Polyaryletherketone-based energy storage dielectric composite material as well as preparation method and application thereof

Abstract

The invention provides a polyaryletherketone-based energy storage dielectric composite material as well as a preparation method and application thereof. According to the preparation method, polyaryletherketone containing active functional groups is adopted as a base material, flame-retardant polyphosphazene particles are adopted as an additive filler, and aromatic groups are grafted on the surfaces of the polyphosphazene particles after functional modification, so that the heat resistance, the breakdown field strength and the energy storage density of the composite material can be improved. The functionalized and modified polyphosphazene particles can be subjected to a cross-linking reaction with a polyaryletherketone matrix to form a three-dimensional network structure, and the polyaryletherketone-based energy storage dielectric composite material with good heat resistance, pressure resistance and flexibility is obtained. The heat resistance grade of the composite dielectric material is higher than 150 DEG C, the energy storage density reaches 6.3-11.0 J / cm < 3 >, and the energy releasable efficiency is not lower than 90%. Meanwhile, the oxygen index value is about 40%, and the material belongs to a flame-retardant material. The invention provides a high-temperature-resistant, high-energy-storage and flame-retardant energy storage dielectric material which can be used for a high-voltage capacitor.

Description

Technical Field

[0001] The present invention relates to the technical field of organic energy storage dielectric films, and in particular to a polyaryletherketone-based energy storage dielectric composite material with flame retardant properties, a preparation method thereof, and applications thereof. Background Art

[0002] High energy storage film capacitors are a type of physical energy storage device with high power density, fast charge and discharge speed, and long cycle life. Capacitors that can operate stably at high temperatures are crucial for the new generation of automotive and aerospace power systems. At present, biaxially oriented polypropylene (BOPP) has the advantages of high voltage resistance (~700MV / m), low loss (tanδ≈0.02%), self-healing and low cost, and is widely used in various power systems and electronic equipment for film capacitors. However, BOPP has a low temperature resistance level and can be used for a long time at a temperature below 85°C. When the temperature rises to above 105°C, the leakage current increases and the loss increases sharply, resulting in a decrease in energy storage density (U e ) and significantly reduced charge and discharge efficiency. Furthermore, BOPP has poor cycle safety. Firstly, the low thermal conductivity of polymer materials (typically less than 0.5W / m·K) makes it difficult to quickly dissipate the large amount of heat accumulated due to leakage losses during cyclic charge and discharge. Secondly, polymers are mostly hydrocarbon organic structures, which are flammable and have poor flame retardancy. When used under high temperature and high pressure, they are prone to accelerated aging, including oxidation, melting, or breakdown. This can induce local insulation failure, generate short-circuit discharge arcs, and cause device fires or even explosions.

[0003] In view of the problems of low temperature resistance and low energy storage density of BOPP metallized film capacitors when used under extreme working conditions such as high temperature and high pressure, it is proposed to use high temperature resistant polymer film to replace BOPP. Currently, several commonly used high temperature resistant polymer materials in commercial use, including polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), polyimide (PI) and polyetherimide (PEI), have high glass transition temperature (T g ) and the temperature resistance level is above 150℃. However, in addition to being difficult to process into thin films, these materials are also difficult to process into thin films when used at temperatures close to T g When the leakage conduction is large, the breakdown is low, and it is difficult to obtain the desired high U e Therefore, the current market urgently needs to develop a new type of high-temperature resistant, high-energy storage and highly flame-retardant dielectric film to replace BOPP and achieve the goals of lightweight and long-term safe service. Summary of the Invention

[0004] The present invention provides a novel high-temperature-resistant, high-energy-storage, flame-retardant polyaryletherketone-based energy storage dielectric composite material and a preparation method thereof. The specific technical scheme is as follows:

[0005] The present invention provides a method for preparing a polyaryletherketone-based energy storage dielectric composite material. The preparation method comprises: using polyaryletherketone containing active functional groups as a matrix and using flame-retardant polyphosphazene particles as an added filler; functionalizing and modifying the flame-retardant polyphosphazene particles, grafting aromatic groups onto the surfaces of the particles, and then cross-linking the particles with the polyaryletherketone containing active functional groups to form a three-dimensional network structure, thereby obtaining the polyaryletherketone-based energy storage dielectric composite material.

[0006] Furthermore, the method includes the following specific steps: (1) preparing a polyaryletherketone containing an active functional group: using 4,4'-difluorobenzophenone, 2-hydroxybenzimidazole and a monomer containing an active functional group A as raw materials, adding a solvent, a water removing agent and a salt forming agent, and mixing to form a solution; carrying out the following reaction under nitrogen protection: reacting through a three-stage heating process, prepolymerizing and forming a salt, heating toluene reflux to remove water, and finally carrying out a condensation reaction at a high temperature to obtain a crude product A; pouring the crude product A into an aqueous solution of hydrochloric acid and crushing it, and then using hot water and ethanol respectively to The active functional group A comprises one or more of a terminal hydroxyl group, a side amino group, a terminal boronic acid group, and an allyl side group; the monomer comprising the active functional group A is one or more of 9,9-bis(4-hydroxyphenyl)fluorene, 5-amino-2-benzimidazolidinone, 4-hydroxyphenylboronic acid, diallylbisphenol A, and 4,4'-sulfonylbis(2-allylphenol); (2) functional modification to prepare polyphosphazene particles having active functional groups: hexachlorocyclotriphosphazene and the active functional group A are used to prepare the polyphosphazene particles having active functional groups. The monomer containing the active functional group B is used as a raw material, a solvent and an acid-binding agent are added, and the mixture is mixed into a solution; the following reaction is carried out under nitrogen protection, the reaction is carried out in an ultrasonic bath, and after the reaction is completed, the mixed solution is centrifuged to obtain a crude product B, the crude product B is washed several times with a solution, ethanol and deionized water respectively, and finally dried to obtain the polyphosphazene particles containing active functional groups; the active functional group B includes one or more of active chlorine atoms, hydroxyl groups, amino groups, boric acid groups, and allyl groups; the monomer containing the active functional group B is hexafluorobisphenol A, sulfonyl diphenol, melamine, 1 , one or more of 4-phenylenediboronic acid, diallylbisphenol A, and 4,4'-sulfonylbis(2-allylphenol); (3) preparing a polyaryletherketone-based energy storage dielectric composite material: taking the polyaryletherketone containing active functional groups and the polyphosphazene particles containing active functional groups and stirring them in N-methyl-2-pyrrolidone to obtain a stable and uniform mixed solution, coating the mixed solution and drying the solvent at 65°C to form a thin film; then treating the thin film at a high temperature of 180°C to 200°C for 4h to obtain the polyaryletherketone-based energy storage dielectric composite material.

[0007] Furthermore, in step (1), the molar ratio of the 2-hydroxybenzimidazole to the monomer containing the active functional group A is (5:1) to (1:7); optionally, the mass ratio of the monomer containing the active functional group A in the solvent is 1% to 30%.

[0008] Furthermore, in step (2), the molar ratio of the hexachlorocyclotriphosphazene to the monomer containing the active functional group B is (1:2) to (1:5); optionally, the mass ratio of the monomer containing the active functional group B in the solvent is 1% to 10%.

[0009] Furthermore, in step (3), the solid content of the units containing active functional groups on the polyaryletherketone molecular chain in the mixed solution is 1% to 30%; optionally, the solid content of the units containing active functional groups on the polyphosphazene molecular chain in the mixed solution is 1% to 10%; and the mass ratio of the polyphosphazene particles containing active functional groups to the polyaryletherketone containing active functional groups is 1wt% to 10wt%.

[0010] Furthermore, in step (1), the solvent is one or more of N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, and sulfolane; the dehydrating agent is toluene; and the salt-forming agent is anhydrous potassium carbonate; in step (2), the solvent is one or more of acetone, tetrahydrofuran, acetonitrile, and dichloromethane; and the acid-binding agent is triethylamine.

[0011] The present invention also provides a polyaryletherketone-based energy storage dielectric composite material prepared by the above-mentioned method for preparing the polyaryletherketone-based energy storage dielectric composite material.

[0012] Furthermore, the thickness of the polyaryletherketone-based energy storage dielectric composite material is 5 μm to 12 μm; and the dielectric constant of the polyaryletherketone-based energy storage dielectric composite material is 3.0 to 5.0.

[0013] Furthermore, the polyaryletherketone-based energy storage dielectric composite material has a breakdown strength of 500MV / m to 800MV / m at 150°C and an energy storage density of 6.3J / cm 3 ~11.0J / cm 3 , energy storage efficiency is not less than 90%.

[0014] The present invention also provides applications of the polyaryletherketone-based energy storage dielectric composite material in high-voltage capacitors, electric vehicle inverters, flexible direct current power transmission systems, new energy power generation, and downhole oil and gas exploration.

[0015] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0016] The present invention provides a polyaryletherketone-based energy storage dielectric composite material, and its preparation method and application. The preparation method uses polyaryletherketone containing active functional groups as a matrix material, and flame-retardant polyphosphazene particles as an added filler. After functional modification, the polyphosphazene particles are grafted with aromatic groups on the surface, which can improve the heat resistance, breakdown field strength and energy storage density of the composite material. The functionally modified polyphosphazene particles can undergo a cross-linking reaction with the polyaryletherketone matrix to form a three-dimensional network structure, thereby obtaining a polyaryletherketone-based energy storage dielectric composite material with good heat resistance, pressure resistance and flexibility. The heat resistance grade of the composite dielectric material in the present invention is greater than 150°C, and the energy storage density is 6.3 to 11.0 J / cm 3 , the energy release efficiency is not less than 90%. At the same time, its oxygen index value is about 40%, which is a flame-retardant material. Its key indicators are better than those of existing high-temperature resistant commercial engineering films, and it has the advantages of high temperature resistance, high energy storage, and flame retardancy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0018] Figure 1 Schematic diagram of the synthesis route of the polyaryletherketone matrix containing active functional groups prepared in Example 1 of the present invention;

[0019] Figure 2 Schematic diagram of the synthesis route of polyphosphazene particles prepared in Example 1 of the present invention;

[0020] Figure 3 Schematic diagram of the synthesis route of the polyaryletherketone-based energy storage dielectric composite material prepared by chemically cross-linking the polyaryletherketone matrix and polyphosphazene particles in Example 1 of the present invention;

[0021] Figure 4 1 is a graph showing the change in dielectric constant and dielectric loss of the polyaryletherketone-based energy storage dielectric composite material prepared in Example 1 of the present invention with frequency;

[0022] Figure 5 Schematic diagram of the DE loop of the polyaryletherketone-based energy storage dielectric composite material prepared in Example 1 of the present invention at 0-650MV / m and 150°C;

[0023] Figure 6 It is a schematic diagram of the energy storage density and energy storage efficiency of the polyaryletherketone-based energy storage dielectric composite material prepared in Example 1 of the present invention at 150°C. DETAILED DESCRIPTION

[0024] Existing commercial high-temperature resistant polymer materials have poor flame retardancy at high temperatures and are prone to accelerated aging when serving under high temperature and high pressure, including oxidation, melting or breakdown, which in turn induces local insulation failure and generates short-circuit discharge arcs, causing device fires or even explosions, greatly reducing the working stability and service life of the capacitor.

[0025] The inventors have discovered that poly(aryletherketone) (PAEK) is an important class of high-performance aromatic polymers with excellent thermal stability, mechanical properties, and chemical resistance. PAEK can be obtained by polycondensation of various multifunctional monomers through nucleophilic reactions. Their molecular structure is highly tunable and easily functionalized, enabling extensive adjustments in temperature resistance, polarity, and flexibility. By introducing high-temperature resistant and charge transport regulating functional groups or structures into their main chains or side chains through chemical synthesis and modification, it is expected that PAEK polymers with both high-temperature resistance and high energy storage properties can be prepared.

[0026] The present invention provides a method for preparing a polyaryletherketone-based energy storage dielectric composite material, comprising the following steps:

[0027] Preparation of polyaryletherketone containing active functional groups: 4,4'-difluorobenzophenone, 2-hydroxybenzimidazole and the monomer containing active functional group A are used as raw materials, the molar ratio of the three is 2:1:1, N,N'-dimethylacetamide is used as solvent, toluene is used as dehydrating agent, and anhydrous potassium carbonate is used as salt-forming agent. The mixture is mixed into a solution and the following reaction is carried out under nitrogen protection. The active functional group A includes one or more of terminal hydroxyl groups, pendant amino groups, terminal boronic acid groups, and allyl pendant groups; the monomer containing active functional group A is one or more of 9,9-bis(4-hydroxyphenyl)fluorene, 5-amino-2-benzimidazolidinone, 4-hydroxyphenylboronic acid, diallylbisphenol A, and 4,4'-sulfonylbis(2-allylphenol);

[0028] The reaction temperature is a three-stage process, wherein the prepolymerization is first carried out at 130-140°C; the temperature is then raised to 140-150°C for azeotropic dehydration of toluene and a salt-forming reaction is carried out simultaneously; and finally, the polycondensation reaction is carried out at 160-165°C for 8 hours to obtain a crude product A.

[0029] The post-treatment is to pour the crude product A into an aqueous solution of hydrochloric acid and crush it, then wash it with hot water and ethanol respectively, and finally dry it to obtain the polyaryletherketone containing active functional groups.

[0030] Functional modification to prepare polyphosphazene particles containing active functional groups: Hexachlorocyclotriphosphazene and a monomer containing active functional group B are used as raw materials in a molar ratio of 1:3, acetonitrile is used as a solvent, and triethylamine is used as an acid-binding agent. The mixture is mixed into a solution; the reaction is carried out under nitrogen protection and in an ultrasonic bath. The active functional group B includes one or more of a terminal hydroxyl group, a pendant amino group, a terminal boronic acid group, and an allyl pendant group. The monomer containing active functional group B is one or more of hexafluorobisphenol A, sulfonyldiphenol, melamine, 1,4-phenylenediboronic acid, diallylbisphenol A, and 4,4'-sulfonylbis(2-allylphenol).

[0031] After the reaction is completed, the mixed solution is centrifuged to obtain a crude product B, which is washed several times with a solution, ethanol, and deionized water, respectively, and finally dried to obtain the polyphosphazene particles containing active functional groups.

[0032] Weigh 0.1-1 g of the prepared polyaryletherketone containing active functional groups and 1-10 mg of polyphosphazene particles containing active functional groups, stir them in 5-50 mL of N-methyl-2-pyrrolidone for more than 4 h, and ultrasonicate them for more than 0.5 h to obtain a stable and uniform mixed solution.

[0033] The mixed solution is coated onto a flat glass plate and dried at 65°C to form a thin film. The film is then placed in an oven and heat-treated at 200°C for 4 hours to produce a cross-linked poly(aryletherketone)-based energy storage dielectric composite. The polyphosphazene particles impart flame retardancy to the dielectric composite, while the cross-linked structure improves both toughness and compressive strength.

[0034] The present invention is described in detail below with reference to specific embodiments.

[0035] Example 1 provides a method for preparing a polyaryletherketone-based energy storage dielectric composite material, which specifically includes the following steps:

[0036] Step 1: Prepare a polyaryletherketone containing active functional groups as the polymer matrix. In a 100mL three-necked flask connected to a nitrogen inlet with a thermometer, a stirring paddle, and a water trap, diallylbisphenol A (3.084g, 0.01mol), 4,4'-difluorobenzophenone (4.364g, 0.02mol), 9,9-bis(4-hydroxyphenyl)fluorene (1.752g, 0.005mol), and 2-hydroxybenzimidazole (0.6707g, 0.005mol) were added in sequence, followed by anhydrous potassium carbonate (3.174g, 0.023mol). 15-25mL of sulfolane solvent and 5-10mL of toluene were added to the system. The system was heated under nitrogen and stirred until the toluene refluxed with water to ensure that the water in the system was removed. The system was heated in stages to 130-140°C, 140-150°C, and 160-165°C for reaction. After a period of reaction, diallyl bisphenol A (0.308 g, 0.001 mol) was added for end-capping. After the reaction was complete, the mixture was poured into a hydrochloric acid solution, pulverized in a pulverizer, and washed multiple times with boiling distilled water and ethanol to remove residual inorganic salts and solvent. The mixture was then dried in an oven to yield the allyl-containing polyaryletherketone.

[0037] Step 2: Functional modification to prepare polyphosphazene particles containing active groups. Hexachlorocyclotriphosphazene (0.4 g, 1.15 mmol) and 4,4'-sulfonylbis(2-allylphenol) (1.064 g, 3.45 mmol) were placed in a 250 ml Shrek bottle in sequence and evacuated three times, and 100 ml of acetonitrile passed through nitrogen was added. After ultrasonic stirring at 240 W, 40 kHz for 10 minutes, triethylamine (4 mL) was added and stirring was continued for 4 hours, while the temperature was precisely maintained at 50 ° C. Then, the product was obtained by centrifugation and washed three times with anhydrous ethanol, acetone and deionized water. Finally, the polyphosphazene particles containing allyl groups were obtained by drying in an oven.

[0038] Step 3: Add 200 mg of allyl-containing polyaryletherketone polymer and 6 mg of allyl-containing polyphosphazene particles into a 20 mL sample bottle, add 10 mL of N-methyl-2-pyrrolidone to dissolve them, and stir at room temperature under ultrasonication for more than 0.5 h.

[0039] Step 4: cast the mixed solution obtained above on a glass sheet, and dry the solvent at 65° C. to form a dielectric film.

[0040] Step 5: Place the dielectric film prepared in the fourth step in an oven at 200° C. and anneal for 6 hours to obtain a cross-linked polyaryletherketone-based energy storage dielectric composite material.

[0041] Step 6: The prepared dielectric film has an energy storage density of 11 J / cm under the conditions that the test temperature is 150 °C, the dielectric constant is 4.2, and the breakdown strength is 650 MV / m. 3 , and the energy storage efficiency is 85%.

[0042] Table 1 Oxygen index values of polymer dielectrics

[0043]

[0044] (OI - Oxygen index (%), CR - Mass percentage of residual carbon when the polymer is heated to 850 °C (%), OI = 17.5 + 0.4CR)

[0045] Table 1 shows the oxygen index values of polymer dielectrics. Materials with OI < 27 are flammable materials, those with 27 < OI < 32 are combustible materials, and those with OI > 32 are flame-retardant materials. The OI value of traditional polyarylether materials is 31%, belonging to combustible materials, while the oxygen index value of the polyaryletherketone-based energy storage dielectric composite prepared in this invention is 40.1%, belonging to flame-retardant materials. This shows that introducing polyphosphazene particles into polyaryletherketone can give full play to the synergistic flame-retardant effect of nitrogen and phosphorus and effectively improve the flame-retardant performance of polymer materials. The polyaryletherketone-based energy storage dielectric composite has better high-temperature applications and effectively solves the problem of the decline in energy storage density and charge-discharge efficiency caused by thermal runaway after the temperature rises.

[0046] Example 2 provides a preparation method for a polyaryletherketone-based energy storage dielectric composite, which specifically includes the following steps:

[0047] Step 1: Prepare a polyaryletherketone prepolymer. In a 100 mL three-neck flask respectively connected with a nitrogen inlet with a thermometer inserted, a stirring paddle, and a water separator, successively add hexafluorobisphenol A (3.362 g, 0.01 mol), 4,4'-difluorobenzophenone (4.364 g, 0.02 mol), sulfonyldiphenol (2.503 g, 0.01 mol), and then add anhydrous potassium carbonate (3.174 g, 0.023 mol). Add 20 - 40 mL of the solvent sulfolane and 5 - 10 mL of the water-carrying agent toluene to the system. Pass nitrogen and heat to reflux with toluene for water-carrying under stirring conditions to ensure the removal of water in the system. Using a stagewise heating method, heat the system to 130 - 140 °C, 140 - 150 °C, and 160 - 165 °C successively for reaction. After reacting for a period of time, add 4,4'-difluorobenzophenone (0.218 g, 0.001 mol) for end-capping. After the reaction is completed, discharge the mixture solution into an aqueous hydrochloric acid solution, pulverize it with a powder machine, and wash the material multiple times with boiling distilled water and ethanol to remove residual inorganic salts and solvents. Dry it in an oven to obtain a polyaryletherketone prepolymer with fluorine atoms at the end groups.

[0048] Step 2: Prepare a poly(aryletherketone) containing active functional groups as the polymer matrix. In a 100ml two-necked flask equipped with a condenser and thermometer, the fluorine-terminated poly(aryletherketone) prepolymer (Mn≈22000, 2.2g, 0.001mol), 4-hydroxyphenylboronic acid (0.69g, 0.005mol), and anhydrous K2CO3 (0.83g, 0.006mmol) were placed in sequence. 40mL of N-methyl-2-pyrrolidone was added to the system, and the system was evacuated three times. Using a stepwise heating method, the system was heated to 80-90°C and then 165-180°C for reaction. After the reaction was complete, the mixture was poured into an aqueous solution, pulverized using a pulverizer, and washed repeatedly with boiling distilled water and ethanol to remove residual inorganic salts and solvent. The mixture was then dried in an oven to obtain the boronic acid-terminated poly(aryletherketone).

[0049] Step 3: Functional modification to prepare polyphosphazene particles containing active functional groups. Hexachlorocyclotriphosphazene (0.2 g, 0.575 mmol) and 4-hydroxyphenylboronic acid (0.58 g, 1.725 mmol) were placed in a 250 ml Shrek bottle in sequence and evacuated three times, and 200 ml of acetonitrile passed through nitrogen was added. After ultrasonic stirring at 280 W, 40 kHz for 1 hour, triethylamine (4 mL) was added and stirring was continued for 24 hours, while the temperature was precisely maintained at 80 ° C. Then, the product was obtained by centrifugation and washed several times with acetone. Finally, the polyphosphazene particles containing boronic acid groups were obtained by drying in an oven.

[0050] Step 4: Add 200 mg of boronic acid-terminated polyaryletherketone and 6 mg of polyphosphazene particles containing boronic acid groups into a 20 mL sample bottle, add 10 mL of N-methyl-2-pyrrolidone to dissolve them, and stir at room temperature under ultrasonication for more than 0.5 h.

[0051] Step 5: Cast the mixed solution obtained above on a glass sheet and dry the solvent at 65° C. to form a dielectric film.

[0052] Step 6: Place the dielectric film prepared in the fifth step in an oven at 180° C. and anneal for 4 hours to obtain a cross-linked polyaryletherketone-based energy storage dielectric composite material.

[0053] Example 3 provides a method for preparing a polyaryletherketone-based energy storage dielectric composite material, which specifically includes the following steps:

[0054] Step 1: Prepare a poly(aryletherketone) containing active functional groups as the polymer matrix. In a 100mL three-necked flask connected to a nitrogen inlet with a thermometer, a stirring paddle, and a water trap, diallylbisphenol A (3.084g, 0.01mol), 4,4'-difluorobenzophenone (4.364g, 0.02mol), 9,9-bis(4-hydroxyphenyl)fluorene (1.752g, 0.005mol), and 5-amino-2-benzimidazolidinone (0.7457g, 0.005mol) were added in sequence, followed by anhydrous potassium carbonate (3.174g, 0.023mol). 15-25mL of DMAc solvent and 5-10mL of toluene were added to the system. The system was heated under nitrogen and stirred until the toluene refluxed with water to ensure that the water in the system was removed. The system was heated in stages to 130-140°C, 140-150°C, and 160-165°C for reaction. After the reaction was complete, the mixture was poured into a hydrochloric acid solution, pulverized in a pulverizer, and washed multiple times with boiling distilled water and ethanol to remove residual inorganic salts and solvent. The mixture was then dried in an oven to obtain the amino-terminated polyaryletherketone.

[0055] Step 2: Functional modification to prepare polyphosphazene particles containing active functional groups. Hexachlorocyclotriphosphazene (0.2 g, 0.575 mmol) and 4-hydroxyphenylboronic acid (0.58 g, 1.725 mmol) were placed in a 250 ml Shrek bottle in sequence and evacuated three times, and 200 ml of acetonitrile passed through nitrogen was added. After ultrasonic stirring at 280 W, 40 kHz for 1 hour, triethylamine (4 mL) was added and stirring was continued for 24 hours, while the temperature was precisely maintained at 80 ° C. Then, the product was obtained by centrifugation and washed three times with anhydrous ethanol, acetone and deionized water in sequence. Finally, the polyphosphazene particles containing boronic acid groups were obtained by drying in an oven.

[0056] Step 3: Add 200 mg of amino-terminated polyaryletherketone polymer and 6 mg of polyphosphazene particles containing boric acid groups into a 20 mL sample bottle, add 10 mL of N-methyl-2-pyrrolidone to dissolve them, and stir at room temperature under ultrasonication for more than 0.5 h.

[0057] Step 4: cast the mixed solution obtained above on a glass sheet, and dry the solvent at 65° C. to form a dielectric film.

[0058] Step 5: Place the dielectric film prepared in the fifth step in an oven at 180° C. and anneal for 4 hours to obtain a cross-linked polyaryletherketone-based energy storage dielectric composite material.

[0059] Figure 1 This is a synthetic route for polyaryletherketone polymers, the monomers of which are diene bisphenol A, 4,4'-difluorobenzophenone, 9,9-bis(4-hydroxyphenyl)fluorene and 2-hydroxybenzimidazole, including but not limited to the monomers of this route. Figure 2 The invention relates to a synthetic route for polyphosphazene, wherein the monomers are hexachlorocyclotriphosphazene and 4,4'-sulfonylbis(2-allylphenol), including but not limited to the monomers of this route. Figure 3 It is a chemical cross-linking process of the matrix polyaryletherketone polymer and the polyphosphazene particles, including but not limited to this route matrix and polyphosphazene particles. Figure 4 The dielectric properties of the composite material with 5wt% polyphosphazene particles are shown, with a dielectric constant of 4.0-4.4 and a dielectric loss of 0.015-0.02. Figure 5 Analysis shows that when the test temperature is 150°C and the breakdown strength is 650MV / m, the maximum polarization value of Example 1 is 3.2μc / m 2 The polyaryletherketone-based energy storage dielectric composite material prepared by the present invention is beneficial to the improvement of discharge energy storage density. Figure 6 Analysis shows that under the conditions of a test temperature of 150°C and a breakdown strength of 500-650 MV / m, the energy storage density of the polyaryletherketone-based energy storage dielectric composite material prepared in Example 1 of the present invention is 6.3-11 J / cm 3 The energy storage release efficiency is between 85% and 90%.

[0060] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A method for preparing a polyaryletherketone-based energy storage dielectric composite material, characterized in that: The preparation method comprises: using polyaryletherketone containing active functional groups as a matrix and flame-retardant polyphosphazene particles as an added filler; functionalizing and modifying the flame-retardant polyphosphazene particles, grafting aromatic groups onto the surface of the particles, and then cross-linking the particles with the polyaryletherketone containing active functional groups to form a three-dimensional network structure, thereby obtaining the polyaryletherketone-based energy storage dielectric composite material.

2. The method for preparing the polyaryletherketone-based energy storage dielectric composite material according to claim 1, characterized in that: The method comprises the following specific steps: (1) Preparation of polyaryletherketone containing active functional groups: 4,4'-difluorobenzophenone, 2-hydroxybenzimidazole and a monomer containing active functional group A are used as raw materials, a solvent, a water scavenger and a salt-forming agent are added, and the mixture is mixed into a solution; the following reaction is carried out under nitrogen protection: a three-stage temperature rise process is carried out to react, a prepolymerization salt-forming reaction is carried out, a temperature rise toluene reflux is carried out to remove water, and finally a condensation reaction is carried out at high temperature to obtain a crude product A; the crude product A is poured into an aqueous solution of hydrochloric acid and crushed, The mixture is then washed with hot water and ethanol respectively, and finally dried to obtain the polyaryletherketone containing active functional groups; the active functional group A includes one or more of a terminal hydroxyl group, a pendant amino group, a terminal boronic acid group, and an allyl pendant group; the monomer containing the active functional group A is one or more of 9,9-bis(4-hydroxyphenyl)fluorene, 5-amino-2-benzimidazolidinone, 4-hydroxyphenylboronic acid, diallylbisphenol A, and 4,4'-sulfonylbis(2-allylphenol); (2) Functional modification to prepare polyphosphazene particles with active functional groups: using hexachlorocyclotriphosphazene and the monomer containing the active functional group B as raw materials, adding a solvent and an acid binder, and mixing to form a solution; carrying out the following reaction under nitrogen protection, reacting in an ultrasonic bath, centrifuging the mixed solution after the reaction to obtain a crude product B, washing the crude product B with a solution, ethanol and deionized water for several times, and finally drying to obtain the polyphosphazene particles containing the active functional group; the active functional group B includes one or more of active chlorine atoms, hydroxyl groups, amino groups, boric acid groups, and allyl groups; the monomer containing the active functional group B is one or more of hexafluorobisphenol A, sulfonyldiphenol, melamine, 1,4-phenylenediboronic acid, diallylbisphenol A, and 4,4'-sulfonylbis(2-allylphenol); (3) Preparation of polyaryletherketone-based energy storage dielectric composite material: taking the polyaryletherketone containing active functional groups and the polyphosphazene particles containing active functional groups and stirring them in N-methyl-2-pyrrolidone to obtain a stable and uniform mixed solution, coating the mixed solution and drying the solvent at 65°C to form a thin film; then treating the thin film at a high temperature of 180°C to 200°C for 4h to obtain the polyaryletherketone-based energy storage dielectric composite material.

3. The method for preparing the polyaryletherketone-based energy storage dielectric composite material according to claim 2, characterized in that: In step (1), the molar ratio of the 2-hydroxybenzimidazole to the monomer containing the active functional group A is (5:1) to (1:7); Optionally, the mass ratio of the monomer containing the active functional group A in the solvent is 1% to 30%.

4. The method for preparing the polyaryletherketone-based energy storage dielectric composite material according to claim 2, characterized in that: In step (2), the molar ratio of the hexachlorocyclotriphosphazene to the monomer containing the active functional group B is (1:2) to (1:5); Optionally, the mass ratio of the monomer containing the active functional group B in the solvent is 1% to 10%.

5. The method for preparing the polyaryletherketone-based energy storage dielectric composite material according to claim 2, characterized in that: In step (3), the solid content of the units containing active functional groups on the polyaryletherketone molecular chain in the mixed solution is 1% to 30%; Optionally, in the mixed solution, the solid content of the units containing active functional groups on the polyphosphazene molecular chain is 1% to 10%; The mass ratio of the polyphosphazene particles containing active functional groups to the polyaryletherketone containing active functional groups is 1 wt % to 10 wt %.

6. The method for preparing the polyaryletherketone-based energy storage dielectric composite material according to claim 2, characterized in that: In step (1), the solvent is one or more of N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, and sulfolane; the dehydrating agent is toluene; and the salt-forming agent is anhydrous potassium carbonate; In step (2), the solvent is one or more of acetone, tetrahydrofuran, acetonitrile, and dichloromethane; and the acid binding agent is triethylamine. 7 . The poly(aryletherketone)-based energy storage dielectric composite material obtained by the method for preparing the poly(aryletherketone)-based energy storage dielectric composite material according to any one of claims 1 to 6 .

8. The polyaryletherketone-based energy storage dielectric composite material according to claim 7, characterized in that: The thickness of the polyaryletherketone-based energy storage dielectric composite material is 5 μm to 12 μm; the dielectric constant of the polyaryletherketone-based energy storage dielectric composite material is 3.0 to 5.

0.

9. The polyaryletherketone-based energy storage dielectric composite material according to claim 8, characterized in that: The polyaryletherketone-based energy storage dielectric composite material has a breakdown strength of 500MV / m to 800MV / m at 150°C and an energy storage density of 6.3J / cm 3 ~11.0J / cm 3 , energy storage efficiency is not less than 90%.

10. Application of the polyaryletherketone-based energy storage dielectric composite material according to claim 9 in the fields of high-voltage capacitors, electric vehicle inverters, flexible direct current power transmission systems, new energy power generation, and downhole oil and gas exploration.

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