High-entropy antiferroelectric ceramic material with high energy storage performance and preparation method and application thereof

Abstract

The application relates to a high-entropy antiferroelectric ceramic material with high energy storage performance and a preparation method and application thereof. 0.2 Ca 0.2 Pb 0.2 Bi 0.2‑x La x Na 0.2 )TiO3, wherein 0 The application successfully designs and obtains a high-entropy antiferroelectric ceramic for the first time, has excellent high energy storage efficiency and high energy storage density, and is widely applied to multilayer ceramic capacitors.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of functional ceramics, and relates to a high-entropy antiferroelectric ceramic material with high energy storage performance and a preparation method and application thereof. BACKGROUND

[0002] High-performance energy storage capacitors based on dielectric materials are an important component of advanced high-power / pulse power electronic systems. Dielectric capacitors have the largest power density, ultrafast charge and discharge rate, and long service time due to their unique electrostatic energy storage mechanism. Therefore, it has been widely used in various high-tech fields, including medical equipment, military equipment and hybrid electric vehicles. The energy storage performance of dielectric capacitors mainly depends on its dielectric layer, but the energy density of commercial dielectric materials is low, which seriously hinders its wider application and the development trend of miniaturization, light weight and low cost. The dielectric materials used as pulse capacitors mainly include linear ceramics, ferroelectric ceramics and antiferroelectric ceramics. Among them, antiferroelectric ceramics are considered to be the most promising material for pulse power capacitors due to their high saturation polarization and low residual polarization. However, due to the huge difference between the positive and negative turning fields, antiferroelectrics exhibit significant hysteresis, greatly reducing the energy storage efficiency and energy storage density. Therefore, it is of great significance to develop antiferroelectric ceramic materials with high energy storage density and energy storage efficiency.

[0003] Recent studies have shown that the high-entropy strategy is an effective and flexible method to improve the physical properties of ferroelectrics. Through its fine design of local polarization configuration and other intrinsic effects caused by entropy increase, such as high-entropy stable phase structure, lattice disorder, lattice distortion to inhibit grain coarsening, improved mechanical properties, and cocktail effect, it has become a new way to promote dielectric energy storage. For example, by introducing multiple elements into the A and B sites of the perovskite structure, multiple-state local distortion is induced, resulting in super-small polar nanoregions, enhanced breakdown field, and delayed polarization saturation, significantly improving the energy storage performance of potassium sodium niobate-based ferroelectric ceramics (Ref: Nat. Commun., 2022, 13(1), 3089.). Researchers have also introduced multiple elements into the Bi and Ti sites of the pyrochlore structure in mole ratio to use configurational entropy as a quantitative evaluation index of local composition inhomogeneity (relaxation characteristics), and through the fine design of entropy, excellent energy storage performance has been achieved (Ref: Nat. Mater., 2022, 21, 1074-1080., Nat. Energy, 2023, 14, 956-964.). Similarly, researchers have introduced five elements into the A site of the tungsten bronze structure in mole ratio, and the high disorder and lattice distortion introduced by the high-entropy strategy have enhanced the relaxation characteristics and electric strength, achieving excellent energy storage performance (Ref: Nat. Commun., 2024, 15(1), 5232.). Currently, the research and development of high-entropy ceramics are mostly focused on linear ceramics and ferroelectric ceramics, and there is no report on high-entropy antiferroelectric ceramic systems. If high-entropy antiferroelectric ceramics can be developed using high-entropy design methods, it is expected to obtain antiferroelectric ceramic materials with relaxation characteristics, and to achieve high electric strength, energy storage density, and energy storage efficiency. The concept of high-entropy design can provide new ideas for the design and development of high-performance antiferroelectric ceramic materials. SUMMARY

[0004] To solve the above problems, the present application considers the effectiveness of the high-entropy strategy in designing high-performance dielectric energy storage ceramic materials and successfully designs and obtains high-entropy antiferroelectric ceramics for the first time. The purpose of the present application is to provide a high-entropy antiferroelectric ceramic material with high energy storage performance and its preparation method and application.

[0005] In a first aspect, the present application provides a high-entropy antiferroelectric ceramic material with high energy storage performance, the composition chemical formula of the high-entropy antiferroelectric ceramic material is: (Sr 0.2 Ca 0.2 Pb 0.2 Bi 0.2-x La x Na 0.2 )TiO3, wherein 0 < x < 0.20.

[0006] Preferably, x = 0.10-0.16; preferably, x = 0.14.

[0007] The application introduces six different radius and valence ions into the A site of the perovskite structure by the strategy of high-entropy design of the A site, to prepare a high-entropy antiferroelectric ceramic, and further regulates the antiferroelectricity of the ceramic material by a component regulation method, and higher energy storage density and energy storage efficiency are obtained.

[0008] Preferably, the configurational entropy ΔS of the high-entropy antiferroelectric ceramic material is ≥1.61R. mix

[0009] Preferably, the breakdown electric field of the high-entropy antiferroelectric ceramic material is 527-878 kV / cm.

[0010] Preferably, the recoverable energy storage density of the high-entropy antiferroelectric ceramic material is 7.1-10.9 J / cm 3 .

[0011] Preferably, the energy storage efficiency of the high-entropy antiferroelectric ceramic material is 81.1%-87.5%.

[0012] In a second aspect, the application provides a preparation method of a high-entropy antiferroelectric ceramic material with high energy storage performance, comprising:

[0013] (1) taking strontium carbonate powder, calcium carbonate powder, lead oxide powder, bismuth oxide powder, lanthanum oxide powder, sodium carbonate powder, and titanium dioxide powder as raw materials, weighing and mixing according to the stoichiometric ratio of the high-entropy antiferroelectric ceramic material, and performing pre-sintering treatment to obtain a ceramic powder;

[0014] (2) after the ceramic powder is finely ground, a binder is added, and granulation, sieving and die pressing are performed to obtain a green ceramic body;

[0015] (3) the green ceramic body is subjected to plastic removal and sintering to obtain the high-entropy antiferroelectric ceramic material.

[0016] Preferably, in step (1), the mixing is performed by ball milling; and the ball milling parameters include: anhydrous ethanol as the ball milling medium, a ball milling speed of 200-240 rpm, and a ball milling time of 4-6 hours.

[0017] The pre-sintering temperature is 900-1000℃, the pre-sintering time is 2-3 hours, and the pre-sintering rate is 1-3℃ / min.

[0018] Preferably, in step (2), the binder is a polyvinyl alcohol aqueous solution with a concentration of 6-7 wt.%; and the amount of the binder added is 6-7 wt.% of the mass of the ceramic powder.

[0019] ​The parameters of the fine grinding include: anhydrous ethanol as the ball milling medium, a rotation speed of 200-240 rpm, and a time of 4-6 hours.

[0020] The screen mesh of the sieving is 40 mesh.

[0021] Preferably, in step (3), the temperature of the plastic removal is 750-850 DEG C, and the time is 2-3 hours; preferably, the temperature of the plastic removal is 800 DEG C, and the time is 2 hours.

[0022] Preferably, in step (3), the parameters of the sintering include: a sintering temperature of 1100-1200 DEG C, a time of 2-3 hours, and a heating rate of 1-3 DEG C / min; preferably, the heating rate of the sintering is 2 DEG C / min.

[0023] In a third aspect, the application provides an energy storage ceramic element, comprising: a high-entropy antiferroelectric ceramic material with high energy storage performance, and electrodes distributed on the surface of the high-entropy ceramic material.

[0024] In a fourth aspect, the application provides an application of a high-entropy antiferroelectric ceramic material with high energy storage performance in a multi-layer ceramic capacitor (MLCC).

[0025] Beneficial effects:

[0026] In the application, (Sr 0.2 Ca 0.2 Pb 0.2 Bi 0.2-x La x Na 0.2 )TiO3(0<x<0.20) high-entropy antiferroelectric ceramic material is prepared for the first time. The high-entropy introduction enhances the relaxation characteristics and promotes the formation of small-size polar nanodomains, so that the ceramic hysteresis loop is refined, which is beneficial to obtain high energy storage efficiency; the strong lattice distortion refines the grains and enhances the electric strength, which is beneficial to obtain high energy storage density. Further, the component regulation method is used to regulate the antiferroelectricity of the ceramic, and the best energy storage characteristics are realized. The preparation process of the application is simple, the energy storage performance is excellent, and the application is suitable for the preparation and application of multi-layer capacitors. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is an X-ray diffraction pattern of the ceramic material prepared in Examples 1-4 and Comparative Examples 1 and 2;

[0028] Figure 2 is a surface micro-morphology diagram of the high-entropy antiferroelectric ceramic material in Example 1;

[0029] Figure 3is a surface micrograph of the high-entropy antiferroelectric ceramic material in Example 1 ;

[0030] Figure 4 is a surface micrograph of the high-entropy antiferroelectric ceramic material in Example 3;

[0031] Figure 5 is a surface micrograph of the high-entropy antiferroelectric ceramic material in Example 4;

[0032] Figure 6 is a dielectric temperature spectrum of the high-entropy antiferroelectric ceramic material in Example 1;

[0033] Figure 7 is a dielectric temperature spectrum of the high-entropy antiferroelectric ceramic material in Example 2;

[0034] Figure 8 is a dielectric temperature spectrum of the high-entropy antiferroelectric ceramic material in Example 3;

[0035] Figure 9 is a dielectric temperature spectrum of the high-entropy antiferroelectric ceramic material in Example 4;

[0036] Figure 10 is a bipolar electric hysteresis loop diagram of the high-entropy antiferroelectric ceramic materials in Examples 1-4 and Comparative Examples 1, 2;

[0037] Figure 11 is a current curve diagram of the high-entropy antiferroelectric ceramic materials in Examples 1-4 and Comparative Examples 1, 2;

[0038] Figure 12 is a unipolar electric hysteresis loop diagram of the high-entropy antiferroelectric ceramic materials in Examples 1-4 and Comparative Examples 1, 2;

[0039] Figure 13 is a surface micrograph of the high-entropy ceramic material in Comparative Example 1;

[0040] Figure 14 is a surface micrograph of the high-entropy ceramic material in Comparative Example 2;

[0041] Figure 15 is a dielectric temperature spectrum of the high-entropy ceramic material in Comparative Example 1;

[0042] Figure 16 is a dielectric temperature spectrum of the high-entropy ceramic material in Comparative Example 2;

[0043] Figure 17 is a comparison diagram of the energy storage performance of the high-entropy antiferroelectric ceramic materials in Examples 1-4 and Comparative Examples 1, 2. DETAILED DESCRIPTION

[0044] To further explain the invention content, features and actual effects of the present application, the following detailed description of the present application is combined with examples. It should be noted that the design of the modification method of the present application is not limited to these specific embodiments. Without departing from the spirit and content of the present application, equivalent substitutions and modifications made by those skilled in the art on the basis of the content of the present application are also within the scope of the present application.

[0045] Firstly, the present application provides a high-entropy antiferroelectric ceramic with high energy storage performance, the composition chemical formula of the high-entropy antiferroelectric ceramic material is: (Sr 0.2 Ca 0.2 Pb 0.2 Bi 0.2-x La x Na 0.2 )TiO3, wherein 0<x<0.20. The present application first obtains a high-entropy antiferroelectric ceramic through high-entropy design of A-site multi-elements. Specifically, the present application is based on the antiferroelectric gene of strontium calcium titanate and bismuth sodium titanate, introduces high-polar Pb 2+ , introduces La 3+ to stabilize the antiferroelectricity, designs the high-entropy antiferroelectric component in an equimolar ratio (wherein the sum of Bi 3+ and La 3+ accounts for 20%), and further increases the La 3+ content to regulate the antiferroelectricity, so as to realize the optimal comprehensive energy storage performance.

[0046] The configuration entropy of the high-entropy antiferroelectric ceramic material prepared by the present application is ΔS mix ≥1.61R; the breakdown electric field of the high-entropy antiferroelectric ceramic material is 527-878kV / cm; the recoverable energy storage density of the high-entropy antiferroelectric ceramic material is 7.1-10.9J / cm 3 ; and the energy storage efficiency of the high-entropy antiferroelectric ceramic material is 81.1%-87.5%. The electric field-current curve of the high-entropy antiferroelectric ceramic material has four current peaks of antiferroelectricity, and the reversible antiferroelectric-ferroelectric phase transition occurs at the turning electric field; the high-entropy antiferroelectric ceramic material has the relaxation characteristics of a slender hysteresis loop.

[0047] In the present application, the high-entropy antiferroelectric ceramic material is prepared by a solid phase method, and the process flow is simple. The following exemplarily describes the preparation method of the high-entropy antiferroelectric ceramic material with high energy storage performance provided by the present application.

[0048] Strontium carbonate powder, calcium carbonate powder, lead oxide powder, bismuth oxide powder, lanthanum oxide powder, sodium carbonate powder, and titanium dioxide powder are used as raw materials, weighed and mixed according to the stoichiometric ratio of the high-entropy antiferroelectric ceramic material, and pre-sintered to obtain ceramic powder.

[0049] In an optional embodiment, the mixing method is ball milling; the parameters of the ball milling include: anhydrous ethanol as the ball milling medium, a ball milling rotation speed of 200 to 240 rpm, and a time of 4 to 6 hours.

[0050] In an optional embodiment, the pre-sintering treatment is performed at a temperature of 900-1000° C., for 2-3 hours, and at a heating rate of 1-3° C. / min (eg, 2° C. / min).

[0051] The obtained ceramic powder is finely ground, a binder is added, and the powder is granulated, sieved and molded to obtain a ceramic green body.

[0052] In an alternative embodiment, the fine grinding parameters include: anhydrous ethanol as the ball milling medium, a rotation speed of 200-240 rpm, and a time of 4-6 hours. The sieving screen is a 40-mesh screen. The binder is a polyvinyl alcohol aqueous solution with a concentration of 6-7 wt.%, and the binder is added in an amount of 6-7 wt.% of the ceramic powder.

[0053] The obtained ceramic green body is subjected to plastic removal and sintering to obtain the high entropy antiferroelectric ceramic material.

[0054] In an optional embodiment, the temperature of the plastic discharge is 750-850° C., and the time is 2-3 hours; preferably, the temperature of the plastic discharge is 800° C., and the time is 2 hours.

[0055] In an optional embodiment, the obtained ceramic body is coated with the obtained ceramic powder and sintered under closed conditions. The sintering parameters include: a sintering temperature of 1100-1200°C, a sintering time of 2-3 hours, and a heating rate of 1-3°C / min; preferably, the sintering heating rate is 2°C / min.

[0056] In the present invention, the high-entropy antiferroelectric ceramic material has a simple composition and a simple preparation process, and has the characteristics of high breakdown strength, high energy storage density and high energy storage efficiency, and is suitable for the preparation and application of dielectric capacitors in pulse power capacitor devices.

[0057] The following examples are further given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description herein, and are not limited to the specific numerical values ​​exemplified below.

[0058] Example 1

[0059] The preparation process of the high-entropy antiferroelectric ceramic material with high energy storage performance provided by the embodiment 1 comprises the following steps:

[0060] (1) The raw materials including SrCO3, CaCO3, Pb3O4, Bi2O3, La2O3, Na2CO3 and TiO2 are weighed by an electronic balance, and the weighing accuracy is 0.001 g, and the purity of the raw material powder is higher than 99.0 %. 0.2 Ca 0.2 Pb 0.2 Bi 0.2-x La x Na 0.2 )TiO3(x=0.10) is calculated, the raw materials used include SrCO3, CaCO3, Pb3O4, Bi2O3, La2O3, Na2CO3 and TiO2, and the weighing is performed by an electronic balance, and the weighing accuracy is 0.001 g, and the purity of the raw material powder is higher than 99.0 %.

[0061] (2) The weighed raw materials are mixed and placed in a nylon tank, not more than 2 / 3 of the height of the tank is added with anhydrous ethanol, and the nylon tank is placed on a planetary ball mill with zirconium oxide balls as the medium for mixing for 6 hours (the particle size of the zirconium oxide balls used is 6 mm and 10 mm); then the mixture is poured out and dried in an oven, and then sieved through a 40-mesh nylon screen, and the sieved mixture is pressed into a cylindrical body with a size of 15 mm in diameter and 2 mm in height on a press; and then the cylindrical body is pre-fired at 900 ℃ for 2 hours in an air atmosphere, and then crushed and passed through a 40-mesh screen to obtain ceramic powder;

[0062] (3) The obtained ceramic powder is placed in a stirring mill, and the ceramic powder is further ground with zirconium balls with a diameter of 1 mm for 6 hours, and then poured out and dried in an oven;

[0063] (4) A polyvinyl alcohol aqueous solution with a concentration of 6 wt% is added to the finely ground ceramic powder, and the amount of the polyvinyl alcohol aqueous solution added is 6.5 % of the mass of the ceramic powder, and then the mixture is uniformly granulated, sieved through a 40-mesh screen, and molded to obtain small cylindrical ceramic green bodies with a size of 13 mm in diameter and 1 mm in height;

[0064] (5) The obtained ceramic green bodies are placed in a muffle furnace cavity for plastic removal, the plastic removal temperature is 800 ℃, the plastic removal time is 2 hours, and the plastic removal sample is taken out after natural cooling to room temperature;

[0065] (6) The plastic removal sample is placed in an alumina crucible and covered with ceramic powder for sealed sintering, the sintering temperature is 1160 ℃, the sintering time is 2 hours, and the sample is taken out after natural cooling to room temperature to obtain a high-entropy antiferroelectric ceramic material.

[0066] The high-entropy antiferroelectric ceramic prepared in the embodiment 1 is subjected to X-ray diffraction test, and the test result is as follows Figure 1As shown in the figure, the high-entropy antiferroelectric ceramic prepared in this embodiment 1 is single-phase perovskite structure without impurity phase.

[0067] The surface morphology of the ceramic prepared in embodiment 1 was photographed after surface treatment, as shown in the figure. Figure 2 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in this embodiment 1 has a dense surface, and the large and small grains are uniformly distributed, with a particle size of about 1.84 μm, and no impurity phase.

[0068] The ceramic prepared in embodiment 1 was ground and polished on both sides, silver electrodes were coated on both sides of the ceramic by screen printing, and silver sintering treatment was performed at 650 ℃ for 30 min. After cooling to room temperature, the dielectric properties were tested, and the test results are shown in the figure. Figure 6 As shown in the figure, the dielectric peak of the high-entropy antiferroelectric ceramic prepared in this embodiment 1 is widened, and the frequency dispersion phenomenon is obvious, which has strong relaxation characteristics.

[0069] The ceramic prepared in embodiment 1 was ground and polished on both sides, and gold electrodes were coated by ion sputtering for ferroelectric property testing. The test results are shown in the figure. Figure 10 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in this embodiment 1 has a typical antiferroelectric double electric hysteresis loop. Figure 11 The current curve of the high-entropy antiferroelectric ceramic prepared in embodiment 1 is shown in the figure. As shown in the figure, there are two obvious current peaks corresponding to the positive and negative turning fields, which further confirms the antiferroelectricity of the high-entropy antiferroelectric ceramic prepared in embodiment 1. Figure 12 The unipolar electric hysteresis loop of the high-entropy antiferroelectric ceramic prepared in embodiment 1 is shown in the figure. As shown in the figure, the breakdown field strength of the obtained high-entropy antiferroelectric ceramic is 527 kV·cm -1 , the energy storage density is 7.1 J·cm -3 , and the energy storage efficiency is 81.1%.

[0070] Embodiment 2

[0071] The preparation process of the high-entropy antiferroelectric ceramic material with high energy storage performance provided in this embodiment 2 refers to embodiment 1, and the only difference is that x = 0.12; in step (6), the sintering temperature is 1140 ℃.

[0072] The high-entropy antiferroelectric ceramic prepared in embodiment 2 was subjected to X-ray diffraction test, and the test results are shown in the figure. Figure 1 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in this embodiment 2 is single-phase perovskite structure without impurity phase.

[0073] The surface morphology of the ceramic prepared in embodiment 2 was photographed after surface treatment, as shown in the figure. Figure 3 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in this embodiment 1 has a dense surface, and the large and small grains are uniformly distributed, with a particle size of about 1.25 μm, and no impurity phase.

[0074] The ceramic obtained in Example 2 was ground and polished on both sides, silver electrodes were coated on both sides of the ceramic by screen printing, and silver firing was performed at 650 DEG C for 30 min. After cooling to room temperature, dielectric performance testing was performed, and the test results are shown in FIG. 2. Figure 7 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in Example 2 has a further decreased Curie temperature, a widened dielectric peak, and intensified frequency dispersion, indicating enhanced relaxation characteristics.

[0075] The ceramic obtained in Example 2 was ground and polished on both sides, and gold electrodes were coated by ion sputtering for ferroelectric performance testing. The test results are shown in FIG. 3. Figure 10 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in Example 2 exhibits antiferroelectric double electric hysteresis loops. Figure 11 The current curve of the high-entropy antiferroelectric ceramic obtained in Example 2 is shown in FIG. 4. As shown in the figure, there are two obvious current peaks corresponding to the positive and negative turning fields, confirming the antiferroelectricity of the high-entropy antiferroelectric ceramic obtained in Example 2. Figure 12 The unipolar electric hysteresis loop of the high-entropy antiferroelectric ceramic obtained in Example 2 is shown in FIG. 5. As shown in the figure, the breakdown field strength of the obtained high-entropy antiferroelectric ceramic is 629 kV·cm -1 , the energy storage density is 9.0 J·cm -3 , and the energy storage efficiency is 83.0%.

[0076] Example 3

[0077] The preparation process of the high-entropy antiferroelectric ceramic material with high energy storage performance provided in Example 3 refers to Example 1, and the only difference is that x = 0.14; in step (6), the sintering temperature is 1120 DEG C.

[0078] The high-entropy antiferroelectric ceramic prepared in Example 3 was subjected to X-ray diffraction testing, and the test results are shown in FIG. 6. Figure 1 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in Example 3 is free of impurity phases and is a single-phase perovskite structure.

[0079] The surface morphology of the ceramic obtained in Example 3 was photographed after surface treatment, as shown in FIG. 7. Figure 4 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in Example 3 has a dense surface, and the large and small grains are uniformly distributed with a particle size of about 1.16 μm, and is free of impurity phases.

[0080] The ceramic obtained in Example 3 was ground and polished on both sides, silver electrodes were coated on both sides of the ceramic by screen printing, and silver firing was performed at 650 DEG C for 30 min. After cooling to room temperature, dielectric performance testing was performed, and the test results are shown in FIG. 8. Figure 8 As shown in the figure, the high-entropy antiferroelectric ceramic prepared in Example 3 has a further decreased Curie temperature.

[0081] The ceramic obtained in Example 3 was ground and polished on both sides, and gold electrodes were plated by ion sputtering for ferroelectric performance testing. The test results are shown in Figure 10 As can be seen from the figure, the high-entropy antiferroelectric ceramic prepared in Example 3 has an antiferroelectric double hysteresis loop, and the relaxation characteristics are significantly enhanced. Figure 11 The current curve of the high-entropy antiferroelectric ceramic obtained in Example 3 is shown, and as can be seen from the figure, there are two obvious current peaks corresponding to the positive and negative turning fields, further confirming the antiferroelectricity of the high-entropy antiferroelectric ceramic obtained in Example 3. Figure 12 The unipolar hysteresis loop of the high-entropy antiferroelectric ceramic obtained in Example 3 is shown, and as can be seen from the figure, the breakdown field strength of the obtained high-entropy antiferroelectric ceramic is 878 kV·cm -1 , the energy storage density is 10.9 J·cm -3 , and the energy storage efficiency is 86.2%.

[0082] Example 4

[0083] The preparation process of the high-entropy antiferroelectric ceramic material with high energy storage performance provided in this embodiment 4 refers to Example 1, and the only difference is that x = 0.16; in step (6), the sintering temperature is 1100°C.

[0084] The high-entropy antiferroelectric ceramic prepared in Example 4 was subjected to X-ray diffraction testing, and the test results are shown in Figure 1 As can be seen from the figure, the high-entropy antiferroelectric ceramic prepared in this embodiment 3 has no impurity phase and is a single-phase perovskite structure.

[0085] The surface morphology of the ceramic obtained in Example 4 was photographed after surface treatment, as shown in Figure 5 As can be seen from the figure, the high-entropy antiferroelectric ceramic prepared in this embodiment 4 has a dense surface, and the large and small grains are uniformly distributed with a particle size of about 0.94 μm, and there is no impurity phase.

[0086] The ceramic obtained in Example 4 was ground and polished on both sides, silver electrodes were coated on both sides of the ceramic by screen printing, and silver sintering treatment was performed at 650°C for 30 min. After cooling to room temperature, dielectric performance testing was performed, and the test results are shown in Figure 9 As can be seen from the figure, the Curie temperature of the high-entropy antiferroelectric ceramic prepared in this embodiment 4 is further reduced.

[0087] The ceramic obtained in Example 4 was ground and polished on both sides, and gold electrodes were plated by ion sputtering for ferroelectric performance testing. The test results are shown in Figure 10 As can be seen from the figure, the high-entropy antiferroelectric ceramic prepared in this embodiment 4 exhibits weak antiferroelectricity, and the double hysteresis loop tends to disappear. Figure 11The current curve of the high-entropy antiferroelectric ceramic obtained in Example 4 is shown, and it can be seen from the figure that the two current peaks corresponding to the positive and negative turning fields are widened and gradually blurred and invisible, indicating the weak antiferroelectricity of the high-entropy antiferroelectric ceramic obtained in Example 4. Figure 12 The unipolar electric hysteresis loop of the high-entropy antiferroelectric ceramic obtained in Example 4 is shown, and it can be seen from the figure that the breakdown field strength of the obtained high-entropy antiferroelectric ceramic is 716 kV·cm -1 , the energy storage density is 8.5 J·cm -3 , and the energy storage efficiency is 87.5%.

[0088] Comparative Example 1

[0089] The preparation process of the high-entropy antiferroelectric ceramic material with high energy storage performance provided in Comparative Example 1 refers to Example 1, and the only difference is that x = 0; in step (6), the sintering temperature is 1200℃.

[0090] The ceramic obtained in Comparative Example 1 was subjected to X-ray diffraction test, and the test results are shown in Figure 1 , and it can be seen from the figure that the ceramic obtained in Comparative Example 1 has no impurity phase and is a single-phase perovskite structure.

[0091] The surface morphology of the ceramic obtained in Comparative Example 1 was photographed after surface treatment, and it is shown in Figure 13 , and it can be seen from the figure that the ceramic obtained in Comparative Example 1 is dense, the size of the grains is uniform, and the grain size is about 2.2 μm, and there is no impurity phase.

[0092] The ceramic obtained in Comparative Example 1 was ground and polished on both sides, silver electrodes were coated on both sides of the ceramic by screen printing, and silver sintering treatment was performed at 650℃ for 30 min. After cooling to room temperature, dielectric performance test was performed, and the test results are shown in Figure 15 , and it can be seen from the figure that the Curie temperature of the ceramic obtained in Comparative Example 1 is about 125℃, and the dielectric constant changes sharply with temperature.

[0093] The ceramic obtained in Comparative Example 1 was ground and polished on both sides, and gold electrodes were coated by ion sputtering for ferroelectric performance test. The test results are shown in Figure 10 , and it can be seen from the figure that the ceramic obtained in Comparative Example 1 has a typical ferroelectric hysteresis loop. Figure 11 The current curve of the ceramic obtained in Comparative Example 1 is shown, and it can be seen from the figure that the ceramic obtained in Comparative Example 1 has only one current peak, indicating that it has no antiferroelectricity and is a typical ferroelectric ceramic. Figure 12 The unipolar electric hysteresis loop of the ceramic obtained in Comparative Example 1 is shown, and it can be seen from the figure that the breakdown field strength of the obtained ceramic is 359 kV·cm -1 , the energy storage density is 2.6 J·cm -3 , and the energy storage efficiency is 69.0%.

[0094] Comparative Example 2

[0095] The preparation process of the high-entropy antiferroelectric ceramic material with high energy storage performance provided by Comparative Example 2 refers to Example 1, and the only difference is that x = 0.2; in step (6), the sintering temperature is 1230°C.

[0096] The ceramic obtained in Comparative Example 2 was subjected to X-ray diffraction test, and the test results are shown in Figure 1 As can be seen from the figure, the ceramic obtained in Comparative Example 1 has no impurity phase and is a single-phase perovskite structure.

[0097] The surface morphology of the ceramic obtained in Comparative Example 2 was photographed after surface treatment, as shown in Figure 14 As can be seen from the figure, the ceramic obtained in Comparative Example 2 has a dense surface, uniform distribution of large and small grains, and a particle size of about 0.52 μm, and has no impurity phase.

[0098] The ceramic obtained in Comparative Example 2 was ground and polished on both sides, silver electrodes were coated on both sides of the ceramic by screen printing, and silver sintering treatment was performed at 650°C for 30 min. After cooling to room temperature, the dielectric properties were tested, and the test results are shown in Figure 16 As can be seen from the figure, the dielectric constant of the ceramic obtained in Comparative Example 2 changes little with temperature, and the dielectric peak further moves to low temperature.

[0099] The ceramic obtained in Comparative Example 2 was ground and polished on both sides, and gold electrodes were coated by ion sputtering for ferroelectric property test. The test results are shown in Figure 10 As can be seen from the figure, the ceramic obtained in Comparative Example 2 has a nearly linear hysteresis loop. Figure 11 The current curve of the ceramic obtained in Comparative Example 2 is shown, and as can be seen from the figure, Comparative Example 2 has almost no observable current peak, indicating that its antiferroelectricity disappears, and the ceramic obtained in Comparative Example 2 is a nearly linear ceramic. Figure 12 The unipolar hysteresis loop of the ceramic obtained in Comparative Example 1 is shown, and as can be seen from the figure, the breakdown field strength of the obtained ceramic is 577 kV·cm -1 , the energy storage density is 5.4 J·cm -3 , and the energy storage efficiency is 83.1%.

[0100] Figure 1 are the X-ray diffraction patterns of the ceramic materials prepared in Examples 1-4 and Comparative Examples 1 and 2. As can be seen from the figures, Examples 1-4 and Comparative Examples 1 and 2 are all single-phase perovskite structures.

[0101] Figure 2-5 are the surface micro-morphology diagrams of the ceramic materials prepared in Examples 1-4. As can be seen from the figures, the grain size gradually decreases with the increase of La substitution Bi content.

[0102] Figure 6-9is the dielectric temperature spectrum of the ceramic materials prepared in Examples 1-4. As can be seen from the figure, with the increase of the content of La replacing Bi, the change of the dielectric constant with temperature is inhibited, the dispersion of the dielectric peak frequency is intensified, and the relaxation characteristics are gradually enhanced.

[0103] Figure 10 is the bipolar electric hysteresis loop diagram of the high-entropy antiferroelectric ceramic materials in Examples 1-4 and Comparative Examples 1 and 2. As can be seen from the figure, when the content of La x = 0, Comparative Example 1 exhibits ferroelectricity; after La starts to replace Bi (0.0 < x < 0.20), the high-entropy ceramic starts to exhibit antiferroelectricity, and in Figure 11 , four current peaks appear. With the increase of the content of La replacing Bi, the high-entropy ceramic gradually exhibits enhanced relaxation characteristics, and the turning field gradually increases, gradually exhibiting enhanced relaxation antiferroelectricity.

[0104] Figure 11 is the current curve diagram of the high-entropy antiferroelectric ceramic materials in Examples 1-4 and Comparative Examples 1 and 2. As can be seen from the figure, with the increase of the content of La replacing Bi, the current peak value of the current curve gradually decreases, the current peak gradually decreases and moves to the right, and presents a widening and gradually disappearing trend, indicating that the component regulation weakens the antiferroelectricity. When La completely replaces Bi (x = 0.20), the antiferroelectricity disappears, and the high-entropy ceramic exhibits a nearly linear electric hysteresis loop. The P-E curve of the ceramic presents a regular change with the increase of the content of La, the relaxation characteristics are enhanced, the electric hysteresis loop is thinned, the remanent polarization gradually decreases, and the polarization response is obviously delayed.

[0105] Figure 12 is the unipolar electric hysteresis loop diagram of the high-entropy antiferroelectric ceramic materials in Examples 1-4 and Comparative Examples 1 and 2. As can be seen from the figure, with the increase of the content of La replacing Bi, the energy storage density of the ceramic material continuously increases with the increase of the electric strength. The breakdown electric field of Examples 1-4 is 527 kV·cm -1 , 629 kV·cm -1 , 878 kV·cm -1 , and 716 kV·cm -1 , respectively, and the maximum energy storage density is 7.1 J·cm -3 , 9.0 J·cm -3 , 10.9 J·cm -3 , and 8.5 J·cm -3 , respectively.

[0106] Figure 17 is the comparison diagram of the energy storage performance of the high-entropy antiferroelectric ceramic materials in Examples 1-4 and Comparative Examples 1 and 2. As can be seen from the figure, the energy storage performance of the high-entropy antiferroelectric ceramic material prepared in Example 3 (x = 0.14) reaches the optimal value, and the energy storage density and energy storage efficiency are 10.9 J·cm -3 , 86.2%, respectively.

[0107] Table 1 lists the key energy storage parameters of the ceramic samples obtained in Examples 1-4 and Comparative Examples 1-2, indicating that the high-entropy antiferroelectric ceramic materials prepared in Examples 1-4 have the characteristics of high breakdown strength, high energy storage density and high energy storage efficiency, and have great application potential in the field of multilayer ceramic capacitors.

[0108] Table 1:

[0109]

Claims

1. A high-entropy antiferroelectric ceramic material with high energy storage performance, characterized in that: The composition chemical formula of the high entropy antiferroelectric ceramic material is: (Sr 0.2 Ca 0.2 Pb 0.2 Bi 0.2-x La x Na 0.2 )TiO3, where 0<x<0.

20.

2. The high-entropy antiferroelectric ceramic material with high energy storage performance according to claim 1, characterized in that: x=0.10～0.16。 3. The high entropy antiferroelectric ceramic material with high energy storage performance according to claim 2, characterized in that: x=0.14。 4. The high entropy antiferroelectric ceramic material with high energy storage performance according to claim 1, characterized in that: The configuration entropy ΔS of the high entropy antiferroelectric ceramic material mix ≥1.61R.

5. The high entropy antiferroelectric ceramic material with high energy storage performance according to claim 1, characterized in that: The breakdown electric field of the high entropy antiferroelectric ceramic material is 527-878 kV / cm; The recyclable energy storage density of the high entropy antiferroelectric ceramic material is 7.1 to 10.9 J / cm 3 ; The energy storage efficiency of the high-entropy antiferroelectric ceramic material is 81.1% to 87.5%.

6. A method for preparing a high-entropy antiferroelectric ceramic material with high energy storage performance according to any one of claims 1 to 5, characterized in that: include: (1) Strontium carbonate powder, calcium carbonate powder, lead oxide powder, bismuth oxide powder, lanthanum oxide powder, sodium carbonate powder, and titanium dioxide powder are weighed and mixed according to the stoichiometric ratio of high entropy antiferroelectric ceramic materials, and pre-sintered to obtain ceramic powder; (2) grinding the obtained ceramic powder, adding a binder, and granulating, screening and molding to obtain a ceramic green body; (3) The obtained ceramic green body is subjected to plastic removal and sintering to obtain the high entropy antiferroelectric ceramic material.

7. The preparation method according to claim 6, characterized in that In step (1), the mixing method is ball milling; the parameters of the ball milling include: anhydrous ethanol as the ball milling medium, a ball milling speed of 200 to 240 rpm, and a time of 4 to 6 hours; The temperature of the pre-sintering treatment is 900-1000° C., and the time is 2-3 hours.

8. The preparation method according to claim 6, characterized in that In step (2), the binder is a polyvinyl alcohol aqueous solution with a concentration of 6 to 7 wt.%; the amount of the binder added is 6 to 7 wt.% of the mass of the ceramic powder; The parameters of the fine grinding include: anhydrous ethanol as the ball milling medium, a rotation speed of 200 to 240 rpm, and a time of 4 to 6 hours; The sieve used is 40 mesh.

9. The preparation method according to claim 6, characterized in that In step (3), the temperature of the plastic removal is 750-850°C, and the time is 2-3 hours; the sintering parameters include: the sintering temperature is 1100-1200°C, the time is 2-3 hours, and the heating rate is 1-3°C / min.

10. The preparation method according to claim 9, characterized in that The temperature of the plastic removal is 800°C and the time is 2 hours; The heating rate of the sintering is 2°C / min.

11. An energy storage ceramic element, comprising: A high-entropy antiferroelectric ceramic material with high energy storage performance according to any one of claims 1 to 5, and an electrode distributed on the surface of the high-entropy ceramic material.

12. Use of the high entropy antiferroelectric ceramic material with high energy storage performance according to any one of claims 1 to 5 in a multilayer ceramic capacitor.

Images