Two-dimensional polyimide material and preparation method therefor, electrode, battery and electric device

Abstract

A two-dimensional polyimide material and a preparation method therefor, a battery and an electric device. The two-dimensional polyimide material is a crystalline porous material, and the molecular structure of the two-dimensional polyimide material forms a ring so as to form nanoscale pores.

Description

Two-dimensional polyimide material, preparation method thereof, electrode, battery and electric device

[0001] The present application claims priority to the Chinese patent application No. 202410841279.X, filed on June 26, 2024, entitled "Two-dimensional polyimide material, preparation method thereof, electrode, battery and electric device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of new energy, in particular, to a two-dimensional polyimide material, a preparation method thereof, an electrode, a battery and an electric device. BACKGROUND

[0003] In the current battery, the electrode is mostly made of inorganic materials. Compared with the commonly used inorganic electrode, the organic material is composed of elements such as C, H and O. Therefore, the organic electrode material can be obtained from industrial chemicals and biological substances. Moreover, the organic material has the outstanding advantages of high structural flexibility, multi-electron reaction, easy manufacturing and low cost.

[0004] As an organic polymer electrode material, polyimide has been widely concerned due to its stability after gaining or losing electrons, carbonyl as an active group and high theoretical specific capacity. However, for the application of polyimide polymer in battery electrode materials, there are problems such as small surface area, limited ion storage sites and lack of ion channels, which will affect the storage capacity and ion transmission efficiency of the electrode, and show low capacity.

[0005] Therefore, it is necessary to improve the two-dimensional polyimide material, the preparation method thereof, the electrode, the battery and the electric device to solve at least one technical problem.

[0006] SUMMARY

[0007] In the summary section, a series of concepts in a simplified form are introduced, which will be further described in detail in the detailed description section. The summary section of the present application does not mean to attempt to limit the key features and essential technical features of the claimed technical solutions, nor to determine the protection scope of the claimed technical solutions.

[0008] The present application is proposed to solve at least one of the above problems. Specifically, the first aspect of the present application provides a two-dimensional polyimide material, which is a crystalline porous material, and the molecular structure of the two-dimensional polyimide material forms a ring shape to form a nanoscale pore.

[0009] According to the two-dimensional polyimide material of the application, the ring-shaped molecules form an ordered crystalline porous structure, have a large surface area, provide a large number of sites for ion storage, and provide channels for ion migration, which not only promotes the rapid diffusion of electrolyte and approaches the redox active carbonyl group, but also ensures the stability of the electrode material in the cycle process and improves the battery capacity.

[0010] Optionally, the molecular structure of the two-dimensional polyimide material comprises the following repeating unit:

[0011] Optionally, the two-dimensional polyimide material has a temperature of 5% thermal weight loss greater than 250℃.

[0012] Optionally, the two-dimensional polyimide material has a temperature of 10% thermal weight loss greater than 380℃.

[0013] Optionally, 50% or more of the nanoscale pores of the two-dimensional polyimide material have a pore size of less than 5nm.

[0014] Optionally, 80% or more of the nanoscale pores of the two-dimensional polyimide material have a pore size of 2.7-2.9nm.

[0015] Optionally, the specific surface area of the two-dimensional polyimide material is 450-550m 2 ·g -1 .

[0016] Optionally, the XRD of the two-dimensional polyimide material has a diffraction peak between 0 and 6 at the 2θ value.

[0017] Optionally, the infrared spectrum test of the two-dimensional polyimide material has a characteristic peak at 1700-1800cm -1 .

[0018] The second aspect of the application provides a preparation method for preparing the two-dimensional polyimide material of the first aspect, the preparation method comprising: dissolving aromatic dianhydride monomers and triamine-based aromatic monomers in an organic solvent, and reacting under the condition of sealed heating to generate the two-dimensional polyimide material.

[0019] According to the preparation method of the application, a crystalline polyimide with a ring structure can be prepared.

[0020] Optionally, the ratio of the number of moles of the aromatic dianhydride monomers to the number of moles of the triamine-based aromatic monomers is 1.4-1.6.

[0021] Optionally, the concentration of the aromatic dianhydride monomers in the organic solvent is 0.01-0.05mol / L.

[0022] Optionally, the aromatic dianhydride monomer comprises at least one of 3,4,9,10-perylenetetracarboxylic dianhydride, 1,6,7,12-tetrahalo-3,4,9,10-tetracarboxylic anhydride, 2,3,6,7-tetrahalonaphthalene-1,4,5,8-tetracarboxylic dianhydride, and 1,4-dihalo-2,3,5,6-benzenetetracarboxylic dianhydride, wherein the halogen is at least one of fluorine, chlorine, and bromine.

[0023] Optionally, the aromatic dianhydride monomer is 3,4,9,10-perylenetetracarboxylic dianhydride.

[0024] Optionally, the triamine-based aromatic monomer is at least one of 1,3,5-triaminobenzene, melem, 1,3,5-tris(4-aminophenyl)benzene, and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine.

[0025] Optionally, the triamine-based aromatic monomer is 1,3,5-triaminobenzene.

[0026] Optionally, the organic solvent is N-methylpyrrolidone.

[0027] Optionally, the preparation method comprises the following steps:

[0028] a preparation step of mixing the aromatic dianhydride monomer and the triamine-based aromatic monomer in the organic solvent;

[0029] a feeding step of adding the mixed solution into a pressure-resistant container, and sealing the pressure-resistant container after vacuumizing;

[0030] a reaction step of heating and keeping the pressure-resistant container at a preset temperature for a preset reaction time.

[0031] Optionally, the preset temperature is 180-220°C.

[0032] Optionally, the preset reaction time is 48-144h.

[0033] Optionally, the preset reaction time is 115-125h.

[0034] Optionally, the feeding step comprises: adding the mixed solution into a pressure-resistant container, and flame-sealing the pressure-resistant container after low-temperature vacuumizing.

[0035] Optionally, the thermodynamic temperature of the low-temperature vacuumizing is 75-80K, and the pressure inside the pressure-resistant container is 0.13-0.16mmHg after vacuumizing.

[0036] Optionally, the preparation method further comprises a cleaning step of filtering the product after reaction, and then washing multiple times with a solvent until the solvent is colorless.

[0037] Optionally, the product after the reaction is filtered, then washed with tetrahydrofuran for several times, and then washed with methanol for several times until the solvent is colorless.

[0038] Optionally, the preparation method further comprises a purification step, the product after the washing is purified by Soxhlet extraction, then filtered, and then dried to constant weight to obtain the two-dimensional polyimide material.

[0039] Optionally, the drying method is heating drying, freeze drying or vacuum drying.

[0040] The third aspect of the present application provides an electrode, wherein the electrode comprises the two-dimensional polyimide material of the first aspect.

[0041] According to the electrode of the present application, the storage capacity is large and the ion transmission efficiency is high.

[0042] The fourth aspect of the present application provides a battery, wherein the battery comprises the electrode of the third aspect.

[0043] According to the battery of the present application, the capacity is large and the cycle stability is high.

[0044] The fifth aspect of the present application provides a power consumption device, wherein the power consumption device comprises the battery of the fourth aspect.

[0045] The power consumption device of the present application has similar beneficial effects as the battery described above. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0047] FIG. 1 shows the XRD analysis diagram of the two-dimensional polyimide material of an embodiment of the present application and the hyperbranched polyimide of the comparative example;

[0048] FIG. 2 shows the thermal gravimetric analysis diagram of the two-dimensional polyimide material of an embodiment of the present application;

[0049] FIG. 3 shows the nitrogen adsorption curve diagram of the two-dimensional polyimide material of an embodiment of the present application;

[0050] FIG. 4 shows the pore size distribution diagram of the two-dimensional polyimide material of an embodiment of the present application;

[0051] FIG. 5 shows the nitrogen adsorption curve diagram of the hyperbranched polyimide of the comparative example;

[0052] Figure 6 shows the infrared spectra of the two-dimensional polyimide material of one embodiment of the present application and the hyperbranched polyimide of the comparative example;

[0053] Figure 7 shows the second cycle charge-discharge curves of the battery made of the two-dimensional polyimide material of one embodiment of the present application and the battery made of the hyperbranched polyimide of the comparative example;

[0054] Figure 8 shows the fiftieth cycle charge-discharge curves of the battery made of the two-dimensional polyimide material of one embodiment of the present application and the battery made of the hyperbranched polyimide of the comparative example; and

[0055] Figure 9 is the cycle discharge capacity curves of the battery made of the two-dimensional polyimide material of one embodiment of the present application and the battery made of the hyperbranched polyimide of the comparative example. DETAILED DESCRIPTION

[0056] In order to make the objects, technical solutions, and advantages of the present application more obvious, the following will describe the example embodiments according to the present application in detail with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present application.

[0057] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present application. However, it should be apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other instances, some well-known features are not described in detail in order to avoid obscuring the present application.

[0058] It should be understood that the present application can be implemented in different forms and should not be interpreted as being limited to the embodiments presented herein. On the contrary, the embodiments are provided to make the disclosure complete and fully convey the scope of the present application to those skilled in the art.

[0059] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0060] For a thorough understanding of the application, a detailed description will be made in the following description with specific reference to the accompanying drawings. The following detailed description is provided to assist in a comprehensive understanding of various embodiments of the application described herein. Various embodiments of the application described herein, however, can be practiced apart from the specific details disclosed herein.

[0061] The application provides a two-dimensional polyimide material, the two-dimensional polyimide material is a crystalline porous material, and the molecular structure of the two-dimensional polyimide material forms a ring shape to form a nanoscale pore.

[0062] The two-dimensional polyimide material according to the application has ordered crystalline porous structure formed by ring-shaped molecules, has a large surface area, provides a large number of sites for ion storage, and provides channels for ion migration, which not only promotes the rapid diffusion of electrolyte and approaches the redox active carbonyl group, but also ensures the stability of the electrode material in the cycle process and improves the battery capacity.

[0063] The two-dimensional polyimide material described above can be prepared by the following preparation method. The preparation method comprises: dissolving aromatic dianhydride monomers and triamine-based aromatic monomers in an organic solvent, and reacting under the condition of sealed heating to obtain a two-dimensional polyimide material.

[0064] The aromatic dianhydride monomers include at least one of 3,4,9,10-perylenetetracarboxylic dianhydride, 1,6,7,12-tetrahalogen-3,4,9,10-tetracarboxylic anhydride, 2,3,6,7-tetrahalogenaphthalene-1,4,5,8-tetracarboxylic dianhydride, and 1,4-dihalogen-2,3,5,6-benzene tetracarboxylic dianhydride, wherein the halogen is at least one of fluorine, chlorine and bromine. Preferably, the aromatic dianhydride monomers are 3,4,9,10-perylenetetracarboxylic dianhydride.

[0065] The triamine-based aromatic monomers are at least one of 1,3,5-triaminobenzene, melem, 1,3,5-tris(4-aminophenyl)benzene, and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine. Preferably, the triamine-based aromatic monomers are 1,3,5-triaminobenzene.

[0066] The organic solvent is preferably N-methylpyrrolidone.

[0067] The ratio of the number of moles of the aromatic dianhydride monomer to the number of moles of the triamine-based aromatic monomer is 1.4 to 1.6. Preferably, the ratio of the number of moles of the aromatic dianhydride monomer to the number of moles of the triamine-based aromatic monomer is 1.5. In other words, the molar ratio of the aromatic dianhydride monomer to the triamine-based aromatic monomer is 3:2.

[0068] Furthermore, the concentration of the aromatic dianhydride monomer in the organic solvent is 0.01 to 0.05 mol / L.

[0069] More specifically, the above preparation method comprises the following steps:

[0070] (1) A preparation step, in which the aromatic dianhydride monomer and the triamine-based aromatic monomer are added to the organic solvent and mixed uniformly.

[0071] (2) A feeding step, in which the mixed solution is added to a pressure-resistant container, which is then sealed after being vacuumized. The vacuumization can be performed by low-temperature vacuumization, and the thermodynamic temperature of the low-temperature vacuumization is 75 to 80 K, for example, using liquid nitrogen to form a low temperature. The pressure-resistant container is vacuumized to a pressure of 0.13 to 0.16 mmHg. Preferably, the pressure-resistant container is vacuumized to a pressure of 0.15 mmHg. Thus, the oxygen in the container is reduced as much as possible. The sealing is performed by flame sealing to obtain better sealing performance.

[0072] (3) A reaction step, in which the pressure-resistant container is heated and kept at a preset temperature for a preset reaction time. The preset temperature is 180 to 220 °C. Preferably, the preset temperature is 200 °C. The preset reaction time is 48 to 144 h. Preferably, the preset reaction time is 115 to 125 h. More preferably, the preset reaction time is 120 h.

[0073] (4) A washing step, in which the product after the reaction is filtered, and then washed multiple times with a solvent until the solvent is colorless. Specifically, the product can be washed multiple times, for example, 3 times, with tetrahydrofuran. Then, the product can be washed multiple times, for example, 3 times, with methanol.

[0074] (5) A purification step, in which the product after washing is purified by Soxhlet extraction, and then filtered and dried to a constant weight to obtain a two-dimensional polyimide material. The drying method can be heating drying, freeze drying or vacuum drying.

[0075] The above preparation method, for example, the combination of the feeding step and the reaction step, can form a sealed and heated solvothermal reaction condition, and the high temperature and sufficient reaction time can create conditions for the reaction, so that the polyimide inside the container can fully react and condense to form a crystalline ring-shaped molecule.

[0076] As a preferred embodiment, the molecular structure of the two-dimensional polyimide material comprises the following repeating units:

[0077] The plurality of repeating units described above are bonded to form a ring shape, enclosing a two-dimensional micropore, providing a channel for ion migration.

[0078] The two-dimensional polyimide material according to the present application has a large molecular weight, and thus has good heat resistance, with a 5% thermal weight loss temperature greater than 250℃. The 10% thermal weight loss temperature is greater than 380℃.

[0079] The two-dimensional polyimide material according to the present application has a pore size of less than 5nm for more than 50% of the nanoscale pores. The pore size of more than 80% of the nanoscale pores is 2.7-2.9nm. The specific surface area of the two-dimensional polyimide material according to the present application is 450-550m 2 ·g - 1 .

[0080] The two-dimensional polyimide material according to the present application has an XRD diffraction peak between 0 and 6 at a 2θ value.

[0081] The two-dimensional polyimide material according to the present application has a characteristic peak in the infrared spectrum test at 1700-1800cm -1 .

[0082] The third aspect of the present application provides an electrode, wherein the electrode comprises the two-dimensional polyimide material of the first aspect described above.

[0083] The electrode according to the present application has a large storage capacity and high ion transmission efficiency.

[0084] The fourth aspect of the present application provides a battery, comprising the electrode of the third aspect described above.

[0085] The battery according to the present application has a large capacity and high cycle stability.

[0086] The fifth aspect of the present application provides a power consuming device, comprising the battery of the fourth aspect described above.

[0087] The power consuming device according to the present application has similar beneficial effects as the battery described above due to the inclusion of the battery.

[0088] The two-dimensional polyimide material and the preparation method thereof according to the present application will be described in more detail below in combination with examples and comparative examples.

[0089] Example 1

[0090] 3,4,9,10-perylenetetracarboxylic dianhydride and 1,3,5-triaminobenzene were dissolved in N-methylpyrrolidone in a molar ratio of 3:2, and the concentration of 3,4,9,10-perylenetetracarboxylic dianhydride in the solution was 0.01-0.05 mol / L.

[0091] The solution was injected into a pressure-resistant tube. The sealed pressure-resistant tube was subjected to freeze-pumping three times at 77 K, and was vacuumized to an internal pressure of 0.15 mmHg, and then was flame-sealed. The pressure-resistant tube was heated to 200°C, and was maintained for 48-120 h.

[0092] After the reaction was completed, the product was filtered, washed with tetrahydrofuran three times, and washed with methanol three times. After purification by Soxhlet extraction, the product was dried at 80°C to a constant weight, to obtain a two-dimensional polyimide material.

[0093] The obtained two-dimensional polyimide material was subjected to thermogravimetric analysis, gas adsorption analysis, XRD analysis, and infrared spectrum analysis.

[0094] The dried two-dimensional polyimide material, polytetrafluoroethylene, and conductive carbon black were mixed in a mass ratio of 60:10:30, NMP was added as a solvent, and stirring was performed for 2 h, to prepare a negative electrode slurry.

[0095] The negative electrode slurry was coated on a 12 μm aluminum foil to a thickness of 40 μm, and was dried at 100°C for 12 h, to obtain a negative electrode sheet.

[0096] The obtained negative electrode sheet was cut into a circular sheet having a diameter of 13 mm. A metal sodium sheet having a diameter of 13 mm was used as a positive electrode.

[0097] NaPF6 was dissolved in a mixed solvent composed of ethylene carbonate and dimethyl carbonate (molar ratio of the two solvents: 1:1), to form an electrolyte having a concentration of 1 mol / L.

[0098] The above-described positive electrode, negative electrode, and electrolyte were assembled into a 2032 type button cell in an argon-filled glove box. The prepared button cell was subjected to charge-discharge tests.

[0099] Comparative Example 1

[0100] Under a nitrogen atmosphere, one of the aromatic dianhydride monomer solution and the triamine-based aromatic monomer solution was slowly added dropwise to the other solution within 2 hours, and was reacted under mechanical stirring for 18-24 hours, to form a hyperbranched polyamide acid.

[0101] Afterwards, acetic anhydride and triethylamine are added to the reaction system, and the imidization reaction is carried out at a constant temperature of 60-80°C in an oil bath for 8-9h. The obtained product is discharged into anhydrous ethanol, washed with anhydrous ethanol, and dried to obtain the hyperbranched polyimide.

[0102] The obtained hyperbranched polyimide is subjected to gas adsorption analysis, XRD analysis, and infrared spectrum analysis.

[0103] The dried hyperbranched polyimide, polytetrafluoroethylene, and conductive carbon black are mixed in a mass ratio of 60:10:30, NMP is added as a solvent, and the mixture is stirred for 2h to prepare a negative electrode slurry.

[0104] The negative electrode slurry is coated on a 12μm aluminum foil with a coating thickness of 40μm, and dried at 100°C for 12h to obtain a negative electrode sheet.

[0105] The obtained negative electrode sheet is cut into a circular sheet with a diameter of 13mm. A metal sodium sheet with a diameter of 13mm is used as a positive electrode.

[0106] NaPF6 is dissolved in a mixed solvent composed of ethylene carbonate and dimethyl carbonate (molar ratio of the two solvents is 1:1) to form an electrolyte with a concentration of 1mol / L.

[0107] The above-mentioned positive electrode, negative electrode, and electrolyte are assembled into a 2032 type button cell in an argon-filled glove box. The prepared button cell is subjected to charge and discharge test.

[0108] The experimental results of Example 1 and Comparative Example 1 are analyzed as follows.

[0109] FIG. 1 shows the XRD analysis graph of the two-dimensional polyimide material of Example 1 and the hyperbranched polyimide of Comparative Example 1.

[0110] The cell parameters α=β=90°, γ=120° are obtained by Pawley refinement, The crystal state two-dimensional polyimide with a theoretical structure is obtained by Pawley refinement.

[0111] The two-dimensional polyimide material of Example 1 is subjected to stacking fitting with the above-mentioned refinement results by powder X-ray diffraction, and the results show that RWP=5.46%, RP=3.28%. The fitting results are basically consistent with the experimental results, which shows that the two-dimensional polyimide material of Example 1 has a crystalline state.

[0112] The hyperbranched polyimide of Comparative Example 1 has no obvious diffraction peak under powder X-ray diffraction, which shows an amorphous state.

[0113] Figure 2 shows the thermogravimetric analysis plot of the two-dimensional polyimide material of Example 1. The results show that the two-dimensional polyimide material has a 5% weight loss at 276.2°C and a 10% weight loss at 408.6°C, indicating the high stability of the two-dimensional polyimide material.

[0114] Nitrogen adsorption measurement was performed on the two-dimensional polyimide material of Example 1 at 77K. Figure 3 shows the nitrogen adsorption plot of the two-dimensional polyimide material of Example 1. The specific surface area of the two-dimensional polyimide material of Example 1 was calculated to be 478.2m 2 -1 This value reflects the degree of interaction between the surface of the material and nitrogen molecules, and a high specific surface area means that the two-dimensional polyimide material has more active sites and better adsorption performance.

[0115] At the same time, through non-local density functional theory (NLDFT) calculation, it is found that the pore size distribution is mainly concentrated at 2.9nm. Figure 4 shows the pore size distribution plot of the two-dimensional polyimide material of Example 1. Figure 4 shows that the pore size of the two-dimensional polyimide material of Example 1 is concentrated at 2.8nm. This result reveals the pore structure characteristics of the two-dimensional polyimide material, and the pore size distribution matches well with the fitting result.

[0116] Nitrogen adsorption measurement was performed on the hyperbranched polyimide of Comparative Example 1 at 77K. Figure 5 shows the nitrogen adsorption plot of the hyperbranched polyimide of Comparative Example 1. In comparison, the hyperbranched polyimide of Comparative Example 1 has very small adsorption capacity, which belongs to non-porous structure. This means that the hyperbranched polyimide of Comparative Example 1 lacks obvious pores or voids in structure, resulting in relatively low specific surface area and adsorption value.

[0117] Figure 6 shows the infrared spectrum of the two-dimensional polyimide material of Example 1 and the hyperbranched polyimide of Comparative Example 1. It is shown that the two-dimensional polyimide material of Example 1 has a characteristic peak at 1750cm -1 , which is different from Comparative Example 1.

[0118] Figure 7 shows the plot of the second round of charge-discharge of the battery made of the two-dimensional polyimide material of Example 1 and the hyperbranched polyimide of Comparative Example 1. As can be seen from Figure 7, under a current density of 0.25C at 0.01-3V, the discharge specific capacity of the battery made of the two-dimensional polyimide material of Example 1 reaches 132mAh / g, which is higher than that of Comparative Example 1.

[0119] ​Figure 8 shows the plot of the fiftieth cycle of charge and discharge of the battery made of the two-dimensional polyimide material of Example 1 and the hyperbranched polyimide of Comparative Example 1. It can be seen that the specific capacity of the battery made of the two-dimensional polyimide material of Example 1 is still as high as 108 mAh / g at the 50th discharge at a current density of 100 mA / g at 0.01-3 V. The specific capacity of the battery made of the two-dimensional polyimide material of Example 1 is maintained at 108 mAh / g after 50 cycles, and the discharge capacity retention rate is 81.82% calculated from the second discharge capacity.

[0120] Figure 9 is a plot of the cycle discharge capacity of the battery made of the two-dimensional polyimide material of Example 1 and the hyperbranched polyimide of Comparative Example 1. The 150-cycle curves of Example 1 and Comparative Example 1 were tested at a current density of 100 mA / g, respectively. The initial discharge capacity of the battery made of the two-dimensional polyimide material of Example 1 was 132 mAh / g, and the capacity retention rate was 78.7% after 150 cycles calculated from the second discharge capacity. The initial discharge capacity of the battery made of the hyperbranched polyimide of Comparative Example 1 was 132 mAh / g, and the capacity retention rate was 73.6%. In comparison, Example 1 not only has a higher capacity but also has stronger cycle stability.

[0121] The processes and steps described in all the preferred embodiments above are only examples. Unless an adverse effect occurs, various processing operations can be performed in an order different from the order of the processes described above. The order of the steps of the processes described above can also be added, combined, or deleted according to actual needs.

[0122] It should be noted that the above embodiments illustrate the application rather than limit the application, and a person skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs located between parentheses shall not be construed as limiting the claims. The application can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. does not imply any order. These words can be understood as names.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit the same; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A two-dimensional polyimide material, wherein, The two-dimensional polyimide material is a crystalline porous material, and the molecular structure of the two-dimensional polyimide material forms a ring shape to form nanoscale pores.

2. The two-dimensional polyimide material according to claim 1, wherein, The molecular structure of the two-dimensional polyimide material includes the following repeating units:

3. The two-dimensional polyimide material according to claim 1, wherein, The temperature at which the two-dimensional polyimide material loses 5% of its thermal weight is greater than 250°C; and / or The temperature at which the two-dimensional polyimide material loses 10% of its thermal weight is greater than 380°C.

4. The two-dimensional polyimide material according to claim 1, wherein, The two-dimensional polyimide material has more than 50% of its nanoscale pores with a pore size of less than 5 nm; and / or The nanoscale pores of the two-dimensional polyimide material have a pore size of 2.7-2.9 nm for more than 80% of the pores.

5. The two-dimensional polyimide material according to claim 1, wherein, The specific surface area of ​​the two-dimensional polyimide material is 450-550 m². 2 ·g -1 .

6. The two-dimensional polyimide material according to claim 1, wherein, The XRD of the two-dimensional polyimide material exhibits diffraction peaks with 2θ values ​​between 0 and 6; and / or The infrared spectrum of the two-dimensional polyimide material was measured in the range of 1700–1800 cm⁻¹. -1 It has a characteristic peak.

7. A preparation method, wherein, The preparation method is used to prepare the two-dimensional polyimide material according to any one of claims 1-6. The preparation method includes: dissolving an aromatic dianhydride monomer and a triamine aromatic monomer in an organic solvent and reacting them under sealed heating conditions to generate the two-dimensional polyimide material.

8. The preparation method according to claim 7, wherein, The molar ratio of the aromatic dianhydride monomer to the molar ratio of the triamine aromatic monomer is 1.4 to 1.6; and / or The concentration of the aromatic dianhydride monomer in the organic solvent is 0.01–0.05 mol / L.

9. The preparation method according to claim 7, wherein, The aromatic dianhydride monomer comprises at least one selected from 3,4,9,10-perylenetetracarboxylic dianhydride, 1,6,7,12-tetrahalogen-3,4,9,10-tetracarboxylic anhydride, 2,3,6,7-tetrahalonaphthalene-1,4,5,8-tetracarboxylic dianhydride, and 1,4-dihalogen-2,3,5,6-benzenetetracarboxylic dianhydride, wherein the halogen is at least one selected from fluorine, chlorine, and bromine; and / or The triamine aromatic monomer is at least one selected from 1,3,5-triaminobenzene, melamine, 1,3,5-tris(4-aminophenyl)benzene, and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine; and / or The organic solvent is N-methylpyrrolidone.

10. The preparation method according to claim 7, wherein, The preparation method includes the following steps: In the preparation step, aromatic dianhydride monomers and triamine aromatic monomers are added to an organic solvent and mixed evenly. In the feeding step, the mixture is added to a pressure-resistant container, and the pressure-resistant container is evacuated and then sealed. The reaction step involves heating and maintaining the pressure-resistant container at a preset temperature for a preset reaction time.

11. The preparation method according to claim 10, wherein, The preset temperature is 180–220°C; and / or The preset reaction time is 48–144 h; and / or The preset reaction time is 115-125 hours.

12. The preparation method according to claim 10, wherein, The feeding step includes: adding the mixture into a pressure-resistant container, and then sealing the pressure-resistant container with a flame after low-temperature vacuuming.

13. The preparation method according to claim 10, wherein, The preparation method further includes: a washing step, in which the reaction product is filtered, followed by repeated washing with a solvent until the solvent is colorless; and The purification step involves purifying the washed product using Soxhlet extraction, filtering it, and then drying it to constant weight to obtain the two-dimensional polyimide material.

14. An electrode, wherein, The electrode comprises a two-dimensional polyimide material according to any one of claims 1-13.

15. A battery, wherein, The battery includes the electrodes according to claim 14.

16. An electrical appliance, wherein, The electrical device includes the battery according to claim 15.

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