirrer at a speed of 550 rpm / min for 10 min to obtain a mixed solution C.

[0027] (4) Add 100 μL of deionized water to the mixed solution C obtained in step (3) and stir for 15 min to obtain mixed solution D.

[0028] (5) Transfer the mixed solution D obtained in step (4) to a polytetrafluoroethylene stainless steel reactor and heat it in an oven to 120 °C for 24 h.

[0029] (6) The precipitate obtained in step (5) is washed with DMF and dried in the dark to obtain Zr-MOF nanomaterials.

[0030] Example 2

[0031] (1) Weigh 20 mg of ETTC into 1 mL of DMF solution to form organic ligand solution B.

[0032] (2) Weigh 10 mg of zirconium chloride (ZrCl4) and 300 μL of acetic acid and add them to 1 mL of DMF solution. Stir with a magnetic stirrer to obtain a colorless solution A.

[0033] (3) Add the organic ligand solution B obtained in step (1) to the solution A obtained in step (2) while stirring, and stir the mixture with a magnetic stirrer at a speed of 500 rpm / min for 10 min to obtain a mixed solution C.

[0034] (4) Add 100 μL of deionized water to the mixed solution C obtained in step (3) and stir for 15 min to obtain mixed solution D.

[0035] (5) Transfer the mixed solution D obtained in step (4) to a polytetrafluoroethylene stainless steel reactor and heat it in an oven to 120 °C for 4 h.

[0036] (6) The precipitate obtained in step (5) is washed with DMF and dried in the dark to obtain Zr-MOF nanomaterials.

[0037] Example 3

[0038] (1) Weigh 25 mg of ETTC into 1 mL of DMF solution to form organic ligand solution B.

[0039] (2) Weigh 15 mg of zirconium chloride (ZrCl4) and 300 μL of acetic acid and add them to 1 mL of DMF solution. Obtain colorless solution A by using a magnetic stirrer.

[0040] (3) Add the organic ligand solution B obtained in step (1) to the solution A obtained in step (2) while stirring, and stir the mixture with a magnetic stirrer at a speed of 450 rpm / min for 10 min to obtain a mixed solution C.

[0041] (4) Add 100 μL of deionized water to the mixed solution C obtained in step (3) and stir for 15 min to obtain mixed solution D.

[0042] (5) Transfer the mixed solution D obtained in step (4) to a polytetrafluoroethylene stainless steel reactor and heat it in an oven to 120 °C for 6 h.

[0043] (6) The precipitate obtained in step (5) is washed with DMF and dried in the dark to obtain Zr-MOF nanomaterials.

[0044] Example 4

[0045] In step (5), the temperature was raised to 100 °C and held for 9 h. The remaining steps were the same as in Example 1, and Zr-MOF nanomaterials were obtained.

[0046] Example 5

[0047] In step (5), the temperature was raised to 110 °C and held for 10 h. The remaining steps were the same as in Example 1, and Zr-MOF nanomaterials were obtained.

[0048] Example 6

[0049] In step (5), the temperature was raised to 130 °C and held for 12 h. The remaining steps were the same as in Example 1, and Zr-MOF nanomaterials were obtained.

[0050] Example 7

[0051] Based on Example 1, the deionized water added in step (4) of Example 1 was changed to 10 μL, 200 μL and 300 μL, and the remaining steps were the same as in Example 1, to obtain Zr-MOF nanomaterials.

[0052] The product prepared in Example 1 was characterized by X-ray powder diffraction (XRD), and the diffraction pattern of the product was obtained as follows: Figure 1 As shown, Zr-MOF nanomaterials were prepared, and Zr-MOF nanomaterials were also prepared in the other embodiments.

[0053] In addition, the functional groups of the Zr-MOF nanomaterials prepared in Example 1 were characterized by FT-IR testing, and the results are as follows: Figure 2 As shown, at 1685 cm -1 The absorption peak at position belongs to δ(C=O) further confirms that Zr-MOF nanomaterials were prepared in Example 1.

[0054] The morphology of Zr-MOF nanomaterials prepared in Examples 1 and 7 using different proportions of deionized water based on Example 1 was characterized by SEM testing. Figure 3 The images show scanning electron microscope (SEM) images of Zr-MOF nanomaterials. The test results indicate that the Zr-MOF nanomaterials were successfully composited and are generally uniform in size and shape. Furthermore, the morphology of the Zr-MOF nanomaterials changes with the amount of deionized water added.

[0055] The cathode material was prepared using Zr-MOF nanomaterials prepared in Example 1 with different deionized water ratios, as described in Examples 1 and 7. The steps are as follows: (1) Weigh 70 mg of Zr-MOF and mix it with iodine at a mass ratio of 1:2. After thorough grinding, transfer the mixture to a polytetrafluoroethylene stainless steel reactor and heat it in an oven to 130 °C for 10 h.

[0056] (2) Take out the polytetrafluoroethylene liner after cooling in step (1), cover it at 80 °C and heat it for 4 h to remove the unstable iodine on the surface, and obtain I2@Zr-MOF composite material.

[0057] Battery assembly was performed using the different I2@Zr-MOF composite materials obtained above, following the steps: (1) Weigh 0.5 g PVDF and add 9.5 g NMP, stir for 24 h to prepare PVDF with a mass fraction of 5%.

[0058] (2) Weigh 80 mg of I2@Zr-MOF composite material and 10 mg of Ketjen black and grind for 30 min.

[0059] (3) Weigh 200 mg of PVDF with a mass fraction of 5% and add it to step (2). Stir for 4 h to prepare electrode slurry.

[0060] (4) The electrode paste prepared in step (3) is uniformly coated onto the surface of a stainless steel mesh using a tetrahedral coating tool and kept in a vacuum drying oven at 60°C for 24 h to obtain an electrode sheet.

[0061] (5) Prepare a 2 M ZnSO4 electrolyte.

[0062] (6) The electrode sheet obtained in step (4) is used as the positive electrode, the zinc sheet as the negative electrode, the glass fiber separator is selected, and the electrolyte is 2 M ZnSO4. The button cell is assembled using the existing method. The assembled cell is left to stand for 8 h before further electrochemical performance testing.

[0063] The assembled battery was subjected to cycle stability testing at a current density of 0.8 A g. -1 The battery performance was evaluated after 200 cycles. The cycle stability graphs of the iodine cathode in the aqueous zinc-iodine batteries of each embodiment are shown below. Figure 5 As shown, the labels 10 μL, 100 μL, 200 μL, and 300 μL correspond to the amount of deionized water added to mixed solution C, namely Example 1 and Example 7.

[0064] The assembled batteries were subjected to rate performance tests with current densities of 0.5, 0.8, 1, 1.2, 1.6, 2, 5, 2, 1.6, 1.2, 1, and 0.8 A g. -1 In Example 7, the rate performance spectrum of I2@Zr-MOF (200 μL of water) prepared by adding 200 μL of deionized water to mixed solution C as the iodine cathode of an aqueous zinc-iodine battery is shown in the figure. Figure 6 As shown.

[0065] In summary, the above results show that Zr-MOF nanomaterials prepared by the method of the present invention can be used to fabricate the positive electrode of zinc-iodine batteries. The Zr-MOF nanomaterials obtained by adding 200 μL of deionized water to mixed solution C, as iodine hosts, have the best electrochemical performance.

Claims

1. A method for preparing Zr-MOF nanomaterials, characterized in that, Deionized water was added to a reaction mixture consisting of zirconium salt, 4',4",4",4"-(ethylene-1,1,2,2-tetraalkyl)tetra([1,1'-biphenyl]-4-carboxylic acid), an acid modifier, and an organic solvent to form a mixed solution. After heating and reacting in a high-pressure reactor, the product was collected by centrifugation, washed, and dried in the dark to obtain Zr-MOF nanomaterials.

2. The method for preparing Zr-MOF nanomaterials according to claim 1, characterized in that, The process includes dissolving a zirconium salt and an acid modifier in an organic solvent to form solution A, dissolving 4',4",4",4"-(ethylene-1,1,2,2-tetraalkyl)tetra([1,1'-biphenyl]-4-carboxylic acid) in an organic solvent to form organic ligand solution B, and mixing solution A and organic ligand solution B and stirring to obtain a reaction mixture.

3. The method for preparing Zr-MOF nanomaterials according to claim 1, characterized in that, When deionized water is added to the reaction mixture, the volume ratio of the amount of deionized water added to the volume of the organic solvent constituting the reaction mixture is (10-300):2000.

4. The method for preparing Zr-MOF nanomaterials according to claim 1, characterized in that, The molar concentration of zirconium in solution A is (4–7) × 10⁻⁶. -2 The organic ligand solution B contains 15–25 g / L of 4',4",4",4"-(ethylene-1,1,2,2-tetraalkyl)tetra([1,1'-biphenyl]-4-carboxylic acid).

5. The method for preparing Zr-MOF nanomaterials according to claim 1, characterized in that, The heating temperature during the reaction in the high-pressure reactor is 100–130 °C.

6. The method for preparing Zr-MOF nanomaterials according to claim 1, characterized in that, The zirconium salt is one or more of ZrCl4, ZrOCl2·8H2O, and ZrO(NO3)2·xH2O, where 1≤x≤5.

7. The method for preparing Zr-MOF nanomaterials according to claim 1, characterized in that, During the stirring reaction, the organic ligand solution B is added to the solution A while stirring, and the stirring speed is not less than 200 r / min.

8. The method for preparing Zr-MOF nanomaterials according to claim 1, characterized in that, The drying time in the dark is 4 to 48 hours.

9. An application of Zr-MOF nanomaterials in aqueous zinc-iodine batteries, characterized in that, The Zr-MOF nanomaterials prepared by the method of any one of claims 1 to 8 are mixed and ground with iodine and then heated and reacted in a high-pressure reactor to obtain I2@Zr-MOF. The I2@Zr-MOF is then made into an electrode slurry, coated on the surface of a stainless steel mesh, and dried to serve as an electrode sheet for an aqueous zinc-iodine battery.

10. The application of the Zr-MOF nanomaterial according to claim 9 in an aqueous zinc-iodine battery, characterized in that, The I2@Zr-MOF electrode slurry comprises electrode material and slurry solvent. The electrode material comprises 65% to 85% I2@Zr-MOF by mass, 5% to 25% Ketjen Black, and the remainder is binder.

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