Semi-alicyclic dipole glass polyimide film, application thereof and capacitor

Abstract

The invention relates to the technical field of energy storage, in particular to a semi-alicyclic dipole glass polyimide film, application thereof and a capacitor. The semi-alicyclic dipole glass polyimide film has a structure as shown in a formula I. In the formula I, a group Al comprises a non-conjugated aliphatic group; the group ArDG comprises an aromatic group with a polarization group modification; and n is an integer from 50 to 250. The semi-alicyclic dipole glass polyimide film has high glass transition temperature, wide band gap, strong self-healing property and high dielectric constant, and a capacitor prepared by using the semi-alicyclic dipole glass polyimide film as a raw material has excellent high-temperature energy storage performance and performance stability. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the technical field of energy storage, and in particular to a semi-alicyclic dipole glass polyimide film and application thereof, and a capacitor. Background Art

[0002] Film capacitor energy storage technology for dual carbon goals is based on physical processes such as polarization / depolarization of dielectrics to achieve green and fast storage / release of electrical energy. It has the advantages of high operating voltage (several kV), high power density (up to GW), wide operating temperature range, safety, and long life. Film capacitors are key components of high-voltage flexible DC transmission converter valves, and are crucial to improving the absorption capacity of renewable energy (such as wind power generation and photovoltaic power generation); they are also core components of electromagnetic energy equipment and new energy vehicle electric drive systems. However, due to the sharp attenuation of the capacitance performance of key material polymer dielectrics under high temperature (≥150℃) and high electric field, its development in the fields of electricity, national defense, and new energy is seriously restricted. Therefore, the development of high-temperature dielectric polymers with high energy density, high efficiency, and reliable performance is a major challenge in this field.

[0003] Discharge energy density (U d =0.5ε0ε r E b , where ε0 is the dielectric constant of vacuum) can be improved by synergistically improving the breakdown strength E b and dielectric constant ε r How to suppress the conductivity loss in high temperature scenarios is the key to achieving high charge and discharge efficiency (η). Self-repair or self-cleaning ability (C sh ) is one of the key indicators for evaluating the reliability of metallized film capacitors. Relevant research is more focused on low-temperature biaxially oriented polypropylene films and capacitors, but research in the high-temperature field is lacking. The electrical weak points (small defects or impurities, etc.) of the dielectric film are broken down to form a discharge channel. The current flowing through the breakdown point generates a large amount of Joule heat, causing the local temperature to rise. The high temperature causes the metal layer around the breakdown point to evaporate and diffuse outward. The metal vapor is easily ionized to form plasma. As the metal evaporation area expands, the plasma discharge arc is extinguished. This process is a unique "self-healing" characteristic of metallized films. If the electrodes are connected through a carbonized channel, the self-healing fails; if the electrodes and the carbonized layer are separated, the self-healing is successful. As we all know, for the general formula C a H b O c N d S e For polymers, the empirically lower S h ((C+N+S) / (O+H))(molar ratio of (a+d+e) to (b+c)) can provide stronger self-healing ability. Self-healing ability sh ( where tsh is the self-healing characteristic time) can quantitatively describe the self-healing.

[0004] The long-standing bottleneck of dielectric polymers with high energy density, high efficiency and high reliability at high temperature is how to collaboratively break the band gap (E g ) and glass transition temperature (T g ), ε r With E g and C sh With T g Due to the multiple inversion coupling, the development of high-temperature (≥150°C) polymer dielectrics with high glass transition temperature, wide band gap, strong self-healing property and high dielectric constant faces many challenges. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the related art to at least some extent. To this end, the present invention provides a semi-alicyclic dipole glass polyimide film and its application and capacitor. The present invention proposes an intrinsic strategy, that is, through low S h The reaction of alicyclic dianhydride ((C+N+S) / (O+H)) and aromatic diamine containing polar groups is used to construct a semi-alicyclic dipolar glass polyimide film (sAl-DG) with a chain structure of alternating alicyclic units and aromatic units containing large dipole moment groups. sAl-DG has high glass transition temperature, wide band gap, strong self-healing property, and high dielectric constant. This intrinsic strategy is universal. The dielectric film obtained by this intrinsic strategy has strong breakdown resistance, excellent high-temperature energy storage performance and performance stability.

[0006] To this end, the first aspect of the present invention provides a semi-alicyclic dipole glass polyimide film, wherein the semi-alicyclic dipole glass polyimide film has a structure shown in Formula I:

[0007]

[0008] Wherein, group Al comprises a non-conjugated aliphatic group;

[0009] The group ArDG includes an aromatic group modified with a polar group;

[0010] n is an integer between 50 and 250.

[0011] The present invention adopts low S hA semi-alicyclic dipole glass polyimide film (sAl-DG) having a chain structure of alternating alicyclic units and aromatic units containing polar groups is constructed by the reaction of alicyclic dianhydrides ((C+N+S) / (O+H)) and aromatic diamines containing polar groups. sAl-DG has excellent performance, including high glass transition temperature, wide band gap, strong self-healing property and high dielectric constant. Its dielectric energy storage performance is significantly higher than that of currently commercially used products.

[0012] According to an embodiment of the present invention, the group A1 includes

[0013] According to an embodiment of the present invention, the polarized group includes a sulfone group.

[0014] According to an embodiment of the present invention, the group ArDG comprises

[0015] According to an embodiment of the present invention, the glass transition temperature of the semi-alicyclic dipole glass polyimide film is ≥215°C, preferably 218°C-387°C.

[0016] According to an embodiment of the present invention, the band gap energy of the semi-alicyclic dipole glass polyimide film is ≥3.8 eV, preferably 3.99 eV-4.26 eV.

[0017] According to an embodiment of the present invention, the element molar ratio of (C+N+S) / (O+H) in the semi-alicyclic dipole glass polyimide film is ≤1.22.

[0018] According to an embodiment of the present invention, the dielectric constant of the semi-alicyclic dipole glass polyimide film is ≥3.3, preferably 3.48-4.3.

[0019] The second aspect of the present invention provides the use of the semi-alicyclic dipole glass polyimide film described in the first aspect in high temperature resistant dielectric energy storage materials or optoelectronic devices.

[0020] A third aspect of the present invention provides a capacitor, comprising the semi-alicyclic dipole glass polyimide film described in the first aspect.

[0021] The capacitor constructed based on the semi-alicyclic dipole glass polyimide film has excellent stability and high-temperature electrostatic energy storage performance, and has great practical application value.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] Figure 1 The molecular structure diagrams of the polymer films prepared in Examples 1-10 of the present invention and Comparative Examples 1-4 are shown;

[0025] Figure 2 The polymer films prepared in Examples 1-4 of the present invention are shown in FIG. 1 H NMR spectrum;

[0026] Figure 3 A graph showing the glass transition temperature of polymer films prepared in Examples 1-10 of the present invention;

[0027] Figure 4 The UV-visible spectra of the polymer films prepared in Examples 1 and 3 of the present invention and Comparative Examples 1-4 are shown;

[0028] Figure 5 shows the band gap energy diagram of the polymer films prepared in Examples 1-10 of the present invention;

[0029] Figure 6 The dielectric constant and dielectric loss diagram of the polymer films prepared in Examples 1 and 3 of the present invention and Comparative Examples 1-4 at 20° C., 150° C., and 200° C. are shown;

[0030] Figure 7 The dielectric constant and dielectric loss diagram of the polymer films prepared in Example 2 and Examples 4-10 of the present invention are shown;

[0031] Figure 8 The graph showing the evolution of voltage and current over time during the self-healing process of BOPP metallized film;

[0032] Fig. 9 The graph showing the evolution of voltage and current over time during the self-healing process of the polymer films prepared in Comparative Examples 1 and 2 and Example 1 of the present invention after metallization;

[0033] Fig.10 A comparison diagram of the self-healing energy of the BOPP metallized film and the polymer film prepared in Example 1 after metallization is shown;

[0034] Fig.11 The Weibull distribution diagram of the breakdown field strength of the polymer films prepared in Examples 1 and 3 of the present invention and Comparative Examples 1-4 at 150° C. is shown;

[0035] Fig.12 The Weibull distribution diagram of the breakdown field strength of the polymer films prepared in Examples 1 and 3 of the present invention and Comparative Examples 1-4 at 200° C. is shown;

[0036] Fig.13 The graph shows the relationship between the discharge energy density and discharge efficiency of the polymer films prepared in Examples 1 and 3 of the present invention and Comparative Examples 1-4 at 150° C. and the electric field strength;

[0037] Fig.14 The graph shows the relationship between the discharge energy density and discharge efficiency of the polymer films prepared in Examples 1 and 3 of the present invention and Comparative Examples 1-4 at 200° C. and the electric field strength;

[0038] Fig.15 The charge-discharge cycle diagram of the polymer film prepared in Example 1 of the present invention at 200° C. and at 200 MV / m, 300 MV / m, 400 MV / m and 500 MV / m respectively is shown;

[0039] Fig.16 A physical picture of a metallized film constructed based on the polymer film prepared in Example 1 of the present invention is shown;

[0040] Fig.17 A physical picture of a stacked capacitor constructed based on the polymer film prepared in Example 1 of the present invention is shown;

[0041] Fig.18 The structural cross-sectional SEM image and the EDS image of the element Al of the multilayer capacitor constructed based on the polymer film prepared in Example 1 of the present invention are shown;

[0042] Fig.19 The graph showing the capacitance and loss factor of the multilayer capacitor constructed based on the polymer film prepared in Example 1 of the present invention as a function of frequency is shown;

[0043] Fig. 20 The graph shows the relationship between the discharge energy density and the charge-discharge efficiency of the stacked capacitor constructed based on the polymer film prepared in Example 1 of the present invention and the change with the electric field strength. DETAILED DESCRIPTION

[0044] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0045] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0046] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0047] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which the present invention belongs.

[0048] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0049] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0050] According to an embodiment of the present invention, a first aspect of the present invention provides a semi-alicyclic dipole glass polyimide film, wherein the semi-alicyclic dipole glass polyimide film has a structure shown in Formula I:

[0051]

[0052] Wherein, group Al comprises a non-conjugated aliphatic group;

[0053] The group ArDG includes an aromatic group modified with a polar group;

[0054] n is an integer between 50 and 250.

[0055] The present invention adopts low S hThe reaction of alicyclic dianhydride ((C+N+S) / (O+H)) and aromatic diamine containing polar groups is used to construct a semi-alicyclic dipolar glass polyimide film (sAl-DG) with a chain structure of alternating alicyclic units and aromatic units containing large dipole moment groups. sAl-DG has excellent performance, including high glass transition temperature, wide band gap, strong self-healing property, and high dielectric constant. Its dielectric energy storage performance is significantly higher than that of products currently used in the commercial market. Aromatic units are highly conjugated systems with excellent heat resistance and intramolecular / intermolecular charge transfer complexation (CT), which greatly promotes the transfer of charges under high temperature and high electric field strength, thereby greatly deteriorating the breakdown performance; at the same time, there is a lack of large dipole moment groups inside the molecular structure, so its dielectric constant is low. Ar-DG constructed by introducing polar groups with large dipole moment into aromatic units can show a high dielectric constant, but its breakdown performance is still restricted by strong conjugation. The introduction of the alicyclic unit greatly weakens the charge transfer effect within and between polymer molecules, thereby greatly weakening the conjugation effect, widening the band gap of the system, and achieving a synergistic improvement in the dielectric constant and breakdown field strength; at the same time, the alicyclic unit has a low S h ((C+N+S) / (O+H)), which can greatly enhance the intrinsic self-healing property of the system; in addition, the semi-alicyclic skeleton gives the system a high glass transition temperature and thus excellent thermal stability.

[0056] The "high temperature" mentioned in the present invention refers to ≥150°C.

[0057] According to a specific embodiment of the present invention, the type of the group A1 is not particularly limited. As some specific examples, the type of the group A1 includes

[0058] According to a specific embodiment of the present invention, the polarized group includes a sulfone group.

[0059] According to a specific embodiment of the present invention, the type of the group ArDG is not particularly limited. As some specific examples, the type of the group ArDG includes

[0060] According to a specific embodiment of the present invention, the glass transition temperature of the semi-alicyclic dipole glass polyimide film is ≥215°C. As some specific examples, the glass transition temperature of the semi-alicyclic dipole glass polyimide film may be 215°C, 218°C, 256°C, 278°C, 308°C, 350°C, 387°C, 399°C, etc., preferably 218°C-387°C. As some specific examples, the glass transition temperature of the semi-alicyclic dipole glass polyimide film may be 218°C, 256°C, 278°C, 308°C, 350°C, 387°C, etc.

[0061] According to a specific embodiment of the present invention, the band gap energy of the semi-alicyclic dipole glass polyimide film is ≥3.8eV. As some specific examples, the band gap energy of the semi-alicyclic dipole glass polyimide film may be 3.8eV, 3.99eV, 4.1eV, 4.2eV, 4.26eV, 4.3eV, etc., preferably 3.99eV-4.26eV. As some specific examples, the band gap energy of the semi-alicyclic dipole glass polyimide film may be 3.99eV, 4.1eV, 4.2eV, 4.26eV, etc.

[0062] According to a specific embodiment of the present invention, the element molar ratio of (C+N+S) / (O+H) in the semi-alicyclic dipole glass polyimide film is ≤1.22. As some specific examples, the element molar ratio of (C+N+S) / (O+H) in the semi-alicyclic dipole glass polyimide film may be 0.98, 1.05, 1.11, 1.18, 1.22, etc.

[0063] According to a specific embodiment of the present invention, the dielectric constant of the semi-alicyclic dipole glass polyimide film is ≥3.3 under the conditions of 20°C-200°C and 1kHz. As some specific examples, the dielectric constant of the semi-alicyclic dipole glass polyimide film may be 3.3, 3.48, 3.8, 4.0, 4.3, 4.4, etc., preferably 3.48-4.3. As some specific examples, the dielectric constant of the semi-alicyclic dipole glass polyimide film may be 3.48, 3.8, 4.0, 4.3, etc.

[0064] According to a specific embodiment of the present invention, the preparation method of the semi-alicyclic dipole glass polyimide film is not particularly limited. As some specific examples, the preparation method of the semi-alicyclic dipole glass polyimide film can be specifically as follows: under an inert atmosphere, an aromatic diamine monomer, an aliphatic dianhydride monomer, and a catalyst are added to an anhydrous solvent in an equivalent ratio of 1:1:0.5 to obtain a mixed solution, wherein the solid content of the mixed solution is 20wt%-30wt%, and the mixture is reacted at 30°C-90°C for 4 hours and at 180°C for at least 20 hours, respectively, purified, and dried to obtain a polymer, the polymer is added to a solvent, cast into a film, and dried to obtain the semi-alicyclic dipole glass polyimide film.

[0065] According to a specific embodiment of the present invention, the type of the catalyst is not particularly limited. As some specific examples, the catalyst includes at least one of benzoic acid and isoquinoline.

[0066] According to a specific embodiment of the present invention, the type of the anhydrous solvent is not particularly limited. As some specific examples, the anhydrous solvent includes but is not limited to N,N-dimethylformamide (NMP).

[0067] According to a specific embodiment of the present invention, the type of the inert atmosphere is not particularly limited. As some specific examples, the inert atmosphere includes but is not limited to nitrogen.

[0068] According to an embodiment of the present invention, a second aspect of the present invention provides an application of the semi-alicyclic dipole glass polyimide film described in the first aspect in a high temperature resistant dielectric energy storage material or a photoelectric device.

[0069] According to an embodiment of the present invention, a third aspect of the present invention provides a capacitor, comprising the semi-alicyclic dipole glass polyimide film described in the first aspect.

[0070] The capacitor constructed based on the semi-alicyclic dipole glass polyimide film has excellent stability and high-temperature electrostatic energy storage performance, and has great practical application value.

[0071] According to a specific embodiment of the present invention, the type of the capacitor is not particularly limited. As some specific examples, the capacitor includes but is not limited to a multilayer capacitor.

[0072] According to a specific embodiment of the present invention, the preparation method of the stacked capacitor is not particularly limited. As some specific examples, the preparation method of the stacked capacitor can be specifically as follows: using aluminum (Al) as an electrode to metallize the semi-alicyclic dipole glass polyimide film on one side to obtain a metallized film; using a laser to accurately cut the metallized film into the required metallized units, wherein the active dielectric area has a diameter of 1 cm, and the units with the terminal electrodes on the left and the units with the terminal electrodes on the right are alternately stacked, and then a non-metallized dielectric layer is used as a sealing layer. Subsequently, a vacuum-function hot press is used to hot press the stacked sheets at a temperature of 150-200°C and a pressure range of 5-10 tons for not less than 5 hours. After hot pressing, the device is precisely cut using a laser to expose the internal electrodes. These electrodes are then interconnected with a conductive silver paste to form terminal electrodes, thereby obtaining the stacked capacitor.

[0073] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0074] Example 1

[0075] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_p1 and a preparation method thereof. The preparation method of the sAl-DG_p1 is as follows:

[0076] In a nitrogen atmosphere at room temperature, a diamine monomer (bis[4-(4-aminophenoxy)phenyl]sulfone, p-BAPS) and a dianhydride monomer (1,2,4,5-cyclohexanetetracarboxylic dianhydride, HPMDA) were sequentially added into a three-necked reaction bottle containing an ultra-dry solvent N,N-dimethylformamide (NMP) solvent at an equivalent ratio of 1:1, and 0.5 equivalent of catalyst benzoic acid was added, and the solid content was 20% by mass. The solution was gradually heated to 90° C. in a nitrogen atmosphere for reaction for 4 hours, and then gradually heated to 180° C. for reaction for 20 hours; after the solution was cooled, it was precipitated into ethanol, and a fibrous polymer was collected by filtration, and then the product was dried at 100° C. for 12 hours to obtain a polymer with a number average molecular weight M n 66.5×10 3 g / mol.

[0077] The polymer was dissolved in NMP solvent at a concentration of 150 mg / ml, and after filtering to remove impurities and vacuum degassing, a wet film was cast on a glass plate by casting; the film was then placed in a vacuum oven at 40°C for 4 hours to remove a large amount of solvent; the film was further heat treated in a blast oven: 60°C for 1 hour, then heated continuously at 80°C, 100°C and 150°C for 1 hour, and finally heated at 180°C for 10 hours. Finally, the film was placed in a vacuum oven under a nitrogen atmosphere and the following procedures were performed: 200°C for 2 hours, then 250°C for 10 hours to completely remove the solvent in the film. After immersing the film in hot water, the film was peeled off from the glass substrate and dried at 100°C for 12 hours to obtain the semi-alicyclic dipole glass polyimide film sAl-DG_p1, which has a thickness of about 12 μm.

[0078] Example 2

[0079] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_m1 and a preparation method thereof. The preparation method of the sAl-DG_m1 is as follows:

[0080] In a nitrogen atmosphere at room temperature, a diamine monomer (bis[4-(3-aminophenoxy)phenyl]sulfone, m-BAPS) and a dianhydride monomer (1,2,4,5-cyclohexanetetracarboxylic dianhydride, HPMDA) were sequentially added into a three-necked reaction bottle containing an ultra-dry solvent N,N-dimethylformamide (NMP) solvent at an equivalent ratio of 1:1, and 0.5 equivalent of catalyst benzoic acid was added, and the solid content was 20% by mass. The solution was gradually heated to 90° C. in a nitrogen atmosphere for reaction for 4 hours, and then gradually heated to 180° C. for reaction for 20 hours; after the solution was cooled, it was precipitated into ethanol, and a fibrous polymer was collected by filtration, and then the product was dried at 100° C. for 12 hours to obtain a polymer with a number average molecular weight Mn 35.3×10 3 g / mol;

[0081] The polymer was dissolved in NMP solvent at a concentration of 150 mg / ml, and after filtering to remove impurities and vacuum degassing, a wet film was cast on a glass plate by casting; the above film was then placed in a vacuum oven at 40°C for 4 hours to remove a large amount of solvent; the film was further heat treated in a blast oven: 60°C for 1 hour, then heated continuously at 80°C, 100°C and 150°C for 1 hour, and finally heated at 180°C for 10 hours. Finally, the film was placed in a vacuum oven under a nitrogen atmosphere and the following procedures were performed: 200°C for 2 hours, then 250°C for 10 hours to completely remove the solvent in the film. After immersing the film in hot water, the film was peeled off from the glass substrate and dried at 100°C for 12 hours to obtain the semi-alicyclic dipole glass polyimide film sAl-DG_m1, which has a thickness of about 12 μm.

[0082] Example 3

[0083] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_p2 and a preparation method thereof. The preparation method of the sAl-DG_p2 is as follows:

[0084] In a nitrogen atmosphere at room temperature, a diamine monomer (bis[4-(4-aminophenoxy)phenyl]sulfone, p-BAPS) and a dianhydride monomer (dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride, HBPDA) are sequentially added to a three-necked reaction bottle containing an ultra-dry solvent N,N-dimethylformamide (NMP) solvent at an equivalent ratio of 1:1, and 0.5 equivalents of a catalyst isoquinoline is added, and the solid content is 30% by mass. The solution is gradually heated to 40° C. in a nitrogen atmosphere for reaction for 4 hours, and then gradually heated to 180° C. for reaction for 20 hours; after the solution is cooled, it is precipitated into ethanol, and a fibrous polymer is collected by filtration, and then the product is dried at 100° C. for 12 hours to obtain a polymer with a number average molecular weight M n 76.8×10 3 g / mol;

[0085] The polymer was dissolved in DMAc solvent at a concentration of 150 mg / ml, filtered to remove impurities and vacuum to remove bubbles, and then cast on a glass plate to obtain a wet film by casting; then the above film was placed in a vacuum oven at 40°C for 4 hours to remove a large amount of solvent; the film was further heat treated in a blast oven: 60°C for 1 hour, then heated continuously at 80°C, 100°C and 150°C for 1 hour, and finally heated at 180°C for 10 hours. Finally, the film was placed in a vacuum oven under a nitrogen atmosphere and the following procedures were performed: 200°C for 2 hours, then 250°C for 10 hours to completely remove the solvent in the film. After immersing the film in hot water, it was peeled off from the glass substrate and dried at 100°C for 12 hours to obtain the semi-alicyclic dipole glass polyimide film sAl-DG_p2, which has a thickness of about 12 μm.

[0086] Example 4

[0087] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_m2 and a preparation method thereof. The preparation method of the sAl-DG_m2 is as follows:

[0088] In a nitrogen atmosphere at room temperature, a diamine monomer (bis[4-(3-aminophenoxy)phenyl]sulfone, m-BAPS) and a dianhydride monomer (dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride, HBPDA) are sequentially added to a three-necked reaction bottle containing an ultra-dry solvent N,N-dimethylformamide (NMP) solvent at an equivalent ratio of 1:1, and 0.5 equivalents of a catalyst isoquinoline is added, and the solid content is 30% by mass. The solution is gradually heated to 40° C. in a nitrogen atmosphere for reaction for 4 hours, and then gradually heated to 180° C. for reaction for 20 hours; after the solution is cooled, it is precipitated into ethanol, and a fibrous polymer is collected by filtration, and then the product is dried at 100° C. for 12 hours to obtain a polymer with a number average molecular weight M n 35×10 3 g / mol;

[0089] The polymer was dissolved in NMP solvent at a concentration of 150 mg / ml, and after filtering to remove impurities and vacuum degassing, a wet film was cast on a glass plate by casting; the above film was then placed in a vacuum oven at 40°C for 4 hours to remove a large amount of solvent; the film was further heat treated in a blast oven: 60°C for 1 hour, then heated continuously at 80°C, 100°C and 150°C for 1 hour, and finally heated at 180°C for 10 hours. Finally, the film was placed in a vacuum oven under a nitrogen atmosphere and the following procedures were performed: 200°C for 2 hours, then 250°C for 10 hours to completely remove the solvent in the film. After immersing the film in hot water, it was peeled off from the glass substrate and dried at 100°C for 12 hours to obtain the semi-alicyclic dipole glass polyimide film sAl-DG_m2, which has a thickness of about 12μm.

[0090] Example 5

[0091] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_pS2 and a preparation method thereof. The preparation method of sAl-DG_pS2 is different from the preparation method of sAl-DG_p1 in Example 1 only in that:

[0092] The diamine monomer is 3,3'-diaminodiphenyl sulfone (m-DS), and the dianhydride monomer is dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride (HBPDA); the polymer number average molecular weight M n 134.9×10 3 g / mol.

[0093] Example 6

[0094] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_mS2 and a preparation method thereof. The preparation method of sAl-DG_mS2 is different from the preparation method of sAl-DG_p1 in Example 1 only in that:

[0095] The diamine monomer is 4,4'-diaminodiphenyl sulfone (p-DS), and the dianhydride monomer is dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride (HBPDA); the polymer number average molecular weight M n 137.3×10 3 g / mol.

[0096] Example 7

[0097] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_pS3 and a preparation method thereof. The preparation method of sAl-DG_pS3 is different from the preparation method of sAl-DG_p1 in Example 1 only in that:

[0098] The diamine monomer is 4,4'-diaminodiphenyl sulfone (p-DS), and the dianhydride monomer is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2"-norbornane-5,5",6,6"-tetracarboxylic dianhydride (CpODA); the polymer number average molecular weight M n 144.7×10 3 g / mol.

[0099] Example 8

[0100] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_mS3 and a preparation method thereof. The preparation method of sAl-DG_mS3 is different from the preparation method of sAl-DG_p1 in Example 1 only in that:

[0101] The diamine monomer is 3,3'-diaminodiphenyl sulfone (m-DS), and the dianhydride monomer is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2"-norbornane-5,5",6,6"-tetracarboxylic dianhydride (CpODA); the polymer number average molecular weight is M n 162.9×10 3 g / mol.

[0102] Example 9

[0103] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_pS4 and a preparation method thereof. The preparation method of sAl-DG_pS4 is different from the preparation method of sAl-DG_p1 in Example 1 only in that:

[0104] The diamine monomer is p-BAPS, and the dianhydride monomer is bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BTDA); the polymer number average molecular weight M n 32.6×10 3 g / mol.

[0105] Example 10

[0106] This embodiment provides a semi-alicyclic dipole glass polyimide film sAl-DG_mS4 and a preparation method thereof. The preparation method of sAl-DG_mS4 is different from the preparation method of sAl-DG_p1 in Example 1 only in that:

[0107] The diamine monomer is m-BAPS, and the dianhydride monomer is bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BTDA); the polymer number average molecular weight M n 143.8×10 3 g / mol.

[0108] Comparative Example 1

[0109] Kapton PI film, thickness 12.5μm, produced by Poly K.

[0110] Comparative Example 2

[0111] PEI film, 13 μm thick, produced by Poly K Company, is the product with the best dielectric energy storage performance currently used in commercial applications.

[0112] Comparative Example 3

[0113] This comparative example provides a wholly aromatic polyimide film Ar-DG_p1 and a preparation method thereof. The preparation method of Ar-DG_p1 is as follows:

[0114] At room temperature N2 atmosphere, equimolar amount of pyromellitic anhydride PMDA (10mmol, 2.9422g, 98%) and p-BAPS (10mmol, 4.3249g, 98%) are dissolved in 20mL DMF solvent, reacted at room temperature for 10 hours, filtered to remove insoluble impurities, then degassed under vacuum. The solution is cast on a flat glass substrate and heat-treated. The substrate is heated in a vacuum oven with a temperature of 40 ℃ for 4 hours. The sample is further processed in an air convection oven according to the following specified heating schedule: 60 ℃ for 1 hour, then continuously heated at 80 ℃, 100 ℃ and 150 ℃ for 1 hour, and finally heated at 180 ℃ for 10 hours. Finally, the film is placed in a vacuum oven and the following procedure is carried out: 200 ℃ for 2 hours, then 250 ℃ for 10 hours to remove the solvent completely. The film was immersed in hot water from the substrate and dried at 100° C. for 12 hours to obtain the wholly aromatic polyimide film Ar-DG_p1, which had a thickness of about 12 μm.

[0115] Comparative Example 4

[0116] This comparative example provides a wholly aromatic polyimide film Ar-DG_p2 and a preparation method thereof. The preparation method of Ar-DG_p2 is as follows:

[0117] Equimolar amounts of 4,4'-diphthalic anhydride BPDA (10 mmol) and p-BAPS (10 mmol) were dissolved in 20 mL of DMF solvent under N2 atmosphere at room temperature, reacted at room temperature for 10 hours, filtered to remove insoluble impurities, and then degassed under vacuum. The solution was cast onto a flat glass substrate and heat treated. The substrate was heated at 40 ° C for 4 hours in a vacuum furnace. The sample was further treated in an air convection oven according to the following specified heating schedule: 60 ° C for 1 hour, then continuously heated at 80 ° C, 100 ° C and 150 ° C for 1 hour, and finally heated at 180 ° C for 10 hours. Finally, the film was placed in a vacuum oven and subjected to the following procedure: 200 ° C for 2 hours, then 250 ° C for 10 hours to completely remove the solvent. The film was immersed in hot water from the substrate and dried at 100 ° C for 12 hours to obtain the fully aromatic polyimide film Ar-DG_p2, which has a thickness of about 12 μm.

[0118] Comparative Example 5

[0119] This comparative example provides a polyimide film and a preparation method thereof. The preparation method of the polyimide film is as follows:

[0120] Under N2 atmosphere at room temperature, 11.17g (0.045mol) of 4,4'-diaminodiphenyl sulfone and 0.57g (0.005mol) of 1,4-cyclohexanediamine were added to 100g of N-methylpyrrolidone for stirring and dissolution, followed by adding 12.54g (0.035mol) of 3,3,4,4-diphenyl sulfone tetracarboxylic acid dianhydride and 5.77g (0.015mol) of cyclopentanone dispiro-norbornene tetracarboxylic acid dianhydride, stirring and reacting until completely dissolved, maintaining the reaction for 48h, and obtaining a homogeneous, transparent and viscous polyamic acid copolymer precursor solution, placing the precursor solution in a vacuum oven for vacuum degassing, and then placing it in a casting machine for casting into a film, performing thermal imidization treatment, and cooling and demolding to obtain the polyimide film with a thickness of 12μm. The procedure of thermal imidization is: 80°C for 2 h, 150°C for 1 h, 200°C for 1 h, 300°C for 1 h, and finally naturally cooling to room temperature.

[0121] The structural formula of the polyimide film obtained in this comparative example is:

[0122]

[0123] Among them, n1=65, n2=5, n3=25, n4=5.

[0124] Compared with the polymer films provided in Examples 1 to 10 of the present invention, the polymer film prepared in Comparative Example 5 has a higher S hThe value is 1.38, which is significantly smaller than the maximum S h The value is 1.22, therefore, its self-healing performance does not reach the level of the embodiment of the present invention; in addition, the polymer structure in the embodiment of the present invention is an alternating arrangement of aromatic units and alicyclic units, achieving conjugated blocking on a unit scale, giving the system a wide band gap, while 65% of the comparative examples are all aromatic structures, with a large proportion of aromatic structures and a large degree of conjugation, and their band gap energy cannot reach 4eV, and their breakdown performance and energy storage performance are not as good as those of the embodiment of the present invention.

[0125] Comparative Example 6

[0126] This comparative example provides a polyimide film and a preparation method thereof. The preparation method of the polyimide film is as follows:

[0127] The diamine monomer (4,4'-diaminodiphenylmethane) and the dianhydride monomer (1,2,4,5-cyclohexanetetracarboxylic dianhydride) were added to a three-necked reaction bottle in sequence at an equivalent ratio of 1:1, and the solvent N,N-dimethylformamide (NMP) was added with a solid content of 30% by mass. 0.5 equivalent of catalyst isoquinoline was added, and the reaction was carried out at 40°C in a nitrogen atmosphere for 3 hours, and then azeotropic reagent toluene with a volume of 2 times that of NMP was added, and the reaction was gradually heated to 140°C, maintained for 3 hours, and gradually heated to 180°C for 6 hours, and cooled. The polymer was cooled to 80°C and purified in ethanol to obtain a polymer; the polymer was dissolved in NMP solvent at a concentration of 150 mg / ml, and a wet film was obtained by casting on a glass plate by a casting method, and then the film was placed in a vacuum oven at 40°C for 4 hours to remove a large amount of solvent, and then the film was placed in a blast oven at 40°C and heated to 220°C for 4 hours, and then the film was placed in a vacuum oven at 200°C under a nitrogen atmosphere for 10 hours to completely remove the solvent in the film, thereby obtaining the polyimide film with a thickness of 13 μm.

[0128] The structural formula of the polyimide film obtained in this comparative example is:

[0129]

[0130] Compared with the polymer films provided in Examples 1-10, the aromatic unit portion of the polymer film prepared in Comparative Example 6 lacks the polar group sulfone group, and its dielectric constant at 150°C and 1kHz is 3.17, and its dielectric constant at 200°C and 1kHz is 3.15, both of which are lower than the dielectric constants of the embodiments; although the band gap of the comparative example is close to 4eV, the introduction of the sulfone group can construct a charge capture potential well in the molecule, thereby giving the embodiment a higher breakdown field strength than Comparative Example 6 (the breakdown field strengths at 150°C and 200°C are 622MV / m and 568MV / m, respectively).

[0131] Test Case

[0132] Examples 1-10 and Comparative Examples 1-4 and commonly used commercial polymer dielectrics (PP, PET, PC, PEN, PEEK, FPE, PAI, Upilex-SPI, PPS) h The intrinsic self-healing properties are shown in Table 1. Molecular structure diagram of polymer films prepared in Examples 1-10 and Comparative Examples 1-4, 1 H NMR spectrum, glass transition temperature, UV-visible spectrum, band gap energy, dielectric constant and dielectric loss, voltage and current evolution over time of the film self-healing process obtained after metallization, Weibull distribution of breakdown field strength, relationship between discharge energy density and discharge efficiency and electric field strength, charge and discharge cycle diagram, etc. Figure 1-15 As shown, the actual image of the metallized film constructed based on the polymer film prepared in Example 1 of the present invention is as follows Fig.16 As shown, the actual picture of the multilayer capacitor constructed based on the polymer film prepared in Example 1 of the present invention is as follows Fig.17 As shown, the structural cross-sectional SEM image of the multilayer capacitor constructed based on the polymer film prepared in Example 1 of the present invention and the EDS image of the element Al are shown in FIG. Fig.18 As shown in FIG. 1 , the capacitance and loss factor of the multilayer capacitor constructed based on the polymer film prepared in Example 1 of the present invention vary with frequency. Fig.19 As shown in FIG. 1 , the relationship between the discharge energy density and the charge-discharge efficiency of the multilayer capacitor constructed based on the polymer film prepared in Example 1 of the present invention and the change of the electric field strength is shown in FIG. Fig. 20 shown.

[0133] Table 1

[0134]

[0135] From the data in Table 1, it can be seen that the S of the polymer films prepared in Examples 1-10 h The values ​​are 0.969-1.219, all less than 1.22, and significantly lower than the S of the polymer films prepared in Comparative Examples 1-4. h Value (S of polymer films prepared in Comparative Examples 1-4) h The values ​​are 1.6, 1.3, 1.423, and 1.433, respectively), indicating that the polymer film provided by the present invention has strong self-healing property.

[0136] from Figure 2 of 1 It can be seen from the H NMR spectrum that the structures of the polymer films prepared in Examples 1-4 have been characterized, indicating the feasibility of the technical solution of the present invention.

[0137] The glass transition temperatures of the polymer films prepared in Examples 1-10 are as follows: Figure 3 As shown, from Figure 3It can be seen that the glass transition temperature T of the polymer films prepared in Examples 1-10 is g Between 218°C and 387°C, respectively 300°C, 257°C, 252°C, 218°C, 295°C, 235°C, 387°C, 331°C, 332°C, 276°C; T of the polymer films prepared in Examples 1-10 g Both are higher than the T of PEI in Comparative Example 2 g (about 217℃).

[0138] Figure 4 The UV-visible spectra of the polymer films prepared in Examples 1, 3 and Comparative Examples 1-4 are shown below. Figure 5 The band gap energy diagrams of the polymer films prepared in Examples 1-10 and Comparative Examples 1-4 are shown in FIG. Figure 5 It can be seen that the band gap energy of the polymer films prepared in Examples 1-10 is 3.99 eV-4.26 eV. For example, the band gap energy E of the polymer films prepared in Examples 1 and 3 is g The band gap energy E of the polymer films prepared in Example 2 and Examples 4-10 is 3.99 eV and 4.04 eV, respectively, which is 59% and 61% higher than that of Kapton PI in Comparative Example 1, 20.2% and 21.7% higher than that of PEI in Comparative Example 2, 26.3% and 27.8% higher than that of the polymer film prepared in Comparative Example 3, and 20.2% and 21.7% higher than that of the polymer film prepared in Comparative Example 4. g They are 4.1eV, 4.16eV, 4.1eV, 4.19eV, 4.13eV, 4.26eV, 4.06eV and 4.16eV respectively, which are all higher than comparative examples 1-4, proving the universality of the technical solution of the present invention and indicating that the band gap of the polymer film prepared by the present invention can be well improved.

[0139] from Figure 6 and Figure 7It can be seen that the dielectric constant of the polymer films prepared in Examples 1-10 at 20°C and 1kHz is 3.48-4.3, and the loss factor is less than 1%; the dielectric constant at 200°C and 1kHz is 3.39-3.71, and the loss factor is less than 1%. For example, the dielectric constants of the polymer films prepared in Examples 1 and 3 at 20°C and 1kHz are 4.30 and 3.83, respectively, both higher than Comparative Example 1 (3.33) and Comparative Example 2 (3.20), and the loss factors are 0.31% and 0.36%, respectively, lower than Comparative Example 1 (0.44%) and Comparative Example 2 (0.47%); the dielectric constants of the polymer films prepared in Examples 1 and 3 at 200°C and 1kHz are 3.71 and 3.45, respectively, both higher than Comparative Example 1 (3.14) and Comparative Example 2 (3.22), and the loss factors are less than 1%, 0.68% and 0.25%, respectively.

[0140] In order to quantitatively characterize the self-healing property, a polymer film with single-sided aluminum metallization was used as the research object. sh To quantitatively characterize, Figure 8-10 As shown. Fig. 9 As shown, Example 1 exhibits the same performance as the biaxially oriented polypropylene film (BOPP film) ( Figure 8 ) similar self-healing curves, confirming the self-healing properties of the sAl-DG metallized film, while Comparative Examples 1 and 2 failed to successfully self-heal. Fig.10 It can be seen that the self-healing energy of Example 1 is 15.03 mJ.

[0141] from Fig.11 It can be seen that the characteristic breakdown field strength E of the polymer films prepared in Example 1 and Example 3 is b At 150°C, they are 644 MV / m and 675 MV / m, respectively, which are 1.92 times and 2.01 times that of Comparative Example 1 (Kapton PI), 1.31 times and 1.37 times that of Comparative Example 2 (PEI), 1.60 times and 1.68 times that of Comparative Example 3 (Ar-DG_p1), and 1.17 times and 1.23 times that of Comparative Example 4 (Ar-DG_p2). Fig.12 It can be seen that the E of the polymer films prepared in Example 1 and Example 3 b At 200°C, they are 610MV / m and 639MV / m, respectively, which are 2.01 times and 2.10 times that of Comparative Example 1 (Kapton PI), 1.32 times and 1.38 times that of Comparative Example 2 (PEI), 1.68 times and 1.76 times that of Comparative Example 3 (Ar-DG_p1), and 1.22 times and 1.28 times that of Comparative Example 4 (Ar-DG_p2), indicating that the breakdown resistance of the polymer film provided by the present invention is greatly improved.

[0142] from Fig.13 It can be seen that the discharge energy density U of the polymer films prepared in Example 1 and Example 3 at 150°C and an energy efficiency of 90% is η90 7.24 J / cm 3 and 7.39 J / cm 3 , which are 23.35 times and 23.84 times of Comparative Example 1, 6.03 times and 6.16 times of Comparative Example 2, 6.90 times and 7.04 times of Comparative Example 3, and 2.83 times and 2.89 times of Comparative Example 4, respectively. Fig.14 The discharge energy density curves of Comparative Examples 3 and 4 overlap. Fig.14 It can be seen that the U of the polymer films prepared in Example 1 and Example 3 η90 At 200℃, they are 6.20J / cm 3 and 6.15 J / cm 3 , which are 34.44 and 34.17 times of Comparative Example 1, 9.12 and 9.04 times of Comparative Example 2, 18.24 and 18.09 times of Comparative Example 3, and 4.73 and 4.69 times of Comparative Example 4. The U of the polymer film prepared in Example 1 at 200°C η90 This greatly exceeds the energy storage performance of BOPP at 25°C (about 4.76 J / cm at 700 MV / m). 3 ), which is the highest value reported so far in the self-healing system at 200°C. This indicates that the polymer film of the present invention has excellent high-temperature energy storage performance.

[0143] from Fig.15 It can be seen that the discharge energy storage density and charge-discharge efficiency of the polymer film prepared in Example 1 maintain excellent stability after 50,000 charge-discharge cycles, demonstrating the excellent reliability of the polymer film provided by the present invention.

[0144] Fig.17 The actual picture of the polymer metallized film stacked capacitor (sAl-DG-mMLPC) constructed based on the polymer film prepared in Example 1 of the present invention, wherein the dielectric active layer has 3 layers, and its preparation process is: using aluminum (Al) as an electrode to metallize the polymer film prepared in Example 1 on one side to obtain a metallized film (the actual picture is as shown in FIG. Fig.16As shown); the single-sided metallized film is precisely cut into the required metallized units by laser, in which the active dielectric area has a diameter of 1 cm; the stacked multilayer capacitor is manufactured by alternately stacking units with the terminal electrode on the left and units with the terminal electrode on the right, and finally a non-metallized dielectric layer is used as a sealing layer. Subsequently, a vacuum-enabled hot press is used to hot press the stack at a temperature of 150°C-200°C and a pressure range of 5 tons-10 tons for no less than 5 hours. After hot pressing, the device is precisely cut using a laser to expose the internal electrodes. These electrodes are then interconnected with a conductive silver paste to form the terminal electrodes, completing the manufacture of the sAl-DG-mMLPC.

[0145] Fig.18 The following is the structural cross-section SEM image of the sAl-DG-mMLPC device and the EDS image of the element Al. The EDS image of Al is used to represent the distribution of the inner electrode layer. Fig.18 This shows that the device has a very uniform stacked structure and dielectric active layer thickness, with each layer thickness ≈ 13 μm, three dielectric active layers, and an inner electrode thickness of about 60 nm. This device will be referred to as sAl-DG-mMLPC-3L.

[0146] from Fig.19 It can be seen that the capacitance of sAl-DG-mMLPC-3L at 20°C, 200°C, and 1kHz is 429pF and 408pF, respectively, and the loss factor is 0.31% and 0.27%, respectively, wherein the curves of the loss factor at 20°C and 200°C partially overlap. The capacitance and loss factor of sAl-DG-mMLPC-3L do not change much in the frequency range of 1kHz-10kHz, indicating the frequency stability of the capacitor performance of the present invention.

[0147] from Fig. 20 It can be seen that the discharge energy density of sAl-DG-mMLPC-3L is 1.06 J / cm at 250 MV / m and 200 °C. 3 and high energy efficiency (94%), indicating that the capacitor of the present invention has excellent high-temperature electrostatic energy storage performance.

[0148] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0149] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A semi-alicyclic dipole glass polyimide film, characterized in that: The semi-alicyclic dipole glass polyimide film has a structure shown in Formula I: Wherein, group Al comprises a non-conjugated aliphatic group; The group ArDG includes an aromatic group modified with a polar group; n is an integer between 50 and 250.

2. The semi-alicyclic dipole glass polyimide film according to claim 1, characterized in that: The group Al includes 3. The semi-alicyclic dipole glass polyimide film according to claim 1, characterized in that: The polarized group includes a sulfone group.

4. The semi-alicyclic dipole glass polyimide film according to claim 1, characterized in that: The group ArDG includes 5. The semi-alicyclic dipole glass polyimide film according to claim 1, characterized in that: The glass transition temperature of the semi-alicyclic dipole glass polyimide film is ≥215°C, preferably 218°C-387°C.

6. The semi-alicyclic dipole glass polyimide film according to claim 1, characterized in that: The band gap energy of the semi-alicyclic dipole glass polyimide film is ≥3.8 eV, preferably 3.99 eV-4.26 eV.

7. The semi-alicyclic dipole glass polyimide film according to any one of claims 1 to 4, characterized in that: The element molar ratio of (C+N+S) / (O+H) in the semi-alicyclic dipole glass polyimide film is less than or equal to 1.

22.

8. The semi-alicyclic dipole glass polyimide film according to claim 1, characterized in that: The dielectric constant of the semi-alicyclic dipole glass polyimide film is ≥3.3, preferably 3.48-4.

3.

9. Use of the semi-alicyclic dipole glass polyimide film according to any one of claims 1 to 8 in high temperature resistant dielectric energy storage materials or optoelectronic devices.

10. A capacitor, characterized in that: The capacitor comprises the semi-alicyclic dipole glass polyimide film according to any one of claims 1 to 8.

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