Two-dimensional covalent organic framework material with double-pore-channel structure as well as preparation method and application of two-dimensional covalent organic framework material

Abstract

The invention provides a two-dimensional covalent organic framework material with a double-pore-channel structure and a preparation method and application thereof.The preparation method comprises the steps that 4, 4 ', 4', 4 ''-(pyrene-1, 3, 6, 8-tetrayl) tetraphenylamine, 4, 4 ', 4''-[benzene-1, 3, 5-triyl-tri (acetylene-2, 1-diyl)] tribenzaldehyde and an acetic acid catalyst are sequentially added into a composite solvent, a reaction system is evenly mixed, ultrasonic treatment is conducted, and the two-dimensional covalent organic framework material is obtained. According to the two-dimensional covalent organic framework material with the double-pore-channel structure, a three-dimensional through pore channel system is formed by rhombic pores and hexagonal pores which are periodically arranged, rhombic pore channels provide high-density active sites, and hexagonal pore channels construct continuous ion transmission channels, so that the material has high specific surface area and chemical stability; efficient loading of active substances and rapid ion migration are achieved through the synergistic effect of the two, and the shuttle effect is greatly reduced. The confinement effect of the double-pore-channel structure can significantly improve the loading capacity of iodine, alkynyl functional groups uniformly distributed in the double-pore-channel structure enhance the zinc affinity and electron conduction performance of the surface of the material, and dendritic crystals are effectively prevented from being formed.

Description

Technical Field

[0001] The present invention relates to the field of organic functional materials, and particularly relates to a two-dimensional covalent organic framework material with a double-channel structure, a preparation method thereof, and an application thereof. Background Art

[0002] With the continuous increase in energy demand and the increasing pressure of environmental protection, clean and efficient energy storage technologies have become one of the hotspots of global research. Driven by the demand for electric vehicles and energy storage devices, the development of high-efficiency, low-cost, and high-safety batteries has important strategic significance. Battery systems based on the coupling of halogen / chalcogen elements with lithium / zinc anodes exhibit excellent performance, and among them, non-metallic elements such as iodine, sulfur, and selenium have attracted much attention due to their high safety, fast reaction kinetics, good reversibility, large theoretical capacity, and rich resources. In particular, aqueous zinc-iodine batteries are regarded as strong competitors for the next-generation energy storage system due to their low cost, high specific capacity, outstanding safety, and rapid redox kinetics.

[0003] However, this system still faces three challenges: the inherently low conductivity of iodine (10 -5 -10 -7 S·cm -1 ), the serious self-discharge and cycle decay caused by the shuttle effect of soluble I3 - / I5 - intermediates, and the overall capacity limitation caused by the generally low active iodine loading in the current cathode (usually <3mg·cm -2 ). These problems seriously restrict its practical application.

[0004] Therefore, it is necessary to develop a new type of porous material with high iodine loading for use in zinc-iodine batteries to solve the technical problems that occur in current traditional zinc-iodine batteries. Summary of the Invention

[0005] In view of this, the present invention provides a two-dimensional covalent organic framework material with a double-channel structure, a preparation method thereof, and an application thereof.

[0006] The technical solution of the present invention is realized as follows:

[0007] A two-dimensional covalent organic framework material with a double-channel structure has a structure shown in Formula I:

[0008]

[0009] Furthermore, the structure of Formula I is a topological structure in which rhombuses and hexagons alternate.

[0010] A preparation method of a two-dimensional covalent organic framework material with a double-channel structure, the specific steps include:

[0011] 4,4’,4”,4”’-(pyrene-1,3,6,8-tetrayl)tetraaniline, 4,4’,4”-[benzene-1,3,5-triyltris(ethyne-2,1-diyl)]tribenzaldehyde and acetic acid catalyst were successively added into a composite solvent, and the reaction system was uniformly mixed and ultrasonically treated to obtain the target two-dimensional covalent organic framework material.

[0012] Furthermore, the molar ratio of 4,4’,4”,4”’-(pyrene-1,3,6,8-tetrayl)tetraaniline, 4,4’,4”-[benzene-1,3,5-triyltris(ethyne-2,1-diyl)]tribenzaldehyde and acetic acid is 1:1.3 - 1.4:5 - 7;

[0013] The concentration of acetic acid is 5 - 7 mol / L.

[0014] Furthermore, the composite solvent is o-dichlorobenzene and n-butanol with a volume ratio of 1:1, and the addition amount is 18 - 22 times the volume of acetic acid;

[0015] The frequency of the ultrasonic treatment is 35 - 45 kHz, the temperature is 20 - 30 °C, and the time is 3 - 5 min.

[0016] Application of a two-dimensional covalent organic framework material with a double-channel structure in the preparation of a cathode material for a zinc-iodine battery.

[0017] Furthermore, the cathode material for the zinc-iodine battery includes the two-dimensional covalent organic framework material described in claim 1 or 2, carbon black and a hydrophilic carbon cloth.

[0018] Furthermore, the preparation method of the cathode material for the zinc-iodine battery specifically includes:

[0019] (1) The two-dimensional covalent organic framework material described in claim 1 or 2, carbon black and a polyvinylidene fluoride / N-methylpyrrolidone solution were uniformly mixed to form a mixed slurry, and the mixed slurry was uniformly coated on the surface of the hydrophilic carbon cloth and vacuum dried to form a composite substrate;

[0020] (2) After the composite substrate was processed into a cathode plate, iodine adsorption treatment was carried out to obtain the target cathode material for the zinc-iodine battery.

[0021] Furthermore, in step (1) of the preparation method of the cathode material for the zinc-iodine battery, the mass ratio of the two-dimensional covalent organic framework material, carbon black and the polyvinylidene fluoride / N-methylpyrrolidone solution is 1:0.4 - 0.6:10 - 15;

[0022] The concentration of the polyvinylidene fluoride / N-methylpyrrolidone solution is 1 wt% - 10 wt%.

[0023] Further, in step (1) of the preparation method of the zinc-iodine battery cathode material, the coating thickness of the mixed slurry is 200-300 μm; the thickness of the hydrophilic carbon cloth is 500-700 μm.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. The two-dimensional covalent organic framework material with a double-channel structure prepared by the present invention forms a three-dimensional through-channel system through periodically arranged rhombic pores and hexagonal pores. The rhombic pores provide high-density active sites, and the hexagonal pores construct continuous ion transport channels, with both high specific surface area and chemical stability. The synergistic effect of the two realizes the efficient loading of active substances and the rapid migration of ions, significantly reducing the shuttle effect. The confinement effect of the double-channel structure of the present invention can significantly increase the iodine loading capacity, and the uniformly distributed alkynyl functional groups inside enhance the zincophilicity and electron conduction performance of the material surface, effectively preventing dendrite formation.

[0026] 2. The process of the present invention is simple and low-cost. The pore size can be precisely regulated by adjusting the spatial configuration of the organic ligand to adapt to different electrolyte systems. In the zinc-iodine battery, its hierarchical pore system can strengthen the fixation of active substances through the geometric matching effect, improving the cycle stability of the battery. In addition, the alkynyl-bridged conjugated framework forms a continuous electron transport network, which can significantly reduce the interfacial impedance, and the inherent chemical inertness of the two-dimensional covalent organic framework can effectively inhibit the electrode-electrolyte side reaction and reduce the risk of metal corrosion. The cathode material obtained by the present invention is suitable for high-energy density energy storage systems, can improve the battery capacity and charge-discharge efficiency, and also ensures the safety of long-term battery use. Description of the Drawings

[0027] Figure 1 It is the structural formula diagram of Py-TAEB-COF of the present invention.

[0028] Figure 2 It is the X-ray diffraction pattern of Py-TAEB-COF of Example 1.

[0029] Figure 3 It is the infrared spectrum diagram of Py-TAEB-COF of Example 1.

[0030] Figure 4 It is the SEM scanning diagram of Py-TAEB-COF of Example 1.

[0031] Figure 5 It is the cyclic voltammogram of the zinc-iodine battery assembled with the cathode material of Example 1.

[0032] Figure 6 For the zinc-iodine battery assembled with the cathode material of Example 1 at 10-20 mA·cm-2 Discharge rate cycle performance graph below.

[0033] Figure 7 Self-discharge performance graph of zinc-iodine batteries assembled with the cathode materials of Example 1 and Comparative Examples 1-2.

[0034] Figure 8 For Example 1, cycle performance graph of zinc-iodine batteries assembled with the cathode materials of Comparative Examples 1-2 at 20 mA·cm -2 Cycle performance graph below. Detailed implementation mode

[0035] To better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0036] The experimental methods used in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0037] The materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial channels unless otherwise specified.

[0038]

[0039]

[0040] Example 1

[0041] (1) Preparation of Py-TAEB-COF:

[0042] Add Py (0.12 mmol, 68 mg), TAEB (0.16 mmol, 74 mg) and acetic acid catalyst (6 mol / L, 0.1 mL) to 2 mL of composite solvent (o-dichlorobenzene and n-butanol with a volume ratio of 1:1) in sequence, uniformly mix the reaction system, perform ultrasonic treatment at 40 kHz and 25 °C for 4 min, freeze with liquid nitrogen for 5 min, vacuum dry, repeat 3 times, heat at 120 °C for 3 days, perform Soxhlet extraction at 70 °C for 24 h, and the Soxhlet extraction solvent is acetone and dichloromethane with a volume ratio of 1:1. After completion, vacuum dry at 120 °C for 24 h to obtain a two-dimensional covalent organic framework material with an alternating rhombic and hexagonal topological structure, namely Py-TAEB-COF.

[0043] (2) Preparation of the cathode material for zinc-iodine batteries:

[0044] Mix 480 mg of Py-TAEB-COF, 240 mg of Cb, and 6 g of 5 wt% PTFE / NMP solution, stir evenly at 400 rpm to form a mixed slurry. Uniformly coat the mixed slurry on the surface of a hydrophilic carbon cloth with a thickness of 600 μm, with the slurry coating thickness being 250 μm. Vacuum dry at 60 °C for 4 h to form a composite substrate. Use a manual slicing machine to process the composite substrate into a cathode plate with a diameter of 9 mm, place it in an iodine bottle containing 100 g of iodine, and perform iodine adsorption treatment in an oven at 75 °C for 48 h to obtain the positive electrode material for the zinc-iodine battery.

[0045] See Figure 2 The X-ray diffraction pattern of Py-TAEB-COF and Figure 3 The infrared spectrum of Py-TAEB-COF. It can be seen that the two-dimensional covalent organic framework material Py-TAEB-COF was successfully synthesized in this invention. See Figure 4 From the SEM scan of Py-TAEB-COF, it can be seen that the material has a fluffy fibrous structure.

[0046] Example 2

[0047] (1) Preparation of Py-TAEB-COF:

[0048] Add Py (0.12 mmol, 68 mg), TAEB (0.16 mmol, 74 mg), and acetic acid catalyst (7 mol / L, 0.1 mL) to 1.8 mL of a composite solvent (o-dichlorobenzene and n-butanol with a volume ratio of 1:1) in sequence, uniformly mix the reaction system, perform ultrasonic treatment at 35 kHz and 20 °C for 3 min, freeze with liquid nitrogen for 5 min, vacuum dry, repeat 3 times, heat at 110 °C for 2 days, perform Soxhlet extraction at 65 °C for 18 h, with the Soxhlet extraction solvent being acetone and dichloromethane with a volume ratio of 1:1. After completion, vacuum dry at 110 °C for 18 h to obtain a two-dimensional covalent organic framework material with an alternating rhombic and hexagonal topological structure, namely Py-TAEB-COF.

[0049] (2) Preparation of the positive electrode material for the zinc-iodine battery:

[0050] Mix 480 mg of Py-TAEB-COF, 200 mg of Cb, and 5 g of 1 wt% PTFE / NMP solution, stir evenly at 300 rpm to form a mixed slurry. Uniformly coat the mixed slurry on the surface of a hydrophilic carbon cloth with a thickness of 500 μm, with the slurry coating thickness being 200 μm. Vacuum dry at 50 °C for 3.5 h to form a composite substrate. Use a manual slicing machine to process the composite substrate into a cathode plate with a diameter of 9 mm, place it in an iodine bottle containing 100 g of iodine, and perform iodine adsorption treatment in an oven at 70 °C for 36 h to obtain the positive electrode material for the zinc-iodine battery.

[0051] Example 3

[0052] (1) Preparation of Py-TAEB-COF:

[0053] Py (0.12 mmol, 68 mg), TAEB (0.16 mmol, 74 mg) and acetic acid catalyst (8 mol / L, 0.1 mL) were successively added to 2.2 mL of a composite solvent (o-dichlorobenzene and n-butanol with a volume ratio of 1:1). The reaction system was uniformly mixed, ultrasonicated at 45 kHz and 30 °C for 5 min, frozen with liquid nitrogen for 5 min, and then dried under vacuum. This process was repeated 3 times. Then it was heated at 130 °C for 4 days, subjected to Soxhlet extraction with a Soxhlet extraction solvent of acetone and dichloromethane with a volume ratio of 1:1 at 75 °C for 30 h. After completion, it was vacuum dried at 130 °C for 30 h to obtain a two-dimensional covalent organic framework material with a topological structure of alternating rhombus and hexagon, namely Py-TAEB-COF.

[0054] (2) Preparation of the positive electrode material for zinc-iodine battery:

[0055] 480 mg of Py-TAEB-COF, 280 mg of Cb and 7 g of 10 wt% PTFE / NMP solution were mixed and stirred evenly at 500 rpm to form a mixed slurry. The mixed slurry was uniformly coated on the surface of a hydrophilic carbon cloth with a thickness of 700 μm, and the coating thickness of the slurry was 300 μm. It was vacuum dried at 70 °C for 4.5 h to form a composite substrate. The composite substrate was processed into a cathode plate with a diameter of 9 mm using a manual slicing machine, placed in an iodine bottle containing 100 g of iodine, and subjected to iodine adsorption treatment in an oven at 80 °C for 50 h to obtain the positive electrode material for zinc-iodine battery.

[0056] Comparative Example 1

[0057] The difference from Example 1 is that Py-TAEB-COF was replaced with Zif-8, and the others were the same as in Example 1.

[0058] That is, the preparation of Zif-8 in this comparative example (1):

[0059] Zinc nitrate (0.5 mmol, 149 mg), 2-methylimidazole (2.0 mmol, 164 mg), and surfactant PVP (0.02 mmol, 5 mg) were mixed, and 10 mL of a composite solvent (methanol and N,N-dimethylformamide with a volume ratio of 3:1) was added. The mixture was sonicated for 10 min at 40 kHz and 25 °C to form a homogeneous and transparent solution. The mixed solution was transferred to a 50 mL stainless-steel autoclave with a PTFE liner, sealed, and placed in an oven. The temperature was raised to 120 °C at a rate of 5 °C / min, and the reaction was carried out at a constant temperature for 24 h. After natural cooling to room temperature, the white precipitate was collected by centrifugation at 8000 rpm for 5 min, washed alternately with methanol and deionized water three times, and the product was dried in vacuo at 80 °C for 12 h to obtain Zif-8 crystals with a rhombic dodecahedron morphology;

[0060] (2) Preparation of the positive electrode material for the zinc-iodine battery:

[0061] 480 mg of Zif-8, 240 mg of Cb, and 6 g of 5 wt% PTFE / NMP solution were mixed and stirred evenly at 400 rpm to form a mixed slurry. The mixed slurry was evenly coated on the surface of a hydrophilic carbon cloth with a thickness of 600 μm, and the coating thickness of the slurry was 250 μm. It was dried in vacuo at 60 °C for 4 h to form a composite substrate. The composite substrate was processed into a cathode electrode sheet with a diameter of 9 mm using a manual slicing machine, placed in an iodine bottle containing 100 g of iodine, and subjected to an iodine adsorption treatment in an oven at 75 °C for 48 h to obtain the positive electrode material for the zinc-iodine battery.

[0062] Comparative Example 2

[0063] The difference from Example 1 is that Py-TAEB-COF was replaced with AC, and the others were the same as in Example 1.

[0064] That is, the preparation of the positive electrode material for the zinc-iodine battery in this comparative example: 480 mg of AC, 240 mg of Cb, and 6 g of 5 wt% PTFE / NMP solution were mixed and stirred evenly at 400 rpm to form a mixed slurry. The mixed slurry was evenly coated on the surface of a hydrophilic carbon cloth with a thickness of 600 μm, and the coating thickness of the slurry was 250 μm. It was dried in vacuo at 60 °C for 4 h to form a composite substrate. The composite substrate was processed into a cathode electrode sheet with a diameter of 9 mm using a manual slicing machine, placed in an iodine bottle containing 100 g of iodine, and subjected to an iodine adsorption treatment in an oven at 75 °C for 48 h to obtain the positive electrode material for the zinc-iodine battery.

[0065] Test Example

[0066] The positive electrode materials prepared in Examples 1-3 and Comparative Examples 1-2 were assembled into a zinc-iodine battery (using an aqueous solution of 3 mol / L ZnSO4 and 0.4 mol / L ZnI2 as the electrolyte) by successively assembling a 12-mm zinc sheet (negative electrode), an 18-mm glass fiber separator, and the positive electrode material from bottom to top, placing them in a packaging material and performing vacuum packaging, and then the performance of the assembled zinc-iodine battery was tested.

[0067] The results are shown in Tables 1 and 2.

[0068] Table 1

[0069]

[0070] Table 2

[0071]

[0072] As can be seen from Tables 1 and 2, the zinc-iodine batteries assembled with the positive electrode materials prepared in Examples 1-3 of the present invention exhibited excellent discharge performance and Coulombic efficiency at different current densities and had good electrochemical performance. The electrochemical performance of the zinc-iodine batteries assembled with the positive electrodes prepared in Comparative Examples 1-2 decreased at different current densities, indicating that the two-dimensional covalent organic framework material with a double-channel structure prepared in the present invention significantly affected the electrochemical performance and stability of the zinc-iodine battery.

[0073] Figure 5 The rate cycling performance of the zinc-iodine battery assembled with the positive electrode material prepared in Example 1 at different current densities (10 - 20 mA·cm -2 ). As can be seen from the figure, the zinc-iodine battery of the present invention could still maintain stable cycling performance and high Coulombic efficiency at different current densities.

[0074] Figure 6 The cyclic voltammogram of the zinc-iodine battery assembled with the positive electrode material prepared in Example 1. As can be seen, the zinc-iodine battery of the present invention had good redox performance at different scanning rates.

[0075] Figure 7 The self-discharge performance diagram of the zinc-iodine batteries assembled with the positive electrode materials prepared in Example 1 and Comparative Examples 1-2 at a high current density of 20 mA·cm -2 . As can be seen, the zinc-iodine battery assembled with the positive electrode material prepared in Example 1 could still maintain a high Coulombic efficiency after standing at a high current density for 48 h. This was because the excellent crystalline structure and high porosity of the Py-TAEB-COF of the present invention endued it with excellent chemical stability, significantly improving the cycle life and charge-discharge stability of the battery.

[0076] Figure 8The cycling performance graphs of the zinc-iodine batteries assembled with the cathode materials prepared in Example 1 and Comparative Examples 1-2 at 20 mA·cm -2 It can be seen that the zinc-iodine battery assembled with the cathode material prepared in Example 1 of the present invention can still maintain stable cycling performance and high Coulomb efficiency at high current density.

[0077] 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 principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A two-dimensional covalent organic framework material with a two-channel structure, characterized in that, It has the structure shown in Formula I:

2. The two-dimensional covalent organic framework material with a double-channel structure according to claim 1, characterized in that, The structure of Formula I is a topological structure in which rhombuses and hexagons alternate.

3. The preparation method of a two-dimensional covalent organic framework material with a double-channel structure according to claim 1, characterized in that, The specific steps include: Add 4,4’,4”,4”’-(pyrene-1,3,6,8-tetrayl)tetraaniline, 4,4’,4”-[benzene-1,3,5-triyltris(ethyne-2,1-diyl)]tribenzaldehyde and acetic acid catalyst into the composite solvent in sequence, uniformly mix the reaction system, and perform ultrasonic treatment to obtain the target two-dimensional covalent organic framework material.

4. The preparation method of a two-dimensional covalent organic framework material with a double-channel structure according to claim 3, wherein, The molar ratio of 4,4’,4”,4”’-(pyrene-1,3,6,8-tetrayl)tetraaniline, 4,4’,4”-[benzene-1,3,5-triyltris(ethyne-2,1-diyl)]tribenzaldehyde and acetic acid is 1:1.3 - 1.4:5 - 7; The concentration of the acetic acid is 5 - 7 mol / L.

5. The preparation method of a two-dimensional covalent organic framework material with a double-channel structure according to claim 3, characterized in that, The composite solvent is o-dichlorobenzene and n-butanol with a volume ratio of 1:1, and the addition amount is 18 - 22 times the volume of acetic acid; The frequency of the ultrasonic treatment is 35 - 45 kHz, the temperature is 20 - 30 °C, and the time is 3 - 5 min.

6. Use of a two-dimensional covalent organic framework material with a double-channel structure described in Claim 1 or 2 in the preparation of a cathode material for a zinc-iodine battery.

7. The application according to claim 6, wherein The cathode material for the zinc-iodine battery includes the two-dimensional covalent organic framework material described in Claim 1 or 2, carbon black and a hydrophilic carbon cloth.

8. The application according to claim 7, wherein The preparation method of the cathode material for the zinc-iodine battery specifically includes: (1) Mix the two-dimensional covalent organic framework material described in Claim 1 or 2, carbon black and a polyvinylidene fluoride / N-methylpyrrolidone solution evenly to form a mixed slurry, uniformly coat the mixed slurry on the surface of the hydrophilic carbon cloth, and perform vacuum drying to form a composite substrate; (2) After processing the composite substrate into a cathode plate, perform iodine adsorption treatment to obtain the target cathode material for the zinc-iodine battery.

9. The application according to claim 8, wherein In step (1) of the preparation method of the cathode material for the zinc-iodine battery, the mass ratio of the two-dimensional covalent organic framework material, carbon black and the polyvinylidene fluoride / N-methylpyrrolidone solution is 1:0.4 - 0.6:10 - 15; The concentration of the polyvinylidene fluoride / N-methylpyrrolidone is 1 wt% - 10 wt%.

10. The application according to claim 8, wherein In step (1) of the preparation method of the cathode material for the zinc-iodine battery, the coating thickness of the mixed slurry is 200 - 300 μm; the thickness of the hydrophilic carbon cloth is 500 - 700 μm.

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