阅读说明：本技术 一种纳米颗粒、复合薄膜及其制备方法和应用 (Nano-particles, composite film, and preparation method and application thereof ) 是由 于淑会 孙蓉 丁亚楠 于 2019-12-09 设计创作，主要内容包括：本发明提供了一种纳米颗粒、复合薄膜及其制备方法和应用,所述纳米颗粒为核壳结构,所述核壳结构的核为晶体结构的钙钛矿型氧化物,所述核壳结构的壳为无定型结构的钙钛矿型氧化物；复合薄膜包括聚合物基体以及均匀分散在聚合物基体中的纳米颗粒,使得到的复合薄膜具有较高的击穿强度和储能密度,其用于薄膜电容器中,能够增加薄膜电容器的击穿强度、介电常数以及储能密度。(The invention provides a nano particle, a composite film, a preparation method and an application thereof, wherein the nano particle is of a core-shell structure, the core of the core-shell structure is perovskite type oxide of a crystal structure, and the shell of the core-shell structure is perovskite type oxide of an amorphous structure; the composite film comprises a polymer matrix and nano-particles uniformly dispersed in the polymer matrix, so that the obtained composite film has higher breakdown strength and energy storage density, and when the composite film is used in a film capacitor, the breakdown strength, dielectric constant and energy storage density of the film capacitor can be increased.)

1. The nano-particles are characterized in that the nano-particles are of a core-shell structure, the core of the core-shell structure is perovskite type oxide of a crystal structure, and the shell of the core-shell structure is perovskite type oxide of an amorphous structure.

2. The nanoparticle according to claim 1, wherein the average diameter of the core-shell structure is 10-500 nm;

preferably, the average thickness of the shell of the core-shell structure is 1 to 50 nm.

3. The nanoparticle according to claim 1 or 2, wherein the perovskite-type oxide of the crystal structure comprises: any one or a combination of at least two of barium titanate crystals, strontium titanate crystals, barium strontium titanate crystals, perovskite crystals, calcium titanate crystals, barium zirconate titanate crystals, lead magnesium niobate crystals, sodium niobate crystals, lead zirconate titanate crystals, potassium sodium niobate crystals, barium stannate crystals, or yttrium barium titanate crystals, preferably barium titanate crystals;

preferably, the amorphous-structured perovskite oxide includes: the material is any one or a combination of at least two of amorphous structure barium titanate, amorphous structure strontium titanate, amorphous structure barium strontium titanate, amorphous structure perovskite, amorphous structure calcium titanate, amorphous structure barium zirconate titanate, amorphous structure lead magnesium niobate, amorphous structure sodium niobate, amorphous structure lead zirconate titanate, amorphous structure potassium sodium niobate, amorphous structure barium stannate or amorphous structure barium yttrium titanate, and amorphous structure barium strontium titanate is preferred.

4. A method for preparing nanoparticles according to any one of claims 1 to 3, characterized in that it comprises the following steps:

(1) mixing perovskite type oxide with a crystal structure and organic solution of perovskite type raw materials for a nanoparticle shell to obtain suspension;

(2) and (2) calcining the suspension obtained in the step (1) to obtain the nano particles.

5. The method for producing nanoparticles according to claim 4, wherein the method for producing the perovskite-type oxide having a crystal structure according to step (1) comprises: carrying out wet ball milling on metal salt and a titanium source, and then calcining to obtain the perovskite type oxide with the crystal structure;

preferably, the molar ratio of the metal salt to the titanium source is (0.95-1.05): 1;

preferably, the titanium source comprises titanium dioxide;

preferably, the solvent for wet ball milling comprises any one of ethanol, acetone or ethylene glycol or a combination of at least two thereof;

preferably, the adding volume of the solvent for wet ball milling is 8-20mL based on the mass of the titanium source being 1 g;

preferably, the mass ratio of the metal salt to the ball material for wet ball milling is (10-100): 1;

preferably, the ball milling speed of the wet ball milling is 400-800 rpm/min;

preferably, the ball milling time of the wet ball milling is 24-36 h;

preferably, the temperature of the calcination is 800-1200 ℃;

preferably, the calcination time is 5-10 h;

preferably, the preparation method of the perovskite oxide with the crystal structure further comprises drying a ball-milled material obtained after wet ball milling;

preferably, the preparation method of the organic solution of perovskite-type raw material for nanoparticle shell in step (1) comprises: adding a titanium source solution into a metal salt solution, and mixing to obtain an organic solution of the perovskite type raw material for the nanoparticle shell;

preferably, the solute of the titanium source solution is tetrabutyl titanate;

preferably, the solvent of the titanium source solution is acetylacetone;

preferably, the concentration of the titanium source solution is 0.2-2 mol/L;

preferably, the concentration of the metal salt solution is 0.5-5 mol/L;

preferably, the solvent of the metal salt solution comprises any one of ethylene glycol methyl ether, ethylene glycol, ethanol, isopropanol or butanone or a combination of at least two of the ethylene glycol methyl ether, the ethylene glycol, the ethanol, the isopropanol or the butanone;

preferably, the mixing is carried out under stirring conditions;

preferably, the mixing time is 0.5-5 h;

preferably, the mixing of step (1) is carried out under stirring conditions;

preferably, the mixing time of the step (1) is 24-48 h;

preferably, the step (2) further comprises the step of performing solid-liquid separation on the suspension before the calcination treatment;

preferably, the calcination of step (2) is carried out in a muffle furnace;

preferably, the temperature of the calcination in the step (2) is 500-800 ℃;

preferably, the calcination time of the step (2) is 3-6 h.

6. A composite film comprising a polymer matrix and the nanoparticles of any one of claims 1-3 uniformly dispersed in the polymer matrix.

7. The composite film according to claim 6, wherein the composite film has a thickness of 1nm to 50 μm;

preferably, the polymer matrix comprises a thermoplastic polymer and/or a thermoset polymer;

preferably, the thermoplastic polymer comprises any one or a combination of at least two of polyvinylidene fluoride, polyacrylonitrile, polytetrafluoroethylene, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyoxymethylene, polycarbonate, polyamide, polyacrylic acid, polysulfone and polyphenylene oxide;

preferably, the thermosetting polymer includes any one or a combination of at least two of bismaleimide resin, bismaleimide-triazine resin, liquid crystal epoxy resin, polybutadiene epoxy resin, water-based epoxy resin, acrylic resin, diglycidyl tetrahydrophthalate, silicone epoxy resin, dicyclopentadiene-type cyanate ester, alicyclic diepoxide, or diglycidyl phthalate;

preferably, the composite film comprises 1-99.9% by mass of a polymer matrix and 0.1-50% by mass of nanoparticles.

8. The method for producing a composite film according to claim 6 or 7, comprising: mixing the nano-particle suspension with a polymer matrix, and curing to obtain the composite film;

preferably, the nanoparticle suspension is obtained by dispersing nanoparticles into an organic solvent;

preferably, the organic solvent is N, N-dimethylformamide;

preferably, the dispersion mode is ultrasonic dispersion;

preferably, the mixing is carried out under stirring conditions;

preferably, the curing includes pouring the slurry obtained by mixing on a glass plate, defoaming, and then drying;

preferably, the defoaming is performed in a vacuum box;

preferably, the drying is carried out in a drying oven;

preferably, the temperature of the drying is 70-90 ℃;

preferably, the drying time is 3-7 h.

9. A thin film capacitor comprising two electrode layers and a dielectric layer disposed between the two electrode layers, wherein the dielectric layer is the composite film according to claim 6 or 7;

preferably, the two electrode layers are made of any one or an alloy formed by at least two of aluminum, silver, copper, gold, nickel or titanium;

preferably, the dielectric constant of the thin film capacitor is not less than 5;

preferably, the dielectric loss of the thin film capacitor is not higher than 0.1;

preferably, the breakdown strength of the thin film capacitor is not lower than 1000 KV/cm;

preferably, the energy storage density of the film capacitor is not lower than 2J/cm³。

10. Use of a film capacitor according to claim 9 as an electrical energy storage device in a kinetic weapon or a hybrid electric vehicle.

Technical Field

The invention belongs to the field of materials, relates to a nanoparticle, a composite film, a preparation method and an application thereof, and particularly relates to a nanoparticle, a preparation method of the nanoparticle, a composite film containing the nanoparticle, a preparation method of the composite film, a film capacitor containing the composite film and an application of the film capacitor.

Background

In electronic and electric power systems, a battery, a super capacitor, a dielectric capacitor, and the like are commonly used as an electric energy storage device. The battery has the highest energy storage density (10-300 W.h/kg), but has low power density (<500W/kg), and the battery has relatively large harm to the environment. The super capacitor has medium energy storage density (<30 W.h/kg) and power density (10-106W/kg), but is complex in structure, low in operating voltage, large in leakage current and short in cycle period. In comparison, the dielectric capacitor not only has high power density (about 108W/kg), but also has the advantages of wide use temperature range, rapid charge and discharge, long service cycle and the like, and has important applications in civil and military power electronic products, including kinetic energy weapons, high-power laser or microwave, and hybrid electric vehicles.

At present, the dielectric materials are mainly divided into three types, namely ceramic, polymer and polymer-based composite materials. Ceramics have a high dielectric constant, but low breakdown strength; polymers have high breakdown strength but low dielectric constants. According to the definition of energy storage density, the energy storage density is related to the breakdown strength and the dielectric constant, so that the energy storage density is improved by combining the energy storage density with the breakdown strength to obtain the composite dielectric film with high breakdown strength and high dielectric constant. However, the dielectric constant of the polymer-based composite material is increased only at a high filler content, and at the same time, the breakdown strength is decreased.

CN108485514A discloses a polymer matrix composite material for capacitor and a preparation method thereof, wherein the composite material comprises the following components by weight: 60-70 parts of polymer matrix; 20-30 parts of dopamine-coated tin-titanium oxide nano-fiber; 5-10 parts of an auxiliary agent; wherein the auxiliary agent is a mixture of aminopropyl silanetriol and vinyl trimethoxy silane, and the mass ratio of the aminopropyl silanetriol to the vinyl trimethoxy silane is (3-8) to 1. According to the polymer-based composite material, the auxiliary agent is added and the nano fiber with the core-shell structure is matched, so that the polymer-based composite material has high thermal conductivity, high dielectric constant and low dielectric loss, and simultaneously has good coating uniformity, but the breakdown strength and the dielectric property of the polymer-based composite material are still to be improved.

CN101677033A discloses a polymer-based composite dielectric material filled with reactive nanoparticles and a plate capacitor, belonging to the technical field of electronic materials and electronic devices. The nano particles are of a core-shell structure in which a layer of insulating layer is coated on the surface of conductive nano particles, and the surface of the insulating layer carries a reactive functional group. The nanoparticles are organically bound together with the polymer through the reactive functional group and are uniformly dispersed in the polymer matrix. The flat-plate capacitor takes a polymer-based composite dielectric material filled with conductive nanoparticles with a reactive core-shell structure and an insulating layer as a dielectric layer, and takes a flexible metal foil as an upper electrode and a lower electrode; the capacitor provided by the invention has higher capacitance density, lower dielectric constant and leakage current, but the energy storage density is lower.

Therefore, it is necessary to provide a composite thin film and a capacitor capable of increasing both the breakdown strength and the dielectric constant and effectively increasing the energy storage density.

Disclosure of Invention

The invention aims to provide a nano particle, a composite film, a preparation method and application thereof, wherein the nano particle takes perovskite with a crystalline structure as a core and perovskite with an amorphous structure as a shell, so that the obtained nano particle has a core-shell structure; the composite film comprises a polymer matrix and nano-particles uniformly dispersed in the polymer matrix, so that the obtained composite film has higher breakdown strength and energy storage density, and when the composite film is used in a film capacitor, the breakdown strength, dielectric constant and energy storage density of the film capacitor can be increased.

In order to achieve the purpose, the invention adopts the following technical scheme:

one of the purposes of the present invention is to provide a nanoparticle, wherein the nanoparticle is of a core-shell structure, the core of the core-shell structure is a perovskite type oxide of a crystal structure, and the shell of the core-shell structure is a perovskite type oxide of an amorphous structure.

The nano particles in the invention take perovskite type oxide with a crystal structure as a core and perovskite type oxide with an amorphous structure as a shell, and the nano particles are applied to a polymer matrix as a filler, so that the obtained composite film is used in a capacitor, and the breakdown strength, the dielectric constant and the energy storage density of the capacitor can be improved.

The perovskite type oxide with the crystal structure has better dielectric constant, and the perovskite type oxide with the amorphous structure has better breakdown strength; the perovskite oxide with the amorphous structure is isotropic, the polarization capability of the perovskite oxide is weak, and the dielectric constant of the perovskite oxide is lower than that of the perovskite oxide with the crystal structure. The perovskite type oxide with a crystal structure and the perovskite type oxide with an amorphous structure have larger dielectric constant difference, a large amount of charges are accumulated at a core and a shell to form interface polarization, so that the dielectric constant can be improved by combining the perovskite type oxide with the amorphous structure; in addition, the surface of the perovskite type oxide with a crystal structure is coated with a layer of amorphous perovskite type oxide, so that the free movement of space charge in a core is limited, and the breakdown strength is improved.

In the present invention, the average diameter of the core-shell structure is 10 to 500nm, for example, 10nm, 30nm, 50nm, 80nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, etc. When the average diameter of the core-shell structure is within this range, there is an advantage in that it is easily dispersed in the polymer matrix.

In the present invention, the average thickness of the shell of the core-shell structure is 1 to 50nm, for example, 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, etc. When the average thickness of the shell is within this range, an improvement in the breakdown strength is facilitated.

In the present invention, the perovskite-type oxide of the crystal structure includes: any one or a combination of at least two of barium titanate crystals, strontium titanate crystals, barium strontium titanate crystals, perovskite crystals, calcium titanate crystals, barium zirconate titanate crystals, lead magnesium niobate crystals, sodium niobate crystals, lead zirconate titanate crystals, potassium sodium niobate crystals, barium stannate crystals, or yttrium barium titanate crystals, preferably barium titanate crystals.

In the present invention, the amorphous-structure perovskite oxide includes: the material is any one or a combination of at least two of amorphous structure barium titanate, amorphous structure strontium titanate, amorphous structure barium strontium titanate, amorphous structure perovskite, amorphous structure calcium titanate, amorphous structure barium zirconate titanate, amorphous structure lead magnesium niobate, amorphous structure sodium niobate, amorphous structure lead zirconate titanate, amorphous structure potassium sodium niobate, amorphous structure barium stannate or amorphous structure barium yttrium titanate, and amorphous structure barium strontium titanate is preferred.

Another object of the present invention is to provide a method for preparing nanoparticles according to the first object, comprising:

(1) mixing perovskite type oxide with a crystal structure and organic solution of perovskite type raw materials for a nanoparticle shell to obtain suspension;

(2) and (2) calcining the suspension obtained in the step (1) to obtain the nano particles.

In the present invention, the method for producing a perovskite-type oxide having a crystal structure according to step (1) comprises: and carrying out wet ball milling on the metal salt and the titanium source, and then calcining to obtain the perovskite type oxide with the crystal structure.

In the present invention, the molar ratio of the metal salt to the titanium source is (0.95-1.05):1, for example, 0.95:1, 0.96:1, 0.97:1, 0.98:1, 0.99:1, 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, etc.

In the present invention, the titanium source comprises titanium dioxide.

In the present invention, the solvent for wet ball milling includes any one of ethanol, acetone or ethylene glycol or a combination of at least two thereof.

In the present invention, the mass ratio of the metal salt to the ball material for wet ball milling is (10-100: 1), for example, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, etc.

In the present invention, the ball milling rate of the wet ball milling is 400-800rpm/min, such as 400rpm/min, 450rpm/min, 500rpm/min, 550rpm/min, 600rpm/min, 650rpm/min, 700rpm/min, 750rpm/min, 800rpm/min, etc.

In the invention, the ball milling time of the wet ball milling is 24-36h, such as 24h, 26h, 28h, 30h, 32h, 34h, 36h and the like.

In the present invention, the temperature of the calcination is 800-. In the present invention, the calcination time is 5 to 10 hours, for example, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, etc.

In the invention, the preparation method of the perovskite oxide with the crystal structure further comprises the step of drying a ball-milled material obtained after wet ball milling.

In the present invention, the step (1) of preparing an organic solution of a perovskite-type raw material for a nanoparticle shell comprises: and adding the titanium source solution into the metal salt solution, and mixing to obtain the organic solution of the perovskite type raw material for the nano particle shell.

In the invention, the solute of the titanium source solution is tetrabutyl titanate.

In the invention, the solvent of the titanium source solution is acetylacetone.

In the present invention, the concentration of the titanium source solution is 0.2 to 2mol/L, for example, 0.2mol/L, 0.5mol/L, 0.8mol/L, 1mol/L, 1.2mol/L, 1.4mol/L, 1.6mol/L, 2mol/L, etc.

In the present invention, the concentration of the metal salt solution is 0.5 to 5mol/L, for example, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L, 3mol/L, 3.5mol/L, 4mol/L, 4.5mol/L, 5mol/L, etc.

In the present invention, the solvent of the metal salt solution includes any one of ethylene glycol methyl ether, ethylene glycol, ethanol, isopropanol or butanone or a combination of at least two thereof.

In the present invention, the mixing is carried out under stirring.

In the present invention, the mixing time is 0.5 to 5 hours, such as 0.5 hour, 1 hour, 1.5 hour, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours and the like.

In the present invention, the mixing in step (1) is carried out under stirring.

In the present invention, the mixing time in step (1) is 24-48h, such as 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h, 48h, etc.

In the present invention, the step (2) further comprises subjecting the suspension to solid-liquid separation before the calcination treatment.

In the present invention, the calcination in step (2) is carried out in a muffle furnace.

In the present invention, the temperature of the calcination in step (2) is 500-.

In the present invention, the calcination time in step (2) is 3-6h, such as 3h, 3.2h, 3.5h, 3.8h, 4h, 4.2h, 4.5h, 4.7h, 5h, etc.

It is a further object of the present invention to provide a composite film comprising a polymer matrix and nanoparticles according to one of the objects uniformly dispersed in the polymer matrix.

The composite film comprises a polymer matrix and nano-particles uniformly dispersed in the polymer matrix, so that the obtained composite film has higher dielectric constant and energy storage density, and the breakdown strength, the dielectric constant and the energy storage density of the film capacitor can be increased when the composite film is used in the film capacitor.

In the present invention, the thickness of the composite film is 1nm to 50 μm, for example, 1nm, 5nm, 10nm, 50nm, 100nm, 300nm, 500nm, 800nm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm and the like. In the present invention, the polymer matrix comprises a thermoplastic polymer and/or a thermosetting polymer.

In the present invention, the thermoplastic polymer includes any one or a combination of at least two of polyvinylidene fluoride, polyacrylonitrile, polytetrafluoroethylene, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyoxymethylene, polycarbonate, polyamide, polyacrylic acid, polysulfone, and polyphenylene oxide.

In the present invention, the thermosetting polymer includes any one of or a combination of at least two of bismaleimide resin, bismaleimide-triazine resin, liquid crystal epoxy resin, polybutadiene epoxy resin, aqueous epoxy resin, acrylic resin, diglycidyl tetrahydrophthalate, silicone epoxy resin, dicyclopentadiene-type cyanate ester, alicyclic diepoxide, or diglycidyl phthalate.

In the present invention, the composite film has a polymer matrix of 1 to 99.9% by mass, for example, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99.9% by mass, etc., and nanoparticles of 0.1 to 99% by mass, for example, 0.1%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99% by mass, etc., preferably 0.1 to 50% by mass.

The fourth object of the present invention is to provide a method for producing the composite film according to the third object, the method comprising: and mixing the nanoparticle suspension with a polymer matrix, and curing to obtain the composite film.

In the present invention, the nanoparticle suspension is obtained by dispersing nanoparticles in an organic solvent.

In the present invention, the organic solvent is N, N-dimethylformamide.

In the present invention, the dispersion mode is ultrasonic dispersion.

In the present invention, the mixing is carried out under stirring.

In the present invention, the curing includes pouring the slurry obtained by mixing on a glass plate, defoaming, and then drying.

In the present invention, the defoaming is performed in a vacuum chamber.

In the present invention, the drying is performed in a drying oven.

In the present invention, the temperature of the drying is 70 to 90 ℃. For example, 70 ℃, 72 ℃, 75 ℃, 77 ℃, 80 ℃, 82 ℃, 85 ℃, 87 ℃, 90 ℃ and the like.

In the present invention, the drying time is 3 to 7 hours, such as 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours and the like.

A fifth object of the present invention is to provide a thin film capacitor comprising two electrode layers and an electrolyte layer disposed between the two electrode layers, wherein the electrolyte layer is the composite film described in the third object.

In the invention, the two electrode layers are made of any one or an alloy of at least two of aluminum, silver, copper, gold, nickel or titanium.

In the present invention, the dielectric constant of the thin film capacitor is not less than 5.

In the present invention, the dielectric loss of the thin film capacitor is not higher than 0.1.

In the present invention, the breakdown strength of the thin film capacitor is not less than 1000KV/cm, such as 1000KV/cm, 1005KV/cm, 1010KV/cm, 1015KV/cm, 1020KV/cm, 1025KV/cm, 1030KV/cm, etc.

In the invention, the energy storage density of the film capacitor is not lower than 2J/cm³E.g. 2J/cm³、5J/cm³、8J/cm³、10J/cm³、12J/cm³、15J/cm³、18J/cm³、20J/cm³And the like.

The sixth purpose of the present invention is to provide an application of the film capacitor as mentioned in the fifth purpose as an electric energy storage device in a kinetic energy weapon, a high power laser, a high power microwave or a hybrid electric vehicle.

Compared with the prior art, the invention has the following beneficial effects:

the nano-particles provided by the invention take perovskite with a crystalline structure as a core and perovskite with an amorphous structure as a shell, so that the obtained nano-particles have a core-shell structure; the composite film comprises a polymer matrix and nano-particles uniformly dispersed in the polymer matrix, so that the obtained composite film has higher breakdown strength and energy storage density, and can be used in a film capacitorThe breakdown strength, dielectric constant and energy storage density of the film capacitor can be increased, wherein the breakdown strength is not lower than 1000kv/cm, the dielectric constant is not lower than 5, the dielectric loss is not higher than 0.1, and the energy storage density is not lower than 2J/cm³。

Drawings

FIG. 1 is a scanning electron micrograph of nanoparticles of example 1 with a 1 μm scale;

FIG. 2 is a TEM image of the nanoparticles of example 1, with 100nm scale;

FIG. 3 is an enlarged view of a portion of FIG. 2, scale 10 nm;

figure 4 is an XRD pattern of barium titanate and crystalline-barium titanate @ amorphous-barium strontium titanate nanoparticles;

FIG. 5 is a scanning electron micrograph of the composite film of example 1, with a scale of 10 μm;

FIG. 6 is a graph of the breakdown strength of the composite film of example 1;

FIG. 7 is a graph comparing the breakdown strength of the composite film of example 1 with that of a pure BT/PVDF composite film.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.