Defective covalent organic framework material and preparation method and application thereof

Abstract

The application discloses a preparation method of a defective covalent organic framework material. The prepared defective covalent organic framework has high porosity, good crystallinity and thermal stability, and contains active anchor points on the framework pore wall which can be functionally modified, and shows good universality in the construction of the defective covalent organic framework methodology. Firstly, based on a three-component co-condensation strategy, the defective covalent organic framework material containing active anchor points is prepared, and then a functional small molecule is introduced through a post-modification reaction to obtain a covalent organic framework-based solid electrolyte material with good lithium ion conduction performance. The material has good lithium ion transmission performance in the temperature range from room temperature to 80 DEG C. These excellent performances prove that the defective covalent organic framework material provided by the application is a kind of parent material which can be functionally modified and has good universality.

Description

Technical Field

[0001] The present invention belongs to the technical field of covalent organic frameworks, and in particular relates to the preparation of a defective covalent organic framework material containing aldehyde active anchoring points and its application in solid electrolytes. Background Art

[0002] Lithium-ion batteries consist of a positive electrode, a negative electrode, and a separator soaked in an organic electrolyte. The electrolyte is a bridge connecting the positive and negative electrode materials, and plays the role of transporting and conducting current between the positive and negative electrodes of the battery. As the only liquid component in lithium-ion batteries, it itself has problems such as flammability, easy decomposition at high temperatures, and corrosiveness, which seriously hinder the development of lithium-ion batteries into safe solid devices, resulting in the loss of the possibility of achieving high safety, high mechanical strength and high reliability. In recent years, solid-state lithium batteries with solid electrolytes as the core component have been widely regarded as the key to the next generation of energy storage technology due to their advantages such as high safety, high energy density, long cycle life, good rate performance and wide operating temperature range.

[0003] At present, the reported solid electrolytes mainly include two categories: inorganic solid electrolytes and polymer solid electrolytes. Although inorganic solid electrolytes have been successfully applied in the field of batteries, there are still some problems, such as large interface impedance after the electrolyte contacts lithium metal, poor compatibility with positive and negative electrodes, low lithium ion conductivity and poor stability in air, which reduces battery performance. Polymer electrolyte materials have the advantages of good processing performance, light weight, and good viscoelasticity. However, this type of electrolyte material has excellent crystallization performance. The material has poor ion conductivity when it is not heat-treated, and its ion transport area is mainly concentrated in the amorphous area. The relationship between the structure and performance of the electrolyte material is unclear. Therefore, how to prepare solid electrolyte materials with good stability and high lithium ion conductivity through reasonable molecular structure design will help further promote the development of lithium-ion batteries.

[0004] To prepare solid-state electrolyte materials with excellent lithium-ion conductivity, the structural design of the materials must meet the following two basic requirements: 1) Excellent lithium-ion conductivity requires the material itself to have good backbone segment regularity and a certain degree of mobility; 2) The material itself must carry a certain amount of positive and negative charges to enhance ion dissociation. Compared with traditional polymers, covalent organic frameworks (COFs) are a class of organic porous polymers with excellent crystallinity. They are designed and manufactured based on the principles of dynamic covalent chemistry. Through the continuous formation and breaking of reversible dynamic covalent bonds, a long-range ordered porous structure is formed. In addition, COFs not only have the advantages of light weight, strong structural designability, and excellent material stability, but their ordered pore structure provides a wide range of modification space for active molecules and also provides specific transport pathways for lithium-ion conduction and migration, making COFs a research hotspot for the design of new solid-state electrolyte materials. Although there have been several reports of improving lithium ion conductivity by fixing anionic groups on COFs frameworks through "bottom-up" and "post-modification methods", the ionic groups themselves are easily free and the flexibility of the ionic segments is relatively limited, making it difficult to introduce or fix anionic groups on the COFs framework, making this strategy difficult to be widely applied and promoted in the field of solid electrolytes. Therefore, how to effectively fix anionic groups on the COFs framework has become a key step in the preparation of COFs-based solid electrolyte materials.

[0005] Functionalization, a post-modification method, is widely used to manipulate the structure and function of COFs. This method can introduce functional groups (anionic groups) while maintaining the stability of the framework structure and is considered the most effective method for introducing functional groups. Generally speaking, functionalization of COFs requires the presence of functional groups within the framework that are reactive and suitable for subsequent chemical reactions (e.g., acetylene, hydroxyl, amine, olefin, azide, and nitrile groups). Among these, amino groups, which are nucleophilic, react with aldehydes through Schiff base reactions, which are mild and require simple post-processing. This type of reaction is ideal for COF functionalization. In recent years, the Bein, Loh, and Dong groups have prepared COFs containing amino-reactive anchors through two-step reaction methods or by carefully screening reaction solvent systems. However, during the reaction and preparation of COFs, these active anchors tend to bind to structural units or inhibit COF crystal formation. Therefore, the introduction or retention of nucleophilic functional groups within the COF framework remains a significant challenge. Summary of the Invention

[0006] In response to the above-mentioned prior art, the present invention provides a preparation method of a defective covalent organic framework material containing aldehyde active anchoring points and its application in solid electrolytes.

[0007] To solve the above technical problems, the present application provides a defective covalent organic framework material, which comprises a C3 aldehyde-based organic monomer, a C3 amino organic monomer and a single-side amino organic monomer, the functional group molar ratio of the C3 aldehyde-based organic monomer to the C3 amino organic monomer and the single-side amino organic monomer is 1:1, the functional group molar ratio of the C3 amino organic monomer to the single-side amino organic monomer is 4:1-2:3, and the defective covalent organic framework material is prepared based on a three-component co-condensation reaction. 2 g -1 .

[0008] Further, the defective covalent organic framework material provided by the present application, wherein:

[0009] The C3 aldehyde-based organic monomer is 1,3,5-tris(p-formylphenyl)benzene or 2,4,6-tris(4-formylphenyl)-1,3,5-triazine; the C3 amino organic monomer is 1,3,5-tris(4-aminophenyl)benzene; and the single-side amino organic monomer is one of aniline, 4-aminobiphenyl, 3',5'-diphenyl biphenyl-4-amine and 5-phenyl-[1,1:3,1-triphenyl]-4,4-diamine.

[0010] In the three-component co-condensation reaction, the mixed solvent is an organic solvent that can mix the above three organic monomers to form a uniform dispersion liquid, and the organic solvent is one or a combination of more of dioxane, n-butanol / o-dichlorobenzene and mesitylene / dioxane; and the catalyst is an acetic acid aqueous solution with a molar concentration of 3M-9M.

[0011] Meanwhile, the present application also provides a preparation method of the above covalent organic framework material, which comprises the following steps:

[0012] Step 1) The molar ratio of the functional groups of each component of the C3 aldehyde-based organic monomer, the C3 amino organic monomer and the single-side amino organic monomer is weighed, and the mixed solvent and the catalyst are weighed according to the molar volume concentration of the total amount of organic monomers to the mixed solvent and the total amount of organic monomers to the catalyst, respectively, which is 1mmol / mL;

[0013] Step 2) The three organic monomers and the mixed solvent weighed in step 1) are put into an ampoule, mixed uniformly under ultrasonic conditions, then the catalyst weighed in step 1) is added, and a defective covalent organic framework material containing aldehyde-based active anchor points is prepared by solvent thermal reaction based on a three-component co-condensation strategy.

[0014] Further, the preparation method provided by the present application, wherein:

[0015] In step 2), the process conditions of the solvent thermal reaction are: reaction in an oven, reaction temperature 90-150 ° C, reaction time 24-96 hours, after the reaction is completed, a precipitate is obtained at the bottom of the ampoule, and the precipitate is subjected to post-treatment reaction to obtain a defective covalent organic framework material containing an aldehyde active anchor point, and the post-treatment process is: cooling the precipitate to room temperature, collecting the precipitate with a centrifuge tube, and then washing with tetrahydrofuran, methanol and acetone several times until the solution is colorless, and the product obtained by drying is a yellow solid powder; Soxhlet extraction is used for purification, using tetrahydrofuran for extraction for 12-96 hours, and then the obtained polymer is vacuum dried for 24-48 hours.

[0016] In step 2), in the solvent thermal reaction, preferably, the reaction temperature is 120° C. and the reaction time is 72 hours.

[0017] In step 2), in the purification by Soxhlet extraction, preferably, the extraction time using tetrahydrofuran is 24 hours, and the obtained polymer is vacuum dried for 24 hours.

[0018] The present invention proposes using the defective covalent organic framework material prepared by the above-mentioned preparation method to prepare a solid electrolyte material. The method comprises: functionalizing the defective covalent organic framework material using a functionalization reaction method, sequentially preparing the functional covalent organic framework material through a Schiff base reaction and an ion exchange reaction, and then preparing the solid electrolyte material by tableting the activated functional covalent organic framework material.

[0019] Furthermore, the defective covalent organic framework material is functionalized based on a functionalization reaction method. The defective covalent organic framework material is used as a matrix, and a functional small molecule 3-aminopropanesulfonic acid with an amino functional group is introduced through a Schiff base reaction. The functional small molecule serves as a molecular group for improving lithium ion conduction. The sulfonic acid group is exchanged into a lithium sulfonate group through an ion exchange reaction to obtain a functional covalent organic framework material. The steps are as follows:

[0020] The defective covalent organic framework material and the functional small molecule were added to a reaction flask at a molar ratio of 1:1.2, and an appropriate amount of anhydrous ethanol was added as a reaction solvent. The mixture was heated to 80°C and reacted for 12 hours. The precipitate was collected with a centrifuge tube, washed with ethanol several times to remove the unreacted functional small molecules, and dried to obtain a bright yellow solid powder intermediate product.

[0021] The intermediate product and a 5M LiOAc aqueous solution were added to a reaction flask at a mass volume ratio of 50 mg / 20 ml and stirred at room temperature for 72 hours. After the reaction was completed, the precipitate was collected and centrifuged and washed with deionized water several times. The yellow solid powder obtained by drying was the functional covalent organic framework material.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention provides a method for preparing a defective covalent organic framework (COFs) material containing an aldehyde active anchor point. Figure 17 The synthesis route is shown. Through the Schiff base reaction between the aldehyde anchoring point in the defective COFs material and the amino group in the functional small molecule, the functional small molecule is efficiently introduced in the post-modification reaction. Figure 18 The post-modification functionalization reaction circuit diagram is shown to achieve the efficient preparation of functional COFs materials.

[0024] (2) The defective COFs (TPT-TPB-DCOF-X) provided by the present invention have the advantages of good chemical and thermodynamic stability, large specific surface area, and ordered one-dimensional channels.

[0025] (3) The solid electrolyte material prepared from the functional COFs material provided by the present invention has excellent lithium ion conductivity in a wide temperature range.

[0026] (4) The preparation method of the present invention has the advantages of convenience, simplicity, good methodological universality, etc., and can provide a reliable parent material and important reference value for the preparation of functional COFs materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 FT-IR results of TPT-TPB-DCOF-X prepared in Example 1;

[0028] Figure 2 This is the TGA result of TPT-TPB-DCOF-X prepared in Example 1;

[0029] Figure 3 This is the XRD result of TPT-TPB-DCOF-X prepared in Example 1;

[0030] Figure 4 The TPT-TPB-DCOF-60 prepared in Example 1 13 C-SNMR results;

[0031] Figure 5 This is the SEM result of TPT-TPB-DCOF-60 prepared in Example 1;

[0032] Figure 6 FT-IR results of TPB-DCOF-X prepared in Example 2;

[0033] Figure 7 This is the TGA result of TPB-DCOF-X prepared in Example 3;

[0034] Figure 8 This is the XRD result of TPB-DCOF-X prepared in Example 4;

[0035] Figure 9 The TPB-DCOF-60 prepared in Example 5 13 C-SNMR results;

[0036] Figure 10 This is the SEM result of TPB-DCOF-60 prepared in Example 2;

[0037] Figure 11 The porous characteristics of TPT-TPB-DCOF-X prepared in Example 1;

[0038] Figure 12 The porous characteristics of TPT-TPB-DCOF-X prepared in Example 1;

[0039] Figure 13 This is the EIS result of the solid electrolyte TPT-TPB-DCOF-60-SO3Li prepared in Example 6;

[0040] Figure 14 EIS results of the solid electrolyte TPT-TPB-DCOF-60-SO3Li prepared in Example 6 before and after current polarization;

[0041] Figure 15 The time-current results before and after polarization of the solid electrolyte TPT-TPB-DCOF-60-SO3Li prepared in Example 6;

[0042] Figure 16 This is the LSV result of TPT-TPB-DCOF-60-SO3Li in the present invention;

[0043] Figure 17 The schematic diagram of the synthesis of TPT-TPB-DCOF-X and TPB-DCOF-X provided by the present invention;

[0044] Figure 18 This is the post-modification functionalization reaction circuit diagram provided by the present invention. DETAILED DESCRIPTION

[0045] The design concept of the preparation method of the defective covalent organic framework material proposed in the present invention is: the aldehyde anchor point serves as a nucleophilic group, which is easy to undergo functional post-modification reaction. In addition to excellent porosity and stability, the functional modification on the COFs skeleton gives the material good structural controllability and ordered ion channels, showing application prospects in the field of solid electrolyte materials. Through a three-component co-condensation strategy, a defective COFs material containing defects and active anchor points is prepared using a unilateral organic monomer as an end-capping group. The present invention first prepares a defective covalent organic framework material containing an active anchor point based on a three-component co-condensation strategy, and then introduces functional small molecules through a post-modification reaction to obtain a covalent organic framework-based solid electrolyte material with good lithium ion conductivity. The material has good lithium ion transport performance in the temperature range of room temperature to 80°C. These excellent properties confirm that the defective covalent organic framework material provided by the present invention is a type of matrix material with good universality and can be post-modified and functionalized. Figure 17 The circuit diagram of the synthesis of defective covalent organic framework materials provided by the present invention is shown. Figure 18 The post-modification functionalization reaction scheme is shown.

[0046] In the present invention, the defective COFs material includes components including a C3-type aldehyde organic monomer, a C3-type amino organic monomer and a unilateral amino organic monomer, wherein the molar ratio of the functional groups of the C3-type aldehyde organic monomer to the C3-type amino organic monomer and the unilateral amino organic monomer is 1:1, and the molar ratio of the functional groups of the C3-type amino organic monomer to the unilateral amino organic monomer is 4:1 to 2:3, and is prepared based on a three-component co-condensation reaction; the pore size distribution of the covalent organic framework material is 1-500 nm, and the specific surface area is 10-2500 m 2 g -1 .

[0047] The present invention, through the design of COFs monomers and a solvothermal method, has produced a COF material with good stability and high porosity. Furthermore, the prepared COFs have aldehyde anchoring points on their pore walls, which can be used for post-functionalization modification. This demonstrates good universality in the methodology for constructing defective covalent organic frameworks. The solid electrolyte material prepared from the functional COFs provided by the present invention exhibits excellent lithium ion transport performance in the temperature range from room temperature to 80°C.

[0048] The organic monomer contains a unilateral amino group-related group, such as any one or a combination of at least two of aniline, 4-aminobiphenyl, 3',5'-diphenylbiphenyl-4-amine, and 5-phenyl-[1,1:3,1-terphenyl]-4,4-diamine. The preferred unilateral amino group is 3',5'-diphenylbiphenyl-4-amine.

[0049] The organic monomers include any one or a combination of at least two of the organic monomers having a C3 configuration, preferably 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-tris(p-formylphenyl)benzene and 2,4,6-tris(4-formylphenyl)-1,3,5-triazine;

[0050] In the three-component co-condensation reaction, the mixed solvent used is an organic solvent that can mix the three organic monomers to form a uniform dispersion, and the organic solvent is a combination of one or more of dioxane, n-butanol / o-dichlorobenzene, and mesitylene / dioxane. Preferably, the catalyst is mesitylene / dioxane.

[0051] In the three-component co-condensation reaction, the catalyst is an aqueous solution of acetic acid with a molar concentration of 3M to 9M. Preferably, the catalyst is a 6M aqueous solution of acetic acid;

[0052] The present invention will be further described below in conjunction with the accompanying drawings and specific examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the invention. In the examples, if no specific technology or conditions are specified, the technology or conditions described in the literature in this area or the product specifications are used. The unspecified manufacturers of the instruments used are conventional products that can be purchased through regular channels. The chemical raw materials used in the present invention can be easily purchased in the domestic chemical product market.

[0053] Example 1

[0054] The synthesis method of defective COFs material (TPT-TPB-DCOF-X) is as follows: Figure 17 As shown, the process is as follows:

[0055] Step 1) In a 10 mL glass tube, add the C3 building block monomers 2,4,6-tris(4-formylphenyl)-1,3,5-triazine and 1,3,5-tris(4-aminophenyl)benzene, and the end-capping building block monomer 3',5'-diphenylbiphenyl-4-amine. Specific amounts are shown in Table 1.

[0056] Table 1 Amount of each organic monomer used in the synthesis of defective TPT-TPB-DCOF-X

[0057]

[0058] Step 2) After adding the above three organic monomers, a mixed solvent (mesitylene / dioxane / 6M acetic acid aqueous solution (1.0 / 1.0 / 0.2mL)) was added, wherein mesitylene and dioxane are organic solvents that can mix the above three organic monomers to form a uniform dispersion, and 6M acetic acid aqueous solution is used as a catalyst in the three-component co-condensation reaction. The monomers were mixed and ultrasonically mixed for 10 minutes to mix them evenly. In Table 1, X = 20, X = 40, and X = 60 correspond to the synthesized defective COFs material samples TPT-TPB-DCOF-20, TPT-TPB-DCOF-40, and TPT-TPB-DCOF-60, respectively. The mixture was frozen by liquid nitrogen, vacuumed and filled with nitrogen for 10 minutes each (repeated three times), and the tube was sealed with a flame gun under vacuum, and reacted in an oven at 120°C for 3 days. After the reaction is completed, the mixture is cooled to room temperature, and the precipitate is collected in a centrifuge tube. The precipitate is then washed multiple times with tetrahydrofuran, acetone, and methanol until the aqueous solution becomes colorless. The product is dried to obtain a yellow solid powder. The yellow solid powder is then further purified using Soxhlet extraction with tetrahydrofuran for 24 hours, followed by vacuum drying for 24 hours.

[0059] The yields were determined by the chemical reaction yield calculation method and were 87%, 86% and 85% (X=20, X=40 and X=60), respectively. Figure 1 This is the FTIR spectrum of TPT-TPB-DCOF-X material, at 1620 cm -1 The stretching vibration characteristic peak of -C=N- indicates the formation of imine bond of COFs material. -1 and 2850cm -1 At , the stretching vibration peaks of -C=O- and C-H bond in the aldehyde group of the active anchor point can be observed, indicating the existence of the aldehyde anchor point. Figure 2 The TGA data of TPT-TPB-DCOF-X material is shown in the figure. It can be seen from the figure that the material has good thermal stability. Figure 3 ) characterizes the crystallization properties of the material. Figure 3 It can be seen that diffraction peaks appear at 4.0°, 6.8°, 7.9°, and 10.4°, corresponding to the crystal planes of (100), (110), (200), and (210). A strong diffraction peak appears at the 4.0° position, indicating that the material has good crystallinity. Figure 4 Solid-state NMR of TPT-TPB-DCOF-60 material 13 C spectrum, the -C=N- carbon peak at 162ppm further illustrates the formation of characteristic connecting bonds of COFs materials, which is consistent with Figure 1 The infrared spectrum data are consistent with those in . Figure 5 The SEM image of the TPT-TPB-DCOF-60 material shows that the material has a typical two-dimensional structure. The above data show that the TPT-TPB-DCOF-X material was successfully prepared.

[0060] Example 2

[0061] The synthesis method of defective COFs material (TPB-DCOF-X) is as follows:

[0062] Step 1) In a 10 mL glass tube, add C3 structural unit monomers 1,3,5-tris(p-formylphenyl)benzene and 1,3,5-tris(4-aminophenyl)benzene and end-capping structural unit monomer 3',5'-diphenylbiphenyl-4-amine. Specific amounts are shown in Table 2.

[0063] Table 2 Amount of each organic monomer used in the synthesis of defective TPB-DCOF-X

[0064]

[0065] Step 2) is the same as step 2) of Example 1, and the final product is a yellow solid powder. In Table 2, X = 20, X = 40, and X = 60 correspond to the synthesized defective COFs material samples TPB-DCOF-20, TPB-DCOF-40, and TPB-DCOF-60, respectively.

[0066] The yields were determined to be 89%, 87% and 88% (X=20, X=40 and X=60), respectively. Figure 6 This is the FTIR spectrum of TPB-DCOF-X material, at 1618 cm -1 The stretching vibration characteristic peak of -C=N- indicates the formation of imine bond of COFs material. -1 and 2855cm -1 At , the stretching vibration peaks of -C=O- and C-H bond in the aldehyde group of the active anchor point can be observed, indicating the existence of the aldehyde anchor point. Figure 7 The TGA data of TPB-DCOF-X material shows that the material has good thermal stability and the material only decomposes significantly at around 450°C. XRD test characterizes the crystallinity of the material, such as Figure 8 As shown in the figure, diffraction peaks appear at 4.0°, 6.8°, 7.9°, and 10.4°, corresponding to the crystal planes of (100), (110), (200), and (210). A strong diffraction peak appears at the 4.0° position, indicating that the material has good crystallinity. Figure 9 Solid-state NMR of TPB-DCOF-60 material 13C spectrum, the -C=N- carbon peak at 160ppm further illustrates the formation of characteristic connecting bonds of COFs materials, which is consistent with Figure 6 The infrared spectrum data are consistent with those in . Figure 10 The SEM image of TPB-DCOF-60 shows a typical two-dimensional structure. The above data indicate that TPB-DCOF-X was successfully prepared.

[0067] Example 3

[0068] Preparation of functional COFs material TPT-TPB-DCOF-60-SO3Li.

[0069] The defective COFs material TPT-TPB-DCOF-60 prepared in Example 1 has a framework pore wall containing rich aldehyde functional groups as anchor points for post-modification reactions. The defective covalent organic framework material is functionalized based on the functionalization reaction method. The defective covalent organic framework material is used as the matrix, and a functional small molecule 3-aminopropane sulfonic acid with an amino functional group is introduced through a Schiff base reaction. The functional small molecule serves as a molecular group for enhancing lithium ion conduction, and the sulfonic acid group is converted into a lithium sulfonate group through an ion exchange reaction. Figure 18 The post-modification functionalization reaction route is shown.

[0070] The preparation process of TPT-TPB-DCOF-60-SO3Li is as follows:

[0071] In a 50 mL reaction flask, 68.83 mg (0.01 mmol) of the parent material TPT-TPB-DCOF-60 was added, followed by 10.08 mg (0.012 mmol) of the functional small molecule 3-aminopropanesulfonic acid and 20 mL of anhydrous ethanol as the reaction solvent. The mixture was heated to 80°C and reacted for 12 h. The product was collected with a centrifuge tube, washed several times with ethanol to remove the unreacted small molecules, and dried to obtain a bright yellow solid powder, which was recorded as TPT-TPB-DCOF-60-SO3H, with a yield of 94%.

[0072] 50 mg of TPT-TPB-DCOF-60-SO3H was added to a reaction flask, followed by 20 ml of a 5M LiOAc aqueous solution. The mixture was stirred at room temperature for 3 days. After the reaction was completed, the precipitate was collected, centrifuged and washed several times with deionized water, and dried to obtain a yellow solid powder, which was the functional COFs material TPT-TPB-DCOF-60-SO3Li, with a yield of 88%.

[0073] Example 4

[0074] The pore performance of the defective COFs materials prepared in Example 1 and Example 2 was analyzed.

[0075] Figure 11 It shows that at 77K, the N2 adsorption isotherm respectively determines that the specific surface areas of the defective COFs material TPT-TPB-DCOF-X synthesized in Example 1 are 762m 2 g -1 、691m 2 g -1 and 570m 2 g -1 (corresponding to TPT-TPB-DCOF-20, TPT-TPB-DCOF-40 and TPT-TPB-DCOF-60 respectively). Figure 12 It shows that at 77K, the N2 adsorption isotherm respectively determines that the specific surface areas of the TPB-DCOF-X material synthesized in Example 2 are 91m 2 g -1 、83m 2 g -1 and 67m 2 g -1 (Corresponding to TPT-TPB-DCOF-20, TPT-TPB-DCOF-40 and TPT-TPB-DCOF-60 respectively) The defective COFs material prepared by the present invention has a large specific surface area, which can provide more active sites in the process of lithium ion transmission, enhance the interaction between the active sites and lithium ions, and improve the transmission capacity of lithium ions. The adsorption NLDFT fitting model shows that the pore size distribution range of TPT-TPB-DCOF-X and TPB-DCOF-X synthesized according to Example 1 and Example 2 is mainly in the range of 1-5nm (Table 3 is the pore performance analysis of Example 1 and Example 2). The pore size distribution of the defective COFs material prepared in Example 1 and Example 2 is within the range of 1-2nm, and the atomic radius of lithium ions is 0.76nm. The pore size distribution range of the defective COFs material can provide an effective channel for the free transmission of lithium ions in the pores. In addition, defective COFs materials have good crystallinity and high order. Their ordered structure provides a good transmission environment for the rapid transmission of lithium ions within the pores of COFs materials, showing excellent potential in the process of rapid lithium ion transmission.

[0076] Table 3 Pore performance analysis of NH2-CTF-1 and NH2-CTF-2

[0077] polymer S BET (m 2 g -1 )]]> <![CDATA[V total (cm 3 g -1 )]]> Pore ​​diameter (nm) TPT-TPB-DCOF-20 762 0.45 1.27 TPT-TPB-DCOF-40 691 0.41 1.27 TPT-TPB-DCOF-60 570 0.39 1.27 TPB-DCOF-20 91 0.12 1.26 TPB-DCOF-40 83 0.11 1.26 TPB-DCOF-60 67 0.09 1.26

[0078] Example 5

[0079] The degree of polymerization of the functional COFs material (TPT-TPB-DCOF-60-SO3Li) prepared in Example 3 was investigated.

[0080] The elemental analysis method was used for characterization. From the data in Table 4, it can be seen that the actual measured values ​​of the three elements C, N, and H in the functional COFs material TPT-TPB-DCOF-60-SO3Li are close to the theoretical contents, indicating that the degree of polymerization of the material is very high.

[0081] Table 4 Elemental analysis results of TPT-TPB-DCOF-60-SO3Li

[0082] C(％) N(％) H(％) Theoretical content 73.72 9.26 4.68 Experimental content 71.95 8.64 4.35

[0083] Example 6

[0084] The functional COFs material (TPT-TPB-DCOF-60-SO3Li) prepared in Example 3 was used to prepare a solid electrolyte material by a tableting method.

[0085] The specific operation steps are as follows: In a nitrogen atmosphere glove box, the activated TPT-TPB-DCOF-60-SO3Li powder (50 mg) was pressed into tablets using a press with a pressure of 15 MPa for 5 minutes. The discs in the mold were then removed for electrochemical performance testing.

[0086] The lithium ion conductivity performance test of the above-mentioned solid electrolyte material: The lithium ion conductivity of the solid electrolyte material was tested by using an electrochemical workstation and characterized by electrochemical impedance spectroscopy (EIS). The test temperature was between 30 and 80°C, and the test was performed every 10°C. The bulk resistance of the solid electrolyte material was obtained by the intersection of the AC impedance spectrum and the real axis, and its ion conductivity at different temperatures was calculated. The formula for calculating the ion conductivity is shown below.

[0087]

[0088] Wherein: L, S and R represent the thickness of the solid electrolyte material disc, the area of ​​the disc and the bulk resistance of the solid electrolyte material respectively.

[0089] Figure 13 The EIS spectra of the solid electrolyte material under the test conditions of 30 to 80 ° C are obtained. According to the above ion conductivity calculation formula, the lithium ion conductivity of TPT-TPB-DCOF-60-SO3Li from 30 to 80 ° C is 2.95×10 -5 ,4.06×10 -5 ,6.17×10 -5 ,1.05×10 -4 ,1.59×10 -4 and 2.56×10 -4 S cm-1 Compared with the reported COFs-type solid electrolytes, TPT-TPB-DCOF-60-SO3Li exhibits excellent lithium ion conductivity and shows great application potential in solid electrolyte materials.

[0090] Example 7

[0091] In order to further verify the practicality of the solid electrolyte material, the lithium ion migration number and electrochemical stability window of the material were tested. For the solid electrolyte material (TPT-TPB-DCOF-60-SO3Li) prepared in Example 6, the lithium ion migration number was measured by assembling a symmetrical battery Li / TPT-TPB-DCOF-60-SO3Li / Li, polarizing the symmetrical battery with a DC voltage, and testing the EIS spectra and polarization current-time curves before and after polarization. The electrochemical stability window of the electrolyte material was tested using a linear sweep voltammetry (LSV) curve, which is used to characterize the stability of the material under high voltage test conditions. Using the classic Vincent method, the lithium ion migration number of the TPT-TPB-DCOF-60-SO3Li material was calculated to be 0.82±0.02, as shown in Figure 2. Figure 14 and Figure 15 As shown. Before 4.54V, the oxidation current of TPT-TPB-DCOF-60-SO3Li electrolyte material did not show a significant increase, indicating that the electrochemical stability window of the material is as high as 4.54V. Figure 16 As shown, it shows potential for application in high-voltage electrode system lithium-ion batteries.

[0092] Although the detailed process flow of the present invention is described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are merely illustrative, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Under the guidance of the present invention, those skilled in the art can make many improvements and changes without departing from the purpose of the present invention, such as equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary ingredients, selection of specific methods, etc., all of which fall within the protection of the present invention.

Claims

1. An application of a defective covalent organic framework material, wherein the covalent organic framework material comprises components including a C3-type aldehyde organic monomer, a C3-type amino organic monomer, and a unilateral amino organic monomer, wherein the molar ratio of the functional groups of the C3-type aldehyde organic monomer to the C3-type amino organic monomer and the unilateral amino organic monomer is 1:1, and the molar ratio of the functional groups of the C3-type amino organic monomer to the unilateral amino organic monomer is 4:1 to 2:3, and the covalent organic framework material is prepared by a three-component co-condensation reaction; the covalent organic framework material has a pore size distribution of 1.0–5.0 nm and a specific surface area of ​​60–800 m 2 g –1 The C3 type aldehyde organic monomer is 1,3,5-tris(p-formylphenyl)benzene or 2,4,6-tris(4-formylphenyl)-1,3,5-triazine; the C3 type amino organic monomer is 1,3,5-tris(4-aminophenyl)benzene; the unilateral amino organic monomer is 3',5'-diphenylbiphenyl-4-amine; characterized in that, Using the defective covalent organic framework to prepare a solid electrolyte material; The defective covalent organic framework material is functionalized based on a functionalization reaction method. The defective covalent organic framework material is used as a matrix. A functional small molecule 3-aminopropanesulfonic acid with an amino functional group is introduced through a Schiff base reaction. The functional small molecule serves as a molecular group for improving lithium ion conduction. The sulfonic acid group is exchanged for a lithium sulfonate group through an ion exchange reaction to obtain a functional covalent organic framework material. The steps are as follows: The defective covalent organic framework material and the functional small molecule were added to a reaction flask at a molar ratio of 1:1.2, and an appropriate amount of anhydrous ethanol was added as a reaction solvent. The mixture was heated to 80 °C and reacted for 12 h. The precipitate was collected with a centrifuge tube, washed with ethanol several times to remove the unreacted functional small molecules, and dried to obtain a bright yellow solid powder intermediate product. The intermediate product and a 5 M LiOAc aqueous solution were added to a reaction flask at a mass volume ratio of 50 mg / 20 mL and stirred at room temperature for 72 hours. After the reaction was completed, the precipitate was collected and washed by centrifugation with deionized water several times. The yellow solid powder obtained by drying was the functional covalent organic framework material.

2. The use of the defective covalent organic framework material according to claim 1, characterized in that: In the three-component co-condensation reaction, the solvent used is an organic solvent that can mix the above three organic monomers to form a uniform dispersion, and the organic solvent is one of dioxane, n-butanol / o-dichlorobenzene, and mesitylene / dioxane; the catalyst is an aqueous solution of acetic acid with a molar concentration of 3M to 9M.

3. The use of the defective covalent organic framework material according to claim 1 or 2, characterized in that: The method for preparing the covalent organic framework material comprises the following steps: Step 1) Weigh the molar ratio of each component functional group of the C3-type aldehyde organic monomer, the C3-type amino organic monomer, and the unilateral amino organic monomer, and weigh the mixed solution and the catalyst so that the molar volume concentration of the total amount of organic monomer to the solvent is 0.1 mmol / mL and the molar volume concentration of the total amount of organic monomer to the catalyst is 1 mmol / mL; Step 2) The three organic monomers and solvent weighed in step 1) are placed in an ampoule and mixed evenly under ultrasonic conditions. Then, the catalyst weighed in step 1) is added, and a condensation reaction is carried out based on a three-component co-condensation strategy through a solvent thermal reaction to prepare a defective covalent organic framework material containing aldehyde active anchor points.

4. The use of the defective covalent organic framework material according to claim 3, characterized in that: In step 2) of the preparation method, the process conditions of the solvent thermal reaction are: The reaction is carried out in an oven at a reaction temperature of 90-150°C for a reaction time of 24-96 hours. After the reaction is completed, a precipitate is obtained at the bottom of the ampoule. The precipitate is subjected to a post-treatment reaction to obtain a defective covalent organic framework material containing an aldehyde active anchor point. The post-treatment process is as follows: the precipitate is cooled to room temperature, collected with a centrifuge tube, and then washed with tetrahydrofuran, methanol, and acetone multiple times until the solution is colorless. The product obtained by drying is a yellow solid powder; Soxhlet extraction is used for purification, and extraction is performed with tetrahydrofuran for 12-96 hours. The obtained polymer is then vacuum-dried for 24-48 hours.

5. The use of the defective covalent organic framework material according to claim 4, characterized in that: In step 2) of the preparation method, in the solvent thermal reaction, the reaction temperature is 120 ° C and the reaction time is 72 hours.

6. The preparation method according to claim 4, characterized in that In step 2) of the preparation method, the Soxhlet extraction method is used for purification, the extraction time using tetrahydrofuran is 24 hours, and the obtained polymer is vacuum dried for 24 hours.

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