Preparation method for improving energy storage performance of polyether sulfone dielectric medium by using relaxor ferroelectric for capacitor

Abstract

The invention discloses a BFBTST relaxor ferroelectric composite dielectric film based on component regulation and control and a preparation method and application thereof, and belongs to the technical field of dielectric energy storage materials, ferroelectric materials with different conductivities are obtained by regulating and controlling BFBTST chemical components, (BF-BT-ST3) nanoparticles with x = 0.4 are used as a filling phase, and the BFBTST relaxor ferroelectric composite dielectric film is prepared by preparing a BFBTST relaxor ferroelectric composite dielectric film based on BFBTST relaxor ferroelectric composite dielectric film based on BFBTST relaxor ferroelectric composite dielectric film. The polyethersulfone (1BF-BT-ST3 / U) composite dielectric film with the content of the relaxor ferroelectric filling phase BF-BT-ST3 being 1 wt.% is prepared and shows excellent high-temperature energy storage performance; experiments show that the discharge energy density of the 1BF-BT-ST3 / U composite dielectric film can reach about at the temperature of 100 DEG C and the electric field intensity of 380 kV / mm, the charge and discharge efficiency is remarkably higher than that of pure polyether sulfone (PESU), the process is simple, the performance is controllable, and an effective material system and a design strategy are provided for designing a next-generation high-performance high-temperature energy storage dielectric.

Description

Technical Field

[0001] This invention belongs to the field of dielectric energy storage materials technology, specifically relating to a method for preparing a relaxor ferroelectric material for capacitors to improve the energy storage performance of polyethersulfone dielectrics. Background Technology

[0002] With the rapid development of renewable energy, electric vehicles, and pulsed power systems, the demand for energy storage devices with high power density, high energy storage efficiency, and high reliability is becoming increasingly urgent. Polymer-based composite dielectric thin-film capacitors, due to their high breakdown strength, low loss, and excellent mechanical flexibility, have become one of the key components for high-power energy storage.

[0003] Currently, while commercially available biaxially oriented polypropylene (BOPP) films possess high breakdown strength, their dielectric constant (~2.2) and energy density are relatively low, making it difficult to meet the ever-increasing energy storage demands. Ferroelectric polymers such as polyvinylidene fluoride (PVDF) and its copolymers, while exhibiting high dielectric constants and polarization strength, suffer from low energy storage efficiency and significant losses. Relaxor ferroelectric ceramics (such as...) base, The base material has a high dielectric constant and low remanent polarization, making it an ideal filler candidate. However, achieving uniform dispersion, good interfacial bonding, and dielectric matching between the filler and the matrix remains a key challenge for improving the overall performance of composite dielectrics. Summary of the Invention

[0004] This invention aims to overcome the shortcomings of existing technologies and provide a component-based control method. (BF-BT-ST) Relaxor Ferroelectric Composite Dielectric Thin Film, its Preparation Method, and Application. This invention achieves this by precisely controlling the chemical composition of the BF-BT-ST filler (…). content, The content of filler and PESU matrix is ​​used to achieve dielectric property matching and interface optimization, thereby significantly improving the energy storage density, energy storage efficiency and breakdown strength of composite dielectric films under wide temperature range and high electric field. To achieve the above objectives, the present invention employs the following technical solution: On one hand, the present invention provides a relaxor ferroelectric improved polyethersulfone dielectric, the dielectric comprising a relaxor ferroelectric as component (M) and a polyethersulfone matrix (PESU), wherein component (M) comprises... , and Each molar percentage content is selected from , where x = 0.1~0.6.

[0005] Preferably, component (M) is a product based on the sol-gel method or a self-propagating high-temperature synthesis method. (BF-BT-ST) Relaxor ferroelectric inorganic filled phase.

[0006] Preferably, the preparation process of the relaxor ferroelectric includes the following steps: (1) Preparation of precursor solution: Dissolve bismuth nitrate pentahydrate and ferric nitrate nonahydrate in acetic acid and stir at 60°C to obtain solution A; dissolve barium hydroxide octahydrate and strontium acetate in acetic acid and stir at 60°C. After the solution is clear, add acetylacetone as a stabilizer, and then slowly add tetrabutyl titanate to obtain solution B.

[0007] (2) Blending and complexation: The clarified solution A and solution B are blended and stirred at a constant temperature of 10-100℃ until the solution is clear. Then, ethanolamine is added dropwise and stirred until the solution is clear to obtain a stable blended sol. (3) Self-propagating high-temperature synthesis: Pour the blended sol into a crucible, add anhydrous ethanol as fuel, ignite it with a clean paper under windproof conditions, and stir it in time during the combustion process to ensure that the material is fully burned; (4) Drying and grinding: The ash obtained from combustion is dried at 50-150℃ for 8-24 hours and then ground to obtain the dry precursor powder; (5) Segmented calcination: The precursor powder is placed in a muffle furnace and heated to 250-350°C at 1-5°C / min and calcined for 1-3 hours; then heated to 800-1000°C at 3-8°C / min and calcined for 1-3 hours, and then cooled with the furnace to obtain BF-BT-ST nanoparticles.

[0008] Preferably, the BF-BT-ST nanoparticles have a perovskite structure and a particle size range of 50-100 nm.

[0009] In a second aspect, the present invention provides a method for preparing a relaxor ferroelectric improved polyethersulfone dielectric, characterized by comprising the following steps: (a) Preparation of dispersion slurry: BF-BT-ST nanoparticles were added to an N-methylpyrrolidone solution containing polyethersulfone at a mass fraction of y wt.% (y=0.1~5), and the mixture was mechanically stirred and ultrasonically dispersed to obtain a uniform composite precursor dispersion. (b) Film coating: The precursor dispersion is coated onto a glass substrate, the wet film thickness is controlled, and then dried at 40-80°C for 8-16 hours; (c) Gradient heat treatment: The dried film is subjected to step heat treatment under vacuum conditions, including treatment at 60~100℃ for 1~5 hours, treatment at 90~110℃ for 1~3 hours, treatment at 140~160℃ for 1~3 hours and treatment at 190~210℃ for 1~3 hours. (d) Peeling and film removal: After heat treatment, the film is peeled off from the substrate to obtain a self-supporting relaxor ferroelectric improved polyethersulfone dielectric film.

[0010] Preferably, the wet film thickness in step (b) is controlled by a doctor blade. .

[0011] Preferably, the thickness of the prepared relaxor ferroelectric improved polyethersulfone dielectric film is [value missing]. .

[0012] Thirdly, the relaxor ferroelectric improved polyethersulfone dielectric film prepared according to the above method has a discharge energy density of not less than [amount missing] at a temperature of 200°C and an electric field strength of 240 kV / mm. The charge / discharge efficiency is not less than 70%.

[0013] Fourthly, this invention provides the application of a relaxor ferroelectric improved polyethersulfone dielectric film in a high-temperature energy storage capacitor.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves precise control of BF-BT-ST. The content (x value) of the filler material enables systematic control of its intrinsic band gap and conduction band energy level. BF-BT-ST3 ( The lowest content) has the widest bandgap (2.909 eV), which can effectively suppress high-field carrier excitation and migration, and improve breakdown strength; while BF-BT-ST1 ( (The highest content) can form deeper electron traps, which is beneficial for space charge capture and polarization regulation.

[0015] The composite dielectric thin film prepared by this invention exhibits excellent comprehensive energy storage performance at high temperatures (100-200℃). For example, the 1.5BF-BT-ST3 / U composite thin film achieves an energy storage density of up to [value missing] at a temperature of 100℃ and an electric field strength of 380 kV / mm. Its efficiency is higher than that of pure PESU; the 1BF-BT-ST2 / U composite film can still maintain its performance at a temperature of 200℃ and an electric field strength of 240 kV / mm. Its high energy density and efficiency of ~72% demonstrate its excellent potential for high-temperature service.

[0016] The preparation process and required equipment of this invention are inexpensive, and the experiment is simple and easy to implement. The preparation method is based on the mature sol-gel method, self-propagating method, and solution coating method. The raw materials are readily available, and the process parameters are controllable, which is conducive to large-scale preparation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope.

[0018] Figure 1 The XRD pattern of the dielectric in this embodiment of the invention; Figure 2 The infrared spectrum of the dielectric in the embodiments of the present invention; Figure 3 The dielectric properties of the dielectric at 200°C in this embodiment of the invention; Figure 4 The example shows the leakage current curve of the dielectric at 200°C. Figure 5 The energy storage performance of the dielectric at 200°C is shown in the example. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0022] This invention provides a composition-tunable BF-BT-ST composite dielectric film. The film uses polyethersulfone (PESU) as the matrix and BF-BT-ST relaxor ferroelectric nanoparticles as the inorganic filler phase with tunable composition. The general chemical formula of the BF-BT-ST is [insert chemical formula here]. Where x = 0.1~0.6, for example x = 0.2, 0.3, 0.4, corresponding to BF-BT-ST1, BF-BT-ST2, and BF-BT-ST3 respectively. By adjusting the x value, the band gap, conduction band energy level, and polarization characteristics of the filler can be systematically controlled, thereby controlling the space charge trapping ability and insulation performance of the composite film.

[0023] In this embodiment, the doping amount of the inorganic filler phase in the polymer matrix is ​​from 0.5 wt.% to 3 wt.%, preferably 0.5 wt.%, 1 wt.%, 1.5 wt.%, 2 wt.%, or 3 wt.%. Within this doping range, the filler can be effectively dispersed, avoiding performance degradation caused by agglomeration.

[0024] In this embodiment, the thickness of the composite dielectric film is 5 μm to 15 μm, preferably about 10 μm.

[0025] This invention provides a method for preparing the above-mentioned BF-BT-ST composite dielectric thin film. The method is simple and highly controllable, and includes the following steps: (1) Preparation of BF-BT-ST nanoparticles: The sol-gel method was used, according to... Precursors such as bismuth nitrate pentahydrate, ferric nitrate nonahydrate, barium hydroxide octahydrate, and tetrabutyl titanate were weighed out in stoichiometric ratios of (x=0.1~0.6), and then dissolved, aged, pre-calcined, calcined, and dried to obtain BF-BT-ST nanopowder.

[0026] (2) Preparation of composite dielectric film: PESU is dissolved in polar solvents such as N-methylpyrrolidone (NMP) to form a clear solution; a certain mass fraction of inorganic filler obtained in step (1) is added to the above PESU solution, and a uniform composite precursor slurry is obtained by mechanical stirring and ultrasonic dispersion; the solution is coated onto a clean glass plate by solution casting method, and the solvent is removed and cured by gradient heat treatment (first drying in a forced-air drying oven at 60-120℃, and then heat treatment in a vacuum drying oven at 60-150℃ for 8-12 hours), and finally peeled off to obtain composite dielectric film.

[0027] A third objective of this invention is to provide the application of the aforementioned BF-BT-ST composite dielectric film in high-temperature energy storage capacitors. Experimental results show that this composite film, especially the sample using BF-BT-ST as filler with a doping amount of 1-2 wt.%, can still maintain a high energy storage density (e.g., at high temperatures of 100-200℃). It also boasts superior charge and discharge efficiency (e.g., 72%), significantly outperforming pure PESU substrates.

[0028] Example 1: Preparation of BF-BT-ST1 nanoparticles According to proportion Weigh out bismuth nitrate pentahydrate and ferric nitrate nonahydrate and dissolve them in beaker A containing acetic acid. Place beaker A on a magnetic stirrer and stir at a constant temperature of 60°C. Weigh out barium hydroxide octahydrate and strontium acetate and dissolve them in beaker B containing acetic acid. Place beaker B on a magnetic stirrer and stir at a constant temperature of 60°C. After the solution in beaker B becomes clear, add acetylacetone as a stabilizer, and then slowly add tetrabutyl titanate.

[0029] After the solutions in beakers A and B have stabilized and become clear, mix and stir the solutions in beakers A and B together, maintaining a constant temperature of 60°C. Add a certain mass of ethanolamine dropwise to the mixed solution and stir until the solution becomes clear.

[0030] Prepare a crucible, crucible tongs, a sheet metal windproof container, a lighter, lens cleaning paper, gloves, and a stable and clear blended solution. The BF-BT-ST1 sample was prepared using a self-propagating high-temperature synthesis method. Specifically, wearing gloves, the stable and clear blended solution was poured into the crucible, and an appropriate amount of anhydrous ethanol was added. The crucible was covered with the sheet metal windproof container, and the lens cleaning paper was held in the crucible with the crucible tongs. The lighter was used to ignite the paper, allowing it to burn. During combustion, the crucible tongs were used to periodically stir the burning solution in the crucible to ensure complete combustion. After complete combustion, the remaining ash was placed in a constant-temperature oven and dried at 80°C for 10 hours.

[0031] After carefully grinding the dried ash, it was placed in a corundum crucible and then placed in a muffle furnace. The temperature was increased to 300°C at a rate of 3°C / min and calcined for 2 hours. Then the temperature was increased to 900°C at a rate of 5°C / min and calcined for 2 hours. After that, it was cooled to room temperature with the furnace.

[0032] The calcined powder was placed in a ball mill jar and milled for 12 hours in a planetary ball mill using anhydrous ethanol as the grinding medium. The milled suspension was then removed, placed in a petri dish, and dried in a constant temperature oven at 80°C for 10 hours. Finally, the dried powder was finely ground to obtain BF-BT-ST1 nanoparticles.

[0033] Example 2: Preparation of BF-BT-ST2 nanoparticles According to proportion Weigh out bismuth nitrate pentahydrate and ferric nitrate nonahydrate and dissolve them in beaker A containing acetic acid. Place beaker A on a magnetic stirrer and stir at a constant temperature of 60°C. Weigh out barium hydroxide octahydrate and strontium acetate and dissolve them in beaker B containing acetic acid. Place beaker B on a magnetic stirrer and stir at a constant temperature of 60°C. After the solution in beaker B becomes clear, add acetylacetone as a stabilizer, and then slowly add tetrabutyl titanate.

[0034] After the solutions in beakers A and B have stabilized and become clear, mix and stir the solutions in beakers A and B together, maintaining a constant temperature of 60°C. Add a certain mass of ethanolamine dropwise to the mixed solution and stir until the solution becomes clear.

[0035] Prepare a crucible, crucible tongs, a sheet metal windproof container, a lighter, lens cleaning paper, gloves, and a stable and clear blended solution. The BF-BT-ST2 sample was prepared using a self-propagating high-temperature synthesis method. Specifically, wearing gloves, the stable and clear blended solution was poured into the crucible, and an appropriate amount of anhydrous ethanol was added. The crucible was covered with the sheet metal windproof container, and the lens cleaning paper was held in the crucible with the crucible tongs. The lighter was used to ignite the paper, allowing it to burn. During combustion, the crucible tongs were used to periodically stir the burning solution in the crucible to ensure complete combustion. After complete combustion, the remaining ash was placed in a constant-temperature oven and dried at 80°C for 10 hours.

[0036] After carefully grinding the dried ash, it was placed in a corundum crucible and then placed in a muffle furnace. The temperature was increased to 300°C at a rate of 3°C / min and calcined for 2 hours. Then the temperature was increased to 900°C at a rate of 5°C / min and calcined for 2 hours. After that, it was cooled to room temperature with the furnace.

[0037] The calcined powder was placed in a ball mill jar and milled for 12 hours in a planetary ball mill using anhydrous ethanol as the grinding medium. The milled suspension was then taken out, placed in a petri dish, and dried in a constant temperature oven at 80°C for 10 hours. Finally, the dried powder was finely ground to obtain BF-BT-ST2 nanoparticles.

[0038] Example 3: Preparation of BF-BT-ST3 nanoparticles According to proportion Weigh out bismuth nitrate pentahydrate and ferric nitrate nonahydrate and dissolve them in beaker A containing acetic acid. Place beaker A on a magnetic stirrer and stir at a constant temperature of 60°C. Weigh out barium hydroxide octahydrate and strontium acetate and dissolve them in beaker B containing acetic acid. Place beaker B on a magnetic stirrer and stir at a constant temperature of 60°C. After the solution in beaker B becomes clear, add acetylacetone as a stabilizer, and then slowly add tetrabutyl titanate.

[0039] After the solutions in beakers A and B have stabilized and become clear, mix and stir the solutions in beakers A and B together, maintaining a constant temperature of 60°C. Add a certain mass of ethanolamine dropwise to the mixed solution and stir until the solution becomes clear.

[0040] Prepare a crucible, crucible tongs, a sheet metal windproof container, a lighter, lens cleaning paper, gloves, and a stable and clear blended solution. The BF-BT-ST3 sample was prepared using a self-propagating high-temperature synthesis method. Specifically, wearing gloves, the stable and clear blended solution was poured into the crucible, and an appropriate amount of anhydrous ethanol was added. The crucible was covered with the sheet metal windproof container, and the lens cleaning paper was held in the crucible with the crucible tongs. The lighter was used to ignite the paper, allowing it to burn. During combustion, the crucible tongs were used to periodically stir the burning solution in the crucible to ensure complete combustion. After complete combustion, the remaining ash was placed in a constant-temperature oven and dried at 80°C for 10 hours.

[0041] After carefully grinding the dried ash, it was placed in a corundum crucible and then placed in a muffle furnace. The temperature was increased to 300°C at a rate of 3°C / min and calcined for 2 hours. Then the temperature was increased to 900°C at a rate of 5°C / min and calcined for 2 hours. After that, it was cooled to room temperature with the furnace.

[0042] The calcined powder was placed in a ball mill jar and milled for 12 hours in a planetary ball mill using anhydrous ethanol as the grinding medium. The milled suspension was then removed, placed in a petri dish, and dried in a constant temperature oven at 80°C for 10 hours. Finally, the dried powder was finely ground to obtain BF-BT-ST3 nanoparticles.

[0043] Example 4: Preparation of PESU-based composite dielectric films with different filler types and contents Take five clean beakers and add 5 ml of NMP solution to each. Based on the different amounts of BF-BT-ST packed phase (y wt.% 0.5, 1, 1.5, 2, and 3), add a calculated amount of BF-BT-ST nanoparticles and label them. Add a certain amount of PESU to each of the five solutions sequentially, and stir on a magnetic stirrer for 1 hour to initially disperse the particles. Then, place the five beakers containing the solutions in an ultrasonic cleaner and ultrasonically disperse them twice for 30 minutes each time, for a total of 1 hour, until the nanoparticles are uniformly dispersed. Place the five beakers on a magnetic stirrer and continue stirring for 10 hours until the PESU is completely dissolved, obtaining the BF-BT-ST / U precursor dispersion.

[0044] The prepared BF-BT-ST / U precursor dispersion was cast onto a smooth glass plate using an automatic coating machine. To obtain a composite film of suitable thickness, the doctor blade height was adjusted to 11 μm. The coated wet film was placed in a constant temperature oven and dried at 60°C for 12 hours. The glass plate was then transferred to a vacuum drying oven, and the heat treatment temperature program was as follows: 80°C for 4 hours, 100°C for 2 hours, 150°C for 2 hours, and 200°C for 2 hours. Under the action of deionized water, the BF-BT-ST / U composite dielectric film adhered to the glass plate was peeled off, resulting in a dense and smooth composite dielectric film.

[0045] Repeat the above steps to obtain BF-BT-ST / U composite films with the remaining components and to prepare BF-BT-ST@Z / U composite dielectric films with different doping ratios. In this paper, yBF-BT-STz / U (y=0.5, 1, 1.5, 2, 3, z=1, 2, 3) is used to represent the composite film of y wt.% BF-BT-ST inorganic filler phase and PESU, and z represents different types of BF-BT-ST.

[0046] Comparative Example 1: Preparation of pure PESU dielectric thin films Weigh 1.0 g of polyethersulfone (PESU) particles and add them to 20 mL of N,N-dimethylformamide (DMF) solvent. Stir magnetically at 60 °C for 6 h until completely dissolved to obtain a uniform and transparent PESU solution. After allowing the solution to stand to remove bubbles, coat it onto a clean glass substrate using a blade coating method. The blade gap is set to [value missing]. The wet film was then pretreated in an 80°C oven for 2 hours, followed by heat treatment in a vacuum oven at 180°C for 4 hours to completely remove residual solvent. After cooling to room temperature, the film was peeled off from the substrate to obtain a film with a thickness of [thickness value missing]. Pure PESU dielectric film.

[0047] Figure 1 This involves XRD pattern analysis of the dielectric. Pure PESU in... The presence of a wide range of amorphous dispersed peaks within the range indicates its typical amorphous structure. After introducing 1 wt.% BF-BT-ST3 filler, the XRD pattern of the composite film still showed predominantly amorphous dispersed peaks of PESU, with no new impurity phase diffraction peaks appearing, indicating that the addition of the filler did not disrupt the amorphous structure of the polymer matrix. Simultaneously, the (110) characteristic diffraction peak of the BF-BT-ST3 perovskite structure was clearly observed near 2θ≈31°, and the peak position did not shift, indicating that BF-BT-ST3 maintained its complete crystal structure during the composite process. This demonstrates that the composite between the filler and the matrix is ​​primarily physical, with the inorganic phase successfully introduced without triggering significant phase transitions or chemical reactions.

[0048] Figure 2 The infrared spectrum of the BF-BT-ST3 / U composite medium further verifies the chemical structure of the composite system. As shown in the figure, pure PESU in… (Stretching vibration of the benzene ring CH) (C=C double bond stretching) (Aromatic ether COC antisymmetric stretching) and Its characteristic absorption peak is observed at (-S-stretch vibration). In the spectrum of the 1 wt.% BF-BT-ST3 / U composite film, the above-mentioned PESU characteristic peak is completely preserved, and the peak position does not show significant shift, indicating that the chemical structure of the polymer backbone is not damaged. At the same time, in the low wavenumber region ( Fe-O (approximately 442 mg / L) belonging to BF-BT-ST3 can be observed. ) and Ti-O (approximately 823, The characteristic absorption peaks of the ) bond were observed. No new chemical bond absorption peaks appeared in the spectrum, further confirming that BF-BT-ST3 and PESU are physically complexed and have good compatibility.

[0049] Figure 3 The figure shows the dielectric properties of the dielectric at 200℃. The 1BF-BT-ST3 / U composite film exhibits good frequency stability across the entire frequency band, with the dielectric constant decreasing only slightly with increasing frequency, and the dielectric loss (tanδ) remaining at a low level (<0.03). Compared to pure PESU, the dielectric constant of the composite film is significantly improved, attributed to the introduction of the high-dielectric-constant BF-BT-ST3 filler and its resulting enhanced interfacial polarization effect. Simultaneously, the low-loss characteristic indicates that the composite material retains good insulation performance and low energy dissipation under high temperature and high frequency conditions, meeting the requirements of high-temperature capacitors for low-loss dielectrics.

[0050] Figure 4 The figure shows the leakage current curve of the dielectric at 200℃. The leakage current density of the 1BF-BT-ST3 / U film increases slowly with increasing electric field, and is significantly lower than that of pure PESU throughout the entire test electric field range. This is mainly due to the wide bandgap characteristic of BF-BT-ST3, which creates a high potential barrier in the composite system, effectively confining charge carriers and suppressing charge injection and migration processes, thereby significantly reducing conductivity losses at high temperatures. The good correlation between low leakage current density and high breakdown field strength further confirms the excellent insulation stability of this composite material under high temperature and high field conditions.

[0051] Figure 5 The figure shows the energy storage performance of the dielectric at 200℃. Under the same electric field strength, the discharge energy density and charge / discharge efficiency of the 1BF-BT-ST3 / U composite film are significantly higher than those of the pure PESU film. For example, under an electric field of 240 kV / mm, the energy density of this composite film can reach approximately... The efficiency remained above 70%, demonstrating excellent high-temperature energy storage stability. This is mainly attributed to the good dielectric matching between the relaxor ferroelectric properties of the BF-BT-ST3 filler and the PESU matrix, which effectively suppressed polarization loss and leakage conduction loss at high temperatures.

[0052] The above results demonstrate that the PESU-based composite film with 1 wt.% BF-BT-ST3 as the filler phase exhibits excellent comprehensive performance at 200℃, including good structural stability, enhanced dielectric constant, low loss, high breakdown field strength, and low leakage current density. This is mainly attributed to the wide bandgap (2.909 eV) of the BF-BT-ST3 filler obtained through compositional control, which effectively suppresses current carrying capacity, optimizes interfacial polarization, and improves overall insulation strength in the composite system. This material system shows significant potential for high-temperature energy storage applications, providing a valuable solution for developing next-generation high-power-density, high-temperature-stability film capacitors. The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A relaxor ferroelectric improved polyethersulfone dielectric, characterized in that, The dielectric comprises a relaxor ferroelectric material and a polyethersulfone matrix (PESU) as component (M), wherein component (M) contains... , and Each molar percentage content is selected from (BFBTST), where x = 0.1~0.

6.

2. The relaxor ferroelectric improved polyethersulfone dielectric according to claim 1, characterized in that, Component (M) is a self-propagating high-temperature synthesis method based on the sol-gel method. (BF-BT-ST) Relaxor ferroelectric inorganic filled phase.

3. The relaxor ferroelectric improved polyethersulfone dielectric according to claim 1, characterized in that, The preparation process of relaxor ferroelectrics includes the following steps: (1) Preparation of precursor solution: Dissolve bismuth nitrate pentahydrate and ferric nitrate nonahydrate in acetic acid and stir at 60°C to obtain solution A; dissolve barium hydroxide octahydrate and strontium acetate in acetic acid and stir at 60°C. After the solution is clear, add acetylacetone as a stabilizer, and then slowly add tetrabutyl titanate to obtain solution B. (2) Blending and complexation: The clarified solution A and solution B are blended and stirred at a constant temperature of 10-100℃ until the solution is clear. Then, ethanolamine is added dropwise and stirred until the solution is clear to obtain a stable blended sol. (3) Self-propagating high-temperature synthesis: Pour the blended sol into a crucible, add anhydrous ethanol as fuel, ignite it with a clean paper under windproof conditions, and stir it in time during the combustion process to ensure that the material is fully burned; (4) Drying and grinding: The ash obtained from combustion is dried at 50-150℃ for 8-24 hours and then ground to obtain the dry precursor powder; (5) Segmented calcination: The precursor powder is placed in a muffle furnace and heated to 250-350°C at 1-5°C / min and calcined for 1-3 hours; then heated to 800-1000°C at 3-8°C / min and calcined for 1-3 hours, and then cooled with the furnace to obtain BF-BT-ST nanoparticles.

4. The relaxor ferroelectric improved polyethersulfone dielectric according to claim 3, characterized in that: The BF-BT-ST nanoparticles have a perovskite structure and a particle size range of 50-100 nm.

5. The method for preparing polyethersulfone dielectric with relaxed ferroelectricity according to claims 1-4, characterized in that, Includes the following steps: (a) Preparation of dispersion slurry: BF-BT-ST nanoparticles were added to an N-methylpyrrolidone solution containing polyethersulfone at a mass fraction of y wt.% (y=0.1~5), and the mixture was mechanically stirred and ultrasonically dispersed to obtain a uniform composite precursor dispersion. (b) Film coating: The precursor dispersion is coated onto a glass substrate, the wet film thickness is controlled, and then dried at 40-80°C for 8-16 hours; (c) Gradient heat treatment: The dried film is subjected to step heat treatment under vacuum conditions, including treatment at 60~100℃ for 1~5 hours, treatment at 90~110℃ for 1~3 hours, treatment at 140~160℃ for 1~3 hours and treatment at 190~210℃ for 1~3 hours. (d) Peeling and film removal: After heat treatment, the film is peeled off from the substrate to obtain a self-supporting relaxor ferroelectric improved polyethersulfone dielectric film.

6. The preparation method according to claim 5, characterized in that, The wet film thickness mentioned in step (b) is controlled by the doctor blade. .

7. The preparation method according to claim 5, characterized in that, The prepared relaxor ferroelectric improved the thickness of the polyethersulfone dielectric film. .

8. The relaxor ferroelectric improved polyethersulfone dielectric thin film prepared according to the method described in claims 5-7, characterized in that, The discharge energy density of the thin film at a temperature of 200℃ and an electric field strength of 240 kV / mm is not less than The charge / discharge efficiency is not less than 70%.

9. The application of the relaxor ferroelectric improved polyethersulfone dielectric film prepared according to the method of claims 5-7 in high-temperature energy storage capacitors.

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