Monatomic-aperture two-dimensional covalent organic framework material suitable for ion intercalation capacitor and preparation method and application of monatomic-aperture two-dimensional covalent organic framework material

Abstract

The invention discloses a monatomic aperture two-dimensional covalent organic framework material suitable for an ion intercalation capacitor, and a preparation method and application of the monatomic aperture two-dimensional covalent organic framework material. The preparation method of the two-dimensional covalent organic framework material comprises the following step: in the presence of an acid, carrying out a reaction on cyclohexanehexone and hydrazine hydrate in a solvent to obtain the two-dimensional covalent organic framework material. The novel COFs material (CH-COF) with a monatomic aperture characteristic is prepared by adopting a solution method which is easy to implement, the used method avoids a traditional tube sealing method, the preparation process is simple and easy to implement, and large-scale preparation can be carried out; when the prepared CH-COF is used as an electrode material of a supercapacitor, ultrahigh specific capacitance performance is shown.

Description

Technical Field

[0001] The present invention belongs to the field of two-dimensional materials, and particularly relates to a two-dimensional covalent organic framework material with a single-atom pore diameter applicable to ion intercalation capacitors, a preparation method thereof, and an application thereof. Background Art

[0002] Two-dimensional (2D) materials are an important research branch in the current fields of chemistry and materials, and are of great significance for future scientific and technological progress. For example, they are expected to lead the development of a new generation of energy materials and energy storage devices (Lukatskaya, M. R., et al., Science 341, 2013, 1502; Bi, S., et al., Nature Mater. 19, 2020, 552; Lukatskaya, M. R., et al., Nat. Energy 2017, 2, 17105), catalysis and energy conversion (Bi, S.; Meng, F.; Wu, D.; Zhang, F., J. Am. Chem. Soc. 2022, 144, 3653; Parvatkar, P. T., et al., J. Am. Chem. Soc. 2023, 145, 5074), optoelectronic functional materials and semiconductor devices (Eagleton, A. M., et al., J. Am. Chem. Soc. 2022, 144, 23297; Wang, Y., et al., J. Am. Chem. Soc. 2019, 141, 8030), etc., and are the scientific cornerstone for future competition among major powers. Among them, 2D covalent organic frameworks (COFs) are porous crystalline network layered materials formed by the bonding of organic ligands through organic reactions to form long-range order. Especially, their high specific surface area characteristics (Patra, B. C.; Bhattacharya, S., Chem. Mater. 2021, 33, 512), porous characteristics (Feng, X. N., et al., J. Am. Chem. Soc. 2023, 145, 21284), adjustable physicochemical characteristics (Burke, D. W., et al., J. Am. Chem. Soc. 2023, 145, 11969), and good electrical conductivity (Yue, Y.; Li, H.; Chen, H.; Huang, N., J. Am. Chem. Soc. 2022, 144, 2873) have made them good candidate materials for electrochemical electrode materials (Xu, X., et al., J. Am. Chem. Soc. 2023, 145, 1022).

[0003] The current design criteria for COF electrode materials mainly include two points. The first is to increase porosity and specific surface area, thereby increasing the potential for electrochemical energy storage. The second is to design active redox groups to enhance the pseudocapacitance performance of COFs. These two criteria improve the performance of electrode materials by enhancing the electric double layer capacitance or surface pseudocapacitance. However, the specific surface area is not equivalent to the electrochemically active area, and an increase in specific surface area does not necessarily lead to an improvement in performance. In addition, the introduction of active redox groups is also challenging, involving complex chemical structure design and potentially causing problems in chemical stability. A fast and reversible ion intercalation process is another important way to achieve efficient electrochemical capacitor devices. Currently, this mechanism has only been realized in some layered inorganic material systems such as Nb2O5, TiO2, MoS2, and Ti3C2 (Augustyn, Nat. Mater. 2013, 12, 518; H., et al., J. Phys. Chem. B 1997, 101, 7717; Acerce, M.; Voiry, D.; Chhowalla, M., Nat. Nanotechnol. 2015, 10, 313; Lukatskaya, M. R., et al., Science 2013, 341, 1502). Therefore, attempting to introduce the ion intercalation mechanism into COF materials is not only instructive for the design of future new COF-based electrode materials but also an important advancement in the expansion of this mechanism to organic material systems. However, the above-mentioned two design criteria are ineffective for designing COF electrodes suitable for ion intercalation capacitance. Currently, attempting to develop new design strategies to construct COF electrodes suitable for the ion intercalation mechanism is of great significance and faces challenges. Summary of the Invention

[0004] The purpose of the present invention is to provide a two-dimensional covalent organic framework material with a single-atom pore diameter suitable for ion intercalation capacitance, its preparation method, and applications.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a preparation method of a two-dimensional covalent organic framework material, including the following steps:

[0007] In the presence of an acid, cyclohexanehexone reacts with hydrazine hydrate in a solvent to obtain the two-dimensional covalent organic framework material.

[0008] In the above preparation method of the two-dimensional covalent organic framework material, the acid can be p-toluenesulfonic acid or acetic acid;

[0009] The feeding mass ratio of the cyclohexanehexone to the acid can be 1:(0.5 - 1.5), specifically 1:1;

[0010] The p-toluenesulfonic acid can specifically be added in the form of p-toluenesulfonic acid monohydrate.

[0011] In the above method for preparing the two-dimensional covalent organic framework material, the solvent is a mixed solution of mesitylene and dioxane or water. Further preferably, in the mixed solution of mesitylene and dioxane, the volume ratio of mesitylene to dioxane is 1:3;

[0012] The feeding ratio of cyclohexanehexone to the solvent is 900 mg:(40 - 80) mL, such as 900 mg:60 mL.

[0013] In the above method for preparing the two-dimensional covalent organic framework material, the feeding molar ratio of cyclohexanehexone to hydrazine hydrate is 1:(3 - 4), and specifically can be 1:3.3.

[0014] The cyclohexanehexone can specifically be added in the form of cyclohexanehexone octahydrate.

[0015] In the above method for preparing the two-dimensional covalent organic framework material, the temperature of the reaction can be 90 - 120 °C, specifically 120 °C; the time can be 48 - 72 hours, specifically 72 hours. The reaction can specifically be set with a condenser device for reflux.

[0016] As an example, the reaction is carried out under stirring conditions, such as at a rotation speed of 400 r / min;

[0017] The reaction is carried out under normal pressure and in an air atmosphere.

[0018] In the above method for preparing the two-dimensional covalent organic framework material, the specific operation of the preparation method is as follows:

[0019] 1) Mix the cyclohexanehexone and the acid, add the solvent to obtain a mixed solution;

[0020] 2) Ultrasonic the mixed solution, and after the ultrasonic is completed, add the hydrazine hydrate to obtain a reaction solution;

[0021] 3) Ultrasonic the reaction solution, and after the ultrasonic is completed, heat and stir to carry out the reaction;

[0022] 4) After the reaction is completed, separate the solid product and dry it to obtain the two-dimensional covalent organic framework material.

[0023] In the above specific operation, the time of the ultrasonic in step 2) can specifically be 10 min;

[0024] The time of the ultrasonic in step 3) can specifically be 10 min;

[0025] The separation described in step 4) can be carried out by suction filtration, and water and methanol are used as washing solvents during the suction filtration process;

[0026] The drying temperature described in step 4) can specifically be 100 °C, and the time can specifically be 24 h.

[0027] In a second aspect, the present invention provides a two-dimensional covalent organic framework material prepared by the preparation method described in any one of the above.

[0028] In a third aspect, the present invention provides the application of the described two-dimensional covalent organic framework material in any one of the following:

[0029] A. As an electrode material for lithium-ion, sodium-ion or potassium-ion energy storage devices;

[0030] B. Gas separation.

[0031] In the above application, the energy storage device is a battery or a supercapacitor.

[0032] It can be understood that an electrode or an energy storage device using the two-dimensional covalent organic framework material as an electrode material is also within the protection scope of the present invention.

[0033] The present invention has the following beneficial effects:

[0034] 1. In this paper, a novel COFs material (CH-COF) with single-atom pore size characteristics was prepared by an easy-to-implement solution method. The method used avoids the traditional sealed tube method, and the preparation process is simple and easy to carry out for large-scale preparation;

[0035] 2. The present invention uses CH-COF to prepare a hybrid electrode. The production method of this electrode is simple and does not involve a complex in-situ growth process, and it is very easy to be extended as an active electrode material for energy storage devices such as lithium-ion and potassium-ion;

[0036] 3. When the CH-COF prepared by the present invention is used as a supercapacitor electrode material, it exhibits ultra-high specific capacitance performance, and the mass specific capacitance reaches 643 F / g at a scan rate of 0.5 mV / s. Description of the Drawings

[0037] Figure 1 It is a synthesis schematic diagram of the novel two-dimensional covalent organic framework material CH-COF with single-atom pore size characteristics of the present invention. a is a reaction schematic diagram, and b-d are schematic diagrams of the crystal structure of the CH-COF material;

[0038] Figure 2 It is the morphology and elemental analysis of the CH-COF material prepared in Example 1. a is a scanning electron micrograph (scale bar 1 μm), and b and c are respectively the surface scanning diagrams of C element and N element.

[0039] Figure 3 Powder diffraction Pawley refinement results of the novel two-dimensional covalent organic framework CH-COF prepared in Example 1 Figure 3 In the figure, the curves from top to bottom are experimental XRD, refined and fitted XRD, simulated XRD, the difference between the experimental and the refined and fitted XRD, and the Bragg positions (the top two experimental XRD and the refined and fitted XRD coincide).

[0040] Figure 4 High-resolution transmission electron microscope images of the novel two-dimensional covalent organic framework CH-COF prepared in Example 1; a, (1 0 0) and (2 0 0) crystal planes; b, c, interplanar spacing dimensions of (1 0 0) and (2 0 0) crystal planes; d, (0 0 1) crystal plane and interplanar spacing dimension (scale bar 5 nm).

[0041] Figure 5 Cyclic voltammograms of the hybrid electrode of the novel two-dimensional covalent organic framework CH-COF prepared in Example 2 (the scan rates corresponding to the outer to inner circles are 12 mV / s, 7 mV / s, 5 mV / s, 2 mV / s, 1 mV / s, 0.5 mV / s in turn). Detailed implementation manners

[0042] The present invention will be further described in detail below in conjunction with the specific implementation manners. The provided examples are only for clarifying the present invention and not for limiting the scope of the present invention. The following provided examples can be used as a guide for those of ordinary skill in the art to make further improvements and do not limit the present invention in any way.

[0043] The methods used in the following examples are all conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

[0044] Example 1

[0045] This example provides a preparation method of a novel two-dimensional covalent organic framework material with single-atom pore characteristics, and the specific steps are as follows:

[0046] 1) Preparation of cyclohexanehexone ligand mixed solution

[0047] 900 mg of cyclohexanehexone octahydrate and 900 mg of p-toluenesulfonic acid monohydrate are added to a 200 ml flat-bottom flask, and a mixed solution of 15 mL of mesitylene and 45 mL of dioxane is added to obtain a cyclohexanehexone ligand mixed solution;

[0048] 2) Preparation of reaction solution

[0049] Ultrasonically treat the ligand mixed solution obtained in step 1) for 10 min, and then add 540 μL of hydrazine hydrate to obtain a reaction solution;

[0050] 3) Reaction

[0051] Ultrasonically treat the above reaction solution for 10 min, and then stir and react it at 120 °C (heating with an oil bath, adding 1 / 3 volume of methyl silicone oil in a glass petri dish with a diameter of 125 mm) for three days at a rotation speed of 400 rpm. Keep normal pressure and an atmospheric atmosphere during the reaction process, and set up a condenser device (coiled condenser) for reflux;

[0052] 4) Post-treatment

[0053] After reaching the reaction time, let the reaction solution stand and cool down to room temperature. Then, perform vacuum filtration on the reaction solution, use water and methanol as washing solvents, and wash repeatedly until the dropped washing liquid becomes colorless. Dry the solid product obtained by filtration in a vacuum drying oven at 100 °C for 24 h to obtain a brownish-black crystal.

[0054] Figure 1 This is a schematic diagram for the synthesis of the novel two-dimensional covalent organic framework material with single-atom pore characteristics of the present invention. a is a schematic diagram of the reaction, and b-d are schematic diagrams of the crystal structure;

[0055] Figure 2 This is the morphology and elemental analysis of the CH-COF material prepared in Example 1. a is a scanning electron micrograph, and b, c are elemental surface scan diagrams.

[0056] Figure 3 This is the Pawley refinement result of the powder diffraction of the novel two-dimensional covalent organic framework CH-COF prepared in Example 1, proving that the crystal structure of the material is α = β = 90.0°, and γ = 120.0°, adopting the P6 / M space group.

[0057] Figure 4 This is a high-resolution transmission electron microscope photograph of the novel two-dimensional covalent organic framework CH-COF prepared in Example 1. a is the (1 0 0) and (2 0 0) crystal planes, b, c are the interplanar spacing dimensions of the (1 0 0) and (2 0 0) crystal planes, and d is the (0 01) crystal plane and the interplanar spacing dimension.

[0058] As can be seen from the above results, the present invention has successfully prepared a two-dimensional covalent organic framework material. The high-resolution transmission electron microscope images and powder polycrystalline diffraction data show that the two-dimensional covalent organic framework material has good crystallinity, and the prepared two-dimensional covalent organic framework material has single-atom pore characteristics.

[0059] Example 2

[0060] In this embodiment, the ion intercalation capacitance characteristics of the novel 2D single-atom aperture feature COFs material obtained in Embodiment 1 were tested. The specific steps are as follows:

[0061] 1) Mix the CH-COF powder, conductive carbon black, and Nafion binder of Embodiment 1. The mass ratios of the CH-COF powder, conductive carbon black, and Nafion binder are 66.7 wt%, 16.7 wt%, and 16.6 wt% respectively. Grind to obtain a mixed slurry. Coat approximately 5 mg of the mixed slurry on a nickel foam substrate with a size of 1 cm × 1 cm, and use a press to compact it to obtain a working electrode.

[0062] 2) Place the working electrode in step 1) into a three-electrode electrochemical test device, assemble a counter electrode (a Pt sheet with a size of 1 cm × 1 cm) and a reference electrode (Ag / AgCl electrode), add 25 ml of 0.5 M Na2SO4 solution as the electrolyte, and use an electrochemical workstation (Chenhua electrochemical workstation CHI 760E) to perform cyclic voltammetry tests. The test voltage range is from 0 to -0.5 V to characterize its capacitance characteristics.

[0063] Figure 5 The cyclic voltammogram of the novel two-dimensional covalent organic framework CH-COF hybrid electrode prepared for Embodiment 2. It was calculated that the specific capacitance of the CH-COF electrode was as high as 643 F / g at a scan rate of 0.5 mV / s.

[0064] The above details the present invention. For those skilled in the art, without departing from the purpose and scope of the present invention, the present invention can be implemented within a relatively wide range under equivalent parameters, concentrations, and conditions. Although specific embodiments of the present invention are given, it should be understood that the present invention can be further improved. In short, according to the principle of the present invention, this application intends to include any changes, uses, or improvements to the present invention, including changes made using conventional techniques known in the art that are outside the scope disclosed in this application.

Claims

1. A preparation method of a two-dimensional covalent organic framework material, characterized in that, It includes the following steps: In the presence of an acid, cyclohexanehexone reacts with hydrazine hydrate in a solvent to obtain the two-dimensional covalent organic framework material.

2. The preparation method of the two-dimensional covalent organic framework material according to claim 1, wherein: The acid is p-toluenesulfonic acid or acetic acid; The feeding mass ratio of the cyclohexanehexone to the acid is 1:(0.5 - 1.5).

3. The preparation method of the two-dimensional covalent organic framework material according to any one of claims 1-2, characterized in that: The solvent is a mixed solution of mesitylene and dioxane or water.

4. The preparation method of the two-dimensional covalent organic framework material according to claim 3, wherein: In the mixed solution of mesitylene and dioxane, the volume ratio of mesitylene to dioxane is 1:3; The feeding ratio of the cyclohexanehexone to the solvent is 900 mg:(40 - 80) mL.

5. The preparation method of the two-dimensional covalent organic framework material according to any one of claims 1-4, characterized in that: The feeding molar ratio of the cyclohexanehexone to the hydrazine hydrate is 1:(3 - 4).

6. The preparation method of the two-dimensional covalent organic framework material according to any one of claims 1-5, characterized in that: The temperature of the reaction is 90 - 120 °C and the time is 48 - 72 hours.

7. The preparation method of the two-dimensional covalent organic framework material according to any one of claims 1-6, characterized in that: The specific operation of the preparation method is as follows: 1) Mix the cyclohexanehexone and the acid, and add the solvent to obtain a mixed solution; 2) Ultrasonicate the mixed solution, and after the sonication, add the hydrazine hydrate to obtain a reaction solution; 3) Ultrasonicate the reaction solution, and after the sonication, heat and stir to carry out the reaction; 4) After the reaction is completed, separate the solid product and dry it to obtain the two-dimensional covalent organic framework material.

8. The two-dimensional covalent organic framework material prepared by the preparation method according to any one of claims 1 - 7.

9. The application of the two-dimensional covalent organic framework material according to claim 8 in any one of the following: A. As an electrode material for lithium ion, sodium ion or potassium ion energy storage devices; B. Gas separation.

10. The application according to claim 9, wherein: The energy storage device is a battery or a supercapacitor.

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