A lead-based antiferroelectric energy storage ceramic for high energy storage performance scenarios and its preparation method

Abstract

An embodiment of the present invention discloses a lead-based antiferroelectric energy storage ceramic for high energy storage performance scenarios and a preparation method thereof, relating to the technical field of energy storage ceramics and their preparation. The present invention includes: weighing raw material powders according to stoichiometric ratios, then putting them into a wet planetary ball mill for ball milling and mixing treatment to obtain initial ceramic powders. After drying and fine grinding, briquetting and synthesis are carried out, and then secondary ball milling is carried out to obtain ceramic powders; first, a binder is added for granulation, and then the mixture is pressed into a green body by a press. Then, the green body is put into a high-temperature furnace for debinding to obtain a ceramic blank; after sintering, a ceramic sheet is obtained; the ceramic sheet is processed. For a part of the ceramic sheets, silver electrodes are brushed on both sides, and for another part of the ceramic sheets, they are polished and gold electrodes are sprayed using an ion sputtering instrument to obtain the lead-based antiferroelectric ceramic, improving the application scope of this type of energy storage ceramic in energy storage application scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage ceramics and their preparation, and particularly to a lead-based antiferroelectric energy storage ceramic for high energy storage performance scenarios and a preparation method thereof. Background Art

[0002] Energy storage materials play an important role in the energy field as new energy materials. Nowadays, common energy storage materials include electrochemical batteries, solid fuel cells, and dielectric capacitors. Energy storage ceramics can be used as electrolyte materials for dielectric capacitors and are indispensable materials for preparing dielectric capacitors. Compared with the other two energy storage materials, dielectric capacitors have higher power density, a wider operating temperature range, and faster charge and discharge rates. They are widely used in many advanced pulsed power electronic systems such as high-power pulses, electronic devices, and hybrid electric vehicles, and have very broad application prospects.

[0003] In current research, the antiferroelectric energy storage ceramic systems mainly include PbZrO3, NaNbO3, and AgNbO3 systems. Although the NaNbO3 and AgNbO3 systems have high energy storage density, their energy storage efficiency is relatively low. The complex preparation process and extremely high cost make it difficult for these materials to be commercially applied. Therefore, considering the requirements of current industrial development, low cost and a wide sintering temperature are often regarded as the key for dielectric materials. Therefore, the PbZrO3 (PZ) - based as a typical antiferroelectric (AFE) material is playing an increasingly important role and has been frequently explored in terms of energy storage performance.

[0004] With the development of electronic components towards miniaturization and intelligence, the performance requirements for dielectric energy storage ceramics are gradually increasing. Energy storage ceramics should not only have high energy storage density W rec , low loss tanδ, high energy storage efficiency η, but also high discharge energy density. Therefore, how to further improve the performance of PZ - based antiferroelectric energy storage ceramics and seek an antiferroelectric energy storage ceramic with excellent comprehensive performance has become an issue to be studied. Summary of the Invention

[0005] An embodiment of the present invention provides a lead-based antiferroelectric energy storage ceramic for high energy storage performance scenarios and a preparation method thereof, which can further improve the comprehensive energy storage performance of PZ - based antiferroelectric energy storage ceramics, thereby expanding the application range of this type of energy storage ceramics in energy storage application scenarios.

[0006] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0007] In a first aspect, a preparation method of a lead-based antiferroelectric energy storage ceramic is provided, including:

[0008] S1. Weigh the raw material powders according to the stoichiometric ratio, and then put them into a wet planetary ball mill for ball milling and mixing to obtain the initial ceramic powders. The initial raw material powders include: PbO, La2O3, SrCO3, ZrO2, TiO2, SnO2, Bi2O3 and Sc2O3 powders. After drying and fine grinding, they are pressed into large blocks, put into a high-temperature furnace for synthesis, and then continue to be finely ground. After secondary ball milling, ceramic powders are obtained. The stoichiometric ratio is: xBS-(1-x)PLSZTS), where x is an adjustment parameter.

[0009] S2. First, add a binder to a part of the ceramic powders for granulation, then age them, and then press them into green bodies with a press. Then put the green bodies into a high-temperature furnace for debinding to obtain ceramic bodies.

[0010] S3. Put the ceramic body into a high-temperature furnace, and cover the ceramic body with the ceramic powders. Then sinter them to obtain ceramic wafers.

[0011] S4. Process the ceramic wafers. Brush silver electrodes on both sides of a part of the ceramic wafers, and grind another part of the ceramic wafers to 50 - 80 μm and spray gold electrodes with an ion sputtering instrument to obtain the lead-based antiferroelectric ceramics. Among them, the processing process includes a silver firing link, and in the silver firing link, it is kept at 700 - 800 °C for less than 60 minutes.

[0012] In the second aspect, a lead-based antiferroelectric energy storage ceramic is provided, and this lead-based antiferroelectric ceramic is prepared by the above preparation method.

[0013] The lead-based antiferroelectric energy storage ceramic and its preparation method for high energy storage performance scenarios provided by the embodiments of the present invention design and improve a kind of xBS-(1-x)PLSZTS) antiferroelectric energy storage ceramic material with high W rec (≥11 J / cm 3 ), low tanδ (≤0.02), high E b (≥500 kV / cm), high W d (7.65 J / cm 3 ), which further improves the competitiveness of the energy storage ceramic material, and designs the material of its preparation method, thereby further improving the comprehensive performance of the PZ-based antiferroelectric energy storage ceramic, and thus expanding the application range of this type of energy storage ceramic in energy storage application scenarios. Description of the Drawings

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 In (a), (b), (c), (d), (e), and (f) are the scanning electron microscope images of the energy storage ceramics xBS-(1-x)PLSZTS) ( x x = 0.00, 0.05, 0.08, 0.10, 0.12, 0.20);

[0016] Figure 2 In (a) is the X-ray diffraction pattern of the energy storage ceramics xBS-(1-x)PLSZTS) ( x x = 0.00, 0.05, 0.08, 0.10, 0.12, 0.20), and (b) is the partial enlarged view of (a);

[0017] Figure 3 In (a), (b), (c), (d), (e), and (f) are the dielectric constant ε x and loss tanδ of the energy storage ceramics xBS-(1-x)PLSZTS) ( r x = 0.00, 0.05, 0.08, 0.10, 0.12, 0.20) varying with temperature. (g) is the dielectric constant ε x and loss tanδ of the energy storage ceramics xBS-(1-x)PLSZTS) ( r x = 0.00, 0.05, 0.08, 0.10, 0.12, 0.20) at room temperature. (h) is the schematic diagram of the curve of ln(1 / ε - 1 / ε x x = 0.00, 0.10, 0.20) ceramics of xBS-(1-x)PLSZTS) fitted at a frequency of 10 kHz as a function of ln(T - T m ); m

[0018] Figure 4 In (a), (b), (c), (d), (e), and (f) are the Weibull distribution, grain size, Eb, impedance spectrum, lnσ - 1 / T curve, ferroelectric hysteresis loop, and schematic diagram of the relationship between saturation polarization intensity and remanent polarization intensity of the xBS-(1-x)PLSZTS) ( x x = 0.00, 0.05, 0.08, 0.10, 0.12, 0.20) ceramics;​

[0019] Figure 5 Among them, (a), (b), (c), (d), (e), and (f) are respectively schematic diagrams of the temperature stability, frequency stability, and cycling stability curves of 0.1BS-0.9PLSZTS ceramics;

[0020] Figure 6 (a), (b), (c), and (d) are schematic diagrams of the DC charge-discharge performance of 0.1BS-0.9PLSZTS ceramics with a load resistance of 13 kΩ;

[0021] Figure 7 It is a schematic diagram of the piezoelectric ceramic preparation method provided by the embodiment of the present invention. Detailed implementation manners

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners. The implementation manners of the present invention will be described in detail below. Examples of the implementation manners are shown in the accompanying drawings. It should be understood that the following implementation manners are only used to illustrate the present invention and not to limit the present invention. Unless otherwise specified, the following percentages by content all refer to mass percentages. The implementation manners described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and cannot be construed as a limitation of the present invention.

[0023] In view of the situation that the comprehensive energy storage performance of existing lead-based antiferroelectric ceramics is relatively low and cannot meet the specific index requirements of high-power pulsed electronic devices, the design purpose of this embodiment is to provide a modified PZ-based antiferroelectric energy storage ceramic with high energy storage density, high energy storage efficiency, low dielectric loss, good temperature stability, and good frequency stability, and its preparation method. The general design idea of this embodiment is as follows: Prepare a modified PZ-based antiferroelectric energy storage ceramic. In terms of mole percentage, the chemical composition of the modified PZ-based antiferroelectric energy storage ceramic is xBiScO3-(1-x)[(Pb 0.81～ 0.87 La 0.05～0.1 Sr 0.05～0.1 )(Zr 0.7 Ti 0.1 Sn 0.2 )O3] ( x = 0.00, 0.05, 0.08, 0.10, 0.12, 0.20). In terms of mole percentage, the xBS-(1-x)PLSZTS) antiferroelectric energy storage ceramic uses PLSZTS as the matrix and adopts solid solution of the new element BiScO3 for co-doping. The combination of BiScO3 and PLSZTS forms a binary solid solution system with a morphotropic phase boundary. At its morphotropic phase boundary, the characteristic temperature T of the system mIt will decrease because the diversity of components leads to an increase in the relaxation of the BS-PLSZTS binary system, which is very beneficial for improving the energy storage performance of the system. In addition, the introduction of Bi element can increase the saturation polarization intensity P max and temperature stability. The introduction of Sc element can refine the grains and improve the breakdown field strength of the system. It provides a new idea for the application of PZ-based antiferroelectric energy storage ceramics in high-power pulsed electronic devices. Specifically, the embodiments of the present invention provide a lead-based antiferroelectric energy storage ceramic for high energy storage performance scenarios and its preparation method, as Figure 7 shown, including:

[0024] S1. Weigh the raw material powders according to the stoichiometric ratio, then put them into a wet planetary ball mill for ball milling and mixing to obtain the initial ceramic powders. The initial raw material powders include: PbO, La2O3, SrCO3, ZrO2, TiO2, SnO2, Bi2O3, and Sc2O3 powders. After drying and fine grinding, they are pressed into large pieces, put into a high-temperature furnace for synthesis, and then continue to be finely ground. After secondary ball milling, ceramic powders are obtained. The stoichiometric ratio is: xBS-(1-x)PLSZTS), where x is the adjustment parameter.

[0025] Among them, according to the chemical composition of the modified PZ-based antiferroelectric energy storage ceramics, using PbO, La2O3, SrCO3, ZrO2, TiO2, SnO2, Bi2O3, and Sc2O3 as raw materials, weigh the above raw materials according to the corresponding stoichiometric ratio and mix them. Keep them at 800 °C for 2 hours for synthesis to obtain ceramic powders; and sinter the ceramic powders at 1220-1280 °C for 3 hours to obtain the modified PZ-based antiferroelectric energy storage ceramics. This preparation method uses solid-phase reaction to prepare BS-PLSZTS antiferroelectric energy storage ceramics. In the preferred scheme, the particle size of the ceramic powders should be processed to the extent of 1-2 μm.

[0026] S2. First, add a binder to a part of the ceramic powders for granulation, then age, and then press them into green bodies with a press. Then put the green bodies into a high-temperature furnace for debinding to obtain ceramic blanks.

[0027] S3. Put the ceramic blanks into a high-temperature furnace, and cover the ceramic blanks with the ceramic powders, and then sinter them to obtain ceramic wafers.

[0028] S4. Process the ceramic wafers. Brush silver electrodes on both sides of a part of the ceramic wafers, and grind another part of the ceramic wafers to 50-80 μm, and spray gold electrodes on them with an ion sputtering instrument to obtain the lead-based antiferroelectric ceramics. Among them, the processing process includes a silver firing link, and in the silver firing link, keep it at 700-800 °C for less than 60 minutes.

[0029] Specifically, in S1, the process of putting into a wet planetary ball mill to obtain ceramic powder includes:

[0030] In the wet planetary ball mill, according to a preset mass ratio, mixing is first carried out and then synthesis is carried out according to preset synthesis conditions. The preset mass ratio includes: the ratio of raw materials, ball milling medium and water is 1:3:1.5. Among them, the ball milling medium is agate balls, and the duration of mixing is 12 hours;

[0031] Among them, the preset synthesis conditions include: holding for synthesis at 600 - 900 °C for 2 - 4 hours. Or, the preset synthesis conditions include: heating at a heating rate not higher than 2 °C / min to 700 - 900 °C, then holding for 1 - 3 hours, and then cooling in the furnace to room temperature and taking out to obtain ceramic powder.

[0032] Furthermore, it may also include: after the ceramic powder is obtained from the first synthesis, the ceramic powder obtained from the first synthesis is finely ground and then dried. Among them, the mass ratio used in the process of fine grinding includes: the ratio of the ceramic powder obtained from the first synthesis, ball milling medium and ethanol is 1:3:1.5. Among them, the duration of fine grinding is 24 hours, and the temperature for drying after fine grinding is maintained at 80 - 100 °C

[0033] In this embodiment, a binder is added to the ceramic powder for granulation, aged and then pressed into shape, and then heated to remove the plasticizer to obtain a ceramic green body. In the preferred scheme, the binder added in S2 is polyvinyl alcohol (PVA), and the addition amount of the binder is 6 - 10 wt% of the ceramic powder; the conditions for heating and removing the plasticizer from the green body include: heating at a heating rate not higher than 2 °C / min to 600 - 700 °C and holding for less than 3 hours.

[0034] In S3, the sintering conditions include: heating at a heating rate not higher than 2 °C / min to 1220 - 1280 °C, then holding for 3 hours, and then ending the holding and cooling in the furnace to room temperature. For example: putting the ceramic green body into a (small) high-temperature furnace, in order to reduce the volatilization of lead oxide and bismuth oxide at high temperature, covering the ceramic green body with the powder of the corresponding components of the ceramic powder obtained in step (a), and then sintering under certain conditions to obtain the ceramic sheet. The sintering conditions can be heating at a heating rate not higher than 2 °C / min to 1220 - 1280 °C, holding for 3 hours, and cooling in the furnace to room temperature.

[0035] Furthermore, in S4, the processing process includes: processing the ceramic sheet into the required size, and then successively carrying out an ultrasonic cleaning step, a silver screen printing step, a drying step, a silver firing step and a gold spraying step; among them, in the silver firing step, it is held at 700 - 800 °C for less than 60 minutes.

[0036] Specifically, the adjustment parameter can be x = 0, x = 0.05, x = 0.10, or x = 0.15. In the preferred solution of this embodiment, the adjustment parameter x = 0.10. In practical applications, x is controlled below 0.10. By only adjusting BiScO3, the structure and properties of the ceramic can be controllably adjusted to meet the requirements of energy storage devices for ceramic materials (high energy storage density, high energy storage efficiency, low dielectric loss, high breakdown field strength). If x is greater than 0.10, the phase structure of the ceramic completely deviates from the MPB, causing a significant decrease in the properties of the material (such as the breakdown field strength), which runs counter to the purpose of this invention to improve the performance of antiferroelectric energy storage ceramics. This invention uses binary composition design to diversify the substitution and replacement of atoms. By introducing BiScO3, a multi-component disordered design is achieved, improving the relaxivity of the system and further enhancing the energy storage performance. Preferably, the energy storage density of the modified BS-PLSZTS antiferroelectric energy storage ceramic is 11.4 J / cm 3 , the energy storage efficiency is 93.4%, and the breakdown field strength is 504 kV / cm.

[0037] Aiming at the situation that the comprehensive energy storage performance of existing lead-based antiferroelectric ceramics is low and cannot meet the specific index requirements of high-power pulsed electronic devices, the lead-based antiferroelectric energy storage ceramics proposed in this embodiment regulate the morphotropic phase boundary by solid-solution of a new component BiScO3. Through multi-component disordered design, the relaxivity of the system is improved, effectively ensuring high energy storage performance while effectively improving the temperature stability, providing a new idea for the application of PZ-based antiferroelectric energy storage ceramics in high-power pulsed electronic devices. The chemical composition of the modified PZ-based antiferroelectric energy storage ceramic is xBS-(1-x)PLSZTS) ( x x = 0.00, 0.05, 0.08, 0.10, 0.12, 0.20).

[0038] The BS-PLSZTS antiferroelectric energy storage ceramic uses PLSZTS as the matrix and is co-doped with the new element BiScO3 by solid solution. The combination of BiScO3 and PLSZTS forms a binary solid solution system with a morphotropic phase boundary. At its morphotropic phase boundary, the characteristic temperature T m will decrease because the diversity of components leads to an increase in the relaxivity of the BS-PLSZTS binary system, which is very beneficial to improving the energy storage performance of the system. In addition, the introduction of Bi element can increase the saturation polarization intensity P max and temperature stability, and the introduction of Sc element can refine the grains and increase the breakdown field strength of the system. By adopting the above composition and regulating the morphotropic phase boundary, the energy storage performance of the energy storage ceramic is improved and a relatively high energy storage density (11.4 J / cm 3), with an energy storage efficiency of 93.4%, meets the requirements of high-power pulsed electronic devices for energy storage materials, and plays a strong promoting role in the application of high-energy storage performance ceramic materials.

[0039] Taking a specific example in the actual trial production process: In practical applications, the solid-phase sintering method can be used to prepare xBS-(1-x)PLSZTS) antiferroelectric energy storage ceramics. Among them, x x = 0.00, 0.05, 0.08, 0.10, 0.12, 0.20.

[0040] First, using PbO, La2O3, SrCO3, ZrO2, TiO2, SnO2, Bi2O3, Sc2O3 as raw materials, weigh the above raw materials according to the corresponding stoichiometric ratio and then mix them. The wet ball milling method is used for mixing, and the raw materials: ball milling medium: ethanol = 1:3:1.5 by mass ratio are mixed for 12 hours to make them evenly mixed. After drying the mixed raw materials at 120 °C, pass them through an 80-mesh sieve, form them under a pressure of 3 MPa, heat them at a heating rate of 2 °C / min to 800 °C and hold for 2 hours to synthesize the required ceramic powder.

[0041] After that, grind the synthesized ceramic powder, pass it through an 80-mesh sieve, and then use the wet ball milling method for fine grinding. The ceramic powder: ball milling medium: ethanol = 1:3:1.5 by mass ratio are mixed for 24 hours to make them evenly mixed, and a powder with a particle size between 1 and 3 μm is obtained. Dry the obtained powder, add 6 wt.% of PVA binder, granulate it, form it under a pressure of 5 MPa, age for 24 hours, pass it through a 200-mesh sieve, press it into a disc with a diameter of 13 mm under a pressure of 1.3 MPa, and then heat it in a low-temperature furnace to 550 °C and hold for 120 minutes to remove the plasticizer to obtain a green body.

[0042] Then, bury the ceramic green body in a closed alumina crucible filled with ceramic powder of the same composition, put it into a high-temperature furnace, heat it at a heating rate of 2 °C / min to the target temperature of 1220 - 1280 °C and hold for 3 hours, cool it to room temperature with the furnace and then take it out to obtain the required ceramic sheet.

[0043] Finally, part of the obtained ceramic sheet is processed to a thickness of 0.5 mm, ultrasonically cleaned, dried, double-sided screen-printed with silver, heated to 750 °C at a heating rate of 2 °C / min and held for 10 minutes to burn the silver. The other part is processed to a thickness of 50 - 80 μm, and then a gold electrode with a diameter of 1 mm is sprayed on it using an ion sputtering instrument to obtain the energy storage ceramic with the perovskite structure.

[0044] The above preparation process can be repeated successively under several conditions such as x = 0, x = 0.05, x = 0.08, x = 0.10, x = 0.12, x = 0.20, etc. After that, the prepared piezoelectric ceramic wafers are tested successively. For example, an X-ray diffractometer from Bruker can be used to analyze the phase structure of the piezoelectric ceramics; a ferroelectric analyzer from Radiant Technology can be used to measure the ferroelectric hysteresis loop; an Agilent Technology 4294A can be used to test the dielectric constant of the ceramics. The test results of various properties of the antiferroelectric energy storage ceramics of the present invention are shown in Table 1.

[0045] Table 1 Performance test table of antiferroelectric energy storage ceramic materials

[0046] ;

[0047] It can be seen from Table 1 that the energy storage density first increases and then decreases with the increase of x, and the breakdown field strength also first increases and then decreases with the increase of x. The energy storage efficiency is about 90%. When x = 0.10 (i.e., near the MPB), the optimal value is obtained; the value of Tanδ increases with the increase of the solid solution amount and still remains at a relatively low value (Tanδ = 0.4%) when x = 0.10.

[0048] Figure 1 (a), (b), (c), (d), (e), (f) are cross-sectional morphology diagrams of the antiferroelectric energy storage ceramics of the present invention (x = 0, x = 0.05, x = 0.08, x = 0.10, x = 0.12, x = 0.20). It can be Figure 1 seen that the microstructures of all ceramic samples are very dense, and the relative density is above 95%. Among them, the average grain size of the PLSZTS ceramic is 4.53 μm. With the doping of BiScO3, the average grain size at x = 0.1 decreases to 2.85 μm. Due to the subsequent increase in the sintering temperature (1250 °C), the grain size increases slightly, but the increase is not significant, as shown in the figure. The smaller the grain size, the more grain boundaries there will be, and the greater the hindrance to the electric field. Therefore, the finer the grains, the higher the densification, which is beneficial to the improvement of the breakdown field strength (E b ).

[0049] Figure 2 (a), (b) are XRD diffraction patterns of the antiferroelectric energy storage ceramics of the present invention (x = 0, x = 0.05, x = 0.08, x = 0.10, x = 0.12, x = 0.20). It can be Figure 2It can be seen from (a) and (b) that the highest peak of the ceramic sample appears near 31.5°. When x ≤ 0.05, no impurity phase peaks are found, and each component forms the perovskite main phase, which indicates that BS is fully incorporated into the perovskite main phase. And near the 43.9° peak, as the x content increases, BiScO3 gradually enters the main phase, and the diffraction peak gradually shifts to the right. This is because Pb 2+ (120 pm) ions are replaced by Bi 3+ (108 pm) and Sc 3+ (81 pm), resulting in lattice contraction and the diffraction peak shifting towards the high-angle direction. When x ≥ 0.08, impurity phase peaks appear near 39°. After analysis with the PDF card, it is Pb2O. It is worth mentioning that these impurity phase peaks are inevitable.

[0050] Figure 3 (a), (b), (c), (d), (e), (f) are the dielectric constant ε x and loss tangent tanδ of the energy storage ceramic xBS-(1-x)PLSZTS) ( r varying with temperature, Figure 3 (g) is the dielectric constant ε x and loss tangent tanδ of the energy storage ceramic xBS-(1-x)PLSZTS) ( r at room temperature, Figure 3 (h) is the schematic diagram of the function curve of ln(1 / ε - 1 / ε x ) as ln(T - T m ) for the ceramics xBS-(1-x)PLSZTS) ( m ) fitted at a frequency of 10 kHz. It can be seen from Figure 3 that the test temperature is 30℃ - 450℃. When the doping amount of BS is 0, it can be seen that the dielectric peak is very broad and flat. As the BS content increases, the dielectric peak shifts to the right, and the dielectric constant also increases significantly. And the characteristic temperature T m corresponding to the dielectric peak is also relatively high. When the BS content is 0.1, the dielectric constant ε r reaches the maximum value. As the BS content further increases, when x ≥ 0.12, the dielectric peak is very flat, indicating that the relaxivity of the ceramic has increased. In addition, as Figure 3(g) shows the dielectric constant and dielectric loss at room temperature. The dielectric loss increases slightly with the increase of BiScO3 content, but the increase is very small and almost remains stable, both less than 0.02. At the same time, in order to further describe the phenomenon of enhanced relaxation of ceramics, we use the modified Curie-Weiss law. The fitting results are shown in Figure 3 As shown in (h), with the increase of BiScO3 content, the relaxivity increases from 1.83 at x=0 to 1.93 at x=0.2, which further confirms the relaxation behavior. The main reason for the enhanced relaxivity is that the change in composition leads to structural disorder, thus producing polarized nano-microdomains. In xBS-(1-x)PLSZTS) ceramics, the perovskite structure is replaced by a variety of ions, resulting in increased disorder within the system. Different types of ions are different, which destroys the long-range order of the internal domains, resulting in increased inhomogeneity of the system at the microscopic scale, which enhances the relaxivity. Enhanced relaxivity is beneficial to the improvement of ceramic energy storage performance, which is mainly manifested in the dielectric temperature spectrum, the dielectric peak becomes wider, and the dielectric constant increases.

[0051] Figure 4 (a), (b), (c), (d), (e), and (f) are the Weibull distribution, grain size and Eb, impedance spectrum, lnσ-1 / T curve, hysteresis loop, and the relationship between saturation polarization intensity and remanent polarization intensity of the antiferroelectric energy storage ceramics (x=0, x=0.05, x=0.08, x=0.10, x=0.12, x=0.20) of the present invention. Figure 4 (a) is used to calculate the breakdown field strength E b It can be seen that the slopes of all Weibull distributions are very high, indicating that the breakdown field strength E b The credibility is high. Figure 4 (b) is the breakdown field strength E calculated by Weibull distribution b The relationship between BiScO3 content and grain size is as follows: b First, it increases, reaching a maximum value of 504 kV / cm when x=0.1, and the change law of grain size is exactly opposite to the change law of breakdown field strength Eb. b It is affected by many internal and external factors, such as sample thickness, conductivity, etc., but the change of grains is definitely the main reason. b There was a decrease, and at this time, the grain size changed very little, which showed that other factors affected E b In order to further analyze the BS-PLSZTS ceramics b As a factor of change, we tested the temperature-dependent impedance. Changes in conductivity will also affect the dielectric breakdown of ceramics. Figure 4(c) is the impedance spectrum of the inserted series R‖CPE equivalent circuit model at 525 °C. From the fitting results, all samples show a single semi-circle arc, indicating that the grain boundary plays a major role in the conduction process. Meanwhile, the lnσ-1 / T curve ( Figure 5 (d) and the inset) was further plotted, and the conductivity activation energy Ea was calculated. The conductivity activation energy shows a trend of first increasing and then decreasing. Among them, when x = 0.1, the conductivity activation energy is the largest, which is 1.855 eV, and this also contributes to the enhancement of E b . In addition, the strain that causes dielectric breakdown may also be the reason for the significant increase in the breakdown field strength E b , and the strain has a quadratic relationship with polarization. Figure 4 (e) is the unipolar P-E loop of the BS-PLSZTS ceramic measured when the electric field is close to E b . It can be seen that when x = 0, both the near breakdown field strength and the saturation polarization intensity P max are relatively low. As the x content increases, the energy storage performance of the ceramic is improved. When x = 0.1, both the saturation polarization intensity and the near breakdown electric field reach the maximum value P max of 39.8 μC / cm 2 , and E b is 504 kV / cm. After x ≥ 0.12, the reason for the decrease in E b may be due to the increase in the amount of secondary phases. Therefore, the high E b at x = 0.10 may be due to the dense microstructure, fine grains, high E a , and reduced strain. Figure 4 (f) shows the P max , P r and P max -P r relationships for different x contents. The results show that P r is very small, almost close to 0, which also conforms to the characteristics of antiferroelectric materials and is beneficial to the improvement of energy storage performance.

[0052] Figure 5 (a), (b), (c), (d), (e), (f) are the temperature stability, frequency stability, and cycling stability curves of the antiferroelectric energy storage ceramics (x = 0, x = 0.05, x = 0.08, x = 0.10, x = 0.12, x = 0.20) of the present invention. It can be seen from Figure 5 that Figure 5 (a) shows the P-E hysteresis loop in the temperature range of 30 °C - 170 °C under a medium electric field of 300 kV / cm. In the range from 30 °C to 130 °C, as the temperature increases, the saturation polarization intensity P max not only does not decrease but instead increases slightly at the beginning, and the energy storage density increases from 3.95 J / cm at 30 °C 3Rise to 4.16 J / cm at 130 °C 3 , which is because as the temperature increases, the number of activated defect dipoles gradually increases, and the actual temperature exceeds the freezing temperature T of the polar nano microregions PNRs f . At this time, the relaxivity of the ceramic is enhanced, improving the energy storage performance. When the temperature exceeds 130 °C, P max begins to decline, but the decline is very small. Figure 5 (b) shows the energy storage density and energy storage efficiency at different temperatures. As the temperature increases, both the energy storage density and energy storage efficiency are relatively stable, and the energy storage efficiency remains above 90%. Therefore, the prepared ceramic has good temperature stability and has great research value in the field of high-temperature energy storage materials. Figure 5 (c) shows the P-E curves at different frequencies under an electric field of 300 kV / cm Figure 5 (d) shows the curves of the change in energy storage density and energy storage efficiency at different frequencies. From the above figures, it can be seen that at low frequencies, P max and P r change very little. This is because the polarization response is mainly affected by the applied electric field and is not sensitive to low frequencies, resulting in very small changes in the energy storage density and energy storage efficiency. The energy storage density decreases from 3.89 J / cm at 10 Hz 3 to 3.75 J / cm at 200 Hz 3 , with a decline of only about 3%. The energy storage efficiency decreases from 92.4% to 91.5%. Only when the frequency is greater than 500 Hz will the energy storage density and energy storage efficiency decrease significantly. Figure 5 (e) and Figure 5 (f) show the cycling stability at 300 kV / cm and 10 Hz. The results show that the BS-PLSZTS ceramic has good anti-fatigue performance.

[0053] Figure 6 (a), (b), (c), (d) show the DC charge-discharge performance of the 0.1BS-0.9PLSZTS ceramic with a load resistance of 13 kΩ. It can be seen that the peak current (I max ) and the energy density (W d ) are both positively correlated with the electric field and reach the maximum values at 350 kV / cm, which are 0.1 A and 7.65 J / cm 3 , respectively. As shown in Figure 6(c) As shown, generally, the energy density calculated by the DC charge-discharge method is usually less than that obtained by the P-E loop method, mainly due to the frequency difference between the two methods. The DC charge-discharge process is usually completed in less than 1 ms. During this process, the AFE domains are easily clamped, and the rapid redirection of the domain walls generates a large viscous force, resulting in more energy loss. Even so, a high energy density is obtained at 350 kV / cm compared with other energy storage materials.

[0054] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, reference can be made to the partial description of the method embodiments. As mentioned above, the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A preparation method of a lead-based antiferroelectric energy storage ceramic for high energy storage performance scenarios, characterized in that, Including: S1. Weigh the raw material powders according to the stoichiometric ratio, and then put them into a wet planetary ball mill for ball milling and mixing to obtain the initial ceramic powders. The initial ceramic powders include: PbO, La2O3, SrCO3, ZrO2, TiO2, SnO2, Bi2O3, and Sc2O3 powders. After drying and fine grinding, they are pressed into large pieces, put into a high-temperature furnace for synthesis, and then continue to be finely ground. After secondary ball milling, ceramic powders are obtained. The stoichiometric ratio is: xBiScO3-(1-x)[(Pb 0.81～0.87 La 0.05～0.1 Sr 0.05～0.1 )(Zr 0.7 Ti 0.1 Sn 0.2 )O3], where x is an adjustment parameter and 0 < x ≤ 0.1; S2. First, add a binder to a part of the ceramic powder for granulation, then age it, then press it into a green body using a press, and then put it into a high-temperature furnace to degrease the green body to obtain a ceramic body; S3. Put the ceramic body into a high-temperature furnace, and cover the ceramic body with the ceramic powder, and then sinter it to obtain a ceramic sheet; S4. Process the ceramic sheet. Brush silver electrodes on both sides of a part of the ceramic sheets, grind another part of the ceramic sheets to 50 - 80 μm, and spray gold electrodes using an ion sputtering instrument to obtain the lead-based antiferroelectric energy storage ceramic. Among them, the processing process includes a silver firing step, and in the silver firing step, keep the temperature at 700 - 800 °C for less than 60 minutes.

2. The preparation method according to claim 1, wherein In S1, the step of putting it into a wet planetary ball mill for treatment to obtain ceramic powder includes: In the wet planetary ball mill, according to a preset mass ratio, first mix the materials and then synthesize them according to preset synthesis conditions. The preset mass ratio includes: the ratio of raw materials, ball milling medium, and ethanol is 1:3:1.

5. Among them, the ball milling medium is agate balls, and the duration of mixing is 12 hours; The preset synthesis conditions include: keep the temperature at 600 - 900 °C for 2 - 4 hours for synthesis.

3. The preparation method according to claim 2, characterized in that, It also includes: After the ceramic powder is obtained by the first synthesis, finely grind the ceramic powder obtained by the first synthesis, and then dry it. Among them, the mass ratio used in the fine grinding process includes: the ratio of the ceramic powder obtained by the first synthesis, ball milling medium, and ethanol is 1:3:1.

5. Among them, the duration of fine grinding is 24 hours, and the temperature for drying after fine grinding is maintained at 80 - 100 °C.

4. The preparation method according to claim 1, characterized in that, The binder added in S2 is polyvinyl alcohol (PVA), and the addition amount of the binder is 6 - 10 wt% of the ceramic powder; The conditions for degreasing the green body include: raise the temperature to 600 - 700 °C at a heating rate not higher than 2 °C / min and keep it warm for less than 3 hours.

5. The preparation method according to claim 1, wherein In S3, the sintering conditions include: raise the temperature to 1220 - 1280 °C at a heating rate not higher than 2 °C / min, then keep it warm for 3 hours, and then end the heat preservation and cool it to room temperature with the furnace.

6. The preparation method according to claim 1, wherein In S4, the processing process includes: process the ceramic sheet into the required size, and then successively carry out an ultrasonic cleaning step, a screen printing silver step, a drying step, a silver firing step, and a gold spraying step; Among them, in the silver firing step, keep the temperature at 700 - 800 °C for less than 60 minutes.

7. A lead-based antiferroelectric energy storage ceramic for high energy storage performance scenarios, characterized in that, The lead-based antiferroelectric energy storage ceramic is prepared by using the preparation method described in any one of claims 1 - 6.

8. A lead-based antiferroelectric energy storage ceramic for high energy storage performance scenarios, characterized in that, When x = 0.10, the lead-based antiferroelectric energy storage ceramic has a binary solid solution system with a morphotropic phase boundary, and the energy storage density W of the energy storage ceramic is obtained rec is 11.4 J / cm 3 , the energy storage efficiency η is 93.4%, the dielectric loss tanδ is 0.4%, and the breakdown field strength is 515 kV / cm.

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