Preparation method and application of a physical cross-linking polyimide dielectric composite based on supramolecular structure

Abstract

The application discloses a preparation method and application of a physical cross-linking polyimide dielectric composite material based on a supramolecular structure and relates to the technical field of dielectric materials. 1,1-di(4-aminophenyl)cyclohexane is used as a diamine monomer, 4,4-hexafluoroisopropyl phthalic anhydride is used as a dianhydride monomer, a mixing reaction is carried out in a solvent, and single-(6-amino-6-deoxy)-beta-cyclodextrin is added in the mixing reaction process to carry out chain end bonding, the reaction solution is coated into a film shape, and after heat treatment, peeling and drying are carried out, the physical cross-linking polyimide dielectric composite material based on the supramolecular structure is obtained. Under the premise of maintaining ultralow dielectric loss, the breakdown strength and the energy storage density of the polyimide dielectric composite material at high temperature are greatly improved, a potential new type of material is provided for a high-temperature high-field thin film capacitor, and a brand-new technical idea is provided for structure optimization of the polyimide and combination with the supramolecular material in the future.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dielectric materials, in particular to a preparation method and application of a physical cross-linking polyimide dielectric composite material based on a supramolecular structure. BACKGROUND

[0002] Electrostatic capacitors are widely used in advanced electrical and electronic systems, including hybrid electric vehicles, grid-connected photovoltaic power generation, oil and gas exploration, etc., and are the core components of high-voltage direct current transmission converter valves, high-power density pulse power supplies, electric vehicles, etc. Nowadays, due to the inevitable generation of a large amount of heat by high-power electronic systems, the internal working temperature of thin film capacitors is basically above 100 ℃, so there is a great demand for dielectric materials with excellent high-temperature capacitance performance. For example, in green energy automobile inverters, the working temperature of capacitors is 140-150 ℃, and in electrified aircraft, the working temperature can reach 200 ℃. However, the current mainstream commercial polymer thin films are difficult to meet the needs of high-temperature environments, such as biaxially oriented polypropylene (BOPP), which has relatively poor high-temperature thermal stability. When the working temperature exceeds 85 ℃, the breakdown field strength of BOPP decreases significantly, and when the temperature exceeds 120 ℃, the conductivity of BOPP increases by about three orders of magnitude, resulting in an exponential increase in conduction loss. Therefore, it is crucial to find new commercial dielectric energy storage materials and develop polymer thin films with excellent high-temperature dielectric, breakdown and energy storage performance.

[0003] Polyimide (PI) has become one of the preferred choices in the dielectric field due to its simple and diverse synthesis route, excellent mechanical properties, high glass transition temperature and outstanding thermal stability. The most common modification strategy is to add inorganic nanofillers with wide band gap to the polyimide matrix to improve performance. However, while the organic-inorganic composite material improves the dielectric energy storage performance, the easy aggregation of inorganic fillers and poor compatibility of the organic-inorganic interface can lead to a decrease in flexibility, uniformity and stability of the material, affecting the overall mechanical properties. More seriously, this disadvantage of the organic-inorganic interface is more pronounced in high-temperature and high-electric-field environments. Another modification method is to select different monomers to weaken the conjugation effect of the PI chain to improve the dielectric and energy storage performance at high temperatures. For example, using alicyclic monomers instead of traditional aromatic monomers, using the strong electronegativity of fluorine to replace the strategy of substituting trifluoromethyl (CF3), and using monomers with non-coplanar structures. However, this single monomer modification can significantly reduce the glass transition temperature (Tg) of PI, and due to the reactivity, it can cause the synthesis degree of PI to decrease to varying degrees, affecting the flexibility of PI while increasing the probability of breakdown at high temperatures.

[0004] Based on the above technical status, it is urgent to develop a new type of polyimide-based dielectric material with excellent high-temperature dielectric properties, mechanical stability and process feasibility, to break through the bottleneck of existing technology and meet the core needs of high-energy density energy storage devices in extreme environments. SUMMARY

[0005] The purpose of the present application is to provide a preparation method and application of a physical cross-linking polyimide dielectric composite material based on a supramolecular structure, to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0007] One of the technical solutions of the present application: a preparation method of a physical cross-linking polyimide dielectric composite material based on a supramolecular structure, comprising the following steps:

[0008] 1,1-bis(4-aminophenyl)cyclohexane is used as a diamine monomer, 4,4-hexafluoroisopropyl phthalic anhydride is used as a dianhydride monomer, a mixing reaction is carried out in a solvent to generate polyamide acid, and single-(6-amino-6-deoxy)-β-cyclodextrin is added to the mixing reaction process to bond with the chain end of the polyamide acid. The obtained reaction solution is coated into a film shape, and after heat treatment, it is peeled off and dried to obtain the physical cross-linking polyimide dielectric composite material based on the supramolecular structure.

[0009] The amino-functionalized single-(6-amino-6-deoxy)-β-cyclodextrin is used as a filler in the present application, which can react with the precursor to achieve end-capping during in-situ polymerization of polyimide, can make cyclodextrin and polyimide better combined, reduce defects, and the single-(6-amino-6-deoxy)-β-cyclodextrin located in the chain segment plays a role in constructing a polymer chain network under the action of supramolecular force.

[0010] As a further preferred embodiment of the present application, the temperature of the mixing reaction is 5-10℃; the time of the mixing reaction is 20-24h.

[0011] As a further preferred embodiment of the present application, the temperature of the heat treatment is 80-250℃.

[0012] As a further preferred embodiment of the present application, the heat treatment adopts gradient temperature rising treatment; the gradient temperature rising treatment is: sequentially keeping at 80℃, 100℃, 150℃, 200℃ and 250℃ for 1-2h.

[0013] As a further preferred embodiment of the present application, the single-(6-amino-6-deoxy)-β-cyclodextrin accounts for 0.1~0.5 wt% of the total mass of the diamine monomer and the dianhydride monomer.

[0014] As a further preferred embodiment of the present application, the molar ratio of the diamine monomer and the dianhydride monomer is 1:1.

[0015] As a further preferred embodiment of the present application, the solvent is N,N-dimethylacetamide.

[0016] As a further preferred embodiment of the present application, the mass ratio of the total mass of the diamine monomer and the dianhydride monomer to the mass of the solvent is 1.5-2.5 g: 6-10 g.

[0017] The second technical solution of the present application provides a physical cross-linking polyimide dielectric composite based on a supramolecular structure prepared by the above preparation method.

[0018] The third technical solution of the present application provides an application of the physical cross-linking polyimide dielectric composite based on a supramolecular structure in the field of dielectric energy storage materials.

[0019] As a further preferred embodiment of the present application, the application environment temperature is 25-150 DEG C.

[0020] The cyclodextrin / polyimide dielectric composite prepared by the method of the present application can reduce the π-π conjugation level of the polymer main chain under the electron-withdrawing induction effect and the steric hindrance effect, improve the energy storage performance, and at the same time, the cyclodextrin located at the chain end can uptake the benzene ring in the polyimide chain with a negative charge under the supramolecular force, so that part of the polymer chain can pass through the inner cavity of the cyclodextrin, realize the physical cross-linking of the polyimide chain, and synergistically enhance the stability and mechanical properties of the polyimide chain.

[0021] The present application discloses the following technical effects:

[0022] The present application uses 1,1-di(4-aminophenyl)cyclohexane as the diamine monomer, 4,4-hexafluoroisopropyl phthalic anhydride as the dianhydride monomer to prepare polyimide as the matrix, and single-(6-amino-6-deoxy)-β-cyclodextrin as the filler, and adopts the in-situ polymerization method to make the added cyclodextrin molecules react to bond at the chain segment end, so that the cyclodextrin located at the chain end can uptake the benzene ring in the polyimide chain with a negative charge under the supramolecular force, part of the polymer chain can pass through the inner cavity of the cyclodextrin, realize the physical cross-linking of the polyimide chain, and synergistically enhance the stability and mechanical properties of the polyimide chain, thereby achieving the technical effect of greatly improving the breakdown strength and energy density at high temperature while maintaining ultra-low dielectric loss.

[0023] The application provides a potential new material for high-temperature and high-field thin film capacitors, and provides a brand-new technical idea for future structure optimization of polyimides and combination with supramolecular materials. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0025] Figure 1 The transmission electron microscope (TEM) image of the physical crosslinking polyimide dielectric composite material based on the supramolecular structure in the embodiment 6 of the present application.

[0026] Figure 2 The atomic force microscope (AFM) image of the physical crosslinking polyimide dielectric composite material based on the supramolecular structure in the embodiment 3 of the present application.

[0027] Figure 3 The dielectric constant and loss diagram of the polyimide in the embodiment 1 and the physical crosslinking polyimide dielectric composite material based on the supramolecular structure in the embodiments 2-6 of the present application.

[0028] Figure 4 The breakdown strength diagram of the polyimide in the embodiment 1 and the physical crosslinking polyimide dielectric composite material based on the supramolecular structure in the embodiments 2-6 of the present application at 150 DEG C.

[0029] Figure 5 The capacitance performance diagram of the polyimide in the embodiment 1 and the physical crosslinking polyimide dielectric composite material based on the supramolecular structure in the embodiments 2-6 of the present application at 150 DEG C.

[0030] Figure 6 The stress-strain curve diagram of the polyimide in the embodiment 1 and the physical crosslinking polyimide dielectric composite material based on the supramolecular structure in the embodiments 2-6 of the present application. DETAILED DESCRIPTION

[0031] The various exemplary embodiments of the present application will be described in detail below, which should not be considered as limiting the present application, but should be understood as a more detailed description of some aspects, characteristics and embodiments of the present application.

[0032] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Additionally, for a range of values of, for example, the upper limit of the range and the lower limit of the range are each disclosed. Each intermediate value of the range is also disclosed. Each smaller range which exists between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is also encompassed. The upper and lower limits of these smaller ranges can independently be included or excluded in the range.

[0033] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe in detail the methods and / or materials which are described in them. In the case of conflict between the present specification and any document incorporated herein by reference, the present specification will control.

[0034] Many modifications and variations of the present application described in the specification are possible without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only. It is to be understood that the application is not limited in any way by the specific application described herein.

[0035] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional, unrecited elements or method steps.

[0036] The application will be described in detail below with reference to specific embodiments. It should be noted that the application is not limited in any way by the specific embodiments described herein, and that the application is not limited to the specific embodiments described herein.

[0037] In the present application, "room temperature" specifically refers to 25 °C.

[0038] Example 1

[0039] The polyimide film material was prepared according to the following steps:

[0040] (1) 5 mmol of diamine monomer (1,1-di(4-aminophenyl)cyclohexane) was weighed into 8 g of N,N-dimethylacetamide (DMAc), and then an equimolar amount of dianhydride monomer (4,4-hexafluoroisopropyl phthalic anhydride) was added to the mixed solution, which was stirred at 8 °C for 24 h to ensure that the diamine monomer reacted with the dianhydride monomer to form polyamide acid;

[0041] (2) Casting the reaction solution of step (1) on a cleaned glass plate, and performing gradient temperature treatment to realize imidization of the polyamic acid; wherein the gradient temperature treatment is specifically as follows: 80°C, 100°C, 150°C, 200°C, and 250°C, each for 1 h;

[0042] (3) After natural cooling to room temperature, the film is peeled off in deionized water, and vacuum dried in an 80°C oven to remove excess water, to obtain a polyimide film material (marked as polyimide).

[0043] Example 2

[0044] A preparation method of a physical crosslinking polyimide dielectric composite material (FPI@0.1 wt% NH2-β-CD) based on a supramolecular structure, steps as follows:

[0045] (1) 5 mmol of diamine monomer (1,1-di(4-aminophenyl)cyclohexane) is weighed and added to 8 g of N,N-dimethylacetamide (DMAc), and then an equimolar amount of dianhydride monomer (4,4-hexafluoroisopropyl phthalic anhydride) is added to the mixed solution, and stirred at 8°C for 24 h to ensure that the diamine monomer reacts with the dianhydride monomer to generate polyamide acid;

[0046] (2) Single-(6-amino-6-deoxy)-β-cyclodextrin (0.1 wt% of the total mass of diamine monomer and dianhydride monomer) is added to the reaction system of step (1) to react with the generated polyamide acid and graft on the polyamide acid for end capping;

[0047] (3) Casting the reaction solution of step (2) on a cleaned glass plate, and performing gradient temperature treatment to realize imidization of the polyamic acid; wherein the gradient temperature treatment is specifically as follows: 80°C, 100°C, 150°C, 200°C, and 250°C, each for 1 h;

[0048] (4) After natural cooling to room temperature, the film is peeled off in deionized water, and vacuum dried in an 80°C oven to remove excess water, to obtain a physical crosslinking polyimide dielectric composite material (FPI@0.1 wt% NH2-β-CD) based on a supramolecular structure.

[0049] Example 3

[0050] A preparation method of a physical crosslinking polyimide dielectric composite material (FPI@0.2 wt% NH2-β-CD) based on a supramolecular structure, steps as follows:

[0051] (1) 5 mmol of diamine monomer (1,1-di(4-aminophenyl)cyclohexane) was added to 8 g of N,N-dimethylacetamide (DMAc), and then an equimolar amount of dianhydride monomer (4,4-hexafluoroisopropyl phthalic anhydride) was added to the mixed solution, which was stirred at 8°C for 24 h to ensure that the diamine monomer reacted with the dianhydride monomer to form polyamic acid;

[0052] (2) Single-(6-amino-6-deoxy)-β-cyclodextrin (0.2 wt% of the total mass of the diamine monomer and the dianhydride monomer) was added to the reaction system of step (1) to react with the generated polyamic acid and graft on the polyamic acid to cap;

[0053] (3) The reaction solution of step (2) was cast on a cleaned glass plate and subjected to gradient temperature treatment to achieve imidization of the polyamic acid; wherein the gradient temperature treatment is specifically as follows: 80°C, 100°C, 150°C, 200°C, and 250°C, each for 1 h;

[0054] (4) After natural cooling to room temperature, the film was peeled off in deionized water and vacuum dried in an 80°C oven to remove excess water to obtain a physical crosslinking polyimide dielectric composite based on a supramolecular structure (FPI@0.2 wt% NH2-β-CD).

[0055] Example 4

[0056] A method for preparing a physical crosslinking polyimide dielectric composite based on a supramolecular structure (FPI@0.3 wt% NH2-β-CD) is as follows:

[0057] (1) 5 mmol of diamine monomer (1,1-di(4-aminophenyl)cyclohexane) was added to 8 g of N,N-dimethylacetamide (DMAc), and then an equimolar amount of dianhydride monomer (4,4-hexafluoroisopropyl phthalic anhydride) was added to the mixed solution, which was stirred at 8°C for 24 h to ensure that the diamine monomer reacted with the dianhydride monomer to form polyamic acid;

[0058] (2) Single-(6-amino-6-deoxy)-β-cyclodextrin (0.3 wt% of the total mass of the diamine monomer and the dianhydride monomer) was added to the reaction system of step (1) to react with the generated polyamic acid and graft on the polyamic acid to cap;

[0059] (3) The reaction solution of step (2) was cast on a cleaned glass plate and subjected to gradient temperature treatment to achieve imidization of the polyamic acid; wherein the gradient temperature treatment is specifically as follows: 80°C, 100°C, 150°C, 200°C, and 250°C, each for 1 h;

[0060] (4) After natural cooling to room temperature, the film is peeled off in deionized water and vacuum dried in an 80 ℃ oven to remove excess water to obtain a physical cross-linking polyimide dielectric composite based on a supramolecular structure (FPI@0.3 wt% NH2-β-CD).

[0061] Example 5

[0062] A preparation method of a physical cross-linking polyimide dielectric composite based on a supramolecular structure (FPI@0.4 wt% NH2-β-CD) is as follows:

[0063] (1) 5 mmol of diamine monomer (1,1-di(4-aminophenyl)cyclohexane) is weighed into 8 g of N,N-dimethylacetamide (DMAc), and then an equimolar amount of dianhydride monomer (4,4-hexafluoroisopropyl phthalic anhydride) is added to the mixed solution, which is stirred at 8 ℃ for 24 h to ensure that the diamine monomer reacts with the dianhydride monomer to generate polyamide acid;

[0064] (2) Single-(6-amino-6-deoxy)-β-cyclodextrin (0.4 wt% of the total mass of the diamine monomer and the dianhydride monomer) is added to the reaction system of step (1) to react with the generated polyamide acid and end-capped by grafting on the polyamide acid;

[0065] (3) The reaction solution of step (2) is cast on a cleaned glass plate, and gradient temperature treatment is performed to achieve imidization of the polyamide acid; wherein the gradient temperature treatment is as follows: 80 ℃, 100 ℃, 150 ℃, 200 ℃, and 250 ℃, each for 1 h;

[0066] (4) After natural cooling to room temperature, the film is peeled off in deionized water and vacuum dried in an 80 ℃ oven to remove excess water to obtain a physical cross-linking polyimide dielectric composite based on a supramolecular structure (FPI@0.4 wt% NH2-β-CD).

[0067] Example 6

[0068] A preparation method of a physical cross-linking polyimide dielectric composite based on a supramolecular structure (FPI@0.5 wt% NH2-β-CD) is as follows:

[0069] (1) 5 mmol of diamine monomer (1,1-di(4-aminophenyl)cyclohexane) is weighed into 8 g of N,N-dimethylacetamide (DMAc), and then an equimolar amount of dianhydride monomer (4,4-hexafluoroisopropyl phthalic anhydride) is added to the mixed solution, which is stirred at 8 ℃ for 24 h to ensure that the diamine monomer reacts with the dianhydride monomer to generate polyamide acid;

[0070] (2) Add single-(6-amino-6-deoxy)-β-cyclodextrin (0.5 wt% of the total mass of diamine monomer and dianhydride monomer) to the reaction system of step (1) to react with the generated polyamic acid to end-cap by grafting on the polyamic acid;

[0071] (3) Cast the reaction solution of step (2) on a cleaned glass plate and perform gradient temperature treatment to achieve imidization of the polyamic acid; the gradient temperature treatment specifically comprises: 80℃, 100℃, 150℃, 200℃, 250℃, each for 1h;

[0072] (4) After natural cooling to room temperature, peel off the film in deionized water and vacuum dry in an 80℃ oven to remove excess water to obtain a physical crosslinking polyimide dielectric composite based on a supramolecular structure (FPI@0.5 wt% NH2-β-CD).

[0073] The transmission electron microscopy (TEM) of the FPI@0.5 wt% NH2-β-CD prepared in Example 6 is shown in Figure 1 As can be seen from the figure, the diameters of the added cyclodextrin fillers are distributed between 5-8nm and are relatively uniformly dispersed.

[0074] The atomic force microscopy (AFM) of the FPI@0.2 wt% NH2-β-CD prepared in Example 3 is shown in Figure 2 As can be seen from the figure, the area where the cyclodextrin is located is highlighted, i.e., the Young's modulus is obviously increased, accompanied by a gradually spreading white halo around, which directly shows the existence of the crosslinking structure.

[0075] A high-vacuum resistance evaporation film plating machine is used to perform copper plating treatment on the thin film, a thin copper layer is deposited on both sides of the composite thin film, and the dielectric energy storage performance is tested. The dielectric constant and dielectric loss obtained by testing the dielectric properties of the polyimide synthesized in Example 1 and the physical crosslinking polyimide dielectric composite based on a supramolecular structure prepared in Examples 2-6 at room temperature in relation to frequency are shown in Figure 3 .

[0076] The breakdown strength tested at 150℃ of the synthesized polyimide (polyimide) and the physical crosslinking polyimide dielectric composite based on a supramolecular structure prepared in Examples 2-6 is shown in Figure 4 .

[0077] The energy storage density and charge-discharge efficiency tested at 150℃ of the synthesized polyimide (polyimide) and the physical crosslinking polyimide dielectric composite based on a supramolecular structure prepared in Examples 2-6 is shown in Figure 5 .

[0078] Figure 6Stress-strain curves of the synthesized polyimide (PI) and the physical crosslinking polyimide dielectric composite based on supramolecular structure prepared in Examples 2-6.

[0079] Table 1 is the dielectric loss of the synthesized polyimide (PI) and the physical crosslinking polyimide dielectric composite based on supramolecular structure prepared in Examples 2-6 at room temperature, the breakdown strength (Eb) and discharge energy density (U d ).

[0080] Table 1

[0081]

[0082] Comparative Example 1

[0083] An unmodified polyetherimide polymer (PEI) was prepared by the following steps:

[0084] (1) 5 mmol of diamine monomer (m-phenylenediamine) was weighed and added to 10 g of N,N-dimethylacetamide (DMAc). Then, an equimolar amount of dianhydride (bisphenol A type diether dianhydride) was added to the mixed solution, and the mixture was stirred at 8 ℃ for 24 h to ensure the reaction of the diamine and dianhydride monomers to form polyamic acid;

[0085] (2) The reaction solution of step (1) was cast on a cleaned glass plate and subjected to gradient temperature treatment to achieve imidization of the polyamic acid; wherein the gradient temperature treatment was as follows: 80 ℃, 100 ℃, 150 ℃, 200 ℃, and 250 ℃, each for 1 h;

[0086] (3) After natural cooling to room temperature, the film was peeled off in deionized water and vacuum dried in an 80 ℃ oven to remove excess water.

[0087] Comparative Example 2

[0088] The only difference between Example 2 and Comparative Example 2 is that the single-(6-amino-6-deoxy)-β-cyclodextrin in step (2) of Example 2 was replaced by the same mass fraction of β-cyclodextrin.

[0089] Comparative Example 3

[0090] The only difference between Example 2 and Comparative Example 3 is that the single-(6-amino-6-deoxy)-β-cyclodextrin in step (2) of Example 2 was replaced by the same mass fraction of TiO2.

[0091] Comparative Example 4

[0092] The only difference between Example 2 and this example is that the diamine monomer in step (1) of Example 2 is replaced by 5 mmol of m-phenylenediamine, and the dianhydride is replaced by 5 mmol of bisphenol A type diether dianhydride.

[0093] Performance test:

[0094] Table 2 is the dielectric loss of the material prepared in Comparative Examples 1-4 at room temperature, the breakdown strength (Eb) and discharge energy density (U d ).

[0095] Table 2

[0096]

[0097] As can be seen from Table 2, the dielectric loss of Comparative Examples 1-4 at room temperature, the breakdown strength (Eb) and discharge energy density (U d ) tested at 150 ℃ are all not as good as Example 2, which shows that the physical crosslinking polyimide film based on supramolecular structure of the present application can effectively improve the dielectric and energy storage performance.

[0098] The above-described examples are only to describe the preferred modes of the present application, and not to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for preparing a physically cross-linked polyimide dielectric composite material based on a supramolecular structure, characterized in that, Includes the following steps: 1,1-Di(4-aminophenyl)cyclohexane was used as a diamine monomer, and 4,4-hexafluoroisopropylphthalic anhydride was used as a dianhydride monomer. The mixture was reacted in a solvent to generate polyamic acid. During the reaction, mono-(6-amino-6-deoxy)-β-cyclodextrin was added to the polyamic acid to form a chain-end bond. The resulting reaction solution was coated into a film, and after heat treatment, it was peeled off and dried to obtain the physically crosslinked polyimide dielectric composite material based on supramolecular structure. The mono-(6-amino-6-deoxy)-β-cyclodextrin accounts for 0.1 to 0.5 wt% of the total mass of the diamine monomer and dianhydride monomer.

2. The preparation method according to claim 1, characterized in that, The temperature of the mixing reaction is 5-10℃; the time of the mixing reaction is 20-24h.

3. The preparation method according to claim 1, characterized in that, The heat treatment temperature is 80-250℃.

4. The preparation method according to claim 3, characterized in that, The heat treatment employs a gradient heating process, which involves sequentially holding the temperature at 80 ℃, 100 ℃, 150 ℃, 200 ℃, and 250 ℃ for 1-2 hours each.

5. The preparation method according to claim 1, characterized in that, The molar ratio of the diamine monomer to the dianhydride monomer is 1:

1.

6. The preparation method according to claim 1, characterized in that, The solvent is N,N-dimethylacetamide.

7. A physically cross-linked polyimide dielectric composite material based on a supramolecular structure, characterized in that, The physically cross-linked polyimide dielectric composite material based on supramolecular structure is prepared by the preparation method according to any one of claims 1-6.

8. The application of the physically cross-linked polyimide dielectric composite material based on supramolecular structure as described in claim 7 in the field of dielectric energy storage materials.

9. The application according to claim 8, characterized in that, The application environment temperature is 25-150 ℃.

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