Low-power-consumption high-polarization dielectric ceramic and preparation method thereof

Abstract

The application provides a low-power-consumption high-polarization dielectric ceramic and a preparation method thereof. The application belongs to the technical field of dielectric ceramics, and the chemical formula of the ceramic material is (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 -xNaNbO3, wherein 0.05<=x<=0.50. By controlling the solid solution amount of Na + and Nb 5+ , a dense calcium barium zirconate titanate-based ceramic is obtained by sintering at 1350-1400 DEG C, and the ceramic can obtain a storage energy performance of up to 5.36 J / cm 3 and 84.1% at room temperature. The shortcomings of low dielectric breakdown field strength, low storage energy density and large dielectric loss of the calcium barium zirconate titanate-based ceramic dielectric material are effectively overcome. The prepared sodium bismuth titanate-based storage energy ceramic dielectric material exhibits excellent storage energy performance, can obtain high polarization at a low electric field, can meet more low-power-consumption application scenarios, and is expected to be applied to advanced storage energy systems.

Description

Technical Field

[0001] This invention belongs to the field of dielectric energy storage ceramic capacitor technology, specifically relating to a low-power, high-polarization dielectric ceramic and its preparation method. Background Technology

[0002] With the increasing functionality of modern electronic devices, higher demands are placed on the energy storage density and charge / discharge efficiency of dielectric capacitors. Therefore, researchers have been dedicated to improving the energy storage density of dielectric capacitors to meet the requirements of integration, compactness, and miniaturization in advanced electronic devices and electrical systems. One method to achieve higher energy storage densities is to increase their breakdown strength, which often leads to overheating and unexpected insulation failures, significantly reducing device stability and lifespan. The findings of this work provide a real opportunity to develop low-power, advanced capacitors for low-field driven nano / microelectronics. Researchers often use recoverable energy density (Wrec), total energy density (Wtotal), and energy storage efficiency (η) as important parameters for evaluating the energy storage performance of dielectric ceramics.

[0003]

[0004] Where Pmax is the maximum polarization intensity, Pr is the remanent polarization intensity, and E is the applied electric field intensity. According to the above formula, a large ΔP(Pmax-Pr) and a high breakdown electric field strength (BDS) are essential conditions for obtaining a high Wrec. The dielectric materials used in energy storage capacitors mainly include linear ceramics, ferroelectric ceramics, antiferroelectric ceramics, and relaxor ferroelectric ceramics. Currently, the linear ceramic systems used for energy storage applications are mainly SrTiO3-based ceramics; the ferroelectric ceramic systems are mainly BaTiO3-based ceramics; and the antiferroelectric ceramic systems are mainly PbZrO3-based ceramics. Relaxor ferroelectric ceramics are very suitable for energy storage applications because they have high Pmax, low Pr, and relatively high BDS. Furthermore, the reliable thermal stability, superior power density, and fast charge / discharge rate of relaxor ferroelectrics also make them suitable for pulse capacitor applications.

[0005] Dielectric ceramics are well-suited for pulsed power applications due to their ultrafast charge / discharge rates and excellent reliability. High application electric fields can limit their use in miniaturized and integrated electronic devices, as well as in wearable or implantable devices requiring low fields. Therefore, improvements under low electric fields are crucial, as low energy density at low electric fields remains a bottleneck for their use in miniaturized integrated electronics. Thus, the electric field provided to dielectric energy storage devices should be significantly lower than the breakdown electric field to ensure the safety of the material and associated supporting insulation systems, especially at high temperatures where defect mobility increases. Indeed, the Wr of ceramics decreases rapidly as the electric field decreases. By using defect engineering, grain size refinement, interface engineering, and stress engineering, the Wr and η of dielectric ceramics under low fields can be continuously optimized. However, high application electric fields can limit their use in miniaturized and integrated electronic devices, as well as in wearable or implantable devices requiring low fields. Therefore, improvements under low electric fields are crucial.

[0006] In 2022, Wang et al. studied a dielectric thin film that achieved a dielectric strength of 1.7 MV cm⁻¹. -1 86 Jcm was obtained under a low electric field -3 The huge W r However, the energy storage performance of the thin film itself may decrease with temperature changes, especially under extreme temperature conditions. Wang et al. also discovered a BNT-based dielectric ceramic in 2024 that achieved a voltage of 170 kV / cm². -1 At low field, 38 μC / cm can be obtained. 2 The polarization intensity is high, while the energy storage density is 2.7 J / cm³. -3 However, research on its charge-discharge performance and fatigue resistance under variable frequencies is lacking, making it impossible to confirm its feasibility for practical application under a wide range of operating conditions. To improve the relaxation characteristics of BCZT and achieve higher polarization under low electric fields, researchers have conducted extensive studies using A / B site composition modulation. However, the composition of current calcium barium zirconate titanate-based energy storage ceramic materials is generally too complex. Most studies on calcium barium zirconate titanate-based energy storage ceramics achieve this by increasing Wrec through A / B site co-doping and constructing complex solid solutions, often requiring high electric fields to obtain good energy storage characteristics. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a low-power, high-polarization dielectric ceramic and its preparation method, so as to solve the shortcomings of the prior art such as poor energy storage performance, low polarization intensity, low breakdown strength and low energy storage efficiency of calcium barium zirconate titanate-based energy storage ceramic materials.

[0008] To achieve the above objectives, the present invention employs the following technical solution:

[0009] A low-power, high-polarization dielectric ceramic with the structural formula: (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3, where x = 0.05~0.5.

[0010] A further improvement of the present invention is that:

[0011] Preferably, x is 0.05, 0.10, 0.20, 0.30 or 0.50.

[0012] Preferably, the energy storage density is 1.87–5.36 J / cm³. 3 The energy storage efficiency is 82.6%–88.5%.

[0013] A method for preparing the above-mentioned low-power, high-polarization dielectric ceramic includes the following steps:

[0014] Step 1, Preparation of Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 powder and NaNbO3 powder, according to (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3 stoichiometric ratio Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 powder and NaNbO3 powder were ball-milled and dried to obtain raw material powder;

[0015] Step 2: The raw material powder is granulated with polyvinyl alcohol, pressed into discs, and then sintered at a constant temperature to obtain calcium barium zirconate titanate-based ceramic material.

[0016] Preferably, in step 1, Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 The preparation process of O3 powder is as follows: CaCO3, BaCO3, TiO2 and ZrO2 are mixed according to the stoichiometric ratio, ball-milled and dried, the dried powder is pressed into blocks and pre-calcined to obtain block solids, the block solids are crushed and sieved to obtain BaCO3 powder. 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 powder.

[0017] Preferably, the pre-firing temperature is 1250-1350℃ and the pre-firing time is 2 hours.

[0018] Preferably, the preparation process of NaNbO3 powder is as follows: weigh Na2CO3 and Nb2O5 according to the stoichiometric ratio of NaNbO3, mix them by ball milling and then dry them, press the dried powder into blocks and pre-calcine them to obtain block solids, crush the block solids and sieve them to obtain NaNbO3 powder.

[0019] Preferably, the pre-firing temperature is 850℃ and the pre-firing time is 2h.

[0020] Preferably, in step 2, the raw material powder and polyvinyl alcohol are mixed and pressed into granules, and the granules are pressed into discs and then sintered at a constant temperature to obtain calcium barium zirconate titanate-based ceramic material.

[0021] Preferably, the sintering temperature is 1350–1400℃ and the sintering time is 3 hours.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention discloses a low-power, high-polarization calcium barium zirconate titanate-based ceramic material, wherein the ceramic material is selected from 0.70 Ba. 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-0.30NaNbO3(0.70BCZT-0.30NN) ceramics were used as the research object. The P of the 0.70BCZT-0.30NN ceramics was... max Value and P r The ion concentration is higher than that of pure BCZT. For 0.70BCZT-0.30NN, adjusting the ion ratio causes lattice expansion and other behaviors, which have a certain impact on the crystal structure of the material, resulting in a coexistence of tetragonal and cubic phases, enhancing the polarization characteristics of the material, and achieving higher polarization under low electric fields. Verification showed that 0.70BCZT-0.30NN ceramics, by adjusting the stoichiometry, can affect the structure, dielectric properties, relaxor ferroelectric properties, and energy storage properties of calcium barium zirconate titanate-based ceramics. The doping of NN with BCZT reduces the domain size of the entire ceramic material and gradually moves it towards the grain boundaries, that is, the domains undergo segregation-refinement behavior with the increase of NN content. Similar to many studies, the domain refinement behavior improves energy storage efficiency by weakening the coercive electric field of the ceramic system. At the same time, the domain segregation behavior induces high polarization walls (HPWs) with higher spontaneous polarization at the cubic phase interface with lower spontaneous polarization. Under the action of an applied electric field, the presence of HPWs not only avoids the polarization reduction behavior caused by domain refinement, but also causes them to increase abnormally. When the doping amount is 0.10, a large polarization intensity can be excited at a low field strength.

[0024] Furthermore, the material of this invention exhibits a slender hysteresis loop with a small loop area at room temperature, resulting in excellent energy storage density and efficiency, with an energy storage density reaching 1.87–5.36 J / cm². 3 The energy storage efficiency reaches 82.6%–88.5%. The ceramic material with the optimal stoichiometry in this invention exhibits excellent energy storage performance and can achieve high polarization under low electric fields, which can meet the needs of many low-power application scenarios and is expected to be applied in the field of advanced energy storage.

[0025] This invention also discloses a method for preparing a low-power, high-polarity calcium barium zirconate titanate-based ceramic material. This method involves uniformly mixing raw material powders, drying and sieving them, then pressing them into shape, and finally sintering. By adjusting the stoichiometric ratio, a calcium barium zirconate titanate-based ceramic material with high energy storage performance, low power consumption, and high polarization can be obtained. The preparation process of this invention is simple and easy to implement. The raw materials used do not contain polluting elements such as lead, are environmentally friendly, and do not contain rare earth elements or precious metal elements. The raw materials are inexpensive and suitable for industrial mass production. Attached Figure Description

[0026] Figure 1 Rietveld refined XRD patterns of low-power, high-polarization calcium barium zirconate titanate-based ceramic materials prepared in all embodiments;

[0027] In this figure, (a) is Example 1; (b) is Example 2; (c) is Example 3; (d) is Example 4; and (e) is Example 5.

[0028] Figure 2 Hysteresis loops of low-power, high-polarization calcium barium zirconate titanate-based ceramic materials prepared in all embodiments at room temperature (test electric field 50 kV / cm, test frequency 10 Hz);

[0029] Figure 3 Hysteresis loops of low-power, high-polarization calcium barium zirconate titanate-based ceramic materials prepared in all embodiments at room temperature (test electric field 200 kV / cm, test frequency 10 Hz);

[0030] Figure 4 Hysteresis loop of the low-power, high-polarization calcium barium zirconate titanate-based ceramic material prepared in Example 2 at room temperature (test electric fields of 50 kV / cm and 200 kV / cm, test frequency of 10 Hz);

[0031] Figure 5 Hysteresis loop of the low-power, high-polarization calcium barium zirconate titanate-based ceramic material prepared in Example 1 at room temperature (test frequency 10Hz);

[0032] Figure 6Hysteresis loop of the low-power, high-polarization calcium barium zirconate titanate-based ceramic material prepared in Example 2 at room temperature (test frequency 10Hz);

[0033] Figure 7 Hysteresis loop of the low-power, high-polarization calcium barium zirconate titanate-based ceramic material prepared in Example 3 at room temperature (test frequency 10Hz);

[0034] Figure 8 Hysteresis loop of the low-power, high-polarization calcium barium zirconate titanate-based ceramic material prepared in Example 4 at room temperature (test frequency 10Hz);

[0035] Figure 9 Hysteresis loop of the low-power, high-polarization calcium barium zirconate titanate-based ceramic material prepared in Example 5 at room temperature (test frequency 10Hz);

[0036] Figure 10 Transmission electron microscope image of the low-power, high-polarization calcium barium zirconate titanate-based ceramic material prepared in Example 4;

[0037] Figure 11 High-magnification transmission electron microscope image of the low-power, high-polarization calcium barium zirconate titanate-based ceramic material prepared in Example 4;

[0038] Figure 12 Dielectric temperature spectra of the low-power, high-polarization calcium barium zirconate titanate-based ceramic materials prepared in all embodiments at different temperatures. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings:

[0040] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0041] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0042] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0043] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0044] A low-power, high-polarity calcium barium zirconate titanate-based ceramic material with the chemical formula: (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3, where x = 0.05, 0.10, 0.20, 0.30, 0.50, and the five examples are represented as BCZT-0.05NN, BCZT-0.10NN, BCZT-0.20NN, BCZT-0.30NN, and BCZT-0.50NN, respectively.

[0045] Low-power, high-polarity calcium barium zirconate titanate-based ceramic materials exhibit energy storage densities ranging from 1.87 to 5.36 J / cm³ at room temperature. 3 The energy storage efficiency is between 82.6% and 88.5%.

[0046] The method for preparing the low-power, high-polarity barium calcium zirconate titanate-based ceramic material of the present invention includes the following steps:

[0047] (1) According to the chemical formula (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 will be used to analyze pure CaCO3, BaCO3, TiO2, and ZrO2, where x represents the mole fraction, and x = 0.05, 0.10, 0.20, 0.30, and 0.50. The five components are 0.95 BaCO3, BaCO3, TiO2, and ZrO2 respectively. 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3, 0.90Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1O3, 0.80Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3, 0.70Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3, 0.50Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 was mixed evenly by ball milling for 8 hours with deionized water as the medium, then dried at 90°C, passed through a 120-mesh sieve, pressed into blocks, and then pre-calcined at 1250-1350°C for 2 hours to obtain a block solid. The block solid was then crushed and passed through a 120-mesh sieve to obtain pre-calcined BCZT powder.

[0048] According to the chemical formula NaNbO3, analytical grade Na2CO3 and Nb2O5 were prepared and mixed evenly by ball milling for 8 hours with deionized water as the medium. Then, the mixture was dried at 90°C, passed through a 120-mesh sieve, pressed into blocks, and then pre-calcined at 850°C for 2 hours to obtain a block solid. The block solid was then crushed and passed through a 120-mesh sieve to obtain pre-calcined NaNbO3 powder.

[0049] (2) The BCZT pre-calcined powder and NaNbO3 pre-calcined powder obtained in step (1) are mixed in proportion (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 The O3-xNaNbO3 ingredients were weighed, ball-milled for 8 hours with anhydrous ethanol as the medium, then dried at 90°C and passed through a 120-mesh sieve to obtain the raw material powder.

[0050] (3) The raw material powder obtained in step (2) is granulated. Using polyvinyl alcohol (PVA) as a binder, the final powder is uniaxially pressed into granules with a diameter of 8 mm and a thickness of 1 mm. The holding time is 3 minutes and the pressure is 20 MPa. After being pressed into discs, the discs are sintered at 1350-1400℃ for 3 hours to obtain calcium barium zirconate titanate-based ceramic material with optimized energy storage by controlling the stoichiometric ratio.

[0051] (4) The prepared calcium barium zirconate titanate-based ceramic material with low power consumption and high polarization achieved by adjusting the stoichiometry was subjected to X-ray diffraction test.

[0052] (5) The sintered sample was processed into a thin sheet with smooth surfaces and a thickness of approximately 0.2 mm. Gold electrodes were then plated on the sheet. The ferroelectric properties were tested at different temperatures and frequencies, and the energy storage characteristics were calculated to obtain the recoverable energy storage density (W). rec Total energy storage density (W) total) and energy storage efficiency (η).

[0053] The following examples provide a clearer understanding of the invention, but are not intended to limit the scope of the invention.

[0054] Example 1

[0055] The chemical formula of the calcium barium zirconate titanate-based ceramic material in this example is: (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3, where x represents the mole fraction and x = 0.05, abbreviated as BCZT-0.05NN.

[0056] The preparation method of the above-mentioned low-power, high-polarization calcium barium zirconate titanate-based ceramic material includes the following steps:

[0057] (1) According to the chemical formula (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 will be prepared by mixing analytically pure CaCO3, BaCO3, TiO2 and ZrO2, where x represents the mole fraction and x = 0.05, using deionized water as the medium, by ball milling for 8 hours to mix evenly, then drying at 90°C, passing through a 120-mesh sieve, pressing into blocks, and then pre-calcining at 1230-1250°C for 2 hours to obtain a block solid. The block solid will then be crushed and passed through a 120-mesh sieve to obtain pre-calcined BCZT powder.

[0058] According to the chemical formula NaNbO3, analytical grade Na2CO3 and Nb2O5 were prepared and mixed evenly by ball milling for 8 hours with deionized water as the medium. Then, the mixture was dried at 90°C, passed through a 120-mesh sieve, pressed into blocks, and then pre-calcined at 850°C for 2 hours to obtain a block solid. The block solid was then crushed and passed through a 120-mesh sieve to obtain pre-calcined NaNbO3 powder.

[0059] (2) The BCZT pre-calcined powder and NaNbO3 pre-calcined powder obtained in step (1) are mixed in proportion (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 The O3-xNaNbO3 ingredients were weighed, ball-milled for 8 hours with anhydrous ethanol as the medium, then dried at 90°C and passed through a 120-mesh sieve to obtain the raw material powder.

[0060] (3) The raw material powder obtained in step (2) is granulated. Using polyvinyl alcohol (PVA) as a binder, the final powder is uniaxially pressed into granules with a diameter of 8 mm and a thickness of 1 mm. The holding time is 3 minutes, and the pressure is 20 MPa. After being pressed into discs, the discs are sintered at 1400℃ for 3 hours to obtain low power consumption and high polarization calcium barium zirconate titanate-based ceramic materials.

[0061] The prepared barium calcium zirconate titanate-based ceramic material was subjected to X-ray diffraction testing, such as... Figure 1 The XRD pattern shows that the ceramic material obtained in this embodiment has a pure perovskite structure, contains no other second phase, and has high crystallinity. The sintered sample was processed into a smooth sheet with a thickness of approximately 0.2 mm, plated with gold electrodes, and then its ferroelectric properties were tested at room temperature and a frequency of 10 Hz. Figure 2 The curve at x = 0.05 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. With a test electric field of 50 kV / cm, its maximum polarization intensity is 13.71 μC / cm. 2 ,like Figure 3 The curve at x = 0.05 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature with a test electric field of 200 kV / cm. It can be seen that its maximum polarization intensity is 25.93 μC / cm. 2 .like Figure 10 As shown, two large ferroelectric domains, 180° and 90°, can be observed in the 0.95BCZT-0.05NN range. Figure 12 The curve at x = 0.05 shows the relationship between the dielectric constant and temperature in this embodiment. As x increases, the Curie temperature (TC) shifts to higher temperatures, with ε increasing near room temperature at 0.80BCZT-0.20NN and 0.70BCZT-0.30NN. Figure 5 The figure shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. Based on the energy storage characteristics calculated from the hysteresis loop, the energy storage density of the energy storage ceramic in this embodiment can reach 1.87 J / cm³ at room temperature. 3 The energy storage efficiency can reach 82.6%. The energy storage characteristics of the energy storage ceramic material in this embodiment at room temperature are shown in Table 1.

[0062] Example 2

[0063] The chemical formula of the calcium barium zirconate titanate-based ceramic material in this example is: (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3, where x represents the mole fraction and x = 0.10, abbreviated as BCZT-0.10NN.

[0064] The preparation method of the above-mentioned low-power, high-polarization calcium barium zirconate titanate-based ceramic material includes the following steps:

[0065] (1) According to the chemical formula (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 will be prepared by mixing analytically pure CaCO3, BaCO3, TiO2 and ZrO2, where x represents the mole fraction and x = 0.10, using deionized water as the medium, by ball milling for 8 hours to mix evenly, then drying at 90°C, passing through a 120-mesh sieve, pressing into blocks, and then pre-calcining at 1230-1250°C for 2 hours to obtain a block solid. The block solid will then be crushed and passed through a 120-mesh sieve to obtain pre-calcined BCZT powder.

[0066] According to the chemical formula NaNbO3, analytical grade Na2CO3 and Nb2O5 were prepared and mixed evenly by ball milling for 8 hours with deionized water as the medium. Then, the mixture was dried at 90°C, passed through a 120-mesh sieve, pressed into blocks, and then pre-calcined at 850°C for 2 hours to obtain a block solid. The block solid was then crushed and passed through a 120-mesh sieve to obtain pre-calcined NaNbO3 powder.

[0067] (2) The BCZT pre-calcined powder and NaNbO3 pre-calcined powder obtained in step (1) are mixed in proportion (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 The O3-xNaNbO3 ingredients were weighed, ball-milled for 8 hours with anhydrous ethanol as the medium, then dried at 90°C and passed through a 120-mesh sieve to obtain the raw material powder.

[0068] The raw material powder obtained in step (2) is granulated. Using polyvinyl alcohol (PVA) as a binder, the final powder is uniaxially pressed into granules with a diameter of 8 mm and a thickness of 1 mm for 3 minutes. After being pressed into discs, the discs are sintered at 1400℃ for 3 hours to obtain a low-power, high-polarization calcium barium zirconate titanate-based ceramic material.

[0069] The prepared barium calcium zirconate titanate-based ceramic material was subjected to X-ray diffraction testing, such as... Figure 1 The XRD pattern shows that the ceramic material obtained in this embodiment has a pure perovskite structure, contains no other second phase, and has high crystallinity. The sintered sample was processed into a smooth sheet with a thickness of approximately 0.2 mm, plated with gold electrodes, and then its ferroelectric properties were tested at room temperature and a frequency of 10 Hz. Figure 2 The curve with x = 0.10 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. The test electric field is 50 kV / cm, and it can be seen that its maximum polarization intensity is 16.35 μC / cm. 2,like Figure 3 The curve with x = 0.10 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. The test electric field was 200 kV / cm, and it can be seen that its maximum polarization intensity is 32.37 μC / cm. 2 This is also the sample with the highest polarization intensity in all embodiments. For example... Figure 11 As shown, this embodiment uses an atomic-scale high-angle annular dark-field scanning transmission electron microscope. The image consists of three parts: two parts are the c-phase, and the remaining part is the t-phase. When the NNN doping concentration increases to 0.10, the c-phase appears, and interface polarization occurs between the t-phase, the c-phase, and adjacent c-phases. Figure 12 The curve for x = 0.10 shows the relationship between the dielectric constant and temperature in this embodiment. As x increases, the Curie temperature (TC) shifts to higher temperatures, with ε increasing near room temperature at 0.80BCZT-0.20NN and 0.70BCZT-0.30NN. Figure 6 The figure shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. Based on the energy storage characteristics calculated from the hysteresis loop, the energy storage density of the energy storage ceramic in this embodiment can reach 3.69 J / cm³ at room temperature. 3 The energy storage efficiency can reach 75.6%. The energy storage characteristics of the energy storage ceramic material in this embodiment at room temperature are shown in Table 1.

[0070] Example 3

[0071] The chemical formula of the calcium barium zirconate titanate-based ceramic material in this example is: (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3, where x represents the mole fraction and x = 0.20, abbreviated as BCZT-0.20NN.

[0072] The preparation method of the above-mentioned low-power, high-polarization calcium barium zirconate titanate-based ceramic material includes the following steps:

[0073] (1) According to the chemical formula (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 will be prepared by mixing analytically pure CaCO3, BaCO3, TiO2 and ZrO2, where x represents the mole fraction and x = 0.20, using deionized water as the medium, by ball milling for 8 hours to mix evenly, then drying at 90°C, passing through a 120-mesh sieve, pressing into blocks, and then pre-calcining at 1230-1250°C for 2 hours to obtain block solids. The block solids will then be pulverized and passed through a 120-mesh sieve to obtain pre-calcined BCZT powder.

[0074] According to the chemical formula NaNbO3, analytical grade Na2CO3 and Nb2O5 were prepared and mixed evenly by ball milling for 8 hours with deionized water as the medium. Then, the mixture was dried at 90°C, passed through a 120-mesh sieve, pressed into blocks, and then pre-calcined at 850°C for 2 hours to obtain a block solid. The block solid was then crushed and passed through a 120-mesh sieve to obtain pre-calcined NaNbO3 powder.

[0075] (2) The BCZT pre-calcined powder and NaNbO3 pre-calcined powder obtained in step (1) are mixed in proportion (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 The O3-xNaNbO3 ingredients were weighed, ball-milled for 8 hours with anhydrous ethanol as the medium, then dried at 90°C and passed through a 120-mesh sieve to obtain the raw material powder.

[0076] The raw material powder obtained in step (2) is granulated. Using polyvinyl alcohol (PVA) as a binder, the final powder is uniaxially pressed into granules with a diameter of 8 mm and a thickness of 1 mm for 3 minutes. After being pressed into discs, the discs are sintered at 1360℃ for 3 hours to obtain a low-power, high-polarization calcium barium zirconate titanate-based ceramic material.

[0077] The prepared barium calcium zirconate titanate-based ceramic material was subjected to X-ray diffraction testing, such as... Figure 1 The XRD pattern shows that the ceramic material obtained in this embodiment has a pure perovskite structure, contains no other second phase, and has high crystallinity. The sintered sample was processed into a smooth sheet with a thickness of approximately 0.2 mm, plated with gold electrodes, and then its ferroelectric properties were tested at room temperature and a frequency of 10 Hz. Figure 2 The curve at x = 0.20 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. With a test electric field of 50 kV / cm, its maximum polarization intensity is 11.79 μC / cm. 2 ,like Figure 3 The curve at x = 0.20 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature with a test electric field of 200 kV / cm. It can be seen that its maximum polarization intensity is 23.49 μC / cm. 2 .like Figure 12 The curve for x = 0.20 shows the relationship between the dielectric constant and temperature in this embodiment. As x increases, the Curie temperature (TC) shifts to higher temperatures, with ε increasing near room temperature at 0.80BCZT-0.20NN and 0.70BCZT-0.30NN. Figure 7 The figure shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. Based on the energy storage characteristics calculated from the hysteresis loop, the energy storage density of the energy storage ceramic in this embodiment can reach 4.05 J / cm³ at room temperature.3 The energy storage efficiency can reach 80.9%. The energy storage characteristics of the energy storage ceramic material in this embodiment at room temperature are shown in Table 1.

[0078] Example 4

[0079] The chemical formula of the calcium barium zirconate titanate-based ceramic material in this example is: (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3, where x represents the mole fraction and x = 0.30, abbreviated as BCZT-0.30NN.

[0080] The preparation method of the above-mentioned low-power, high-polarization calcium barium zirconate titanate-based ceramic material includes the following steps:

[0081] (1) According to the chemical formula (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 will be prepared by mixing analytically pure CaCO3, BaCO3, TiO2 and ZrO2, where x represents the mole fraction and x = 0.30, using deionized water as the medium, by ball milling for 8 hours to mix evenly, then drying at 90°C, passing through a 120-mesh sieve, pressing into blocks, and then pre-calcining at 1230-1250°C for 2 hours to obtain block solids. The block solids will then be pulverized and passed through a 120-mesh sieve to obtain pre-calcined BCZT powder.

[0082] According to the chemical formula NaNbO3, analytical grade Na2CO3 and Nb2O5 were prepared and mixed evenly by ball milling for 8 hours with deionized water as the medium. Then, the mixture was dried at 90°C, passed through a 120-mesh sieve, pressed into blocks, and then pre-calcined at 850°C for 2 hours to obtain a block solid. The block solid was then crushed and passed through a 120-mesh sieve to obtain pre-calcined NaNbO3 powder.

[0083] (2) The BCZT pre-calcined powder and NaNbO3 pre-calcined powder obtained in step (1) are mixed in proportion (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 The O3-xNaNbO3 ingredients were weighed, ball-milled for 8 hours with anhydrous ethanol as the medium, then dried at 90°C and passed through a 120-mesh sieve to obtain the raw material powder.

[0084] The raw material powder obtained in step (2) is granulated. Using polyvinyl alcohol (PVA) as a binder, the final powder is uniaxially pressed into granules with a diameter of 8 mm and a thickness of 1 mm for 3 minutes. After being pressed into discs, the discs are sintered at 1360℃ for 3 hours to obtain a low-power, high-polarization calcium barium zirconate titanate-based ceramic material.

[0085] The prepared barium calcium zirconate titanate-based ceramic material was subjected to X-ray diffraction testing, such as... Figure 1 The XRD pattern shows that the ceramic material obtained in this embodiment has a pure perovskite structure, contains no other second phase, and has high crystallinity. The sintered sample was processed into a smooth sheet with a thickness of approximately 0.2 mm, plated with gold electrodes, and then its ferroelectric properties were tested at room temperature and a frequency of 10 Hz. Figure 2 The curve at x = 0.30 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature with a test electric field of 50 kV / cm. It can be seen that its maximum polarization intensity is 8.20 μC / cm. 2 ,like Figure 3 The curve at x = 0.30 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature with a test electric field of 200 kV / cm. It can be seen that its maximum polarization intensity is 19.31 μC / cm. 2 .like Figure 12 The curve for x = 0.30 shows the relationship between the dielectric constant and temperature in this embodiment. As x increases, the Curie temperature (TC) shifts to higher temperatures, with ε increasing near room temperature at 0.80BCZT-0.20NN and 0.70BCZT-0.30NN. Figure 8 The figure shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. Based on the energy storage characteristics calculated from the hysteresis loop, the energy storage density of the energy storage ceramic in this embodiment can reach 5.36 J / cm³ at room temperature. 3 The energy storage efficiency can reach 84.1%. The energy storage characteristics of the energy storage ceramic material in this embodiment at room temperature are shown in Table 1.

[0086] Example 5

[0087] The chemical formula of the calcium barium zirconate titanate-based ceramic material in this example is: (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3, where x represents the mole fraction and x = 0.50, abbreviated as BCZT-0.50NN.

[0088] The preparation method of the above-mentioned low-power, high-polarization calcium barium zirconate titanate-based ceramic material includes the following steps:

[0089] (1) According to the chemical formula (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1O3 will be prepared by mixing analytically pure CaCO3, BaCO3, TiO2 and ZrO2, where x represents the mole fraction and x = 0.50, using deionized water as the medium, by ball milling for 8 hours to mix evenly, then drying at 90°C, passing through a 120-mesh sieve, pressing into blocks, and then pre-calcining at 1230-1250°C for 2 hours to obtain block solids. The block solids will then be pulverized and passed through a 120-mesh sieve to obtain pre-calcined BCZT powder.

[0090] According to the chemical formula NaNbO3, analytical grade Na2CO3 and Nb2O5 were prepared and mixed evenly by ball milling for 8 hours with deionized water as the medium. Then, the mixture was dried at 90°C, passed through a 120-mesh sieve, pressed into blocks, and then pre-calcined at 850°C for 2 hours to obtain a block solid. The block solid was then crushed and passed through a 120-mesh sieve to obtain pre-calcined NaNbO3 powder.

[0091] (2) The BCZT pre-calcined powder and NaNbO3 pre-calcined powder obtained in step (1) are mixed in proportion (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 The O3-xNaNbO3 ingredients were weighed, ball-milled for 8 hours with anhydrous ethanol as the medium, then dried at 90°C and passed through a 120-mesh sieve to obtain the raw material powder.

[0092] The raw material powder obtained in step (2) is granulated. Using polyvinyl alcohol (PVA) as a binder, the final powder is uniaxially pressed into granules with a diameter of 8 mm and a thickness of 1 mm for 3 minutes. After being pressed into discs, the discs are sintered at 1350℃ for 3 hours to obtain a low-power, high-polarization calcium barium zirconate titanate-based ceramic material.

[0093] The prepared barium calcium zirconate titanate-based ceramic material was subjected to X-ray diffraction testing, such as... Figure 1 The XRD pattern shows that the ceramic material obtained in this embodiment has a pure perovskite structure, contains no other second phase, and has high crystallinity. The sintered sample was processed into a smooth sheet with a thickness of approximately 0.2 mm, plated with gold electrodes, and then its ferroelectric properties were tested at room temperature and a frequency of 10 Hz. Figure 2 The curve at x = 0.50 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature, with a test electric field of 50 kV / cm. It can be seen that its maximum polarization intensity is 6.91 μC / cm. 2 ,like Figure 3 The curve at x = 0.50 shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature with a test electric field of 200 kV / cm. It can be seen that its maximum polarization intensity is 16.23 μC / cm. 2 .like Figure 12The curve at x = 0.50 shows the relationship between the dielectric constant and temperature in this embodiment. As x increases, the Curie temperature (TC) shifts to higher temperatures, with ε increasing near room temperature at 0.80BCZT-0.20NN and 0.70BCZT-0.30NN. Figure 9 The figure shows the hysteresis loop of the ceramic material in this embodiment measured at room temperature. Based on the energy storage characteristics calculated from the hysteresis loop, the energy storage density of the energy storage ceramic in this embodiment can reach 3.03 J / cm³ at room temperature. 3 The energy storage efficiency can reach 88.5%. The energy storage characteristics of the energy storage ceramic material in this embodiment at room temperature are shown in Table 1.

[0094] Table 1. Energy storage characteristics of low-power, high-polarization barium calcium zirconate titanate-based ceramic materials at room temperature and 10 Hz in the examples.

[0095]

[0096]

[0097] Table 2. Polarization intensity of low-power, high-polarization barium calcium zirconate titanate-based ceramic materials at 50 kV / cm and 200 kV / cm in the examples.

[0098]

[0099] As shown in Table 1, Example 4 of this invention is the matrix with the best energy storage performance. Due to the coexistence of tetragonal and cubic phases in the matrix, Example 4 has the largest breakdown field strength, so this matrix has the optimal stoichiometry. The energy storage density and efficiency can reach 5.36 J / cm² at room temperature. 3 And 84.1%; it can be seen from the above examples that doping Na into the BCZT matrix + and Nb 5+ The proportion of [specific element] significantly affects the energy storage performance of ceramics. This method effectively improves upon the shortcomings of low dielectric breakdown field strength and energy density, as well as high dielectric loss, found in traditional calcium barium zirconate titanate-based ceramic dielectric materials. The prepared calcium barium zirconate titanate-based energy storage ceramic dielectric material exhibits excellent energy storage performance and can achieve high polarization under low electric fields. Therefore, this ceramic can meet the requirements of some low-power applications and is suitable for a wide operating temperature, frequency range, and application field, showing promise for use in advanced energy storage systems.

[0100] As shown in Table 2, Example 2 of this invention exhibits the highest polarization intensity at low electric fields of 50 kV / cm and 200 kV / cm. Therefore, this example represents the optimal composition, with a polarization intensity reaching 16.35 μc / cm at room temperature. 2 and 32.37 μc / cm 2Therefore, this ceramic can meet some low-power application scenarios and can provide a promising method for the design of high-performance lead-free energy storage ceramics under low electric field conditions.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-power, high-polarization dielectric ceramic, characterized in that, The structural formula is: (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3, The x value is 0.05, 0.10, 0.20, 0.30, or 0.50; the energy storage density is 1.87~5.36 J / cm³. 3 The energy storage efficiency is 82.6%~88.5%. The method for preparing low-power, high-polarization dielectric ceramics includes the following steps: Step 1, Preparation of Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 powder and NaNbO3 powder, according to (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3 stoichiometric ratio Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 powder and NaNbO3 powder were ball-milled and dried to obtain raw material powder; Step 2: Granulate the raw material powder with polyvinyl alcohol, press it into discs, and then sinter it at a constant temperature to obtain calcium barium zirconate titanate-based ceramic material. The sintering temperature is 1350~1400 ℃, and the sintering time is 3h.

2. A method for preparing the low-power, high-polarization dielectric ceramic according to claim 1, characterized in that, Includes the following steps: Step 1, Preparation of Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 powder and NaNbO3 powder, according to (1-x)Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3-xNaNbO3 stoichiometric ratio Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 powder and NaNbO3 powder were ball-milled and dried to obtain raw material powder; Step 2: The raw material powder is granulated with polyvinyl alcohol, pressed into discs, and then sintered at a constant temperature to obtain calcium barium zirconate titanate-based ceramic material.

3. The method for preparing low-power, high-polarization dielectric ceramics according to claim 2, characterized in that, In step 1, Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 The preparation process of O3 powder is as follows: CaCO3, BaCO3, TiO2 and ZrO2 are mixed according to the stoichiometric ratio, ball-milled and dried, the dried powder is pressed into blocks and pre-calcined to obtain block solids, the block solids are crushed and sieved to obtain BaCO3 powder. 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O3 powder.

4. The method for preparing low-power, high-polarization dielectric ceramics according to claim 3, characterized in that, The pre-firing temperature is 1250~1350 ℃, and the pre-firing time is 2h.

5. The method for preparing low-power, high-polarization dielectric ceramics according to claim 2, characterized in that, The preparation process of NaNbO3 powder is as follows: Na2CO3 and Nb2O5 are weighed according to the stoichiometric ratio of NaNbO3, ball-milled and mixed, and then dried. The dried powder is pressed into blocks and pre-calcined to obtain block solids. The block solids are crushed and sieved to obtain NaNbO3 powder.

6. The method for preparing low-power, high-polarization dielectric ceramics according to claim 5, characterized in that, The pre-firing temperature is 850℃ and the pre-firing time is 2 hours.

7. The method for preparing low-power, high-polarization dielectric ceramics according to claim 2, characterized in that, In step 2, the raw material powder and polyvinyl alcohol are mixed and pressed into granules. The granules are then pressed into discs and sintered at a constant temperature to obtain calcium barium zirconate titanate-based ceramic material.

8. The method for preparing low-power, high-polarization dielectric ceramic according to claim 7, characterized in that, The sintering temperature is 1350~1400 ℃, and the sintering time is 3h.

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