Polyimide covalent organic framework material based on truxene ketone as well as preparation method and application of polyimide covalent organic framework material

Abstract

The invention discloses a polyimide covalent organic framework material based on truxene ketone, a preparation method and application, and belongs to the technical field of preparation of covalent organic framework materials, the covalent organic framework material is prepared by taking 2, 7, 12-triamino-5H-diindole [1, 2-A: 1 ', 2'-C] fluorene-5, 10, 15-triketone as an amino ligand, taking pyromellitic dianhydride or 2, 3, 6, 7-tetramethyl-4-piperidine as an amino ligand, taking 2, 7, 12-triamino-5H-diindole [1, 2-A: 1 ', 2'-C] fluorene-5, 10, 15-triketone as an amino ligand, taking 2, 7, 12-triamino-5H-diindole [1, 1, 7-naphthalenetetracarboxylic dianhydride is used as an aldehyde group connecting unit and is formed through acylation reaction condensation; according to the preparation method, a TRO ligand is introduced, high-activity sites with 18 carbonyl groups are formed in each pore channel of each layer, a shorter path is provided for rapid diffusion of Li < + >, and rapid reaction kinetics is achieved. And conjugate units are added and expanded in a COF framework through chain engineering, so that the electronic structure and the aperture are effectively adjusted, and the electron conductivity and the diffusion rate of Li < + > are improved. Due to the increase of the number of benzene rings, active sites are continuously activated under large current, and even under the current of 20A g <-1 >, the material still has the state that the active sites are continuously activated, so that high reversible specific capacity, high energy density and high power density under the large current are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of covalent organic framework materials, and in particular relates to a polyimide covalent organic framework material based on trimerized indenone, a preparation method and an application thereof. Background Art

[0002] Covalent organic frameworks (COFs) are a new type of crystalline porous polymers that can effectively solve the solubility problem of organic molecules in electrolytes and have become potential electrode materials. It provides an ideal environment for the adsorption, diffusion and reaction of lithium ions, promotes the interfacial contact between electrodes and electrolytes, and accelerates the insertion / detachment process of lithium ions. In addition, COFs also have structural tunability, which can introduce redox groups and accurately adjust the active sites and their number, thereby improving the performance of lithium-ion batteries.

[0003] Among the numerous COFs, polyimide has the advantages of high mechanical strength, strong thermal stability, and good chemical inertness, and therefore has satisfactory capacity, excellent cycle performance, and good rate performance when used as a lithium-ion anode material. However, the synthesis and development of PI-COFs are limited due to the fast reaction rate and poor reversibility between monomers. Specifically, achieving high reversible capacity and long cycle performance at high current density remains a challenge for COFs.

[0004] Therefore, it is necessary to explore new COFs anode materials for high-performance LIBs. Summary of the invention

[0005] In order to solve the defects of low specific capacity, volume expansion, poor cycle performance and easy damage under high current of existing lithium ion battery negative electrode materials, the present invention provides a polyimide covalent organic framework material based on trimerized indenone, a preparation method and an application thereof; by introducing TRO ligands, the method realizes the formation of high active sites with 18 carbonyl groups in each pore of each layer, which is Li + The rapid diffusion of provides a shorter path, thus achieving fast reaction kinetics. In addition, the incorporation and extension of conjugated units in the COF framework through chain engineering effectively modulates the electronic structure and pore size, thereby improving electronic conductivity and Li + More importantly, due to the increase in the number of benzene rings, the active sites are continuously activated under high currents, even at 20A g -1 Under high current, the material still has active sites that are continuously activated, thus achieving high reversible specific capacity, high energy density and power density under high current.

[0006] The present invention is achieved through the following technical solutions:

[0007] In the first aspect, the present invention provides a polyimide covalent organic framework material based on tripolyindene, which is formed by acylation reaction condensation of 2,7,12-triamino-5H-diindole[1,2-A:1',2'-C]fluorene-5,10,15-trione as an amino ligand and pyromellitic anhydride or 2,3,6,7-naphthalenetetracarboxylic dianhydride as an aldehyde linking unit, and the structural formula is as follows:

[0008]

[0009]

[0010] In a second aspect, the present invention provides a method for preparing a polyimide covalent organic framework material based on trimerized indenone, and the specific steps are as follows:

[0011] 2,7,12-triamino-5H-diindole[1,2-A:1',2'-C]fluorene-5,10,15-trione and a connecting unit substance are ground evenly in a mortar according to a certain ratio, and the connecting unit substance includes pyromellitic anhydride or 2,3,6,7-naphthalenetetracarboxylic dianhydride; after being ground evenly, they are added into a glass tube, an organic solvent is added, and then a catalyst is added, the glass tube is placed in liquid nitrogen for freezing, the tube is sealed with a vacuum flame, and finally placed in an oven for heating, so as to obtain tripolyindene-based polyimide covalent organic framework materials COF-JLU85 and COF-JLU86.

[0012] Furthermore, the molar ratio of the 2,7,12-triamino-5H-diindole[1,2-A:1',2'-C]fluorene-5,10,15-trione to the linking unit substance is 2:3.

[0013] Furthermore, the organic solvent is N-methylpyrrolidone and o-dichlorobenzene, and the total volume of the solvent is 1 ml. When the covalent organic framework material is COF-JLU85, the volume ratio of N-methylpyrrolidone and o-dichlorobenzene is 7:3, and when the covalent organic framework material is COF-JLU86, the volume ratio of N-methylpyrrolidone and o-dichlorobenzene is 5:5; the volume of the catalyst is 0.05 mL.

[0014] Furthermore, the catalyst is isoquinoline; the oven heating temperature is 180° C., and the reaction time is 5 days.

[0015] In a third aspect, the present invention also provides an application of a polyimide covalent organic framework material based on trimerized indenone in lithium ion batteries, specifically, the prepared covalent organic framework material, single-walled carbon nanotubes and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 6:3:1, and N-methyl-2-pyrrolidone (NMP) is used as a solvent; then, the slurry is uniformly coated on a copper foil and dried at 60°C for 12 hours; thereafter, the copper foil is rolled using a roller press, and then the copper foil is cut into an electrode sheet with a diameter of 1.4 cm; the mass loading of the active material is 0.4-1.2 mg cm -2 ; The covalent organic framework material electrode sheet was used as the working electrode, lithium foil was used as the counter electrode, 1.0M LiPF6 containing 5.0% FEC in EC / DEC (v / v=1:1) solution was used as the electrolyte, and glass fiber was used as the separator; subsequently, the CR-2016 button cell was assembled in a glove box filled with Ar.

[0016] Compared with the prior art, the advantages of the present invention are as follows:

[0017] 1. The present invention introduces multi-carbonyl groups for the first time, that is, a high-activity site material with 18 carbonyl groups is formed in each pore of each layer, which can be used as the negative electrode of lithium-ion batteries;

[0018] 2. This invention introduces 2,3,6,7-naphthalenetetracarboxylic dianhydride for the first time, and adds and expands conjugated units in the COF framework through chain engineering, which effectively adjusts the electronic structure and pore size, thereby improving electronic conductivity and Li + The diffusion rate of

[0019] 3. COF-JLU86 in the present invention is 10A g -1 The specific capacity was not lost, the structure was not changed, the volume was not expanded, and the reversible specific capacity was maintained at 618.1 mA h g under high current for 8000 cycles. -1 , the energy density is 377.2Wh kg -1 , power density up to 18860W kg -1 .

[0020] 4. This invention uses COFs for high current testing for the first time, even at 15A g -1 Even under high current, active sites are still activated in the material, and the material has great potential to meet the market demand for high energy density and fast charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0022] Figure 1 Powder X-ray diffraction patterns of COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7;

[0023] Among them, a is COF-JLU85, b is COF-JLU86;

[0024] Figure 2 Fourier transform infrared spectra of COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7 and raw material monomers;

[0025] Among them, a is COF-JLU85, b is COF-JLU86;

[0026] Figure 3 Solid carbon spectra of COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7;

[0027] Among them, a is COF-JLU85, b is COF-JLU86;

[0028] Figure 4 Thermogravimetric analysis diagrams of COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7;

[0029] Figure 5 N2 adsorption diagram and pore size distribution diagram of COF-JLU85 synthesized in Example 2 and Example 7;

[0030] Where a is gas adsorption and b is pore size distribution;

[0031] Figure 6 N2 adsorption diagram and pore size distribution diagram of COF-JLU86 synthesized in Example 2 and Example 7;

[0032] Where a is gas adsorption and b is pore size distribution;

[0033] Figure 7 The rate diagram of COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7 as negative electrodes of lithium-ion batteries;

[0034] Figure 8 The COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7 were subjected to 10A g-1 Long cycle diagram under electric current;

[0035] Fig. 9 The morphology of COF-JLU86 synthesized in Example 2 and Example 7 before and after long-term cycling at a current of 10A g-1;

[0036] Among them, a is before the cycle, b is after 2000 cycles, c is after 4000 cycles, and d is after 8000 cycles;

[0037] Fig.10 The COF-JLU86 synthesized in Example 2 and Example 7 was 10A g -1 Electrode surface morphology before and after long-term cycling under current;

[0038] Among them, a is before the cycle, b is after 2000 cycles, c is after 4000 cycles, and d is after 8000 cycles;

[0039] Fig.11 The COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7 were heated to 15A g -1 Long cycle diagram under electric current;

[0040] Fig.12 The application of the COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7 and graphite in a self-made LED lamp after being assembled into a battery;

[0041] Among them, a is COF-JLU85, b is COF-JLU86, and c is graphite;

[0042] Fig.13 The impedance and Warburg coefficient of COF-JLU85 and COF-JLU86 synthesized in Example 2 and Example 7 and graphite;

[0043] Among them, a is the impedance diagram of the three electrode materials, and b is the Warburg coefficient diagram of the three materials;

[0044] Fig.14 The constant current intermittent titration (GITT) curves and lithium ion diffusion coefficient diagrams of COF-JLU85 synthesized in Example 2 and Example 7. DETAILED DESCRIPTION

[0045] In order to clearly and completely describe the technical solution and its specific working process of the present invention, the specific implementation methods of the present invention are as follows in conjunction with the accompanying drawings of the specification:

[0046] Example 1

[0047] This embodiment provides a method for preparing a polyimide covalent organic framework material COF-JLU85 based on tripolyindanone, which specifically comprises the following steps:

[0048] The amino type 2,7,12-triamino-5H-diindole [1,2-A:1',2'-C] fluorene-5,10,15-trione and the aldehyde type pyromellitic anhydride are used as linear connecting units and condensed through an acylation reaction. The above two monomers are weighed in a mortar at a molar ratio of 2:3 and ground to fully mix the two monomers. Then, the two monomers are transferred to a heat-resistant tube with a volume of 20.0 mL, a body length of 18.0 cm, and a neck length of 9 cm. 0.1 mL of o-dichlorobenzene, 0.05 mL of isoquinoline, and 0.9 mL of N-methyl-2-pyrrolidone are added. The heat-resistant glass tube is quickly frozen in liquid nitrogen, evacuated to an internal pressure of about 19.0 mbar, and flame-sealed, and the total length is reduced by about 10.0 cm. After standing to room temperature, the heat-resistant tube is placed in an oven at 180°C for reaction for five days.

[0049] Example 2

[0050] This embodiment provides a method for preparing a polyimide covalent organic framework material COF-JLU85 based on trimerized indanone. Compared with Example 1, only the ratio of the solvent is regulated, and the method specifically comprises the following steps:

[0051] It is formed by acylation reaction condensation of amino type 2,7,12-triamino-5H-diindole [1,2-A:1',2'-C] fluorene-5,10,15-trione and aldehyde type pyromellitic anhydride as linear connecting units. The above two monomers are weighed in a mortar at a molar ratio of 2:3 and ground to fully mix the two monomers. Then, they are transferred to a heat-resistant tube with a volume of 20.0 mL, a body length of 18.0 cm, and a neck length of 9 cm. 0.3 mL of o-dichlorobenzene, 0.05 mL of isoquinoline, and 0.7 mL of N-methyl-2-pyrrolidone are added. The heat-resistant glass tube is quickly frozen in liquid nitrogen, evacuated to an internal pressure of 19.0 mbar, and flame-sealed, and the total length is reduced by about 10.0 cm. After standing to room temperature, the heat-resistant tube is placed in an oven at 180°C for five days. Its structure is as follows:

[0052]

[0053] Example 3

[0054] This embodiment provides a method for preparing a polyimide covalent organic framework material COF-JLU85 based on trimerized indanone. Compared with Example 1, only the ratio of the solvent is regulated, and the method specifically comprises the following steps:

[0055] The amino type 2,7,12-triamino-5H-diindole [1,2-A:1',2'-C] fluorene-5,10,15-trione and the aldehyde type pyromellitic anhydride are used as linear connecting units through acylation reaction condensation. The above two monomers are weighed in a mortar at a molar ratio of 2:3 and ground to fully mix the two monomers. Then, they are transferred to a heat-resistant tube with a volume of 20.0 mL, a body length of 18.0 cm, and a neck length of 9 cm. 0.5 mL of o-dichlorobenzene, 0.05 mL of isoquinoline, and 0.5 mL of N-methyl-2-pyrrolidone are added. The heat-resistant glass tube is quickly frozen in liquid nitrogen, evacuated to an internal pressure of about 19.0 mbar, and flame-sealed, and the total length is reduced by 10.0 cm. After standing to room temperature, the heat-resistant tube is placed in an oven at 180°C for five days.

[0056] Example 4

[0057] This embodiment provides the application of the polyimide covalent organic framework material COF-JLU85 based on trimerized indene in lithium-ion batteries. COF-JLU85, single-walled carbon nanotubes and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 6:3:1, and N-methyl-2-pyrrolidone (NMP) is used as a solvent. Subsequently, the slurry is evenly coated on a copper foil and dried at 60 ° C for 12 hours. After that, the copper foil is rolled using a roller press, and then the copper foil is cut into electrode sheets with a diameter of 1.4 cm. The mass loading of the active material is about 0.4-1.2 mg cm -2 The COFs electrode was used as the working electrode, the lithium foil was used as the counter electrode, the 1.0M LiPF6 EC / DEC (v / v=1:1) solution containing 5.0% FEC was used as the electrolyte, and the glass fiber was used as the separator. Subsequently, the CR-2016 button cell was assembled in a glove box filled with Ar.

[0058] Example 5

[0059] This embodiment provides a method for preparing a polyimide covalent organic framework material COF-JLU86 based on trimerized indanone, which specifically comprises the following steps:

[0060] The amino type 2,7,12-triamino-5H-diindole [1,2-A:1',2'-C] fluorene-5,10,15-trione and the aldehyde type 2,3,6,7-naphthalenetetracarboxylic dianhydride are used as linear connecting units through acylation reaction condensation. The above two monomers are weighed in a mortar at a molar ratio of 2:3 and ground to fully mix the two monomers. Then, they are transferred to a heat-resistant tube with a volume of 20.0 mL, a body length of 18.0 cm, and a neck length of 9 cm. 0.1 mL of o-dichlorobenzene, 0.05 mL of isoquinoline, and 0.9 mL of N-methyl-2-pyrrolidone are added. The heat-resistant glass tube is quickly frozen in liquid nitrogen, evacuated to an internal pressure of 19.0 mbar, and flame-sealed, and the total length is reduced by 10.0 cm. After standing to room temperature, the heat-resistant tube is placed in an oven at 180°C for five days.

[0061] Example 6

[0062] This embodiment provides a method for preparing a polyimide covalent organic framework material COF-JLU86 based on trimerized indanone. Compared with Example 5, only the ratio of the solvent is regulated, and the method specifically comprises the following steps:

[0063] The amino type 2,7,12-triamino-5H-diindole [1,2-A: 1',2'-C] fluorene-5,10,15-trione and the aldehyde type 2,3,6,7-naphthalenetetracarboxylic dianhydride are used as linear connecting units through acylation reaction condensation. The above two monomers are weighed in a mortar at a molar ratio of 2:3 and ground to fully mix the two monomers. Then, they are transferred to a heat-resistant tube with a volume of 20.0 mL, a body length of 18.0 cm, and a neck length of 9 cm. 0.3 mL of o-dichlorobenzene, 0.05 mL of isoquinoline, and 0.7 mL of N-methyl-2-pyrrolidone are added. The heat-resistant glass tube is quickly frozen in liquid nitrogen, evacuated to an internal pressure of 19.0 mbar, and flame-sealed, and the total length is reduced by 10.0 cm. After standing to room temperature, the heat-resistant tube is placed in an oven at 180°C for five days.

[0064] Example 7

[0065] This embodiment provides a method for preparing a polyimide covalent organic framework material COF-JLU86 based on trimerized indanone. Compared with Example 5, only the ratio of the solvent is regulated, and the method specifically comprises the following steps:

[0066] It is formed by acylation reaction condensation of amino type 2,7,12-triamino-5H-diindole [1,2-A:1',2'-C] fluorene-5,10,15-trione and aldehyde type 2,3,6,7-naphthalenetetracarboxylic dianhydride as linear connecting units. The above two monomers are weighed in a mortar at a molar ratio of 2:3 and ground to fully mix the two monomers. Then, they are transferred to a heat-resistant tube with a volume of 20.0 mL, a body length of 18.0 cm, and a neck length of 9 cm. 0.5 mL of o-dichlorobenzene, 0.05 mL of isoquinoline, and 0.5 mL of N-methyl-2-pyrrolidone are added. The heat-resistant glass tube is quickly frozen in liquid nitrogen, evacuated to an internal pressure of 19.0 mbar, and flame-sealed. The total length is reduced by about 10.0 cm. After standing to room temperature, the heat-resistant tube is placed in an oven at 180°C for five days; its structure is as follows:

[0067]

[0068] Example 8

[0069] This embodiment provides the application of the polyimide covalent organic framework material COF-JLU86 based on trimerized indene in lithium-ion batteries. COF-JLU86, single-walled carbon nanotubes and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 6:3:1, and N-methyl-2-pyrrolidone (NMP) is used as a solvent. Subsequently, the slurry is evenly coated on a copper foil and dried at 60°C for 12 hours. After that, the copper foil is rolled using a roller press, and then the copper foil is cut into electrode sheets with a diameter of 1.4 cm. The mass loading of the active material is about 0.4-1.2 mg cm-2. The COFs electrode is used as a working electrode, the lithium foil is used as a counter electrode, the EC / DEC (v / v=1:1) solution containing 5.0% FEC in 1.0MLiPF6 is used as an electrolyte, and the glass fiber is used as a separator. Subsequently, the CR-2016 button cell is assembled in a glove box filled with Ar.

[0070] When the two COFs materials were used as negative electrodes for lithium-ion batteries, they both exhibited excellent electrochemical performance, especially COF-JLU86, which still had high reversible specific capacity and energy density at high current density.

[0071] like Figure 1 As shown, through the powder X-ray diffraction spectra of Rietveld refinement and the powder X-ray diffraction spectra of COF-JLU85 and COF-JLU86 synthesized in this embodiment, it can be determined that two AA-stacked two-dimensional PI-COFs are successfully synthesized by the method of this embodiment;

[0072] like Figure 2As shown, by comparing the Fourier infrared spectra of the monomer and the COF-JLU85 and COF-JLU86 synthesized in this example, 1765 cm -1 The anhydride peak at 3350 and 3222 cm -1 The amino peak at 1345 cm -1 A new peak was observed at , which was attributed to the formation of imine CNCs, demonstrating the successful synthesis of both COFs.

[0073] like Figure 3 As shown, in the solid state of these COFs 13 The carbon characteristic signals observed in the C CP / MAS NMR spectra were assigned to the corresponding chemical structures, and the peak observed at approximately 129 ppm was attributed to the imine bond carbon, further confirming the successful condensation of these COFs.

[0074] like Figure 4 As shown, thermogravimetric analysis shows that the mass of these two materials begins to decrease after 550 °C, indicating that they have excellent thermal stability under nitrogen conditions.

[0075] like Figure 5 and Figure 6 As shown in Figure 2, the specific surface area of ​​COF-JLU86 is 491.87 m 2 g -1 , higher than COF-JLU85's 215.34m 2 g -1 The pore sizes are all mesopores, mainly distributed around 3.0 and 3.2 nm respectively.

[0076] like Figure 7 As shown in Figure 2, both COF-JLU85 and COF-JLU86 have good rate performance and high reversible specific capacity, especially COF-JLU86 has better rate performance (10Ag -1 224.9mA hg -1 ) and higher specific capacity (0.1A g -1 1161.1mA hg -1 ).

[0077] like Figure 8 As shown, at 10A g -1 The long-life cycle test of COF-JLU85 and COF-JLU86 was carried out under high current. After 8000 cycles, there was no obvious loss in the specific capacity of both. In particular, the reversible specific capacity of COF-JLU86 after the cycle was as high as 618.1 mA h g -1 , the energy density is 377.2W h kg -1, power density up to 18860W kg -1 .

[0078] like Fig. 9 As shown, in the high rate (10A g -1 During the cycling test, the microstructure of the electrode material was observed in detail using a scanning electron microscope. At each cycle stage of the battery, including the activation stage at 2,000 cycles, the equilibrium state at 4,000 cycles, and even after 8,000 cycles, the morphology of the electrode material showed remarkable stability, remaining consistent with the morphology before the cycle and showing a unique filamentous structure.

[0079] like Fig.10 As shown, in the high rate (10A g -1 ) During the cycling tests, the surface structure of the electrode materials was observed in detail using a scanning electron microscope. During the entire cycling process, neither material showed any cracks or fissures. Only after completing 8,000 cycles did the material show microcracks. These observations not only confirm the high morphological stability of the studied materials, but also provide important evidence for understanding their structural integrity during long-term battery cycling.

[0080] like Fig.11 As shown, at 15A g -1 COF-JLU85 and COF-JLU86 were subjected to long-life cycle tests under a high current. After 10,000 cycles, there was no significant decrease in the specific capacity of both materials, and under this high current, the active sites of the materials were still in an activated state, which demonstrates the characteristics of the high active sites of the two materials.

[0081] like Fig.12 As shown, after lithium-ion batteries assembled with different electrode materials were tested with homemade red LED lights, it was found that the battery with COF-JLU86 as the electrode material had the highest brightness, followed by COF-JLU85, while the battery with graphite electrode had the lowest brightness. This shows that the COF-JLU86 electrode can store and release electrical energy more efficiently, thereby providing a stronger current to light up the LED light.

[0082] like Fig.13 As shown, by conducting impedance tests on batteries composed of different electrode materials, COF-JLU86 showed the lowest charge transfer resistance, with a measured value of 390Ω, while COF-JLU85 was 450Ω and graphite was 490Ω. In addition, by calculating the Warburg impedance of the three materials, COF-JLU86 showed the highest lithium ion diffusion rate. This modification improves electronic conductivity and promotes more efficient charge transport.

[0083] like Fig.14As shown in the GITT test of the two materials, the Li+ diffusion coefficient of COF-JLU86 is between 10 -10 to 10 -7 cm 2 S -1 Between, and COF-JLU85 (between 10 -8 -10 -11 cm 2 S -1 This result shows that by modifying the chain engineering and increasing the conjugation of the framework, it is beneficial to Li + diffusion.

[0084] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0085] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0086] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A polyimide covalent organic framework material based on tripolyindene, characterized in that: It is formed by acylation reaction of 2,7,12-triamino-5H-diindole[1,2-A:1',2'-C]fluorene-5,10,15-trione as an amino ligand and pyromellitic anhydride or 2,3,6,7-naphthalenetetracarboxylic dianhydride as an aldehyde linking unit. The structural formula is as follows:

2. The method for preparing a polyimide covalent organic framework material based on trimerized indanone according to claim 1, characterized in that: The specific steps are as follows: 2,7,12-triamino-5H-diindole[1,2-A:1',2'-C]fluorene-5,10,15-trione and a connecting unit substance are ground evenly in a mortar according to a certain ratio, and the connecting unit substance includes pyromellitic anhydride or 2,3,6,7-naphthalenetetracarboxylic dianhydride; after being ground evenly, they are added into a glass tube, an organic solvent is added, and then a catalyst is added, the glass tube is placed in liquid nitrogen for freezing, the tube is sealed with a vacuum flame, and finally placed in an oven for heating, so as to obtain tripolyindene-based polyimide covalent organic framework materials COF-JLU85 and COF-JLU86.

3. The method for preparing the polyimide covalent organic framework material based on trimerized indanone according to claim 2, characterized in that: The molar ratio of the 2,7,12-triamino-5H-diindole[1,2-A:1',2'-C]fluorene-5,10,15-trione to the linking unit substance is 2:

3.

4. The method for preparing a polyimide covalent organic framework material based on trimerized indanone according to claim 2, characterized in that: The organic solvents are N-methylpyrrolidone and o-dichlorobenzene, and the total volume of the solvent is 1 ml. When the covalent organic framework material is COF-JLU85, the volume ratio of N-methylpyrrolidone to o-dichlorobenzene is 7:3, and when the covalent organic framework material is COF-JLU86, the volume ratio of N-methylpyrrolidone to o-dichlorobenzene is 5:

5. The volume of the catalyst is 0.05 mL.

5. The method for preparing the polyimide covalent organic framework material based on trimerized indanone according to claim 2, characterized in that: The catalyst is isoquinoline; the oven heating temperature is 180° C., and the reaction time is 5 days.

6. The use of the polyimide covalent organic framework material based on tripolyindene as claimed in claim 1 in lithium ion batteries, characterized in that: Specifically, the prepared covalent organic framework material, single-walled carbon nanotubes and polyvinylidene fluoride were mixed in a weight ratio of 6:3:1, and N-methyl-2-pyrrolidone was used as a solvent; then, the slurry was evenly coated on a copper foil and dried at 60°C for 12 hours; after that, the copper foil was rolled using a roller press and then cut into electrode sheets with a diameter of 1.4 cm; the mass loading of the active material was 0.4-1.2 mg cm -2 ; The covalent organic framework material electrode sheet was used as the working electrode, lithium foil was used as the counter electrode, 1.0M LiPF6 EC / DEC solution containing 5.0% FEC was used as the electrolyte, and glass fiber was used as the separator; Subsequently, CR-2016 coin cells were assembled in an Ar-filled glove box.

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