Alkynyl-rich covalent organic framework material diaphragm for zinc-iodine battery and preparation method of alkynyl-rich covalent organic framework material diaphragm

Abstract

The invention provides an alkynyl-rich covalent organic framework material diaphragm for a zinc-iodine battery and a preparation method of the alkynyl-rich covalent organic framework material diaphragm, and the diaphragm comprises an alkynyl-rich covalent organic framework material, a zinc conduction diaphragm and amino graphene. And the conductivity of the battery is effectively improved. The composite diaphragm can effectively inhibit the growth of zinc dendrites, avoids the problem of battery short circuit caused by the fact that the zinc dendrites penetrate through the diaphragm, and prolongs the service life of the battery. Meanwhile, by adding the amino graphene, the electronic conductivity of the battery is enhanced, the ion migration rate is increased, and the charge-discharge efficiency is improved. Due to the existence of alkynyl, the surface affinity and the conductivity of the material are enhanced, and the energy density and the cycling stability of the zinc-iodine battery are greatly improved. As the diaphragm material has better chemical stability, the diaphragm material can effectively reduce side effects of internal reaction of the battery, reduce negative effects caused by zinc metal corrosion, and further improve the overall performance of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of zinc-iodine batteries, and particularly to a separator made of alkynyl-rich covalent organic framework material for zinc-iodine batteries and a preparation method thereof. Background Art

[0002] With the continuous increase in energy demand and the growing pressure of environmental protection, clean and efficient energy storage technologies have become one of the hotspots of global research. Among various energy storage technologies, zinc-iodine batteries have gradually become a promising energy storage technology due to their relatively high energy density, long cycle life, and relatively low cost. The working principle of zinc-iodine batteries is based on the reversible electrochemical reaction of zinc ions and iodine ions, and they have relatively superior performance. However, zinc-iodine batteries face some challenges in practical applications, especially in terms of long-term stability, efficiency, and performance of the batteries. Among them, the design and performance of the zinc-iodine battery separator play a crucial role in its overall performance. Traditional battery separator materials usually use polyolefin-based polymer materials such as polypropylene (PP) and polyethylene (PE). These materials have good chemical stability and low internal resistance, but their stability under high current density and high temperature conditions is poor, and their ability to control ion migration inside the battery is limited. Especially in zinc-iodine batteries, since zinc metal is prone to dendrite growth, traditional separator materials often have difficulty effectively suppressing dendrite growth, resulting in an increase in battery internal resistance, a decline in cycle performance, and even potential safety hazards such as short circuits.

[0003] Therefore, it is necessary to develop a separator for zinc-iodine batteries to solve the problems of current traditional separator materials. Summary of the Invention

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

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

[0006] A separator made of alkynyl-rich covalent organic framework material for zinc-iodine batteries includes an alkynyl-rich covalent organic framework material, a zinc-conducting separator, and amino graphene; the alkynyl-rich covalent organic framework material has a hexagonal topological structure, and its structural formula is as shown in Ⅰ:

[0007]

[0008] Furthermore, the thickness of the zinc-conducting separator is 50 - 70 μm, serving as the base layer of the separator; the thickness of the alkynyl-rich covalent organic framework material is 20 - 30 μm, serving as the middle layer of the separator; the thickness of the amino graphene is 5 - 10 μm, serving as the top layer of the separator.

[0009] Further, the preparation method of the alkynyl-rich covalent organic framework material includes:

[0010] Mix 1,3,5-triformylphloroglucinol, 4,4'-(ethyne-1,2-diyl)dianiline and an acetic acid catalyst and add them to a composite solvent, perform ultrasonic treatment, freeze with liquid nitrogen, vacuum dry, bake, Soxhlet extract, and vacuum dry to obtain the alkynyl-rich covalent organic framework material.

[0011] Further, the molar ratio of 1,3,5-triformylphloroglucinol to 4,4'-(ethyne-1,2-diyl)dianiline and acetic acid is 1:1.3 - 1.5:1.3 - 2.6; the concentration of the acetic acid catalyst is 5 - 7 mol / L; the composite solvent is m-xylene and cyclohexene oxide with a volume ratio of 1:1; the volume ratio of acetic acid to the composite solvent is 1:10 - 20; the ultrasonic treatment is carried out at 35 - 45 kHz and 20 - 30 °C for 10 - 20 min; the baking is carried out at 110 - 130 °C for 2 - 4 days; the solvent for Soxhlet extraction is a mixed solution of acetone and dichloromethane with a volume ratio of 1:1, the extraction temperature is 80 - 90 °C, and the extraction time is 12 - 24 h.

[0012] Further, the preparation method of the amino graphene includes: according to a solid-liquid ratio of 1:400 - 500 g / mL, add graphene oxide to deionized water, ultrasonically disperse it evenly, add concentrated ammonia water with a concentration of 25% - 30%, the volume ratio of concentrated ammonia water to deionized water is 1:10 - 20, hydrothermally react in a reaction kettle at 120 - 140 °C for 12 - 20 h, cool, centrifuge, wash and dry to obtain amino graphene.

[0013] Further, the preparation method of the graphene oxide includes: grind and mix graphite powder and potassium nitrate with a mass ratio of 1:10 - 15, add concentrated sulfuric acid with a concentration of 95% - 98% under an ice bath environment and stir until it becomes a paste, the solid-liquid ratio of graphite powder to concentrated sulfuric acid is 1:50 - 70 g / mL, add potassium permanganate, the molar ratio of potassium permanganate to potassium nitrate is 2 - 3:1, control the temperature at 5 - 10 °C and react for 30 - 40 min, then raise the temperature to 60 - 70 °C and react for 1 - 3 h, neutralize and wash the product to neutrality, and freeze-dry to obtain graphene oxide.

[0014] A preparation method of a diaphragm made of an alkynyl-rich covalent organic framework material for a zinc-iodine battery, the specific steps include:

[0015] (1) Add the alkynyl-rich covalent organic framework material to absolute ethanol for ultrasonic treatment to form a suspension, filter the suspension on a zinc-conducting diaphragm to obtain an alkynyl-rich covalent organic framework material composite diaphragm;

[0016] (2) Add amino graphene into absolute ethanol, dropwise add polyvinylidene fluoride / N-methylpyrrolidone solution, and perform ultrasonic treatment to obtain an amino graphene suspension. Filter the amino graphene suspension on the alkyne-rich covalent organic framework material composite separator prepared in step (1). The zinc-conductive separator serves as the base layer of the separator, the alkyne-rich covalent organic framework material serves as the intermediate layer, and amino graphene serves as the top layer of the separator. Then, perform vacuum drying to obtain an alkyne-rich covalent organic framework material / amino graphene composite separator.

[0017] Further, step (1) is specifically as follows: Add the alkyne-rich covalent organic framework material into absolute ethanol according to a solid-liquid ratio of 1:1 - 5 mg / mL, perform ultrasonic dispersion at 35 - 45 kHz and 20 - 30 °C for 10 - 20 min to form a suspension, and filter the suspension on the zinc-conductive separator to obtain an alkyne-rich covalent organic framework material composite separator.

[0018] Further, step (2) is specifically as follows: Add amino graphene into absolute ethanol according to a solid-liquid ratio of 1:6 - 7 mg / mL, dropwise add 1 - 10 wt% of polyvinylidene fluoride / N-methylpyrrolidone solution, with the volume ratio of polyvinylidene fluoride / N-methylpyrrolidone solution to absolute ethanol being 1:10 - 15. Then, perform ultrasonic treatment at 35 - 45 kHz and 20 - 30 °C for 10 - 20 min to obtain an amino graphene suspension. Filter the amino graphene suspension on the alkyne-rich covalent organic framework material composite separator prepared in step (1). The zinc-conductive separator serves as the base layer of the separator, the alkyne-rich covalent organic framework material serves as the intermediate layer, and amino graphene serves as the top layer of the separator. Perform vacuum drying at 55 - 65 °C for 3 - 5 h to obtain an alkyne-rich covalent organic framework material / amino graphene composite separator.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. The composite separator of the present invention significantly improves the cycle stability and safety of zinc-iodine batteries, and effectively improves the conductive performance of the batteries. The composite separator can effectively inhibit the growth of zinc dendrites, avoid the problem of battery short circuit caused by zinc dendrites penetrating the separator, and extend the service life of the battery. At the same time, the addition of amino graphene enhances the electronic conductivity of the battery, improves the ion migration rate, and increases the charge-discharge efficiency. The presence of alkynes enhances the surface affinity and conductivity of the material, greatly improving the energy density and cycle stability of zinc-iodine batteries. Due to the good chemical stability of the separator material, it can effectively reduce the side effects of internal reactions in the battery, reduce the negative impact caused by zinc metal corrosion, and further improve the overall performance of the battery.

[0021] 2. Compared with traditional battery separator materials, the composite separator of the present invention has low cost, can be prepared by a simple solvothermal method, is easy to scale up production, and has strong industrial application prospects. In addition, it has good tunability and adaptability, can be optimized according to the needs of different batteries, and has broad application potential. Description of the Drawings

[0022] Figure 1 It is a structural formula diagram of Tp-EDDA-COF in Example 1.

[0023] Figure 2 It is an X-ray diffraction pattern of Tp-EDDA-COF in Example 1.

[0024] Figure 3 It is an infrared spectrum diagram of Tp-EDDA-COF in Example 1.

[0025] Figure 4 It is an SEM scanning diagram of the composite separator in Example 1.

[0026] Figure 5 It is a mapping scanning diagram of the composite separator in Example 1.

[0027] Figure 6 It is the rate cycling performance diagram of the zinc-iodine battery assembled with the composite separator in Example 1 at 10-20 mA·cm -2 under.

[0028] Figure 7 It is the cycling performance diagram of the zinc-iodine batteries assembled with the composite separators of Example 1 and Comparative Examples 1-3 at 20 mA·cm -2 under.

[0029] Figure 8 It is the impedance performance diagram of the zinc-iodine batteries assembled with the composite separators of Example 1 and Comparative Examples 1-3. Detailed Embodiments

[0030] To better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0031] The experimental methods used in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0032] The materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial channels unless otherwise specified.

[0033] 1,3,5-triformylphloroglucinol Tp 4,4’-(ethyne-1,2-diyl)dianiline EDDA alkyne-rich covalent organic framework material Tp-EDDA-COF aminated graphene AG zinc-conducting separator GF polyvinylidene fluoride / N-methylpyrrolidone PTFE / NMP graphene GR methoxy-rich covalent organic framework material TAPT-DMTA-COF

[0034] Example 1

[0035] The composite separator of this embodiment is composed of a 60-μm GF (base layer), a 25-μm Tp-EDDA-COF (intermediate layer), and a 7.5-μm AG (top layer).

[0036] The preparation steps of the above composite separator are as follows:

[0037] (1) Preparation of Tp-EDDA-COF: Mix Tp (0.3 mmol, 63 mg), EDDA (0.45 mmol, 94 mg), and an acetic acid catalyst (6 mol / L, 0.1 mL), add them to 1 mL of a composite solvent (mesitylene and cyclohexene oxide with a volume ratio of 1:1), perform ultrasonic treatment at 40 kHz and 25 °C for 15 min, freeze with liquid nitrogen for 5 min, vacuum dry, repeat 3 times, dry at 120 °C for 3 days, perform Soxhlet extraction at 85 °C for 18 h, the extraction solvent is acetone and dichloromethane with a volume ratio of 1:1, and vacuum dry at 120 °C for 24 h to obtain Tp-EDDA-COF with a hexagonal topological structure.

[0038] (2) Preparation of AG: Grind and mix 0.5 g of graphite powder and 6.5 g of potassium nitrate, add 30 mL of 98% concentrated sulfuric acid under an ice bath environment and stir until it becomes a paste, add potassium permanganate, the molar ratio of potassium permanganate to potassium nitrate is 2.5:1, control the temperature at 8 °C and react for 35 min, then raise the temperature to 65 °C and react for 2 h, neutralize the product with dilute hydrochloric acid, wash until neutral, and freeze-dry to obtain graphene oxide. Add 0.5 g of graphene oxide to 225 mL of deionized water, ultrasonically disperse it evenly, add 15 mL of 25% concentrated ammonia water, hydrothermally react in a reaction kettle at 130 °C for 15 h, cool, centrifuge, wash and dry to obtain AG.

[0039] (3) Preparation of the composite separator: Add 20 mg of Tp-EDDA-COF to 40 mL of absolute ethanol, perform ultrasonic treatment at 40 kHz and 25 °C for 15 min to form a suspension, filter the suspension on GF. Add 6.2 mg of AG to 40 mL of absolute ethanol, dropwise add 3 mL of 5 wt% PTFE / NMP solution, then perform ultrasonic treatment at 40 kHz and 25 °C for 15 min to obtain an AG suspension, continue to filter the AG suspension on GF, and vacuum dry at 60 °C for 4 h to obtain the target composite separator.

[0040] Example 2

[0041] The composite separator of this embodiment is composed of a 50-μm GF (base layer), a 20-μm Tp-EDDA-COF (intermediate layer), and a 5-μm AG (top layer).

[0042] The preparation steps of the above composite separator are as follows:

[0043] (1) Preparation of Tp-EDDA-COF: Mix Tp (0.3 mmol, 63 mg), EDDA (0.39 mmol, 81.47 mg) and acetic acid catalyst (5 mol / L, 0.08 mL), add them into 0.8 mL of composite solvent (mesitylene and cyclohexene oxide with a volume ratio of 1:1), perform ultrasonic treatment at 35 kHz and 20 °C for 10 min, freeze with liquid nitrogen for 5 min, dry under vacuum, repeat 3 times, dry at 110 °C for 2 days, extract with Soxhlet at 80 °C for 12 h, the extraction solvent is acetone and dichloromethane with a volume ratio of 1:1, dry under vacuum at 120 °C for 24 h to obtain Tp-EDDA-COF with a hexagonal topological structure.

[0044] (2) Preparation of AG: Grind and mix 0.5 g of graphite powder and 5 g of potassium nitrate, add 25 mL of concentrated sulfuric acid with a concentration of 95% under an ice bath environment and stir until it becomes a paste, add potassium permanganate, the molar ratio of potassium permanganate to potassium nitrate is 2:1, control the temperature at 5 °C and react for 30 min, then raise the temperature to 60 °C and react for 3 h, neutralize the product with dilute hydrochloric acid, wash until neutral, and freeze-dry to obtain graphene oxide. Add 0.5 g of graphene oxide into 200 mL of deionized water, disperse it evenly by ultrasonic treatment, add 20 mL of concentrated ammonia water with a concentration of 25%, hydrothermal react in a reaction kettle at 120 °C for 12 h, cool, centrifuge, wash and dry to obtain AG.

[0045] (3) Preparation of composite separator: Add 20 mg of Tp-EDDA-COF into 38 mL of absolute ethanol, perform ultrasonic treatment at 35 kHz and 20 °C for 10 min to form a suspension, filter the suspension on GF. Add 6.2 mg of AG into 38 mL of absolute ethanol, dropwise add 3.8 mL of 1 wt% PTFE / NMP solution, then perform ultrasonic treatment at 35 kHz and 20 °C for 10 min to obtain an AG suspension. Continue to filter the AG suspension on GF and dry it under vacuum at 55 °C for 3 h to obtain the target composite separator.

[0046] Example 3

[0047] The composite separator in this example is a 70-μm GF (base layer), 30-μm Tp-EDDA-COF (intermediate layer) and 10-μm AG (top layer).

[0048] The preparation steps of the above composite separator are as follows:

[0049] (1) Preparation of Tp-EDDA-COF: Tp (0.3 mmol, 63 mg), EDDA (0.42 mmol, 87.73 mg) and acetic acid catalyst (7 mol / L, 0.11 mL) were mixed and added to 1.1 mL of a composite solvent (mesitylene and cyclohexene oxide with a volume ratio of 1:1). The mixture was sonicated at 45 kHz and 30 °C for 20 min, frozen with liquid nitrogen for 5 min, dried under vacuum, and this process was repeated 3 times. Then it was dried at 130 °C for 4 days, extracted with Soxhlet at 90 °C for 24 h, and the extraction solvent was acetone and dichloromethane with a volume ratio of 1:1. Finally, it was dried under vacuum at 120 °C for 24 h to obtain Tp-EDDA-COF with a hexagonal topological structure.

[0050] (2) Preparation of AG: 0.5 g of graphite powder and 7.5 g of potassium nitrate were ground and mixed. Under an ice bath, 35 mL of concentrated sulfuric acid with a concentration of 98% was added and stirred until it became a paste. Then potassium permanganate was added, and the molar ratio of potassium permanganate to potassium nitrate was 3:1. The temperature was controlled at 10 °C and reacted for 40 min, then the temperature was raised to 70 °C and reacted for 1 h. The product was neutralized with dilute hydrochloric acid, washed until neutral, and freeze-dried to obtain graphene oxide. 0.5 g of graphene oxide was added to 250 mL of deionized water, sonicated to disperse evenly, 12.5 mL of 30% concentrated ammonia water was added, and the hydrothermal reaction was carried out at 140 °C for 20 h in a reaction kettle. After cooling, centrifugation, washing, and drying, AG was obtained.

[0051] (3) Preparation of the composite separator: 20 mg of Tp-EDDA-COF was added to 62 mL of absolute ethanol and sonicated at 45 kHz and 30 °C for 20 min to form a suspension. The suspension was filtered on GF. 6.2 mg of AG was added to 43 mL of absolute ethanol, 4.3 mL of 10 wt% PTFE / NMP solution was added dropwise, and then sonicated at 45 kHz and 30 °C for 20 min to obtain an AG suspension. The AG suspension was continuously filtered on GF and dried under vacuum at 65 °C for 5 h to obtain the target composite separator.

[0052] Comparative Example 1

[0053] The difference from Example 1 is that amino graphene was replaced with graphene, and the others were the same as in Example 1.

[0054] That is, the composite separator of this comparative example is 60 μm of GF (base layer), 25 μm of Tp-EDDA-COF (intermediate layer), and 7.5 μm of GR (top layer).

[0055] The preparation steps of the above composite separator are as follows:

[0056] (1) Preparation of Tp-EDDA-COF: Tp (0.3 mmol, 63 mg), EDDA (0.45 mmol, 94 mg) and acetic acid catalyst (6 mol / L, 0.1 mL) were mixed and added to 1 mL of a composite solvent (mesitylene and cyclohexene oxide with a volume ratio of 1:1). Ultrasonic treatment was carried out at 40 kHz and 25 °C for 15 min, followed by freezing with liquid nitrogen for 5 min and vacuum drying. This process was repeated 3 times. Then, it was dried at 120 °C for 3 days, extracted with Soxhlet at 85 °C for 18 h using a solvent of acetone and dichloromethane with a volume ratio of 1:1, and finally dried in vacuum at 120 °C for 24 h to obtain Tp-EDDA-COF with a hexagonal topological structure.

[0057] (2) Preparation of the composite separator: 20 mg of Tp-EDDA-COF was added to 40 mL of absolute ethanol and ultrasonicated at 40 kHz and 25 °C for 15 min to form a suspension. The suspension was filtered on GF. 6.2 mg of GR was added to 40 mL of absolute ethanol, and 3 mL of 5 wt% PTFE / NMP solution was added dropwise. Then, it was ultrasonicated at 40 kHz and 25 °C for 15 min to obtain a GR suspension. The GR suspension was further filtered on GF and vacuum dried at 60 °C for 4 h to obtain the composite separator.

[0058] Comparative Example 2

[0059] The difference from Example 1 is that the alkyne-rich covalent organic framework material was replaced with a methoxy-rich covalent organic framework material, and the others were the same as in Example 1.

[0060] That is, the composite separator of this comparative example is a 60-μm GF (base layer), a 25-μm TAPT-DMTA-COF (intermediate layer), and a 7.5-μm AG (top layer).

[0061] The preparation steps of the above composite separator are as follows:

[0062] (1) Preparation of TAPT-DMTA-COF: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (0.08 mmol, 28.1 mg), 2,5-dimethoxyterephthalaldehyde (0.12 mmol, 23.3 mg) and acetic acid catalyst (6 mol / L, 0.1 mL) were mixed and added to 1 mL of a composite solvent (benzene and n-butanol with a volume ratio of 1:1). Ultrasonic treatment was carried out at 40 kHz and 25 °C for 15 min, followed by freezing with liquid nitrogen for 5 min and vacuum drying. This process was repeated 3 times. Then, it was dried at 120 °C for 3 days, extracted with Soxhlet at 85 °C for 18 h using a solvent of mesitylene and cyclohexene oxide with a volume ratio of 1:1, and finally dried in vacuum at 120 °C for 24 h to obtain TAPT-DMTA-COF with a hexagonal topological structure.

[0063] (2) Preparation of AG: 0.5 g of graphite powder and 6.5 g of potassium nitrate were ground and mixed. Under an ice bath environment, 30 mL of concentrated sulfuric acid with a concentration of 98% was added and stirred until it became a paste. Potassium permanganate was added, and the molar ratio of potassium permanganate to potassium nitrate was 2.5:1. The temperature was controlled at 8 °C and the reaction was carried out for 35 min. Then the temperature was raised to 65 °C and the reaction was carried out for 2 h. The product was neutralized with dilute hydrochloric acid, washed until neutral, and freeze-dried to obtain graphene oxide. 0.5 g of graphene oxide was added to 225 mL of deionized water, ultrasonically dispersed evenly, 15 mL of 25% concentrated ammonia water was added, and the reaction kettle was hydrothermally treated at 130 °C for 15 h. After cooling, centrifugation, washing, and drying, AG was obtained.

[0064] (3) Preparation of the composite separator: 20 mg of TAPT-DMTA-COF was added to 40 mL of absolute ethanol, and ultrasonically treated at 40 kHz and 25 °C for 15 min to form a suspension. The suspension was filtered on GF. 6.2 mg of AG was added to 40 mL of absolute ethanol, 3 mL of 5 wt% PTFE / NMP solution was added dropwise, and then ultrasonically treated at 40 kHz and 25 °C for 15 min to obtain an AG suspension. The AG suspension was continuously suction-filtered on GF and vacuum-dried at 60 °C for 4 h to obtain the composite separator.

[0065] Comparative Example 3

[0066] The difference from Example 1 is that the composite separator is a 60-μm GF (base layer), a 25-μm TAPT-DMTA-COF (intermediate layer), and a 7.5-μm GR (top layer), and the others are the same as in Example 1.

[0067] That is, the preparation steps of the composite separator in this comparative example are as follows:

[0068] (1) Preparation of TAPT-DMTA-COF: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (0.08 mmol, 28.1 mg), 2,5-dimethoxyterephthalaldehyde (0.12 mmol, 23.3 mg), and acetic acid catalyst (6 mol / L, 0.1 mL) were mixed and added to 1 mL of a composite solvent (benzene and n-butanol with a volume ratio of 1:1). Ultrasonically treated at 40 kHz and 25 °C for 15 min, frozen with liquid nitrogen for 5 min, and vacuum-dried. Repeat 3 times, dried at 120 °C for 3 days, Soxhlet extracted at 85 °C for 18 h, and the extraction solvent was m-xylene and cyclohexene oxide with a volume ratio of 1:1. Vacuum-dried at 120 °C for 24 h to obtain TAPT-DMTA-COF with a hexagonal topological structure.

[0069] (2) Preparation of the composite separator: Add 20 mg of TAPT-DMTA-COF to 40 mL of absolute ethanol, and ultrasonically treat it at 40 kHz and 25 °C for 15 min to form a suspension. Filter the suspension on GF. Add 6.2 mg of GR to 40 mL of absolute ethanol, dropwise add 3 mL of 5 wt% PTFE / NMP solution, and then ultrasonically treat it at 40 kHz and 25 °C for 15 min to obtain a GR suspension. Continue to filter the GR suspension on GF and vacuum dry it at 60 °C for 4 h to obtain the composite separator.

[0070] Test examples

[0071] Cut the composite separators prepared in Examples 1-3 and Comparative Examples 1-3 into fragments with a diameter of 18 mm. Place the zinc sheet (negative electrode), Examples 1-3 and Comparative Examples 1-3 (composite separators), and the activated carbon iodine electrode sheet (positive electrode) into the packaging material in order from bottom to top and perform vacuum packaging to assemble a zinc-iodine battery (3 mol / L ZnSO 4 and 0.4 mol / L ZnI 2 aqueous solution as the electrolyte), and perform performance detection on the assembled zinc-iodine battery.

[0072] Among them, the preparation method of the activated carbon iodine electrode sheet is to dissolve 10 wt% of PTFE in NMP to form a PTFE suspension. Mix and stir the porous carbon, carbon black, and PTFE suspension in a weight ratio of 6:4:1 for 30 min to obtain a slurry. Uniformly coat the slurry on the surface of a traditional hydrophilic carbon cloth, vacuum dry it at 60 °C for 4 h, cut the dried carbon cloth into circular cathode electrode sheets with a diameter of 9 mm, and perform iodine adsorption at 75 °C for 48 h to reach an I 2 loading of 6.2 mg / cm 2 load.

[0073] The results are shown in Tables 1-2.

[0074] Table 1

[0075]

[0076] Table 2

[0077]

[0078]

[0079] As can be seen from Table 1 and Table 2, the zinc-iodine batteries assembled with the composite separators prepared in Examples 1-3 of the present invention exhibit excellent discharge performance and Coulomb efficiency at different current densities, demonstrating excellent electrochemical performance. Compared with Example 1, the zinc-iodine batteries assembled with the composite separators prepared in Comparative Examples 1-3 of the present invention show a decline in their electrochemical performance at different current densities, indicating that both the methoxy-rich covalent organic framework material and amino graphene in the composite separator of the present invention will significantly affect the performance and stability of the zinc-iodine battery.

[0080] See Figure 2 X-ray diffraction pattern of and Figure 3 infrared spectrum of, it can be seen that the methoxy-rich covalent organic framework material was successfully synthesized. See Figure 4 SEM scan of and Mapping scan of 5, it can be seen that the composite separator presents a complete and dense three-layer structure and has an obvious layered morphology.

[0081] Figure 6 is the rate cycling performance of the zinc-iodine battery assembled with the composite separator of Example 1 at a current density of 10-20 mA·cm -2 , it can be seen that the zinc-iodine battery can still maintain stable cycling performance and high Coulomb efficiency at different current densities.

[0082] Figure 7 is the cycling performance graph of the zinc-iodine batteries assembled with the composite separators of Example 1 and Comparative Examples 1-3 at a high current density of 20 mA·cm -2 , it can be seen that the zinc-iodine battery of Example 1 can still maintain stable cycling performance and high Coulomb efficiency at a high current density. This is because of the excellent crystalline structure and high porosity of the composite separator of Example 1. At the same time, amino graphene further improves the conductivity and thermal stability of the separator, making it have excellent chemical stability, thus significantly improving the cycle life and charge-discharge stability of the battery.

[0083] Figure 8 is the electrochemical impedance performance graph of the zinc-iodine batteries assembled with the composite separators of Example 1 and Comparative Examples 1-3. It can be seen that the separator modified with amino graphene in Example 1 shows a lower impedance overall, indicating better ion transport and interfacial charge transfer performance. And amino graphene can significantly reduce the internal resistance of the battery, further improving the electrochemical performance of the material.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A diaphragm of alkyne-rich covalent organic framework material for zinc-iodine battery, characterized in that: It includes an alkynyl-rich covalent organic framework material, a zinc-conducting diaphragm and amino graphene; the alkynyl-rich covalent organic framework material is a hexagonal topological structure, and the structural formula is shown in I:

2. The alkyne-rich covalent organic framework material diaphragm for zinc-iodine battery according to claim 1, characterized in that: The zinc conductive membrane has a thickness of 50-70 μm and serves as a base layer of the membrane; the alkynyl-rich covalent organic framework material has a thickness of 20-30 μm and serves as an intermediate layer of the membrane; and the amino graphene has a thickness of 5-10 μm and serves as a top layer of the membrane.

3. The alkyne-rich covalent organic framework material diaphragm for zinc-iodine battery according to claim 1, characterized in that: The preparation method of the alkyne-rich covalent organic framework material comprises: 1,3,5-triformylphloroglucinol, 4,4'-(ethynyl-1,2-diyl)diphenylamine and acetic acid catalyst are mixed and added into a composite solvent, and ultrasonic treatment is performed, liquid nitrogen freezing is performed, vacuum evacuation is performed, drying is performed, Soxhlet extraction is performed, and vacuum drying is performed to obtain an alkynyl-rich covalent organic framework material.

4. The alkyne-rich covalent organic framework material diaphragm for zinc-iodine battery according to claim 3, characterized in that: The molar ratio of the 1,3,5-triformylphloroglucinol to 4,4'-(acetylene-1,2-diyl)diphenylamine and acetic acid is 1:1.3-1.5:1.3-2.6; the concentration of the acetic acid catalyst is 5-7 mol / L; the composite solvent is m-trimethylbenzene and oxirane in a volume ratio of 1:1; the volume ratio of the acetic acid to the composite solvent is 1:10-20; the ultrasonic treatment is carried out at 35-45kHz and 20-30°C for 10-20min; the drying is carried out at 110-130°C for 2-4 days; the solvent for the Soxhlet extraction is a mixed solution of acetone and dichloromethane in a volume ratio of 1:1, the extraction temperature is 80-90°C, and the extraction time is 12-24h.

5. The alkyne-rich covalent organic framework material diaphragm for zinc-iodine battery according to claim 1, characterized in that: The preparation method of the amino graphene comprises: According to the solid-liquid ratio of 1:400-500 g / mL, graphene oxide is added to deionized water, ultrasonically dispersed evenly, 25%-30% concentrated ammonia water is added, the volume ratio of concentrated ammonia water to deionized water is 1:10-20, the reactor is hydroheated at 120-140° C. for 12-20 hours, cooled, centrifuged, washed and dried to obtain amino graphene.

6. The alkyne-rich covalent organic framework material diaphragm for zinc-iodine battery according to claim 5, characterized in that: The preparation method of graphene oxide comprises: grinding and mixing graphite powder and potassium nitrate in a mass ratio of 1:10-15, adding concentrated sulfuric acid with a concentration of 95%-98% in an ice bath environment and stirring until the mixture is in a paste state, wherein the solid-liquid ratio of the graphite powder to the concentrated sulfuric acid is 1:50-70 g / mL, adding potassium permanganate, wherein the molar ratio of potassium permanganate to potassium nitrate is 2-3:1, controlling the temperature at 5-10° C. for reaction for 30-40 minutes, then heating the temperature to 60-70° C. for reaction for 1-3 hours, neutralizing and washing the product until it is neutral, and freeze-drying the product to obtain graphene oxide.

7. The method for preparing an alkynyl-rich covalent organic framework material diaphragm for a zinc-iodine battery according to claim 1, characterized in that: The specific steps include: (1) adding an alkynyl-rich covalent organic framework material to anhydrous ethanol for ultrasonic treatment to form a suspension, filtering the suspension on a zinc conductive membrane to obtain an alkynyl-rich covalent organic framework material composite membrane; (2) Adding amino graphene to anhydrous ethanol, adding polyvinylidene fluoride / N-methylpyrrolidone solution dropwise, ultrasonically treating to obtain an amino graphene suspension, and filtering the amino graphene suspension on the alkynyl-rich covalent organic framework material composite diaphragm of step (1), wherein the zinc conductive diaphragm is the base layer of the diaphragm, the alkynyl-rich covalent organic framework material is the middle layer, and the amino graphene is the top layer of the diaphragm, vacuum drying to obtain an alkynyl-rich covalent organic framework material / amino graphene composite diaphragm.

8. The method for preparing an alkynyl-rich covalent organic framework material diaphragm for a zinc-iodine battery according to claim 7, characterized in that: Step (1) is specifically as follows: adding the alkynyl-rich covalent organic framework material into anhydrous ethanol at a solid-liquid ratio of 1:1-5 mg / mL, performing ultrasonic dispersion at 35-45 kHz and 20-30° C. for 10-20 min to form a suspension, filtering the suspension on a zinc conductive diaphragm to obtain a composite diaphragm of the alkynyl-rich covalent organic framework material.

9. The method for preparing an alkynyl-rich covalent organic framework material diaphragm for a zinc-iodine battery according to claim 7, characterized in that: Step (2) is specifically as follows: according to a solid-liquid ratio of 1:6-7 mg / mL, amino graphene is added to anhydrous ethanol, 1-10 wt% of polyvinylidene fluoride / N-methylpyrrolidone solution is added dropwise, the volume ratio of polyvinylidene fluoride / N-methylpyrrolidone solution to anhydrous ethanol is 1:10-15, and then ultrasonic treatment is performed at 35-45 kHz and 20-30° C. for 10-20 min to obtain an amino graphene suspension, and the amino graphene suspension is filtered on the alkynyl-rich covalent organic framework material composite diaphragm of step (1), the zinc conductive diaphragm is the base layer of the diaphragm, the alkynyl-rich covalent organic framework material is the middle layer, and the amino graphene is the top layer of the diaphragm, and vacuum drying is performed at 55-65° C. for 3-5 h to obtain an alkynyl-rich covalent organic framework material / amino graphene composite diaphragm.

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