All-organic high-breakdown composite dielectric thin film and preparation method thereof

Abstract

The application discloses a kind of all-organic high-breakdown composite dielectric thin film and preparation method thereof.The preparation method of the thin film includes:1) synthesis of ArPTU particles;2) preparation of composite thin film material;ArPTU particles are synthesized by microwave synthesis method, including: dissolving reaction monomer diamino diphenyl methane, thiourea and catalyst p-toluenesulfonic acid in polar solvent, microwave heating reaction, precipitating, washing, drying, collecting ArPTU particles;Composite thin film material is prepared by phase separation method, including: dissolving ArPTU particles in polar solvent, then adding P(VDF-HFP) powder to configure mixed sol, then electrospinning to prepare non-woven fabric, then sequentially heat pressing treatment, ice water quenching, warm water quenching, and it is obtained.The composite material can realize the formation of in-situ nanoparticles in the material, and the uniformly dispersed nanoparticles result in good interface bonding, uniform and stable dielectric composite material.

Description

Technical Field

[0001] This invention belongs to the field of electronic composite material preparation technology, and particularly relates to an all-organic high-breakdown composite dielectric thin film and its preparation method. Background Technology

[0002] Against the backdrop of a growing demand for improved energy efficiency and the search for clean, renewable energy sources, research into environmentally friendly and highly efficient energy storage and conversion systems has become increasingly important. Among current energy storage systems, capacitors possess the highest power density compared to batteries, fuel cells, and electrochemical cells, thus holding significant application potential in fields such as medical devices, hybrid vehicles, pulsed power supplies, and electromagnetic catapult weapons. However, the energy density of currently commercially available dielectric capacitors is relatively low, making the improvement of capacitor energy density a hot research topic.

[0003] Traditional dielectric energy storage materials include ceramic and polymer materials. Each has its advantages and disadvantages. While high-dielectric ceramic capacitors possess a high dielectric constant, their low breakdown strength, high molding temperature, and high density make them unsuitable for some energy storage devices. In contrast, polymer dielectric energy storage materials offer advantages such as high breakdown field strength, low density, flexibility, and excellent processing performance. Currently, commercially available dielectric capacitors are made of biaxially oriented polypropylene (BOPP) film, with an energy storage density of only ~2 J / cm³. 3 To achieve high energy density, it is necessary to improve the dielectric constant and breakdown field strength of the material. Among common polymer systems, polyvinylidene fluoride (PVDF)-based polymer dielectric materials have relatively high energy density. This is because PVDF-based polymer materials have a relatively high dielectric constant. At room temperature and 1 kHz, the relative dielectric constant of PVDF and its copolymers is above 10, which is generally higher than that of commonly used linear polymers such as polyetheretherketone (PEEK, 3.6), polyetherimide (PEI, 3.3), and biaxially oriented polypropylene (BOPP, 2.3). Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing an all-organic composite thin film material for dielectric capacitors with high voltage resistance and excellent energy storage capacity.

[0005] The method for preparing the all-organic composite thin film material provided by this invention includes two steps:

[0006] 1) Synthesis of aromatic polythiourea ArPTU particles;

[0007] 2) Use the ArPTU powder to synthesize composite thin film materials.

[0008] The ArPTU particles were synthesized using a microwave synthesis method, which included the following steps: First, the reactants diaminodiphenylmethane (MDA), thiourea (AR), and the catalyst p-toluenesulfonic acid were dissolved in a polar solvent, and the reaction was carried out by microwave heating for a certain period of time. After precipitation, washing, and drying, the ArPTU particles were collected for later use.

[0009] The composite film material is prepared by a phase separation method, including the following steps: first, ArPTU particles are dissolved in a polar solvent, then PVDF-based powder material is added to prepare a mixed sol of appropriate concentration, then the composite nonwoven fabric is prepared by electrospinning, and then the composite film material is obtained by high-temperature hot pressing, ice-water quenching, and warm water cold quenching.

[0010] Furthermore, in the synthesis of the ArPTU particles, the molar ratio of diaminodiphenylmethane (MDA), thiourea (AR), and p-toluenesulfonic acid is 1:(0.95-1.05):0.1.

[0011] In the synthesis of the ArPTU particles, the polar solvent may be selected from at least one of the following: N-methylpyrrolidone (NMP) or N,N-dimethylacetamide (DMAC).

[0012] In the synthesis of the ArPTU particles, the microwave heating conditions are as follows: microwave power can be 320-400W, and heating time can be 8-60min (specifically, 30min, 45min, or 60min).

[0013] In the synthesis of the ArPTU particles, a microwave preheating step is included before microwave heating, as follows: the mixed solution is placed in a microwave reactor, nitrogen gas is introduced, and microwave preheating is performed for 7-10 minutes with a preheating power of 240-320W.

[0014] In the synthesis of the ArPTU particles, precipitation refers to the process of precipitating the ArPTU generated in the reaction from the dark red reaction system using methanol or ethanol solvent after the reaction is completed.

[0015] In the synthesis of the ArPTU particles, the cleaning refers to washing the precipitate obtained after precipitation multiple times with an ethanol solution, and then soaking and washing the precipitate in warm water (50-70℃).

[0016] In the synthesis of the ArPTU particles, the drying process refers to placing the precipitate in a forced-air drying oven for 2-4 hours at a drying temperature of 70-80℃; and placing the air-dried precipitate in a vacuum drying oven for 4-8 hours at a drying temperature of 90-110℃.

[0017] The ArPTU particles have a particle size of 400 nm to 2 μm.

[0018] Furthermore, in the preparation of the composite film material, the mass content of ArPTU particles in the mixed sol is 0.5-50%; and the mass content of the PVDF-based powder material is 50-99.5%.

[0019] The PVDF-based powder materials include, but are not limited to, PVDF, P(VDF-TrFE), P(VDF-HFP), etc.

[0020] In the preparation of the composite thin film material, the polar solvent may be selected from N-methylpyrrolidone (NMP) or N,N-dimethylacetamide (DMAC).

[0021] In the preparation of the composite film material, the electrospinning is carried out in a DC high-voltage electrospinning device. The process parameters of the electrospinning are as follows: applied voltage is 12-18KV; lateral displacement of the syringe is 80-100mm; distance between the roller and the needle tip is 10-30cm; roller speed is 100-1000r / min; and syringe advance speed is 0.1-1.5ml / h.

[0022] In the preparation of the composite film material, the high-temperature hot pressing treatment is carried out in a hot press, with a hot pressing temperature of 120-180℃, a pressure of 6-10MPa, and a hot pressing time of 0.5-2h.

[0023] In the preparation of the composite thin film material, the ice-water quenching treatment involves taking the thin film material out of the high temperature and immediately placing it in ice water (0°C) for cold quenching.

[0024] In the preparation of the composite thin film material, the warm water quenching treatment involves first placing the ice-water quenched thin film material on a heating table at 180-210℃ and heating for 7-15 minutes; then placing the heated thin film in hot water for warm water quenching treatment for 1-5 minutes; the temperature of the hot water is 30℃-100℃ (specifically, 45℃, 60℃ or 75℃).

[0025] Furthermore, the detailed synthesis method of the ArPTU powder is as follows:

[0026] 1.1 Prepare the reaction solution.

[0027] Weigh out appropriate amounts of diaminodiphenylmethane (MDA), thiourea (AR), and the catalyst p-toluenesulfonic acid and dissolve them in N-methylpyrrolidone (NMP) solvent.

[0028] 1.2 Microwave preheating.

[0029] The solution was placed in a microwave reactor, nitrogen gas was introduced, and microwave preheating was performed for 7 minutes at a power of 240W.

[0030] 1.3 Microwave heating reaction.

[0031] Set the microwave reactor power to 400W for high-temperature reaction heating for 8-60 minutes.

[0032] 1.4 Precipitated reactants.

[0033] ArPTU generated in the reaction was precipitated from the dark red reaction solution using methanol solvent.

[0034] 1.5 Clean the sediment.

[0035] The precipitate was washed multiple times with an ethanol solution, and then soaked and washed with warm water (50-70℃).

[0036] 1.6 Drying.

[0037] The precipitate was dried in a forced-air oven for 4 hours at a temperature of 70°C. The air-dried precipitate was then placed in a vacuum oven and vacuum dried for 8 hours at a temperature of 110°C.

[0038] 1.7 The obtained light yellow ArPTU particles were dried and stored for later use.

[0039] Furthermore, the detailed preparation method for synthesizing composite thin film materials using the ArPTU powder is as follows:

[0040] 2.1 Preparation of Polar Sol

[0041] Weigh the dried ArPTU particles according to the specified ratio, place them in N,N-dimethylformamide (DMF) solvent, and ultrasonically stir for 0.5 h until completely dissolved. Then, weigh the P(VDF-HFP) particles according to the specified ratio, add them to the ArPTU / DMF solution, and magnetically stir for 8 h to prepare a transparent and homogeneous mixed sol. The solid content of ArPTU particles in the mixed sol is 10%-30%.

[0042] 2.2 Preparation of nonwoven fabrics by high-voltage electrospinning

[0043] The obtained sol is transferred to a syringe and electrospun using a DC high-voltage electrospinning device. The composite nonwoven fabric is collected at the negative electrode. During electrospinning, the applied voltage is 12-18KV; the lateral displacement of the syringe is 80-100mm; the distance between the roller and the needle tip is 10-30cm; the roller rotation speed is 100-1000r / min; and the syringe advance speed is 0.1-1.5ml / h.

[0044] 2.3 High-temperature hot pressing

[0045] The nonwoven fabric with electrode material is transferred to a hot press for high-temperature hot pressing; the hot pressing temperature is 160℃, the pressure is 10MPa, and the hot pressing time is 0.5h.

[0046] 2.4 Ice water quenching treatment

[0047] After hot pressing, the thin film material is taken out from the high temperature and immediately placed in ice water (0°C) for cold quenching, forming a dispersed microstructure after phase separation and a densified thin film material.

[0048] 2.5 Secondary heat treatment

[0049] The removed film material is placed on a 200℃ heating table and heated for 7 minutes. Then, the heated film is placed in hot water for warm water quenching treatment. The temperature of the hot water is 30℃-100℃ (specifically, 45℃, 60℃ or 75℃).

[0050] The all-organic composite thin film material prepared by the above method also falls within the protection scope of this invention.

[0051] In the composite film material, the mass content of ArPTU particles is 0.5-50%, specifically 1%, 2%, 5%, or 10%. The thickness of the composite film material can be 6-20 μm.

[0052] The method for preparing ArPTU particles provided by this invention, as well as the ArPTU particles obtained by this method, are also within the scope of protection of this invention.

[0053] This invention also provides the application of the above-mentioned all-organic composite thin film material in the preparation of dielectric materials.

[0054] This invention also protects a dielectric thin-film capacitor.

[0055] The dielectric film capacitor includes a dielectric layer, the material of which includes the all-organic composite film material provided by the present invention.

[0056] This invention employs an electrospinning, hot pressing, and multiple heat treatment processes to prepare polymer nanocomposites. The two heat treatment cooling processes differ, including ice-water quenching after high-temperature hot pressing and warm-water quenching after high-temperature heat treatment. Compared to traditional molding methods, this approach offers the following improvements: 1. Ice-water quenching increases the supercooling of the material's solidification, accelerating the nucleation process of the ArPTU phase while effectively inhibiting further ArPTU growth. This promotes the formation of a uniformly distributed, dispersed structure of the ArPTU phase within the matrix phase, which is beneficial for improving the film material's breakdown resistance and film quality uniformity. 2. Under the quenching process conditions, the dispersed ArPTU phase precipitates from the homogeneous two phases, forming nanoparticles in situ. This increases the interfacial area within the material while ensuring tight bonding between the two phases at the interface. Compared to traditional introduced nanoparticle-filled composite materials, this reduces the probability of defects at the interface, alleviates the problem of reduced breakdown resistance caused by mismatched physicochemical properties at the interface, and effectively improves the material's dielectric breakdown strength and energy storage density. 3. Subsequent high-temperature heat treatment combined with warm water treatment can further regulate the phase structure of the matrix phase and further optimize the dielectric properties of the material based on the formation of the above-mentioned in-situ dispersed structure.

[0057] The present invention has the following beneficial effects:

[0058] The composite material of this invention enables the formation of in-situ nanoparticles within the composite material. The uniformly dispersed nanoparticles result in a dielectric composite material with good interfacial bonding, uniform and stable film quality, and excellent dielectric properties as well as high performance stability. Attached Figure Description

[0059] Figure 1 SEM image of the cross-section of the ArPTU / P(VDF-HFP) composite film prepared in Example 1;

[0060] Figure 2 SEM image of the microstructure of the ArPTU / P(VDF-HFP) composite film prepared in Example 2;

[0061] Figure 3 The breakdown electric field intensity distribution at room temperature is shown for pure P(VDF-HFP) thin film and 2wt.% ArPTU / P(VDF-HFP) composite material;

[0062] Figure 4 The energy storage density and efficiency of pure P(VDF-HFP) thin film, BaTiO3 / P(VDF-HFP) composite material and ArPTU / P(VDF-HFP) composite material at room temperature under different field strengths are presented. Detailed Implementation

[0063] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments. Unless otherwise specified, the methods described are conventional methods. Unless otherwise specified, the raw materials are all available from publicly available commercial sources.

[0064] Example 1: Preparation of ArPTU / P(VDF-HFP) thin films

[0065] Weigh 9.913g of MDA powder and 3.806g of thiourea granules, dissolve them in 10ml of NMP solvent, and magnetically stir until a colorless and transparent solution is formed. Weigh 0.431g of p-benzenesulfonic acid and add it to the mixed solvent. Transfer the mixed solution to a microwave reactor, introduce N2, adjust the microwave power to 240W, and preheat for 7 minutes. Then adjust the microwave power to 400W and microwave for 30 minutes to form a deep red sol. Add methanol solution to the mixed sol and stir to form a yellow precipitate. Soak and wash the precipitate with ethanol, then wash and filter the precipitate with 60℃ warm water. Place the resulting pale yellow precipitate in a forced-air drying oven and dry for 12 hours to obtain 11g of ArPTU particles (particle size 400nm-2μm), which are collected for later use.

[0066] 0.1g of ArPTU particles were dissolved in 5ml of DMF solvent and stirred for 30min until a yellow transparent solution was formed. 0.9g of P(VDF-HFP) was added to the mixture, and the solution was magnetically stirred for 8h until a uniform, translucent sol was formed. The sol was spun into a composite nonwoven fabric using electrospinning technology. Specific spinning parameters were: output voltage 13kV, distance between the roller and needle tip 15cm, roller speed 500r / min, and syringe advance speed 1ml / h. The nonwoven fabric with electrodes was removed and placed in a 160℃ high-temperature hot press at a pressure of 12MPa for 30min. After hot pressing, the film was quickly placed in 0℃ ice water for quenching. The film was then removed and placed on a 200℃ heating platform for 7min, followed by a 45℃ warm water heat treatment for 4min. Finally, the film was placed in a vacuum oven at 50℃ to remove moisture, yielding a 10% ArPTU / P(VDF-HFP) film with a thickness of 8μm.

[0067] Example 2: Preparation of ArPTU / P(VDF-HFP) thin films

[0068] Weigh 9.913g of MDA powder and 3.806g of thiourea granules, dissolve them in 10ml of NMP solvent, and magnetically stir until a colorless and transparent solution is formed. Weigh 0.431g of p-benzenesulfonic acid and add it to the mixed solvent. Transfer the mixed solution to a microwave reactor, introduce N2, adjust the microwave power to 240W, and preheat for 7 minutes. Then adjust the microwave power to 400W and microwave for 45 minutes to form a deep red sol. Add methanol solution to the mixed sol and stir to form a yellow precipitate. Soak and wash the precipitate with ethanol, then wash and filter the precipitate with 60℃ warm water. Place the resulting pale yellow precipitate in a forced-air drying oven for 12 hours to obtain ArPTU particles (particle size 400nm-2μm), which are collected for later use.

[0069] 0.02g of ArPTU particles were dissolved in 5ml of DMF solvent and stirred for 30min to form a yellow transparent solution. 0.98g of P(VDF-HFP) was added to the mixture, and the solution was magnetically stirred for 8h to form a uniform, translucent sol. The sol was spun into a composite nonwoven fabric using electrospinning technology. Specific spinning parameters were: output voltage 13kV, distance between the roller and needle tip 15cm, roller speed 500r / min, and syringe advance speed 1ml / h. The nonwoven fabric with electrodes was removed and placed in a 160℃ high-temperature hot press at a pressure of 12MPa for 30min. After hot pressing, the film was quickly placed in 0℃ ice water for quenching. The film was then removed and placed on a 200℃ heating platform for 7min, followed by 60℃ warm water heat treatment for 3min. Finally, it was placed in a vacuum oven at 50℃ to remove moisture, yielding a 2% (w / w) ArPTU / P(VDF-HFP) film with a thickness of 9μm.

[0070] Example 3: Preparation of ArPTU / P(VDF-HFP) thin films

[0071] Weigh 9.913g of MDA powder and 3.806g of thiourea granules, dissolve them in 10ml of NMP solvent, and stir magnetically until a colorless and transparent solution is formed. Weigh 0.431g of p-benzenesulfonic acid and add it to the mixed solvent. Transfer the mixed solution to a microwave reactor, introduce N2, adjust the microwave power to 240W, and preheat for 7 minutes. Then adjust the microwave power to 400W and microwave for 60 minutes to form a deep red sol. Add methanol solution to the mixed sol and stir to form a yellow precipitate. Soak and wash the precipitate with ethanol, then wash and filter the precipitate with 60℃ warm water. Place the resulting pale yellow precipitate in a forced-air drying oven for 12 hours and collect it for later use.

[0072] 0.01g of ArPTU particles were dissolved in 5ml of DMF solvent and stirred for 30min until a yellow transparent solution was formed. 0.99g of P(VDF-HFP) was added to the mixture, and the solution was magnetically stirred for 8h until a uniform, translucent sol was formed. The sol was spun into a composite nonwoven fabric using electrospinning technology. Specific spinning parameters were: output voltage 13kV, distance between the roller and needle tip 15cm, roller speed 500r / min, and syringe advance speed 1ml / h. The nonwoven fabric with electrodes was removed and placed in a 160℃ high-temperature hot press at a pressure of 12MPa for 30min. After hot pressing, the film was quickly placed in 0℃ ice water for quenching. The film was then removed and placed on a 200℃ heating platform for 7min, followed by 75℃ warm water heat treatment for 4min. Finally, it was placed in a vacuum oven at 50℃ to remove moisture, yielding a 1% (w / w) ArPTU / P(VDF-HFP) film with a thickness of 10μm.

[0073] Comparative Example 1: Preparation of pure P(VDF-HFP) thin films

[0074] This example compares the differences in structure and properties between composite materials prepared by adding ArPTU to a P(VDF-HFP) matrix and pure films without ArPTU.

[0075] Weigh 1g P(VDF-HFP) was added to 5 ml of NMP solvent and magnetically stirred for 8 hours until a uniform, translucent sol was formed. The sol was then spun into a nonwoven fabric using electrospinning technology. Specific spinning parameters were: output voltage 13 kV, distance between the roller and needle tip 15 cm, roller speed 500 r / min, and syringe injection speed 1 ml / h. The nonwoven fabric with electrodes was removed and placed in a 160℃ high-temperature hot press at a pressure of 12 MPa for 30 minutes. After hot pressing, the film was immediately placed in 0℃ ice water for quenching. The film was then removed and placed on a 200℃ heating platform for 7 minutes, followed by a 75℃ warm water heat treatment for 4 minutes. Finally, it was placed in a vacuum oven at 50℃ to remove moisture, yielding a pure P(VDF-HFP) film with a thickness of 10 μm.

[0076] Comparative Example 2: Preparation of BaTiO3 / P(VDF-HFP) thin films

[0077] This example compares the structural and performance differences between composite materials prepared by spontaneously forming ArPTU particle structures in a P(VDF-HFP) matrix and traditional BaTiO3-filled composite materials filled with introduced inorganic particles.

[0078] 0.02g of BaTiO3 particles were dissolved in 5ml of DMF solvent and stirred for 30min until a yellow transparent solution was formed. 0.98g of P(VDF-HFP) was added to the mixture, and the solution was magnetically stirred for 8h until a uniform, translucent sol was formed. The sol was spun into a composite nonwoven fabric using electrospinning technology. Specific spinning parameters were: output voltage 13kV, distance between the roller and needle tip 15cm, roller speed 500r / min, and syringe advance speed 1ml / h. The nonwoven fabric with electrodes was removed and placed in a 160℃ high-temperature hot press at a pressure of 12MPa for 30min. After hot pressing, the film was quickly placed in 0℃ ice water for quenching. The film was then removed and placed on a 200℃ heating platform for 7min, followed by a 75℃ warm water heat treatment for 4min. Then, the moisture was removed by placing it in a vacuum oven at 50°C to obtain a BaTiO3 / P(VDF-HFP) film with a mass fraction of 2% and a thickness of 10μm.

[0079] Performance tests of the ArPTU / P(VDF-HFP) thin film prepared in this invention and the pure P(VDF-HFP) thin film prepared in Comparative Example 1:

[0080] Figure 3 The breakdown electric field intensity distribution at room temperature is shown for pure P(VDF-HFP) thin film and 2wt.% ArPTU / P(VDF-HFP) composite material. Figure 3 It can be seen that by adding ArPTU particles and combining them with the composite material preparation process adopted in this invention, the dispersed nano-reinforcing structure makes the ArPTU / P(VDF-HFP) composite material significantly improve its breakdown resistance compared with the pure P(VDF-HFP) film material.

[0081] Figure 4 The energy storage density and efficiency of pure P(VDF-HFP) film, BaTiO3 / P(VDF-HFP) film, and ArPTU / P(VDF-HFP) composite material prepared in Example 2 are shown at room temperature under different field strengths. Figure 4 It is known that the spontaneously formed dispersed reinforcement structure and dense interface structure in the ArPTU / P(VDF-HFP) composite material provide excellent breakdown resistance and interface polarization enhancement capability for the composite thin film material, thus significantly improving the energy storage capacity compared with pure P(VDF-HFP) and traditional introduced inorganic particle BaTiO3 / P(VDF-HFP) composite thin films.

Claims

1. A method for preparing a full-organic composite film material, comprising: 1) synthesis of aromatic polythiourea ArPTU particles; 2) synthesis of a composite film material using the ArPTU particles; The synthesis of the ArPTU particles adopts a microwave synthesis method, comprising the following steps: First, the reaction monomers diamino diphenyl methane, thiourea and the catalyst p-toluenesulfonic acid are dissolved in a polar solvent, and the reaction is heated by microwave; after the reaction is completed, the ArPTU particles are obtained by precipitation, washing and drying; The preparation of the composite film material adopts a phase separation method, comprising the following steps: First, the ArPTU particles are dissolved in a polar solvent, and then a PVDF-based powder material is added to prepare a mixed sol of a suitable concentration; then a composite material non-woven fabric is prepared by electrospinning; and then the composite material non-woven fabric is sequentially subjected to high-temperature hot pressing treatment, ice water quenching treatment and warm water quenching treatment to obtain the full-organic composite film material.

2. The method of claim 1, wherein: In the synthesis of the ArPTU particles, the molar ratio of the diamino diphenyl methane, the thiourea and the p-toluenesulfonic acid is 1: (0.95-1.05): 0.1; and the polar solvent is selected from N-methyl pyrrolidone and N, N-dimethylacetamide; Alternatively, in the synthesis of the ArPTU particles, the microwave heating conditions are as follows: the microwave power is 320-400 W, and the heating time is 8-60 min.

3. The production method according to claim 1 or 2, characterized by: In the synthesis of the ArPTU particles, a microwave preheating step is further included before the microwave heating, and the microwave preheating is as follows: the mixed solution is placed in a microwave reactor, nitrogen is introduced, and the microwave is preheated; the microwave preheating time is 7-10 min, and the microwave preheating power is 240-320 W.

4. The method of claim 1, wherein: In the synthesis of the ArPTU particles, the precipitation refers to that after the reaction is completed, the ArPTU particles generated in the reaction are precipitated from the deep red reaction system by using methanol or ethanol; Alternatively, the washing refers to that the precipitate obtained after the precipitation is washed multiple times with an ethanol solution, and then the precipitate is immersed and washed with warm water at 50-70℃; Alternatively, the drying refers to that the precipitate is placed in a blast drying oven for drying for 2-4 h at a drying temperature of 70-80℃; or the precipitate is placed in a vacuum drying oven for vacuum drying for 4-8 h at a drying temperature of 90-110℃.

5. The method of claim 1, wherein: In the preparation of the composite film material, the mass content of the ArPTU particles in the mixed sol is 0.5-50%; and the mass content of the PVDF-based powder material is 50-99.5%; Alternatively, the PVDF-based powder material is selected from PVDF, P(VDF-TrFE) or P(VDF-HFP); Alternatively, the polar solvent is selected from N-methyl pyrrolidone or N, N-dimethylacetamide; Alternatively, the electrospinning is performed in a direct current high-voltage electrospinning device, and the process parameters of the electrospinning are as follows: the applied voltage is 12-18 KV; the transverse displacement of the needle cylinder is 80-100 mm; the distance between the drum and the needle tip is 10-30 cm; the drum rotation speed is 100-1000 r / min; and the injection speed of the syringe is 0.1-1.5 ml / h.

6. The method of claim 1, wherein: The high-temperature hot-pressing treatment is performed at a temperature of 120-180℃, a pressure of 6-10 MPa, and a time of 0.5-2 h. Alternatively, the ice-water quenching treatment is to take out the film material from the high temperature instantly and quench in ice water at 0℃. Alternatively, the warm water quenching treatment is to first heat the film material after the ice-water quenching treatment on a heating table at 180-210℃ for 7-15 min, and then quench in warm water at 30-100℃ for 1-5 min.

7. The all-organic composite film material prepared by the method of any one of claims 1-6.

8. The use of the all-organic composite film material of claim 7 in the preparation of dielectric materials.

9. A dielectric film capacitor comprising a dielectric layer, wherein the material of the dielectric layer comprises the all-organic composite film material of claim 7.

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