A methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries and its preparation method

Abstract

The present invention provides a methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries and a preparation method thereof. The composite diaphragm is composed of a methoxy-rich covalent organic framework material with a thickness ratio of 4-6:10-14:1-2, a zinc conductive diaphragm, and graphene. The preparation steps are as follows: (1) adding the methoxy-rich covalent organic framework material to anhydrous ethanol, ultrasonically dispersing it, and filtering it on a glass fiber diaphragm to obtain a double-layer diaphragm; (2) adding graphene to anhydrous ethanol, dripping a polyvinylidene fluoride / N-methylpyrrolidone solution, ultrasonically treating it, and filtering it on the other side of the glass fiber diaphragm to obtain a multilayer composite diaphragm. The composite diaphragm of the present invention maintains a crystalline structure and high porosity, and exhibits excellent thermal stability, chemical stability, and cycle performance. The zinc-iodine battery assembled with the composite diaphragm can effectively inhibit the formation of zinc dendrites and the shuttle effect of positive electrode polyiodide, greatly improving the cycle life and charge and discharge stability of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of zinc-iodine batteries, and in particular to a methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries and a preparation method thereof. Background Art

[0002] Zinc-iodine batteries have attracted much attention due to their high energy density, environmental friendliness, and low cost. With the global emphasis on renewable energy and environmental protection, zinc-iodine batteries have shown great potential in static energy storage and have broad application prospects in renewable energy systems. However, traditional zinc-iodine battery separators still face many challenges in practical applications. First, the growth of zinc dendrites is one of the main causes of battery short circuits and shortened lifespans. Traditional separators cannot effectively prevent the penetration of zinc dendrites, thereby affecting the cycle life and stability of the battery. Secondly, the ionic conductivity of the separator is low, which limits the overall performance of the battery. In addition, the chemical stability of the separator in the corrosive environment of the electrolyte is also an issue that needs to be addressed urgently.

[0003] Therefore, it is necessary to develop a highly stable diaphragm that can improve the ionic conductivity of the electrolyte and effectively prevent the penetration of zinc dendrites, thereby improving the discharge capacity, coulombic efficiency and rate performance of zinc-iodine batteries. This is a difficult problem that needs to be solved urgently in the field of zinc-iodine batteries. Summary of the Invention

[0004] In view of this, the present invention proposes a methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries and a preparation method thereof.

[0005] The technical solution of the present invention is achieved as follows:

[0006] A methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries consists of a methoxy-rich covalent organic framework material with a thickness ratio of 4-6:10-14:1-2, a zinc conductive diaphragm and graphene.

[0007] Furthermore, the thickness of the methoxy-rich covalent organic framework material is 20-30 μm; the thickness of the zinc conductive diaphragm is 50-70 μm; and the thickness of the graphene is 5-10 μm.

[0008] Furthermore, the methoxy-rich covalent organic framework material has a hexagonal topological structure.

[0009] Furthermore, the preparation method of the methoxy-rich covalent organic framework material includes: mixing 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 2,5-dimethoxyterephthalaldehyde and a catalyst, adding them to a mixed solvent, dropwise adding a polyvinylidene fluoride / N-methylpyrrolidone solution, ultrasonic treatment, liquid nitrogen freezing, vacuum drying, repeating 2-4 times, drying, Soxhlet extraction, and vacuum drying to obtain a methoxy-rich covalent organic framework material.

[0010] Furthermore, the molar ratio of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine to 2,5-dimethoxyterephthalaldehyde is 1:1-2; the catalyst is any one of acetic acid, acetic acid, hydrochloric acid and perchloric acid, with a concentration of 5-7 mol / L; the molar ratio of 2,5-dimethoxyterephthalaldehyde to the catalyst is 1:5; the volume ratio of the polyvinylidene fluoride / N-methylpyrrolidone solution to the catalyst and the mixed solvent is 25-35:1:10; The concentration of the polyvinylidene fluoride / N-methylpyrrolidone solution is 1-10wt%; the mixed solvent consists of benzene and n-butanol in a volume ratio of 1:1; the ultrasonic treatment is performed at 35-45kHz and 20-30°C for 10-20min; the drying temperature is 110-130°C and the drying time is 2-4d; the solvent for the Soxhlet extraction is any one of tetrahydrofuran, acetone, ethanol, chloroform and ethyl acetate, the temperature is 80-90°C, and the drying time is 12-24h.

[0011] Furthermore, the zinc conductive diaphragm is any one of a glass fiber diaphragm, a filter paper diaphragm or a non-woven fabric diaphragm.

[0012] A method for preparing a methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries, comprising the following steps:

[0013] (1) adding a methoxyl-rich covalent organic framework material to anhydrous ethanol, dispersing the material through ultrasonic radiation to obtain a slurry, and filtering the slurry on a glass fiber membrane to obtain a methoxyl-rich covalent organic framework material@glass fiber membrane;

[0014] (2) Graphene was added to anhydrous ethanol, polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise, and ultrasonic treatment was performed to obtain a graphene suspension. The graphene suspension was filtered on the other side of the glass fiber membrane and vacuum dried to obtain a methoxy-rich covalent organic framework material@glass fiber membrane@graphene composite membrane.

[0015] Furthermore, in step (1), the solid-liquid ratio of the methoxy-rich covalent organic framework material to anhydrous ethanol is 1:3-5 mg / mL; and the ultrasonic radiation dispersion is performed at 35-45 kHz and 20-30° C. for 10-20 min.

[0016] Furthermore, in step (2), the solid-liquid ratio of graphene to anhydrous ethanol is 1:6-7 mg / mL; the volume ratio of the polyvinylidene fluoride / N-methylpyrrolidone solution to anhydrous ethanol is 1:10-15, and the concentration of the polyvinylidene fluoride / N-methylpyrrolidone solution is 1-10wt%; the power of the ultrasonic treatment is 35-45kHz, the temperature is 20-30°C, and the time is 10-20min; the temperature of the vacuum drying is 55-65°C, and the time is 3-5h.

[0017] Furthermore, the methoxy-rich covalent organic framework material@glass fiber membrane@graphene composite membrane is cut into a circular membrane with a diameter of 18 mm.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention's methoxy-rich covalent organic framework material, glass fiber separator, and graphene composite separator can maintain its crystalline structure and high porosity in harsh environments, exhibiting excellent thermal and chemical stability. The zinc-iodine battery assembled with the composite separator can effectively inhibit the formation of zinc dendrites and the shuttling effect of polyiodide in the positive electrode, significantly improving the battery's cycle life and charge-discharge stability. It can also maintain stable cycle performance and high coulombic efficiency at high current densities, providing a reliable and environmentally friendly solution for static energy storage.

[0020] 2. The composite membrane of the present invention has a simple preparation process, low cost, and strong universal applicability. By dropwise adding polyvinylidene fluoride / N-methylpyrrolidone, the present invention overcomes the technical problem of the inability of methoxyl-rich covalent organic framework materials and graphene to stably adhere to the glass fiber membrane, thereby ensuring the structural stability and functionality of the zinc-iodine battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the structural formula of the methoxy-rich covalent organic framework material prepared in Example 1.

[0022] Figure 2 This is the X-ray diffraction pattern of the methoxy-rich covalent organic framework material prepared in Example 1.

[0023] Figure 3 This is the infrared spectrum of the methoxy-rich covalent organic framework material prepared in Example 1.

[0024] Figure 4 This is an SEM scan image of the methoxy-rich covalent organic framework material@glass fiber membrane@graphene composite membrane prepared in Example 1.

[0025] Figure 5This is a cycling performance diagram of the zinc-iodine battery assembled with the methoxy-rich covalent organic framework material@glass fiber membrane@graphene composite membrane prepared in Example 1 at 5A / g. DETAILED DESCRIPTION

[0026] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0027] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0028] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0029] Example 1

[0030] A methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries, comprising a methoxy-rich covalent organic framework material, a glass fiber diaphragm and graphene; the methoxy-rich covalent organic framework material has a thickness of 25 μm, the glass fiber diaphragm has a thickness of 60 μm, and the graphene has a thickness of 7.5 μm.

[0031] The preparation steps of the composite diaphragm include:

[0032] (1) Methoxy-rich covalent organic framework material: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (0.080 mmol, 28.1 mg), 2,5-dimethoxyterephthalaldehyde (0.120 mmol, 23.3 mg) and acetic acid (6 mol / L, 0.1 mL) were mixed, 1 mL of a mixed solvent (benzene and n-butanol with a volume ratio of 1:1) was added, 3 mL of a 5 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise, ultrasonic treatment was performed for 15 min (40 kHz, 25 ° C), liquid nitrogen freezing was performed for 5 min, vacuum drying was performed, repeated 3 times, drying was performed at 120 ° C for 3 d, Soxhlet extraction was performed at 85 ° C for 18 h (solvent tetrahydrofuran), and vacuum drying was performed at 120 ° C for 24 h to obtain a methoxy-rich covalent organic framework material (hexagonal topology structure);

[0033] (2) Methoxy-rich covalent organic framework material @ glass fiber membrane: 12.4 mg of methoxy-rich covalent organic framework material was added to 40 mL of anhydrous ethanol and dispersed under ultrasonic radiation for 15 min (40 kHz, 25°C) to obtain a slurry. The slurry was filtered on a glass fiber membrane to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane;

[0034] (3) Methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane: 6.2 mg of graphene was added to 40 mL of anhydrous ethanol, and 3 mL of 5 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise. The mixture was ultrasonically treated for 15 min (40 kHz, 25 ° C) to obtain a graphene suspension. The graphene suspension was filtered on the other side of the glass fiber membrane and vacuum dried at 60 ° C for 4 h to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane.

[0035] Example 2

[0036] A methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries, comprising a methoxy-rich covalent organic framework material, a glass fiber diaphragm and graphene; the methoxy-rich covalent organic framework material has a thickness of 20 μm, the glass fiber diaphragm has a thickness of 50 μm, and the graphene has a thickness of 5 μm.

[0037] The preparation steps of the composite diaphragm include:

[0038] (1) Methoxy-rich covalent organic framework material: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (0.080 mmol, 28.1 mg), 2,5-dimethoxyterephthalaldehyde (0.080 mmol, 15.7 mg) and acetic acid (5 mol / L, 0.08 mL) were mixed, 0.8 mL of a mixed solvent (benzene and n-butanol with a volume ratio of 1:1) was added, 2.4 mL of a 1 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise, ultrasonic treatment was performed for 10 min (35 kHz, 20 ° C), liquid nitrogen freezing was performed for 5 min, vacuum drying was performed, repeated twice, drying was performed at 110 ° C for 2 d, Soxhlet extraction was performed at 80 ° C for 12 h (solvent tetrahydrofuran), and vacuum drying was performed at 120 ° C for 24 h to obtain a methoxy-rich covalent organic framework material (hexagonal topology structure);

[0039] (2) Methoxy-rich covalent organic framework material @ glass fiber membrane: 12.4 mg of methoxy-rich covalent organic framework material was added to 38 mL of anhydrous ethanol and dispersed under ultrasonic radiation for 10 min (35 kHz, 20°C) to obtain a slurry. The slurry was filtered on a glass fiber membrane to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane;

[0040] (3) Methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane: 6.2 mg of graphene was added to 38 mL of anhydrous ethanol, and 3.8 mL of 1 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise. The mixture was ultrasonically treated for 10 min (35 kHz, 20 ° C) to obtain a graphene suspension. The graphene suspension was filtered on the other side of the glass fiber membrane and vacuum dried at 55 ° C for 3 h to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane.

[0041] Example 3

[0042] A methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries, comprising a methoxy-rich covalent organic framework material, a glass fiber diaphragm and graphene; the methoxy-rich covalent organic framework material has a thickness of 30 μm, the glass fiber diaphragm has a thickness of 70 μm, and the graphene has a thickness of 10 μm.

[0043] The preparation steps of the composite diaphragm include:

[0044] (1) Methoxy-rich covalent organic framework material: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (0.080 mmol, 28.1 mg), 2,5-dimethoxyterephthalaldehyde (0.160 mmol, 31.4 mg) and acetic acid (7 mol / L, 0.11 mL) were mixed, 1.1 mL of a mixed solvent (benzene and n-butanol with a volume ratio of 1:1) was added, 3.3 mL of a 10 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise, ultrasonic treatment was performed for 20 min (45 kHz, 30 ° C), liquid nitrogen freezing was performed for 5 min, vacuum drying was performed, repeated 4 times, drying was performed at 130 ° C for 4 d, Soxhlet extraction was performed at 90 ° C for 24 h (solvent tetrahydrofuran), and vacuum drying was performed at 120 ° C for 24 h to obtain a methoxy-rich covalent organic framework material (hexagonal topology structure);

[0045] (2) Methoxy-rich covalent organic framework material @ glass fiber membrane: 12.4 mg of methoxy-rich covalent organic framework material was added to 62 mL of anhydrous ethanol and dispersed under ultrasonic radiation for 20 min (45 kHz, 30°C) to obtain a slurry. The slurry was filtered on a glass fiber membrane to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane;

[0046] (3) Methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane: 6.2 mg of graphene was added to 43 mL of anhydrous ethanol, and 4.3 mL of 10 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise. The mixture was ultrasonically treated for 20 min (45 kHz, 30 ° C) to obtain a graphene suspension. The graphene suspension was filtered on the other side of the glass fiber membrane and vacuum dried at 65 ° C for 5 h to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane.

[0047] Comparative Example 1

[0048] The difference from Example 1 is that the composite membrane is composed of a methoxy-rich covalent organic framework material and a glass fiber membrane, and the rest is the same as Example 1.

[0049] The preparation steps of the composite diaphragm of this comparative example include:

[0050] (1) Methoxy-rich covalent organic framework material: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (0.080 mmol, 28.1 mg), 2,5-dimethoxyterephthalaldehyde (0.120 mmol, 23.3 mg) and acetic acid (6 mol / L, 0.1 mL) were mixed, 1 mL of a mixed solvent (benzene and n-butanol with a volume ratio of 1:1) was added, 3 mL of a 5 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise, ultrasonic treatment was performed for 15 min (40 kHz, 25 ° C), liquid nitrogen freezing was performed for 5 min, vacuum drying was performed, repeated 3 times, drying was performed at 120 ° C for 3 d, Soxhlet extraction was performed at 85 ° C for 18 h (solvent tetrahydrofuran), and vacuum drying was performed at 120 ° C for 24 h to obtain a methoxy-rich covalent organic framework material (hexagonal topology structure);

[0051] (2) Methoxy-rich covalent organic framework material @ glass fiber membrane: 12.4 mg of methoxy-rich covalent organic framework material was added to 40 mL of anhydrous ethanol and dispersed by ultrasonic radiation for 15 min (40 kHz, 25°C) to obtain a slurry. The slurry was filtered on a glass fiber membrane to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane.

[0052] Comparative Example 2

[0053] The difference from Example 1 is that the composite diaphragm is composed of graphene and glass fiber diaphragm, and the rest is consistent with Example 1.

[0054] The preparation steps of the composite diaphragm of this comparative example include:

[0055] Graphene@glass fiber membrane composite membrane: 6.2 mg of graphene was added to 40 mL of anhydrous ethanol, 3 mL of 5 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise, and ultrasonic treatment was performed for 15 min (40 kHz, 25 ° C) to obtain a graphene suspension. The graphene suspension was filtered through a glass fiber membrane and vacuum dried at 60 ° C for 4 h to obtain a graphene@glass fiber membrane composite membrane.

[0056] Comparative Example 3

[0057] The difference from Example 1 is that the graphene and the methoxy-rich covalent organic framework material are mixed and then filtered on a glass fiber membrane. Other steps are the same as in Example 1.

[0058] The preparation steps of the composite diaphragm of this comparative example include:

[0059] (1) Methoxy-rich covalent organic framework material: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (0.080 mmol, 28.1 mg), 2,5-dimethoxyterephthalaldehyde (0.120 mmol, 23.3 mg) and acetic acid (6 mol / L, 0.1 mL) were mixed, 1 mL of a mixed solvent (benzene and n-butanol with a volume ratio of 1:1) was added, 3 mL of a 5 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise, ultrasonic treatment was performed for 15 min (40 kHz, 25 ° C), liquid nitrogen freezing was performed for 5 min, vacuum drying was performed, repeated 3 times, drying was performed at 120 ° C for 3 d, Soxhlet extraction was performed at 85 ° C for 18 h (solvent tetrahydrofuran), and vacuum drying was performed at 120 ° C for 24 h to obtain a methoxy-rich covalent organic framework material (hexagonal topology structure);

[0060] (2) 12.4 mg of methoxy-rich covalent organic framework material was added to 40 mL of anhydrous ethanol and dispersed under ultrasonic radiation for 15 min (40 kHz, 25 ° C) to obtain a slurry. 6.2 mg of graphene was added to 40 mL of anhydrous ethanol, and 3 mL of 5 wt% polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise. The mixture was ultrasonically treated for 15 min (40 kHz, 25 ° C) to obtain a graphene suspension. The slurry and the graphene suspension were fully mixed, filtered on a glass fiber membrane, and vacuum dried at 60 ° C for 4 h to obtain a composite membrane.

[0061] Comparative Example 4

[0062] The difference from Example 1 is that the polyvinylidene fluoride / N-methylpyrrolidone solution is not added dropwise during the preparation process, and the other steps are the same as Example 1.

[0063] The preparation steps of the composite diaphragm of this comparative example include:

[0064] (1) Methoxy-rich covalent organic framework material: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (0.080 mmol, 28.1 mg), 2,5-dimethoxyterephthalaldehyde (0.120 mmol, 23.3 mg) and acetic acid (6 mol / L, 0.1 mL) were mixed, 1 mL of a mixed solvent (benzene and n-butanol with a volume ratio of 1:1) was added, ultrasonic treatment was performed for 15 min (40 kHz, 25 °C), liquid nitrogen freezing was performed for 5 min, vacuum drying was performed, repeated 3 times, drying was performed at 120 °C for 3 d, Soxhlet extraction was performed at 85 °C for 18 h (solvent tetrahydrofuran), and vacuum drying was performed at 120 °C for 24 h to obtain a methoxy-rich covalent organic framework material (hexagonal topology structure);

[0065] (2) Methoxy-rich covalent organic framework material @ glass fiber membrane: 12.4 mg of methoxy-rich covalent organic framework material was added to 40 mL of anhydrous ethanol and dispersed under ultrasonic radiation for 15 min (40 kHz, 25°C) to obtain a slurry. The slurry was filtered on a glass fiber membrane to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane;

[0066] (3) Methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane: 6.2 mg of graphene was added to 40 mL of anhydrous ethanol and ultrasonically treated for 15 min (40 kHz, 25 ° C) to obtain a graphene suspension. The graphene suspension was filtered on the other side of the glass fiber membrane and vacuum dried at 60 ° C for 4 h to obtain a methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane.

[0067] Comparative Example 5

[0068] The difference from Example 1 is that the thickness ratio of the composite diaphragm is 1:2:1, and the rest is the same as Example 1.

[0069] The composite membrane of this comparative example is composed of a methoxy-rich covalent organic framework material, a glass fiber membrane and graphene; the thickness of the methoxy-rich covalent organic framework material is 20 μm, the thickness of the glass fiber membrane is 100 μm, and the thickness of the graphene is 20 μm.

[0070] Test example

[0071] A manual slicer was used to cut the composite diaphragm into segments with a diameter of 18 mm. The zinc sheet (negative electrode), Examples 1-3 and Comparative Examples 1-5 (composite diaphragms), and activated carbon iodine electrode sheets (positive electrode) were placed in the packaging material in order from bottom to top and vacuum-sealed. The zinc-iodine battery was assembled (an aqueous solution of 3 mol / L ZnSO4 and 0.4 mol / L ZnI2 was used as the electrolyte). The performance of the assembled zinc-iodine battery was tested (discharge capacity and coulombic efficiency). The results are shown in Table 1.

[0072] The preparation method of activated carbon iodine electrode is to dissolve 10wt% PVDF in NMP to form a PVDF suspension. The porous carbon, carbon black and PVDF suspension are mixed and stirred at a weight ratio of 6:4:1 for 30 minutes to obtain a slurry. The slurry is evenly coated on the surface of a traditional hydrophilic carbon cloth and vacuum dried at 60℃ for 4 hours. The dried carbon cloth is cut into a circular cathode electrode with a diameter of 9mm. Iodine is adsorbed at 75℃ for 48 hours to achieve 5.2mg / cm 2 I2 load capacity.

[0073] Table 1

[0074]

[0075] As can be seen from Table 1, the zinc-iodine batteries assembled with the methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane prepared in Examples 1-3 of the present invention have excellent discharge performance and coulombic efficiency at different current densities (0.2, 0.5, 2, 5, 10 A / g), and have excellent electrochemical performance. Compared with Example 1, the electrochemical performance of the zinc-iodine batteries assembled with the composite membranes of Comparative Examples 1-5 decreased. This shows that the composite membrane obtained by the specific preparation method of the present invention, the thickness of each membrane layer, and the addition of polyvinylidene fluoride / N-methylpyrrolidone solution during the preparation process will affect the performance and stability of the zinc-iodine battery.

[0076] Figure 1 is the structural formula of the methoxy-rich covalent organic framework material prepared in Example 1, Figure 2 is the X-ray diffraction pattern of the methoxy-rich covalent organic framework material prepared in Example 1, Figure 3 This is the infrared spectrum of the methoxy-rich covalent organic framework material prepared in Example 1. Figure 2-3 It can be seen that the present invention successfully synthesizes methoxy-rich covalent organic framework materials. Figure 4 This is an SEM scan of the methoxy-rich covalent organic framework material@glass fiber membrane@graphene composite membrane prepared in Example 1. It can be seen that the composite membrane presents a complete and dense sandwich structure with a distinct layered morphology. Figure 5 The cycle performance diagram of the zinc-iodine battery assembled with the methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane prepared in Example 1 at 5A / g shows that stable cycle performance and high coulombic efficiency can be maintained at high current density. This is due to the crystalline structure and high porosity of the methoxy-rich covalent organic framework material @ glass fiber membrane @ graphene composite membrane of the present invention, which has excellent chemical stability and greatly improves the cycle life and charge and discharge stability of the battery.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries, characterized in that: The invention is composed of a methoxy-rich covalent organic framework material, a glass fiber separator and graphene with a thickness ratio of 4-6:10-14:1-2.

2. The methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries according to claim 1, characterized in that: The thickness of the methoxy-rich covalent organic framework material is 20-30 μm; the thickness of the glass fiber separator is 50-70 μm; and the thickness of the graphene is 5-10 μm.

3. The methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries according to claim 1, characterized in that: The methoxy-rich covalent organic framework material has a hexagonal topological structure.

4. The methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries according to claim 1, characterized in that: The preparation method of the methoxy-rich covalent organic framework material comprises: mixing 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, 2,5-dimethoxyterephthalaldehyde and a catalyst, adding the mixture into a mixed solvent, dropwise adding a polyvinylidene fluoride / N-methylpyrrolidone solution, ultrasonically treating, freezing with liquid nitrogen, vacuum drying, repeating the process 2-4 times, drying, Soxhlet extraction, and vacuum drying to obtain the methoxy-rich covalent organic framework material.

5. The methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries according to claim 4, characterized in that: The molar ratio of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine to 2,5-dimethoxyterephthalaldehyde is 1:1-2; the catalyst is any one of acetic acid, acetic acid, hydrochloric acid and perchloric acid, and the concentration is 5-7 mol / L; the molar ratio of 2,5-dimethoxyterephthalaldehyde to the catalyst is 1:5; the volume ratio of the polyvinylidene fluoride / N-methylpyrrolidone solution to the catalyst and the mixed solvent is 25-35:1:10; the polyvinylidene fluoride The concentration of the fluoroethylene / N-methylpyrrolidone solution is 1-10wt%; the mixed solvent consists of benzene and n-butanol in a volume ratio of 1:1; the ultrasonic treatment is performed at 35-45kHz and 20-30°C for 10-20min; the drying temperature is 110-130°C and the drying time is 2-4d; the solvent for the Soxhlet extraction is any one of tetrahydrofuran, acetone, ethanol, chloroform and ethyl acetate, the temperature is 80-90°C, and the drying time is 12-24h.

6. The method for preparing a methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries according to claim 1, characterized in that: The specific steps include: (1) adding a methoxyl-rich covalent organic framework material to anhydrous ethanol, dispersing it under ultrasonic radiation to obtain a slurry, and filtering the slurry on a glass fiber membrane to obtain a methoxyl-rich covalent organic framework material@glass fiber membrane; (2) Graphene was added to anhydrous ethanol, and polyvinylidene fluoride / N-methylpyrrolidone solution was added dropwise, and ultrasonic treatment was performed to obtain a graphene suspension. The graphene suspension was filtered on the other side of the glass fiber membrane and vacuum dried to obtain a methoxy-rich covalent organic framework material@glass fiber membrane@graphene composite membrane.

7. The method for preparing a methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries according to claim 6, characterized in that: In step (1), the solid-liquid ratio of the methoxy-rich covalent organic framework material to anhydrous ethanol is 1:3-5 mg / mL; and the ultrasonic radiation dispersion is performed at 35-45 kHz and 20-30° C. for 10-20 min.

8. The method for preparing a methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries according to claim 6, characterized in that: In step (2), the solid-liquid ratio of graphene to anhydrous ethanol is 1:6-7 mg / mL; the volume ratio of the polyvinylidene fluoride / N-methylpyrrolidone solution to anhydrous ethanol is 1:10-15, and the concentration of the polyvinylidene fluoride / N-methylpyrrolidone solution is 1-10wt%; the power of the ultrasonic treatment is 35-45kHz, the temperature is 20-30°C, and the time is 10-20min; the temperature of the vacuum drying is 55-65°C, and the time is 3-5h.

9. The method for preparing a methoxy-rich covalent organic framework material composite diaphragm for zinc-iodine batteries according to claim 6, characterized in that: The methoxy-rich covalent organic framework material@glass fiber membrane@graphene composite membrane is cut into a circular membrane with a diameter of 18 mm.

Images