Preparation method of 10 mu m all-inorganic relaxor type anti-ferroelectric thick film with high energy storage performance under low electric field

Abstract

The application belongs to the technical field of electronic functional materials and devices, and particularly relates to a preparation method of a 10-micron all-inorganic relaxor antiferroelectric thick film with high energy storage performance under a low electric field. The application aims to solve the problems of a high driving electric field, low energy storage density and total energy storage, complex preparation process and poor stability in practical application of a small, intensive and light thick film type dielectric energy storage capacitor. The method comprises the following steps: preparing a powder by a coprecipitation method, mixing a sol after surface modification of the ceramic powder by polydopamine to form a suspension, and obtaining a 10-micron all-inorganic relaxor antiferroelectric thick film by an improved sol powder method. The prepared inorganic dielectric thick film has super-high energy storage performance under a low electric field, and has excellent temperature, frequency and fatigue cycle stability, which is extremely important for the application of a high-performance advanced pulse power system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic functional materials and devices, and particularly relates to a preparation method of a 10-micron all-inorganic relaxor-type anti-ferroelectric thick film with high energy storage performance under a low electric field. BACKGROUND

[0002] Electrostatic capacitors with dielectric materials as charge storage media have been widely used in hybrid electric vehicles, microwave communication, medical equipment and pulse power systems due to their ultrafast charge and discharge speed, ultra-high power density, low dielectric loss and excellent storage stability. They have become key components in advanced electronic industry and power systems. With the development of electronic devices towards miniaturization, integration and lightweight, higher requirements for the energy storage performance of dielectric capacitors have been put forward. In order to obtain higher energy storage performance, dielectric capacitors should have both high energy storage density and high total energy storage. In general, dielectric capacitors must have high saturation polarization, small residual polarization, large breakdown field strength and slow polarization saturation to achieve high energy storage density. Currently, there are four main types of dielectric capacitors: inorganic ceramic, inorganic thin film, inorganic thick film and organic thick film. Thin film dielectric capacitors with a thickness less than 1 μm have a high breakdown field strength, so they can release a high energy density per unit volume. However, due to their small thickness and volume, the total energy storage and releasable energy are quite low, which is not conducive to practical application. Bulk ceramics have a thickness of more than 100 μm, which tends to produce more defects in the internal during preparation, seriously affecting the breakdown field strength and resulting in a small energy storage density. Therefore, high total energy storage can only be achieved by a large volume, which is a challenge to the miniaturization, integration and lightweight of electronic devices. Compared with thin film and bulk capacitors, thick film capacitors (thickness of 1-100 μm) have a more moderate total energy storage and energy density, as well as the potential for large-scale production, making them one of the most promising technologies for energy storage devices. At present, organic polymer and organic-inorganic composite thick film dielectric capacitors have become an important choice for new flexible energy storage devices due to their light weight, good mechanical flexibility, strong scalability, easy processing into flexible, and higher breakdown strength than ceramic dielectric. However, the working environment of dielectric capacitors is relatively harsh, and the stability of organic polymer and organic-inorganic composite capacitors under high temperature, humidity and ultraviolet light is far inferior to that of inorganic dielectric capacitors. This instability limits their practical application to some extent. In addition, compared with inorganic dielectric capacitors, organic polymer and organic-inorganic composite dielectric capacitors have a lower dielectric constant (in most cases <30) and polarization value, so they can only obtain a higher energy storage density under a relatively high electric field (>6000 kV / cm). The requirement of high electric field may limit the application of the device, making it unable to work at low voltage, which poses a great challenge to the high voltage resistance and failure-related reliability of the entire electronic circuit and electronic components that match it. Conversely, at a low electric field (<1000 kV / cm), the probability of capacitor failure is very small, and the probability of failure will be greatly reduced.Meanwhile, the application of electrostatic capacitors in low electric field conditions can be expanded, making them a viable option for many electronic devices that operate at low voltages. Therefore, it is desirable to obtain higher energy density (≥ 10 J / cm. 3 ) at low electric fields. Inorganic thick film type ceramic capacitors generally achieve high energy storage performance at low electric fields due to their high dielectric constant and large total energy storage of ceramic bulk and high energy storage density of thin film dielectric. Among various inorganic film material preparation techniques, sol-gel technology has a series of unique advantages such as low cost, short cycle, large area production, and synthesis of high crystallinity crystal materials at low temperature, etc. By using single crystal silicon substrate, sol-gel technology is closely linked with integrated semiconductor industry. Generally, for sol-gel, the crack-free single layer film thickness is limited to within 0.3 μm. To increase the film thickness, inorganic films can be integrated onto the substrate by sol-gel-thermal annealing cycle preparation technology, which often forms multiple interfaces, thereby exposing some serious problems such as component gradient, interface second term, and interdiffusion between film and electrode adhesion, which greatly damage the film morphology, structure and electrical properties. Therefore, for multi-layer dense and crack-free thick films, 3 μm is usually the upper limit of their thickness; limited thickness is very limited for the improvement of the total storage energy of dielectric capacitors. The deposition of thick film dielectric with uniform, dense, crack-free and excellent energy storage performance and thickness of more than several tens of microns is a challenging technical problem in the field of inorganic dielectric energy storage. Therefore, it is necessary to invent a reliable new material design strategy to overcome the above difficulties. SUMMARY

[0003] The present application aims to solve the problems of high driving electric field, low energy storage density and total energy storage, complex preparation process, and poor stability in practical application of current small, intensive, lightweight thick film type dielectric energy storage capacitors, and to provide a preparation method of 10 μm full inorganic relaxor type antiferroelectric thick film with high energy storage performance at low electric field.

[0004] The preparation method of 10 μm full inorganic relaxor type antiferroelectric thick film with high energy storage performance at low electric field is to prepare ABO3 perovskite type ceramic powder by dry gel method, then modify the surface of the powder by polydopamine, mix the modified powder with ABO3 perovskite type oxide sol, and continuously ultrasonic and stir to form a uniform dispersion of sol powder suspension. Finally, the sol powder is prepared into a thick film with a thickness of 10 μm by repeated spin coating-sintering method.

[0005] The preparation method of the 10-micron all-inorganic relaxor-type anti-ferroelectric thick film with high energy storage performance under low electric field is as follows: ABO3 perovskite ceramic powder is prepared by co-precipitation method, then the powder is surface modified by polydopamine, mixed into ABO3 perovskite oxide sol and continuously ultrasonicated and stirred to form a uniformly dispersed sol powder suspension, and finally the sol powder is prepared into a 10-micron thick film by repeated spin coating-sintering method.

[0006] The sol powder mentioned in the present application is prepared by spin coating in the later thick film preparation process, and in addition, screen printing method, tape casting method, electrophoretic deposition method and traditional solid-phase ceramic sintering method can also be used.

[0007] The present application has the following advantages: the present application provides a method for preparing 0-3 composite inorganic dielectric thick film with a single layer thickness of 2 microns and a total thickness of tens of microns by sol powder method: a suspension composed of PLBNZST sol and PLBNZST powder surface modified by polydopamine is uniformly spin coated on the FTO substrate by a film applicator to successfully prepare a pure-phase PLBNZST relaxor-type anti-ferroelectric thick film. The micron-sized powder size and high crystallinity of the inorganic dielectric ceramic powder prepared by traditional solid-phase method are significantly reduced by the new design of co-precipitation method. The reduction of crystallinity makes the newly designed ceramic powder have similar dielectric constant with the thin film medium prepared by pure sol-gel method, so the electric field distribution between the 0-dimensional ceramic powder and the 3-dimensional film material in the composite material is uniform, which improves the breakdown electric field of the thick film and delays the polarization. At the same time, the agglomeration of the nano-powder is eliminated and the powder size is reduced to less than the crystal size prepared by sol-gel method, so that the added powder cannot be distinguished from the crystal, the defects such as pores, cracks and space charges in the thick film medium are improved, and the uniformity of the microstructure is significantly improved, which promotes the significant reduction of the dielectric loss and leakage current density of the thick film and the significant improvement of the breakdown electric field. The delay of polarization and the significant improvement of breakdown field strength greatly improve the energy storage performance of the thick film medium. In addition, compared with the nano-ceramic powder prepared by dry gel method in the common 0-3 composite material, the co-precipitation method is improved based on the traditional solid-phase sintering method, which not only significantly reduces the raw material cost and improves the single batch preparation capacity, laying a foundation for high yield, high efficiency and large-scale industrialization process, but also the thick film material prepared has smaller grain size, larger specific surface area and greater interfacial polarization effect between the co-precipitation powder and the sol-gel film, which promotes the significant improvement of the dielectric constant and polarization value of the thick film medium, and finally realizes the enhancement of the energy storage performance. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1Surface scanning electron microscope images of the PLBNZST powder prepared in the comparative example, example one and example two; wherein A represents the comparative example, B represents example one, and C represents example two.

[0009] Figure 2 Surface scanning electron microscope images of the thick film prepared by the sol powder method after the PLBNZST powder is prepared in the comparative example, example one and example two, and the surface scanning electron microscope images of the thin film prepared by the sol gel method using only the PLBNZST sol; wherein A represents the comparative example, B represents example one, C represents example two, and D represents the pure sol thin film.

[0010] Figure 3 A cross-section scanning electron microscope image of the PLBNZST thick film prepared in example two.

[0011] Figure 4 A comparative diagram of the relationship curves between the dielectric constant and the frequency of the PLBNZST thick film prepared in the comparative example, example one and example two.

[0012] Figure 5 A comparative diagram of the relationship curves between the leakage current density and the electric field of the PLBNZST thick film prepared in the comparative example, example one and example two.

[0013] Figure 6 A comparative diagram of the relationship curves between the polarization value and the field strength of the PLBNZST thick film prepared in the comparative example, example one and example two at the respective breakdown field strengths.

[0014] Figure 7 A comparative diagram of the relationship curves between the polarization value and the field strength of the PLBNZST thick film prepared in example two at the same field strength (500 kV / cm) and different temperatures.

[0015] Figure 8 A bar chart of the energy storage density values of the PLBNZST thick film prepared in example two at different temperatures.

[0016] Figure 9 A bar chart of the energy storage efficiency values of the PLBNZST thick film prepared in example two at different temperatures. DETAILED DESCRIPTION

[0017] The technical solution of the present application is not limited to the following specific embodiments, and also includes any combination between the specific embodiments.

[0018] Specific embodiment one: the preparation method of the 10 μm all-inorganic relaxor antiferroelectric thick film with high energy storage performance under low electric field is to prepare ABO3 perovskite ceramic powder by dry gel method, then mix the powder into ABO3 perovskite oxide sol after surface modification by polydopamine, and continuously ultrasonic and stir to form a uniformly dispersed sol powder suspension, and finally repeatedly use spin-coating-sintering method to prepare the thick film with a thickness of 10 μm.

[0019] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the preparation method of the 10 μm all-inorganic relaxor antiferroelectric thick film with high energy storage performance under low electric field is completed according to the following steps:

[0020] I. Preparation of sol-gel: ① according to the chemical formula of the target product, the corresponding raw materials are weighed and added into the solvent, and a clear solution is obtained by mixing and heating; ② complexing agent and stabilizer are added into the clear solution to obtain a mixed solution; ③ catalyst is added into the mixed solution to obtain a sol-gel solution;

[0021] II. Preparation of dry gel ceramic powder: ① a part of the sol-gel solution is heated and dried to obtain a dry gel; ② the dry gel is treated by degassing and then sintered to obtain a crystallized dry gel ceramic; ③ the crystallized dry gel ceramic is ground and sieved to obtain a ceramic powder;

[0022] III. Preparation of sol powder suspension: ① the ceramic powder is dispersed in Tris-HCl buffer solution to obtain a ceramic powder suspension; ② dopamine is added into the ceramic powder suspension to form a shell structure of polydopamine on the surface of the ceramic powder, and then the PDA@ceramic powder is collected by washing and centrifugal separation; ③ the PDA@ceramic powder is added into the sol-gel solution of step I to obtain a sol powder suspension; ④ the sol powder suspension is treated by ultrasonic dispersion, and then span-85 dispersant and polyvinyl butyral binder are added into the suspension to obtain a uniformly stable sol powder;

[0023] IV. Preparation of thick film by repeated spin-coating-sintering method: ① the sol powder is dropped on the FTO substrate and uniformly spin-coated by using a spin coater to obtain a smooth and flat wet film; ② the wet film is heat treated to obtain a thick film; ③ the thick film is gold plated to obtain a 10 μm all-inorganic relaxor antiferroelectric thick film with high energy storage performance under low electric field. The other steps are the same as specific embodiment two.

[0024] Specific embodiment three: the preparation method of the 10 μm all-inorganic relaxor antiferroelectric thick film with high energy storage performance under low electric field is to prepare ABO3 perovskite ceramic powder by co-precipitation method, then mix the powder into ABO3 perovskite oxide sol after surface modification by polydopamine, and continuously ultrasonic and stir to form a uniformly dispersed sol powder suspension, and finally repeatedly use spin-coating-sintering method to prepare the thick film with a thickness of 10 μm.

[0025] The present embodiment provides a novel preparation method of ultrafine nano-powder based on coprecipitation method. The powder can be used to prepare a full inorganic relaxor type antiferroelectric thick film with ultra-high energy storage performance under low electric field, and the single layer thickness can reach 2 μm and the total thickness can reach 10 μm. Compared with the ceramic powder prepared by the traditional solid phase method used in common 0-3 composite material, the micron-sized powder size and high crystallinity are significantly reduced after the modification by the precipitation method.

[0026] The reduction of crystallinity makes the newly designed ceramic powder have similar dielectric constant with the thin film medium prepared by the corresponding pure sol-gel method, so that the electric field distribution between the 0-dimensional ceramic powder and the 3-dimensional film material in the composite material is uniform, which makes the thick film achieve the improvement of breakdown electric field and the delay of polarization. At the same time, due to the elimination of the agglomeration of nano-powder and the reduction of the powder size to less than the crystal size prepared by the sol-gel method, the powder added from the crystal can hardly be distinguished, the defects such as pores, cracks and space charge in the thick film medium are improved, and the uniformity of the microstructure is significantly improved, which promotes the significant reduction of the thick film dielectric loss and leakage current density and the significant improvement of the breakdown electric field. The delay of polarization and the significant improvement of the breakdown field strength greatly improve the energy storage performance of the thick film medium. The ceramic powder required in the preparation of sol-powder by coprecipitation method not only significantly reduces the raw material cost and improves the single batch preparation capacity, but also lays the foundation for high yield, high efficiency and large-scale industrialization process. Moreover, due to the reduction of the grain size and the increase of the specific surface area of the prepared thick film material, the greater interfacial polarization effect is formed between the coprecipitation powder and the sol-gel film, which promotes the significant improvement of the dielectric constant and polarization value of the thick film medium, and finally realizes the enhancement of the energy storage performance. The PLBNZST thick film prepared from the coprecipitation ceramic powder has a releasable energy storage density of 14.62 J / cm 3 , which is 2.21 times of the thick film prepared from the traditional solid phase sintering ceramic powder.

[0027] The inorganic dielectric thick film prepared by us shows ultra-high energy storage performance under low electric field of 1100 kV / cm, and also has excellent temperature, frequency and fatigue cycle stability, which is extremely important for the application of high-performance advanced pulse power system.

[0028] Specific embodiment four: the difference between the present embodiment and the specific embodiment three is that the preparation method of 10 μm full inorganic relaxor type antiferroelectric thick film with high energy storage performance under low electric field is completed according to the following steps:

[0029] I. Preparation of sol-gel: ① The corresponding raw materials are weighed according to the chemical formula of the target product, added into a solvent, and mixed and heated to obtain a clear solution; ② The complexing agent and stabilizer are added into the clear solution to obtain a mixed solution; ③ The catalyst is added into the mixed solution to obtain a sol-gel solution;

[0030] II. Preparation of co-precipitation ceramic powder: AB03 perovskite type ceramic powder is prepared by co-precipitation method to obtain ceramic powder;

[0031] III. Preparation of sol powder suspension: ①Disperse the ceramic powder in Tris-HCl buffer solution to obtain a ceramic powder suspension; ②Add dopamine to the ceramic powder suspension to form a polydopamine shell structure on the surface of the ceramic powder, wash and centrifuge to collect PDA@ceramic powder; ③Add PDA@ceramic powder to the sol-gel solution of step one to obtain a sol powder suspension; ④Ultrasonic dispersion treatment is performed on the sol powder suspension, then Span-85 dispersant and polyvinyl butyral binder are added to obtain a uniform and stable sol powder;

[0032] IV. Preparation of thick film by repeated spin-coating and sintering: ①Drop the sol powder on the FTO substrate and use a spin coater to uniformly spin-coat to obtain a smooth and flat wet film; ②Heat treat the wet film to obtain a thick film; ③Gold plating is performed on the thick film to obtain a 10μm all-inorganic relaxor type antiferroelectric thick film with high energy storage performance under low electric field. The rest is the same as in embodiment three.

[0033] Embodiment five: The difference between this embodiment and embodiment one or three is that the chemical formula of the AB03 perovskite type ceramic powder is Pb 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O3. The rest is the same as in embodiment one or three.

[0034] Embodiment six: The difference between this embodiment and embodiment two or four is that the preparation of the sol-gel in step one is performed according to the following steps:

[0035] ①According to the chemical formula of the target product, the corresponding raw materials are taken as the solute raw materials, acetic acid is taken as the solvent, and heating and stirring are carried out at a temperature of 110-130℃. After boiling for 2-5 min, heating is stopped, and cooling and stirring are carried out until room temperature is reached to obtain a clear solution. The concentration of the clear solution is 0.4-0.6 mol / L; ②acetylacetone and citric acid are taken as complexing agents, concentrated nitric acid and ethylene glycol are taken as stabilizers, and deionized water is taken as a hydrolysis reaction agent. They are added to the clear solution, and magnetic stirring is carried out at room temperature for 30-50 min to obtain a mixed solution. The total mass fraction of acetylacetone and citric acid in the complexing agent is 8%-12% of the clear solution. The total mass fraction of concentrated nitric acid and ethylene glycol in the stabilizer is 2%-4% of the clear solution; ③lactic acid catalyst is added to the mixed solution, and stirring is carried out at room temperature for 30-50 min to obtain a sol-gel solution with a concentration of 0.4-0.6 mol / L. The molar ratio of lactic acid to lead in the lactic acid catalyst is 1:1. The addition amount of the lactic acid catalyst is 0.4-0.6 mol / L. The other steps are the same as those in embodiment two or four.

[0036] Embodiment seven: different from embodiment two, the preparation of the xerogel ceramic powder in step two is carried out according to the following steps:

[0037] ①A part of the sol-gel solution is heated and magnetically stirred at a temperature of 110-130℃. When the colloid is viscous and the magnetic stirrer cannot continue to stir, a wet gel is obtained. The wet gel is transferred to a forced air drying oven and dried at a temperature of 110-130℃ to obtain a dry gel; ②The dry gel is uniformly ground and then poured into a corundum crucible. Subsequently, it is transferred to a box furnace. In an air atmosphere, the temperature rising rate is set to 1-2℃ / min. When the temperature rises to 500-550℃, the temperature is kept at 500-550℃ for 6-8 h. Then, the temperature is raised to 600-700℃ at a temperature rising rate of 2-5℃ / min. The temperature is kept at 600-700℃ for 120-240 min. Then, the temperature is reduced to room temperature at a temperature reduction rate of 3-8℃ / min to obtain a crystallized xerogel ceramic; ③The crystallized xerogel ceramic is placed in a mortar and ground and crushed. It is sieved through a 200-350 mesh sieve to obtain a ceramic powder. The other steps are the same as those in embodiment two.

[0038] Embodiment eight: different from embodiment four, the preparation of the coprecipitation ceramic powder in step two is carried out according to the following steps:

[0039] ①According to the chemical formula of the target product, the corresponding raw materials are taken as the solute raw materials, acetic acid is taken as the solvent, and heating and stirring are carried out at a temperature of 110-130℃. After boiling for 2-5 min, heating is stopped, and cooling and stirring are carried out until room temperature is reached to obtain a clear solution. The concentration of the clear solution is 0.4-0.6 mol / L; ②acetylacetone and citric acid are taken as complexing agents, concentrated nitric acid and ethylene glycol are taken as stabilizers, and deionized water is taken as a hydrolysis reaction agent. They are added to the clear solution, and magnetic stirring is carried out at room temperature for 30-50 min to obtain a mixed solution. The total mass fraction of acetylacetone and citric acid in the complexing agent is 8%-12% of the clear solution. The total mass fraction of concentrated nitric acid and ethylene glycol in the stabilizer is 2%-4% of the clear solution; ③lactic acid catalyst is added to the mixed solution, and stirring is carried out at room temperature for 30-50 min to obtain a sol-gel solution with a concentration of 0.4-0.6 mol / L. The molar ratio of lactic acid to lead in the lactic acid catalyst is 1:1. The addition amount of the lactic acid catalyst is 0.4-0.6 mol / L. The other steps are the same as those in embodiment two or four.

[0040] ②First ball milling: the weighed zirconium ball, anhydrous ethanol and powder raw material are put into the ball mill tank according to the weight ratio of 1.5:1:1 of zirconium ball: anhydrous ethanol: powder; wet ball milling is carried out by using a planetary ball mill at a rotating speed of 300-500 r / min, the ball milling time is 10-30 h, and the wet material after ball milling is obtained;

[0041] ③Pre-sintering: the wet material after ball milling is put into an oven, baked at a temperature of 80-120 ℃ until the wet material is dry, then transferred to a corundum crucible and moved to a box furnace, an air atmosphere is set, the temperature rising rate is set to 2-5 ℃ / min, when the temperature rises to 800-920 ℃, the temperature is kept at 800-920 ℃ for 120-150 min for pre-reaction, and the pre-sintered powder is obtained;

[0042] ④Preparation of ultra-fine nano powder by co-precipitation method: the pre-sintered powder is taken in a beaker, concentrated nitric acid with a mass of 3-5 times of the pre-sintered powder is added dropwise as a dissolving agent, the beaker is completely sealed with tin foil paper to block light, then placed on a magnetic stirrer, stirred at a temperature of 60-80 ℃ for 1-2 h, after the pre-sintered powder is completely dissolved in the concentrated nitric acid, the solution is transferred to room temperature for continuous stirring, when the solution temperature is reduced to room temperature, the ceramic powder-concentrated nitric acid solution is obtained; another beaker is prepared and pre-added with concentrated ammonia water with the same volume as the concentrated nitric acid, the ceramic powder-concentrated nitric acid solution is added dropwise into the concentrated ammonia water and continuously stirred, the pH value of the concentrated ammonia water is measured while the ceramic powder-concentrated nitric acid solution is added, the concentrated ammonia water is added in a certain amount to keep the pH value of the whole suspension at 10-12, until the pre-sintered powder is precipitated in the concentrated ammonia water, the co-precipitated powder is washed repeatedly with deionized water for 5-7 times, and then dried;

[0043] ⑤Second ball milling: the dried co-precipitated powder is put into a ball mill tank according to the weight ratio of 1.5:1:1 of zirconium ball: powder: anhydrous ethanol, high-energy ball milling is carried out by using a high-energy ball mill at a rotating speed of 300-500 r / min for 10-15 h, and the co-precipitated powder after ball milling is obtained;

[0044] ⑥Sintering: the co-precipitated powder after ball milling is dried and transferred to a box furnace, the temperature is raised to 600-700 ℃ at a temperature rising rate of 2-5 ℃ / min, the temperature is kept at 600-700 ℃ for 120-240 min, then the temperature is reduced to room temperature at a temperature reducing rate of 3-8 ℃ / min, and the crystallized co-precipitated ceramic powder is obtained;

[0045] ⑦Grinding and sieving: the crystallized co-precipitated ceramic powder is placed in a mortar and ground, sieved through a 200-350 mesh sieve, and the ceramic powder is obtained. The other steps are the same as those in the fourth embodiment.

[0046] Specific embodiment nine: the difference between this embodiment and specific embodiment two or four is that: the preparation of the sol powder suspension in step three is specifically carried out as follows:

[0047] ①The ceramic powder is dispersed in a Tris-HCl buffer solution with a pH of 8.5-10 and 15-20 times the mass fraction of the ceramic powder, and is ultrasonically dispersed by a cell crusher. After the powder is uniformly dispersed, it is magnetically stirred for 10-20 min to obtain a ceramic powder suspension; ②Dopamine is added to the ceramic powder suspension at 5-10% of the mass fraction of the ceramic powder, and is stirred at a temperature of 55-70℃ for 2-3 h to form a shell structure of polydopamine on the surface of the ceramic powder. The PDA@ceramic powder is collected by centrifugal separation after being washed with hot deionized water, alcohol and glacial acetic acid in turn; ③The PDA@ceramic powder is added to the sol-gel solution in step one to obtain a sol powder suspension; the mass fraction of the sol powder suspension to the PDA@ceramic powder is 10-20%; ④The sol powder suspension is ultrasonically dispersed by a cell crusher, and is then transferred to a stirrer for magnetic stirring after the powder is uniformly dispersed. Span-85 dispersant and polyvinylidene chloride binder are added to obtain a uniform and stable sol powder; the addition amount of the Span-85 dispersant and the polyvinylidene chloride binder is 1-3% of the mass fraction of the suspension. The rest is the same as specific embodiment two or four.

[0048] Specific embodiment ten: the difference between this embodiment and specific embodiment two or four is that: the preparation of the thick film by the repeated spin-coating and sintering method in step four is specifically carried out as follows:

[0049] ①The sol powder is dropped on the FTO substrate, and is uniformly spin-coated by using a film applicator at a pre-rotation speed of 800-1000 r / min for 6-15 s, a formal rotation speed of 3000-4500 r / min for 20-40 s to obtain a smooth and flat wet film; ②After each spin-coating, the wet film is first heated on a heating plate at 150-180℃ for 5-10 min, and then is placed in a tube furnace. The temperature is raised to 350-450℃, and is heated at 350-450℃ for 5-10 min. Then the temperature is raised to 600-650℃, and is heated at 600-650℃ for 10-20 min. The film is taken out of the furnace and naturally cooled at room temperature for 10-20 min. Step ② is repeated for 5 times to obtain a thick film with a thickness of 10 μm; ③The thick film is placed in a small direct current sputtering gold spraying instrument for 3-7 min; then the thick film with gold electrode is placed on a heating plate and heated at a temperature of 270-290℃ for 30-40 min to obtain a 10 μm all-inorganic relaxor-type antiferroelectric thick film with high energy storage performance under low electric field. The rest is the same as specific embodiment two or four.

[0050] The beneficial effects of the present application are verified by the following examples:

[0051] The comparative example (conventional solid phase sintering method): after the PLBNZST ceramic powder is prepared by the solid phase sintering method, the powder is surface modified by polydopamine, then mixed into the PLBNZST sol and continuously ultrasonicated and stirred to form a uniformly dispersed sol powder suspension, and finally the sol powder is prepared into a thick film with a thickness of 10 μm by repeated spin coating-sintering method.

[0052] The specific steps are as follows:

[0053] I. ①Pb3O4, La2O3, BaCO3, Na2CO3, ZrO2, SnO2 and TiO2 are weighed according to the chemical formula Pb 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O 3and the proportion of Pb3O4 is 5-10% moL in excess during the batching process;

[0054] ②First ball milling: the weighed zirconium balls, anhydrous ethanol and powder raw materials are put into the ball mill tank according to the weight ratio of zirconium balls: anhydrous ethanol: powder of 1.5:1:1; wet ball milling is carried out by using a planetary ball mill at a speed of 500 r / min, the ball milling time is 24 h, and the wet ball-milled material is obtained;

[0055] ③Pre-sintering: the wet ball-milled material is placed in an oven and baked at a temperature of 100 ℃ until the wet material is dry, then transferred to a corundum crucible and placed in a box furnace, the temperature is set to 850 ℃ at an air atmosphere, the temperature is raised to 850 ℃ at a rate of 2 ℃ / min, and the pre-sintering is carried out at a temperature of 850 ℃ for 150 min, and the pre-sintered powder is obtained;

[0056] ④Second ball milling: the pre-sintered powder is put into the ball mill tank according to the weight ratio of zirconium balls: powder: anhydrous ethanol of 1.5:1:1, and high-energy ball milling is carried out by using a high-energy ball mill at a speed of 510 r / min for 10 h, and the ball-milled pre-sintered powder is obtained;

[0057] ⑤Dry pressing: the ball-milled pre-sintered powder is poured into a cylindrical steel mold with a diameter of 15 mm, and the fine powder is vibrated and laid flat; the pressure is slowly increased to 3-5 MPa by a tablet press and kept for 2 min, and the fine powder is pressed into a circular blank;

[0058] ⑥Sintering: the circular blank is heated to 1150 ℃ at a rate of 2 ℃ / min, and the ceramic particles are fully reacted and the high-purity perovskite phase is realized, then the temperature is lowered to room temperature at a rate of 3 ℃ / min, and the sintered ceramic sheet is obtained;

[0059] ⑦Grinding and sieving: the sintered ceramic sheet is ground in a mortar and sieved through a 300-mesh sieve to obtain ceramic powder;

[0060] II. Preparation of sol-gel: ①Pb(CH3COO)2, La(CH3COO)3, Ba(CH3COO)2, NaNO3, Zr(OCH2CH2CH3)4, C Pb 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O 3 were weighed according to the chemical formula 32 H 64 O4Sn and C 12 H 28 O4Ti were used as solute raw materials, acetic acid was used as solvent, and heating and stirring were carried out at a temperature of 110°C. After boiling for 2 min, heating was stopped, and cooling and stirring were carried out until room temperature was reached to obtain a clear PLBNZST solution. The concentration of the clear PLBNZST solution was 0.4 mol / L. ②Acetylacetone and citric acid were used as complexing agents, concentrated nitric acid and ethylene glycol were used as stabilizers, and deionized water was used as a hydrolysis reaction agent. They were added to the clear PLBNZST solution, and magnetic stirring was carried out at room temperature for 30 min to obtain a mixed solution. The total mass fraction of acetylacetone and citric acid in the complexing agent accounted for 10% of the clear solution. The total mass fraction of concentrated nitric acid and ethylene glycol in the stabilizer accounted for 3% of the clear solution. The addition amounts of the complexing agent, stabilizer and hydrolysis reaction agent were 10%, 3% and 10%, respectively. ③Lactic acid catalyst was added to the mixed solution, and stirring was carried out at room temperature for 40 min to obtain a sol-gel solution with a concentration of 0.4 mol / L. The molar ratio of lactic acid to lead in the lactic acid catalyst was 1:1. The addition amount of the lactic acid catalyst was 0.4 mol / L.

[0061] III. Preparation of sol-powder suspension: ①Ceramic powder was dispersed in Tris-HCl buffer solution with a pH of 8.5 and 15-20 times the mass fraction of the ceramic powder. Ultrasonic dispersion was carried out using a cell crusher. After the powder was uniformly dispersed, magnetic stirring was carried out for 10 min to obtain a ceramic powder suspension. ②Dopamine was added to the ceramic powder suspension at 5-10% of the mass fraction of the ceramic powder. Stirring was carried out at a temperature of 55-70°C for 2-3 h to form a shell structure of polydopamine on the surface of the ceramic powder. Hot deionized water, alcohol and glacial acetic acid were used for cleaning in turn. PDA@PLBNZST powder was collected by centrifugal separation. ③The PDA@PLBNZST powder was added to the sol-gel solution of step one to obtain a sol-powder suspension. The mass fraction of the sol-powder suspension to the PDA@PLBNZST powder was 10-20%. ④Ultrasonic dispersion treatment was carried out on the sol-powder suspension using a cell crusher. After the powder was uniformly dispersed, it was transferred to a stirrer for magnetic stirring. Span-85 dispersant and polyvinyl butyral binder were added to obtain a uniform and stable sol-powder. The addition amounts of the Span-85 dispersant and the polyvinyl butyral binder were both 2% of the mass fraction of the suspension.

[0062] Four, repeated spin-sintering method for preparing thick film: ①dropping the sol powder on the FTO substrate, using a spin coater to get a smooth and flat wet film under the parameters of pre-rotation speed of 1000 r / min, time of 6 s, formal spin speed of 4000 r / min, time of 40 s; ②after each spin, first put the wet film on the heating plate at 150℃ for 5 min, then put it into the tube furnace, raise the temperature to 400℃, heat for 5 min at 400℃, then raise the temperature to 600℃, heat for 10 min at 600℃, take it out of the furnace and cool it naturally at room temperature for 5 min, repeat step ② for 5 times, get a 10 μm thick film; ③put the thick film into a small direct current sputtering gold sprayer and spray gold for 3-7 min; then put the thick film with gold electrode on the heating plate and heat at 270-290℃ for 30-40 min, get a 10 μm thick film.

[0063] Example one (dried gel method): preparation method of 10 μm all-inorganic relaxor type antiferroelectric thick film with high energy storage performance under low electric field is completed according to the following steps:

[0064] One, preparation of sol-gel: ①according to the chemical formula Pb 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O 3, weigh Pb(CH3COO)2, La(CH3COO)3, Ba(CH3COO)2, NaNO3, Zr(OCH2CH2CH3)4, C 32 H 64 O4Sn and C 12 H 28 O4Ti as solute raw materials, acetic acid as solvent, heat and stir at 110℃, stop heating and cool to room temperature after boiling for 2 min to get a clear PLBNZST solution; the concentration of the clear PLBNZST solution is 0.4 mol / L; ②add acetylacetone and citric acid as complexing agent, concentrated nitric acid and ethylene glycol as stabilizer, deionized water as hydrolysis agent to the clear PLBNZST solution, stir for 30 min at room temperature to get a mixed solution; the total mass fraction of acetylacetone and citric acid in the complexing agent is 10% of the clear solution; the total mass fraction of concentrated nitric acid and ethylene glycol in the stabilizer is 3% of the clear solution; the adding amount of the complexing agent, stabilizer and hydrolysis agent is 10%, 3% and 10% respectively; ③add lactic acid catalyst to the mixed solution, stir for 40 min at room temperature to get a sol-gel solution with a concentration of 0.4 mol / L; the molar ratio of lactic acid to lead in the lactic acid catalyst is 1:1; the adding amount of the lactic acid catalyst is 0.4 mol / L;

[0065] II. Preparation of dry gel ceramic powder: ① A part of the sol-gel solution is heated at a temperature of 110-130℃ and magnetically stirred. When the colloid is thick enough that the magnet cannot continue to stir, a wet gel is obtained. The wet gel is transferred to a forced air drying oven and dried at a temperature of 110-130℃ to obtain a dry gel; ② The dry gel is uniformly ground and then poured into a corundum crucible, which is then transferred to a box furnace. The furnace is set to have an air atmosphere and a temperature increase rate of 1℃ / min. When the temperature reaches 500℃, the temperature is maintained at 500℃ for 6-8h. Then the temperature is increased to 650℃ at a rate of 2℃ / min, and the temperature is maintained at 650℃ for 180min. Then the temperature is decreased to room temperature at a rate of 3℃ / min to obtain a crystallized dry gel ceramic; ③ The crystallized dry gel ceramic is ground in a mortar and passed through a 300 mesh sieve to obtain a ceramic powder;

[0066] III. Preparation of sol powder suspension: ① The ceramic powder is dispersed in a Tris-HCl buffer solution with a pH of 8.5 and a mass fraction of 15-20 times that of the ceramic powder. The ceramic powder is uniformly dispersed by ultrasonic dispersion using a cell crusher, and then magnetically stirred for 10min to obtain a ceramic powder suspension; ② Dopamine is added to the ceramic powder suspension at a mass fraction of 5-10% of the ceramic powder. The mixture is stirred at a temperature of 55-70℃ for 2-3h to form a shell structure of polydopamine on the surface of the ceramic powder. The mixture is washed with hot deionized water, alcohol and glacial acetic acid in sequence, and then centrifuged to collect the PDA@PLBNZST powder; ③ The PDA@PLBNZST powder is added to the sol-gel solution of step one to obtain a sol powder suspension; the mass fraction of the PDA@PLBNZST powder in the sol powder suspension is 10-20%; ④ The sol powder suspension is ultrasonically dispersed using a cell crusher, and then transferred to a stirrer for magnetic stirring. Span-85 dispersant and polyvinyl butyral binder are added to obtain a uniform and stable sol powder; the addition amount of the Span-85 dispersant and the polyvinyl butyral binder is 2% of the mass fraction of the suspension;

[0067] IV. Preparation of thick films by repeated spin coating-sintering method: ① Sol powder is dropped onto an FTO substrate and uniformly spin-coated using a spin coater at a pre-coating speed of 1000 r / min for 6 s and a final spin coating speed of 4000 r / min for 40 s to obtain a smooth and flat wet film; ② After each spin coating, the wet film is first placed on a 150°C heating plate and heated for 5 min, then placed in a tube furnace and heated to 400°C for 5 min. Then, the temperature is raised to 600℃ and heated at 600℃ for 10 minutes. The film is then removed from the furnace and allowed to cool naturally at room temperature for 5 minutes. Step ② is repeated 5 times to obtain a thick film with a thickness of 10 μm. Step ③ is placed in a small DC sputtering gold sputtering machine for 3-7 minutes to sputter gold. Then, the thick film with gold electrodes is placed on a heating plate and heated at 270-290℃ for 30-40 minutes to obtain a 10 μm all-inorganic relaxor antiferroelectric thick film with high energy storage performance under low electric field.

[0068] Example 2 (Co-precipitation method): The preparation method of a 10μm all-inorganic relaxor antiferroelectric thick film with high energy storage performance under low electric field is carried out according to the following steps:

[0069] I. Preparation of sol-gel: ① According to the general chemical formula... Pb 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O 3. Weigh out Pb(CH3COO)2, La(CH3COO)3, Ba(CH3COO)2, NaNO3, Zr(OCH2CH2CH3)4, and C in the specified proportions. 32 H 64 O4Sn and C 12 H 28 Using O4Ti as the solute and acetic acid as the solvent, the mixture was heated and stirred at 110°C. After boiling for 2 minutes, heating was stopped, and the mixture was cooled and stirred to room temperature to obtain a clear PLBNZST solution. The concentration of the clear PLBNZST solution was 0.4 mol / L. ② Using acetylacetone and citric acid as complexing agents, concentrated nitric acid and ethylene glycol as stabilizers, and deionized water as the hydrolysis agent, the mixture was added to the clear PLBNZST solution and magnetically stirred at room temperature for 30 minutes to obtain a mixed solution. The complexing agent contained... The total mass fraction of acetylacetone and citric acid in the clarified solution is 10%; the total mass fraction of concentrated nitric acid and ethylene glycol in the stabilizer is 3%; the amounts of the complexing agent, stabilizer, and hydrolysis agent added are 10%, 3%, and 10%, respectively; ③ A lactic acid catalyst is added to the mixed solution and stirred at room temperature for 40 min to obtain a sol-gel solution with a concentration of 0.4 mol / L; the molar ratio of lactic acid to lead in the lactic acid catalyst is 1:1; the amount of lactic acid catalyst added is 0.4 mol / L;

[0070] II. Preparation of coprecipitated ceramic powder: ① According to the general chemical formula... Pb 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O 3. The Pb3O4, La2O3, BaCO3, Na2CO3, ZrO2, SnO2 and TiO2 are weighed as powder raw materials, and the Pb3O4 is made to be 5-10% excess in the process of batching;

[0071] 2. First ball milling: the zirconium balls, anhydrous ethanol and powder raw materials are put into the ball mill tank according to the weight ratio of 1.5:1:1; the wet ball milling is carried out by using a planetary ball mill at a speed of 500 r / min, the ball milling time is 24 h, and the wet material after ball milling is obtained;

[0072] 3. Pre-sintering: the wet material after ball milling is put into an oven and baked at a temperature of 100℃ until the wet material is dry, then it is transferred into a corundum crucible and moved to a box furnace, the temperature is set to 850℃ at a heating rate of 2℃ / min, and when the temperature is raised to 850℃, the temperature is kept for 150 min at 850℃ for pre-reaction, and the pre-sintered powder is obtained;

[0073] 4. Preparation of ultra-fine nano-powder by co-precipitation method: the pre-sintered powder is taken in a beaker, and concentrated nitric acid with a mass of 3-5 times of the pre-sintered powder is added dropwise as a dissolving agent, the beaker is completely sealed with tin foil to block light, and then placed on a magnetic stirrer at a temperature of 60-80℃ for 1-2 h, after the pre-sintered powder is completely dissolved in the concentrated nitric acid, the solution is transferred to room temperature for continuous stirring, and when the solution temperature is reduced to room temperature, the ceramic powder-concentrated nitric acid solution is obtained; another beaker is prepared and pre-loaded with concentrated ammonia water with the same volume as the concentrated nitric acid, the ceramic powder-concentrated nitric acid solution is added dropwise into the concentrated ammonia water and continuously stirred with a magnetic stirrer, the pH value of the concentrated ammonia water is measured while adding the ceramic powder-concentrated nitric acid solution, the concentrated ammonia water is added in a certain amount to keep the pH value of the whole suspension at 10-12, until the pre-sintered powder is precipitated in the concentrated ammonia water, and the co-precipitated powder is dried after being washed repeatedly with deionized water for 5-7 times;

[0074] 5. Second ball milling: the dried co-precipitated powder is put into a ball mill tank according to the weight ratio of 1.5:1:1, and high-energy ball milling is carried out at a speed of 510 r / min for 10 h, and the co-precipitated powder after ball milling is obtained;

[0075] 6. Sintering: the co-precipitated powder after ball milling is dried and transferred to a box furnace, the temperature is raised to 650℃ at a heating rate of 2℃ / min, the temperature is kept for 180 min at 650℃, and then the temperature is reduced to room temperature at a cooling rate of 3℃ / min, and the crystallized co-precipitated ceramic powder is obtained;

[0076] 7. Grinding and sieving: the crystallized co-precipitated ceramic powder is ground in a mortar and sieved through a 300-mesh sieve, and the ceramic powder is obtained;

[0077] Three, preparation of sol powder suspension: ① ceramic powder is dispersed in Tris-HCl buffer solution with a pH of 8.5, 15-20 times the mass fraction of ceramic powder, and ultrasonic dispersion is used by a cell crusher. After the powder is uniformly dispersed, magnetic stirring is performed for 10 min to obtain a ceramic powder suspension; ② 5-10% of the mass fraction of ceramic powder is added to the ceramic powder suspension to form a polydopamine shell structure on the surface of the ceramic powder under the condition of stirring at a temperature of 55-70℃ for 2-3 h. The PDA@PLBNZST powder is collected by washing with hot deionized water, alcohol and glacial acetic acid in turn and centrifugal separation; ③ the PDA@PLBNZST powder is added to the sol-gel solution of step one to obtain a sol powder suspension; the mass fraction of the sol powder suspension to PDA@PLBNZST powder is 10-20%; ④ the sol powder suspension is ultrasonic dispersed by a cell crusher, and then transferred to a stirrer for magnetic stirring after the powder is uniformly dispersed. Span-85 dispersant and polyvinyl butyral binder are added to obtain a uniform and stable sol powder; the addition amount of the Span-85 dispersant and the polyvinyl butyral binder is 2% of the mass fraction of the suspension;

[0078] Four, preparation of thick film by repeated spin-coating and sintering: ① the sol powder is dropped on the FTO substrate, and a uniform wet film is obtained by uniform spin coating using a spin coater under the parameters of a pre-rotation speed of 1000 r / min for 6 s, an official uniform spin speed of 4000 r / min for 40 s, and the wet film is placed on a heating plate at 150℃ for 5 min and then put into a tube furnace, the temperature is raised to 400℃, heated at 400℃ for 5 min, then the temperature is raised to 600℃, heated at 600℃ for 10 min, taken out from the furnace and naturally cooled at room temperature for 5 min, repeat step ② for 5 times to obtain a thick film with a thickness of 10 μm; ③ the thick film is placed in a small direct current sputtering gold spraying instrument for 3-7 min; then the thick film with gold electrode is placed on a heating plate and heated at a temperature of 270-290℃ for 30-40 min to obtain a 10 μm all-inorganic relaxor-type antiferroelectric thick film with high energy storage performance under low electric field.

[0079] Analysis of the above three kinds of PLBNZST thick films:

[0080] Reference Figure 1, i.e. the surface scanning electron microscope images of the PLBNZST powders prepared according to the processes of the comparative example, example one and example two, respectively, using the traditional solid phase method, the coprecipitation method and the dry gel method. First, from the images, it can be seen that the surface morphology and grain size of the PLBNZST powders prepared by the three different processes are obviously different. The ceramic powder prepared by the traditional solid phase method presents an irregular huge block morphology, and the length and height can reach micron level. The ceramic powder prepared by the dry gel method presents a relatively uniform and regular flake growth mode, and the powder surface is smooth. After determination by the particle size analysis software, the length of the powder is about 324.89 nm, and the thickness is only 7 nm. The ceramic powder prepared by the coprecipitation method presents a relatively uniform and regular spherical growth mode, and the powder surface is smooth. After determination by the particle size analysis software, the diameter of the powder is about 50.15 nm. Generally, for lead-based ceramic powder, the larger the particle size, the higher the crystallinity, the higher the dielectric constant and polarization value, and it has a good effect on the energy storage performance. However, at the same time, the dielectric loss and leakage current density will also increase, which has a very adverse effect on the breakdown field and energy storage efficiency. Referring to Figure 2The images show surface scanning electron microscope (SEM) images of thick films prepared by sol-gel method and thin films prepared by PLBNZST sol alone using the conventional solid-state method, co-precipitation method, and dry gel method, respectively, according to the processes of the comparative examples, Example 1, and Example 2. From the images, we can see that the surface of the sol-gel thick film prepared by the conventional solid-state ceramic powder is uneven and has obvious large pores. Upon magnification, a large number of pores and cracks are found throughout the surface of the thick film. In contrast, the sol-gel thick films prepared by the dry gel powder and co-precipitated ceramic powder have smooth, dense surfaces and uniform particle size distribution, and their morphology is consistent with that of the thin films prepared by the sol-gel method using only PLBNZST sol. This is because the thickness of a single sol-gel film coated on the powder surface has its own limitations; therefore, after spin-coating, only a portion of the sol adheres to the powder surface, leaving gaps between the powder particles. The larger the powder size, the larger the gap volume. Because ceramic powders prepared by traditional solid-state methods are relatively large, the sol-gel solution after spin-coating is insufficient to completely cover the powder, leaving numerous pores between the powder particles. This severely damages the dielectric loss, leakage current density, breakdown electric field, and energy storage performance of the thick film. To address this problem, we used a dry gelation method and co-precipitation method to prepare nano-sized powders instead of micron-sized solid-state ceramic powders to improve the film density. By modifying the surface of the nanoparticles with polydopamine, the agglomeration of the powders is resolved through the chemical effects of steric and electrostatic hindrance, as well as the mechanical effects of ultrasonic dispersion and magnetic stirring. Simultaneously, the powder size is smaller than the crystal size prepared by the sol-gel method, and the powder surface is completely covered by the sol-gel solution. Therefore, the morphology of the sol-gel thick film prepared using dry gel powder and co-precipitated ceramic powder is consistent with that of the film prepared solely using PLBNZST sol via the sol-gel method. The added powder particles are almost indistinguishable from the crystals, and the uniformity of the microstructure is significantly improved. This is beneficial for reducing leakage current density, improving breakdown electric field, and enhancing energy storage performance in thick films. (Refer to...) Figure 3 This is a cross-sectional scanning electron microscope (SEM) image of the PLBNZST thick film prepared by the sol-powder method using co-precipitated powder. The image shows a film thickness of 10 μm, with a smooth, dense cross-section free of obvious defects. The magnified view also reveals a clear interface between the substrate and the film, with no diffusion or interfacial cracks, indicating that the prepared thick film material is of high quality and will not degrade the film's electrical properties. (Reference) Figure 4Figure 6 is a graph showing the relationship between the dielectric constant and the frequency of the PLBNZST thick film prepared by the sol powder method using the traditional solid phase powder, the co-precipitation powder and the xerogel powder. As shown in the graph, the dielectric constant of the three thick films remains constant and does not change with the frequency in the entire frequency range. At the frequency of 1000 Hz, the dielectric constant of the thick film prepared using the traditional solid phase powder is 1500, while the dielectric constant of the thick films prepared using the xerogel powder and the co-precipitation powder is 400 and 600 respectively. The dielectric constant of the thick film prepared using the traditional solid phase powder is obviously higher, because the grain size of the traditional solid phase powder is one order of magnitude higher than the xerogel powder and the co-precipitation powder, and the crystallinity is higher, which has great advantages in the entire thick film, and thus has a higher dielectric constant. However, although the grain size of the co-precipitation powder is smaller than the xerogel powder, it has a higher dielectric property. This is because under the premise that the mass fraction of the powder in the thick film is consistent, the smaller the particle size, the more the number of particles, and the larger the specific surface area. Therefore, a larger interface area is formed between the small particles and the sol-gel matrix, thereby inducing greater interfacial polarization. Since the interfacial polarization has a significant effect on the dielectric constant and the polarization value, the thick film medium composed of small particles of the co-precipitation powder has a higher dielectric constant and a larger polarization value. Figure 5 Figure 7 is a graph showing the relationship between the leakage current density and the electric field of the PLBNZST thick film prepared by the sol powder method using the traditional solid phase powder, the co-precipitation powder and the xerogel powder. As shown in the graph, at the electric field of 100 kV / cm, the leakage current density of the thick film prepared using the traditional solid phase powder is 1*10 -8 A / cm 2 , while the leakage current density of the thick films prepared using the xerogel powder and the co-precipitation powder is almost consistent, about 5*10 -9 A / cm 2 . The leakage current density of the thick films prepared using the xerogel powder and the co-precipitation powder is obviously lower, which is due to the fact that there are no pores and defects on the surface of the thick film, and the grains constituting the thick film are more uniform and denser, which reduces the leakage current density, and is conducive to achieving a higher breakdown field strength and excellent energy storage performance of the thick film. Referring to Figure 6The graph shows the relationship between polarization and electric field strength for PLBNZST thick films prepared by the sol-powder method using traditional solid-phase powder, co-precipitated powder, and dry gel powder, respectively, under their respective breakdown electric field strengths. First, the graph shows that all PLBNZST perovskite thick films exhibit obvious double hysteresis loops, indicating their antiferroelectricity. Second, the graph shows that the thick film prepared from solid-phase ceramic powder has a high polarization but a low breakdown electric field; the thick film prepared from dry gel ceramic powder has a high breakdown electric field but a low polarization; and the thick film prepared from co-precipitated ceramic powder exhibits both high polarization and a high breakdown electric field similar to that prepared from dry gel ceramic powder. The increased polarization and breakdown electric field in the thick film prepared from co-precipitated ceramic powder result in higher energy storage performance. Referring to Table 1, the graph shows the relationship between polarization and electric field strength for the three groups of PLBNZST thick films prepared using the processes of Comparative Example 1 and Example 2. Figure 6 The energy storage density and efficiency were calculated using energy storage formulas. The table shows that, for the same thickness, the thick film prepared from co-precipitated ceramic powder achieved polarization delay and increased breakdown, thus significantly increasing both energy storage density and efficiency. Under a low electric field of 1100 kV / cm, it could release an energy storage density of 14.62 J / cm³. 3 The energy storage efficiency was 62.74%. This energy storage density is 2.21 times that of thick films prepared by traditional solid-state sintered ceramic powder. The above discussion demonstrates that the method described in Example 2 can achieve significant energy storage performance for a 10 μm thick all-inorganic thick film under low electric fields. (Refer to...) Figures 7 to 9 The PLBNZST thick film, prepared according to the process in Example 2, was subjected to a constant electric field of 500 kV / cm and a temperature range of 30–120°C. The relationship between its polarization value and the electric field strength was measured, and the energy storage density and efficiency of the PLBNZST thick film at different temperatures were calculated using the energy storage formula. It can be seen that the energy storage density and efficiency of the PLBNZST thick film exhibit only minor changes with temperature across the entire temperature range, demonstrating that this thick film possesses good temperature stability in practical applications.

[0081] The performance comparisons of the comparative examples, Example 1, and Example 2 are shown in Table 1:

[0082] Table 1

[0083] Solid phase sintered powder Xerogel powder Co-precipitated powder Breakdown field (kV / cm) 548.96 1292.88 1094.62 Saturation polarization (pC / cm 2 )]]> 45.09 36.26 49.79 Energy storage density (J / cm 3 ) 6.61 11.63 14.62 Energy storage efficiency (%) 62.23 54.37 62.71

Claims

1. A method for preparing a 10 pm all-inorganic relaxor-anti-ferroelectric thick film with high energy storage performance at low electric field, characterized in that The following steps are completed: I. Preparation of sol-gel: ① According to the target product chemical formula is Pb 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O3 corresponding raw materials are weighed and added to the solvent, mixed and heated to obtain a clear solution; ② complexing agent and stabilizer are added to the clear solution to obtain a mixed solution; ③ catalyst is added to the mixed solution to obtain a sol-gel solution; II. Preparation of co-precipitation ceramic powder: ① According to the target product chemical formula Pb 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O3, the corresponding raw materials are weighed as powder raw materials, and Pb3O4 is made to be 5~10% mol in excess during batching; ② primary ball milling; ③ pre-sintering to obtain pre-sintered powder; ④ preparation of ultra-fine nano powder by co-precipitation method: take the pre-sintered powder in a beaker, and add concentrated nitric acid with 3-5 times the mass of the pre-sintered powder as a dissolving agent drop by drop, completely seal the beaker with tin foil paper to block light, and place it on a magnetic stirrer at a temperature of 60-80℃ for 1-2h, after the pre-sintered powder is completely dissolved in concentrated nitric acid, transfer it to room temperature for continuous stirring, and when the solution temperature decreases to room temperature, a ceramic powder-concentrated nitric acid suspension is obtained; another beaker is prepared and pre-sintered with concentrated ammonia water with the same volume as the concentrated nitric acid, the ceramic powder-concentrated nitric acid suspension is added dropwise into the concentrated ammonia water and continuously stirred with a magnetic stirrer, the pH value of the concentrated ammonia water is measured while adding the ceramic powder-concentrated nitric acid suspension, and the pH value of the whole suspension is kept at 10-12 by adding concentrated ammonia water, until the pre-sintered powder is precipitated in the concentrated ammonia water, the suspension is washed repeatedly with deionized water for 5-7 times, and the co-precipitated powder is dried; ⑤ secondary ball milling; ⑥ sintering to obtain crystallized co-precipitated ceramic powder; ⑦ grinding and sieving: place the crystallized co-precipitated ceramic powder in a mortar and grind it to pass through a 200-350 mesh sieve to obtain ceramic powder; Three, preparation of sol powder: ① disperse the ceramic powder in Tris-HCl buffer solution to obtain a ceramic powder suspension; ② add dopamine to the ceramic powder suspension to form a polydopamine shell structure on the surface of the ceramic powder, wash and centrifuge to collect PDA@ceramic powder; ③ add the PDA@ceramic powder to the sol-gel solution of step one to obtain a sol powder suspension; ④ ultrasonic dispersion treatment is performed on the sol powder suspension, then spab-85 dispersant and polyvinyl butyral binder are added to obtain uniform and stable sol powder; Four, preparation of thick film by repeated spin coating-sintering method: ① add the sol powder dropwise on the FTO substrate, and use a spin coater to uniformly spin coat to obtain a smooth and flat wet film; ② heat treatment of the wet film to obtain a thick film; ③ gold plating of the thick film to obtain a 10µm all-inorganic relaxor-type antiferroelectric thick film with high energy storage performance under low electric field.

2. The method for preparing 10 pm all-inorganic relaxor antiferroelectric thick films with high energy storage performance at low electric field according to claim 1, characterized in that The preparation of sol-gel in step one is specifically performed according to the following steps: 0.855 La 0.06 Ba 0.06 Na 0.01 (Zr 0.4 Sn 0.56 Ti 0.04 )O3, the corresponding raw materials are weighed as solute raw materials, acetic acid is used as a solvent, heating and stirring is carried out under the condition that the temperature is 110-130℃, after boiling for 2-5 min, heating is stopped, cooling and stirring are carried out until room temperature to obtain a clear solution; the concentration of the clear solution is 0.4-0.6 mol / L; 2) acetylacetone and citric acid are used as complexing agents, concentrated nitric acid and ethylene glycol are used as stabilizers, deionized water is used as a hydrolysis reaction agent, and are added to the clear solution, magnetic stirring is carried out at room temperature for 30-50 min to obtain a mixed solution; the total mass fraction of acetylacetone and citric acid in the complexing agent accounts for 8%-12% of the clear solution; the total mass fraction of concentrated nitric acid and ethylene glycol in the stabilizer accounts for 2%-4% of the clear solution; 3) lactic acid catalyst is added to the mixed solution, stirring is carried out at room temperature for 30-50 min to obtain a sol-gel solution with a concentration of 0.4-0.6 mol / L; the molar ratio of lactic acid to lead in the lactic acid catalyst is 1:1; the addition amount of the lactic acid catalyst is 0.4-0.6 mol / L.​ 3. The method of claim 1, wherein the method is characterized by The first ball milling in step two ② is that the zirconium ball, anhydrous ethanol and powder raw material are put into a ball mill tank according to the weight ratio of 1.5:1:1 of zirconium ball:anhydrous ethanol:powder; the wet ball milling is carried out by using a planetary ball mill at a rotating speed of 300-500 r / min, the ball milling time is 10-30 h, and the wet material after ball milling is obtained; the pre-sintering in step two ③ is that the wet material after ball milling is put into an oven, baked at a temperature of 80-120 ℃ until the wet material is dry, then transferred into a corundum crucible and into a box furnace, the temperature rising rate is set to 2-5 ℃ / min, when the temperature rises to 800-920 ℃, the temperature is kept at 800-920 ℃ for 120-150 min of pre-reaction; the second ball milling in step two ⑤ is that the dried co-precipitation powder is put into a ball mill tank according to the weight ratio of 1.5:1:1 of zirconium ball:powder:anhydrous ethanol, the high-energy ball mill is used to carry out the second ball milling at a rotating speed of 300-500 r / min for 10-15 h, and the co-precipitation powder after ball milling is obtained; the sintering in step two ⑥ is that the co-precipitation powder after ball milling is dried and transferred into a box furnace, the temperature is raised to 600-700 ℃ at a temperature rising rate of 2-5 ℃ / min, the temperature is kept at 600-700 ℃ for 120-240 min, and then the temperature is lowered to room temperature at a temperature lowering rate of 3-8 ℃ / min.

4. The method of claim 1, wherein the method is characterized by The preparation of the sol powder in step three is specifically carried out according to the following steps: ① the ceramic powder is dispersed in a Tris-HCl buffer solution with a pH of 8.5-10 and a mass of 15-20 times that of the ceramic powder, and ultrasonic dispersion is carried out by using a cell crusher, and after the powder is uniformly dispersed, magnetic stirring is carried out for 10-20 min to obtain a ceramic powder suspension; ② 5-10% of the mass of the ceramic powder is added to the ceramic powder suspension as dopamine, and a shell structure of polydopamine is formed on the surface of the ceramic powder by stirring at a temperature of 55-70 ℃ for 2-3 h, and the PDA@ceramic powder is collected by washing with hot deionized water, alcohol and glacial acetic acid in turn and centrifugal separation; ③ the PDA@ceramic powder is added to the sol-gel liquid of step one to obtain a sol powder suspension; the mass fraction of the PDA@ceramic powder in the sol powder suspension is 10-20%; ④ the sol powder suspension is subjected to ultrasonic dispersion treatment by using a cell crusher, and after the powder is uniformly dispersed, it is transferred to a stirrer for magnetic stirring, and span-85 dispersant and polyvinyl butyral binder are added to obtain a uniform and stable sol powder; the addition amount of the span-85 dispersant and the polyvinyl butyral binder is 1-3% of the mass of the ceramic powder in the suspension.

5. The method of claim 1, wherein the method is characterized by The preparation of the thick film by the repeated spin coating-sintering method in step four is specifically carried out according to the following steps: ①The sol powder is dropped on the FTO substrate, and uniform spin coating is performed using a spin coater under the following parameters: a pre-rotation speed of 800-1000 r / min, a time of 6-15 s, an official spin coating rotation speed of 3000-4500 r / min, and a time of 20-40 s, to obtain a smooth and flat wet film; ②After each spin coating, the wet film is first placed on a heating plate at a temperature of 150-180°C and heated for 5-10 min, then placed in a tube furnace, the temperature is raised to 350-450°C, heated at a temperature of 350-450°C for 5-10 min, then the temperature is raised to 600-650°C, heated at a temperature of 600-650°C for 10-20 min, taken out of the furnace and naturally cooled at room temperature for 10-20 min, repeat step ② for 5 times, to obtain a thick film with a thickness of 10 µm; ③The thick film is placed in a small direct current sputtering gold spraying instrument and sprayed with gold for 3-7 min; then the thick film with the plated gold electrode is placed on a heating plate and heated at a temperature of 270-290°C for 30-40 min, to obtain a 10 µm all-inorganic relaxor antiferroelectric thick film with high energy storage performance under low electric field.

Images