A Sodium Bismuth Titanate-Based High-Entropy Energy Storage Ceramic Material and Its Preparation Method

Abstract

The present invention provides a sodium bismuth titanate-based high-entropy energy storage ceramic material and a preparation method thereof, belonging to the technical field of dielectric functional ceramic materials. The high-entropy energy storage ceramic material provided by the present invention is based on Bi 0.5 Na 0.5 TiO3, and six elements of Bi, Na, Ba, La, Sr and K are designed at its A site, wherein Ba 2+ , La 3+ ion doping is beneficial to reducing the sintering temperature and decreasing the grain size. Sr 2+ ion doping can enhance the dielectric relaxation characteristics. K + ion doping helps to further destroy the long-range ordered structure and form a polar nano-microregion (PNRs) structure, so that the material obtains comprehensive properties of low remanent polarization, high breakdown field strength and slender P-E hysteresis loop, thereby improving the energy storage performance of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of dielectric functional ceramic materials, and particularly relates to a sodium bismuth titanate-based high-entropy energy storage ceramic material and a preparation method thereof. Background Art

[0002] With the rapid development of pulsed power systems, the research and development of miniaturized, integrated and high-performance energy storage components are becoming more and more urgent. Dielectric materials with high power density and excellent energy storage density meet the requirements of advanced pulsed power systems in a small built-in space. As a member of relaxor ferroelectric materials, Bi 0.5 Na 0.5 TiO3 (BNT)-based ceramics have extremely high spontaneous polarization intensity (~38 μC / cm) and relatively high Curie temperature (~320 °C) due to the same electronic structure as Bi 3+ and Pb 3+ , making BNT-based ceramics a popular material that can replace lead-based ceramics. However, the high coercive field and large remanent polarization of BNT-based ceramics undoubtedly become obstacles to the excellent energy storage performance of BNT-based ceramics.

[0003] Currently, for the regulation of the energy storage performance of BNT-based ceramics, it is mainly through experimental means such as chemical composition doping and optimization of preparation processes. Introducing other ABO3-type ceramic components into BNT ceramics, such as strontium titanate (SrTiO3) or barium titanate (BaTiO3), etc., by constructing a random field to destroy the long-range ordered structure, promoting the formation of nano-domain structures or polar nano-microregions, enhancing the response to the applied electric field, thereby reducing the coercive field and decreasing the remanent polarization. And for the problem that Bi and Na elements are prone to volatilization, usually the preparation process is optimized, such as adding combustion aids (ZnO, MnO2) to reduce the sintering temperature, reducing the oxygen vacancy concentration, and hindering the grain boundary migration rate, achieving the purpose of reducing the grain size. These results are beneficial to enhancing the breakdown strength of BNT-based ceramics. However, most studies show that the breakdown strength and polarization strength cannot be taken into account at the same time, which severely limits the improvement of the energy storage performance of BNT-based ceramics. Therefore, how to improve the energy storage performance of BNT-based ceramic materials has become a technical problem to be solved urgently in this field. Summary of the Invention

[0004] The purpose of the present invention is to provide a sodium bismuth titanate-based high-entropy energy storage ceramic material and a preparation method thereof. The sodium bismuth titanate-based high-entropy energy storage ceramic material provided by the present invention has extremely high breakdown strength and a slender P-E hysteresis loop, greatly improving the energy storage density and energy storage efficiency.

[0005] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a sodium bismuth titanate-based high-entropy energy storage ceramic material, and the chemical composition of the sodium bismuth titanate-based high-entropy energy storage ceramic material is: (Bi 0.5 Na 0.5 ) x (Ba 0.25 La 0.25 Sr 0.25 K 0.25 ) (1-x) TiO3, where x is 0.1 to 0.25.

[0007] Preferably, x is 0.15 to 0.2.

[0008] The present invention also provides a preparation method of the sodium bismuth titanate-based high-entropy energy storage ceramic material described in the above technical solution, including the following steps:

[0009] (1) Mix Na2CO3, K2CO3, SrCO3, BaCO3, Bi2O3, La2O3 and TiO2, and perform primary ball milling to obtain a precursor powder;

[0010] (2) Pre-sinter the precursor powder obtained in step (1) to obtain a pre-sintered powder;

[0011] (3) Perform secondary ball milling on the pre-sintered powder obtained in step (2) to obtain a ceramic powder;

[0012] (4) Press and form the ceramic powder obtained in step (3) to obtain a green body;

[0013] (5) Sinter the green body obtained in step (4) to obtain a sodium bismuth titanate-based high-entropy energy storage ceramic material.

[0014] Preferably, the rotation speed of the primary ball milling in step (1) is 450 to 500 r / min, and the time of the primary ball milling is 12 to 20 h.

[0015] Preferably, the pre-sintering temperature in step (2) is 850 to 900 °C, and the pre-sintering time is 3 to 6 h.

[0016] Preferably, the heating rate to the pre-sintering temperature is 3 to 5 °C / min.

[0017] Preferably, the rotation speed of the secondary ball milling in step (3) is 450 to 500 r / min, and the time of the secondary ball milling is 12 to 20 h.

[0018] Preferably, the press and forming in step (4) includes pre-pressing and cold isostatic pressing performed in sequence.

[0019] Preferably, the temperature of the cold isostatic pressing is room temperature, the pressure of the cold isostatic pressing is 200-250 MPa, and the time of the cold isostatic pressing is 2-5 min.

[0020] Preferably, in step (5), the sintering temperature is 1220-1250 °C, and the sintering time is 3-5 h.

[0021] The present invention provides a sodium bismuth titanate-based high-entropy energy storage ceramic material, and the chemical composition of the sodium bismuth titanate-based high-entropy energy storage ceramic material is: (Bi 0.5 Na 0.5 ) x (Ba 0.25 La 0.25 Sr 0.25 K 0.25 ) (1-x) TiO3, where x is 0.1-0.25. The high-entropy energy storage ceramic material provided by the present invention is based on Bi 0.5 Na 0.5 TiO3, and six elements of Bi, Na, Ba, La, Sr, and K are designed at its A site. Among them, Ba 2+ , La 3+ ion doping is beneficial to reducing the sintering temperature and decreasing the grain size. Sr 2+ ion doping can enhance the dielectric relaxation characteristics. K + ion doping helps to further destroy the long-range ordered structure and form a polar nano-microregion (PNRs) structure, so that the material obtains comprehensive properties of low remanent polarization, high breakdown field strength, and slender P-E hysteresis loop, thereby improving the energy storage performance of the material. Experimental results show that the maximum breakdown strength of the sodium bismuth titanate-based high-entropy energy storage ceramic material provided by the present invention can reach 510 kV / cm, the recoverable energy storage density can reach 4.68 J / cm 3 , the energy storage efficiency can reach 85%, and the total energy storage density can reach 5.5 J / cm 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the Weibull distribution diagram of the sodium bismuth titanate-based high-entropy energy storage ceramic materials prepared in Examples 1-3;

[0023] Figure 2 It is the single-pole P-E hysteresis loop diagram of the sodium bismuth titanate-based high-entropy energy storage ceramic materials prepared in Examples 1-3 under the breakdown strength;

[0024] Figure 3 It is the relationship curve between the recoverable energy storage density and the energy storage efficiency of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 and the electric field;

[0025] Figure 4Single-stage P-E hysteresis loop diagrams of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 at different temperatures;

[0026] Figure 5 Relationship curves of the recoverable energy storage density and energy storage efficiency of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 with temperature;

[0027] Figure 6 Single-stage P-E hysteresis loop diagrams of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 at different frequencies;

[0028] Figure 7 Relationship curves of the recoverable energy storage density and energy storage efficiency of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 with frequency. Detailed implementation manners

[0029] The present invention provides a sodium bismuth titanate-based high-entropy energy storage ceramic material, and the chemical composition of the sodium bismuth titanate-based high-entropy energy storage ceramic material is: (Bi 0.5 Na 0.5 ) x (Ba 0.25 La 0.25 Sr 0.25 K 0.25 ) (1-x) TiO3, where x is 0.1 to 0.25. In the present invention, the x is preferably 0.15 to 0.2. In the present invention, x is the molar fraction.

[0030] The sodium bismuth titanate-based high-entropy energy storage ceramic material provided by the present invention is based on Bi 0.5 Na 0.5 TiO3 ceramic. Six elements of Bi, Na, Ba, La, Sr and K are designed at the A site to construct a high-entropy ceramic material with an entropy value higher than 1.61R. Among them, Ba 2+ , La 3+ ion doping is beneficial to reducing the sintering temperature and reducing the grain size. Sr 2+ ion doping can enhance the dielectric relaxation characteristics. K + ion doping helps to further destroy the long-range ordered structure and form a polar nano-region (PNRs) structure, so that the material obtains comprehensive properties of low remanent polarization, high breakdown field strength and slender P-E hysteresis loop, thereby improving the energy storage performance of the material; at a field strength of 510 kV / cm, (Bi 0.5 Na 0.5 ) 0.2 (Ba 0.25 La 0.25 Sr 0.25 K 0.25 ) 0.8The energy storage density of the TiO3 high-entropy ceramic reaches 4.6 J / cm 3 , while maintaining a high energy storage efficiency of 85%; in addition, excellent frequency and temperature stability are also obtained. It is expected to replace lead-based ceramic materials and become a candidate material for the new generation of advanced pulse power systems.

[0031] The present invention also provides a preparation method for the sodium bismuth titanate-based high-entropy energy storage ceramic material described in the above technical solution, including the following steps:

[0032] (1) Mix Na2CO3, K2CO3, SrCO3, BaCO3, Bi2O3, La2O3, and TiO2, and perform primary ball milling to obtain a precursor powder;

[0033] (2) Pre-sinter the precursor powder obtained in step (1) to obtain a pre-sintered powder;

[0034] (3) Perform secondary ball milling on the pre-sintered powder obtained in step (2) to obtain a ceramic powder;

[0035] (4) Compress and mold the ceramic powder obtained in step (3) to obtain a green body;

[0036] (5) Sinter the green body obtained in step (4) to obtain the sodium bismuth titanate-based high-entropy energy storage ceramic material.

[0037] Unless otherwise specified, the present invention has no special limitation on the sources of each raw material, and commercially available products well-known to those skilled in the art can be used.

[0038] The present invention mixes Na2CO3, K2CO3, SrCO3, BaCO3, Bi2O3, La2O3, and TiO2, and performs primary ball milling to obtain a precursor powder.

[0039] In the present invention, the purity of the Na2CO3, K2CO3, SrCO3, BaCO3, Bi2O3, La2O3, and TiO2 is independently preferably analytical pure.

[0040] The present invention has no special limitation on the operation of mixing the Na2CO3, K2CO3, SrCO3, BaCO3, Bi2O3, La2O3, and TiO2, and a technical solution for preparing a mixed material well-known to those skilled in the art can be used.

[0041] In the present invention, the primary ball milling is preferably performed in a planetary ball mill; the ball milling tank in the planetary ball mill is preferably a nylon ball milling tank. The present invention has no special limitation on the model of the planetary ball mill, and an instrument well-known to those skilled in the art can be used.

[0042] In the present invention, the ball milling medium for the primary ball milling is preferably zirconia balls and ethanol; the mass ratio of the obtained powder mixture to zirconia balls and ethanol is preferably 1:(2.5 - 3):(1.5 - 2).

[0043] In the present invention, the rotation speed of the primary ball milling is preferably 450 - 500 r / min; the time of the primary ball milling is preferably 12 - 20 h. By controlling the process parameters of the primary ball milling, the raw materials can be evenly mixed in the present invention.

[0044] After the primary ball milling is completed, the present invention preferably dries and manually grinds the product obtained from the primary ball milling in sequence to obtain a precursor powder.

[0045] In the present invention, the drying temperature is preferably 80 - 90 °C; the drying time is preferably 12 - 24 h.

[0046] The present invention has no special limitation on the operation of the manual grinding, and the operations well-known to those skilled in the art can be adopted.

[0047] After obtaining the precursor powder, the present invention pre-sinter the precursor powder to obtain a pre-sintered powder.

[0048] In the present invention, preferably, the precursor powder is compacted in a crucible and then covered with a lid before pre-sintering. Compacting the precursor powder in the present invention can enable the powders to fully contact and react; covering with a lid in the present invention can prevent other impurities from entering the crucible, and also reduce the volatilization of volatile elements (Na, Bi, K) to a certain extent.

[0049] The present invention has no special limitation on the operations of compacting the precursor powder in the crucible and covering with a lid, and the operations well-known to those skilled in the art can be adopted.

[0050] In the present invention, the pre-sintering temperature is preferably 850 - 900 °C; the pre-sintering time is preferably 3 - 6 h; the heating rate to the pre-sintering temperature is preferably 3 - 5 °C / min.

[0051] After the pre-sintering is completed, the present invention preferably cools the product obtained from the pre-sintering in the furnace and manually grinds it in sequence to obtain a pre-sintered powder.

[0052] The present invention has no special limitation on the operations of cooling in the furnace and manual grinding, and the operations well-known to those skilled in the art can be adopted.

[0053] After obtaining the pre-sintered powder, the present invention performs secondary ball milling on the pre-sintered powder to obtain a ceramic powder.

[0054] In the present invention, the secondary ball milling is preferably carried out in a planetary ball mill; the ball milling tank in the planetary ball mill is preferably a nylon ball milling tank. The present invention does not have a special limitation on the model of the planetary ball mill, and the instruments and equipment well-known to those skilled in the art can be used.

[0055] In the present invention, the ball milling medium for the secondary ball milling is preferably zirconia balls and ethanol; the mass ratio of the pre-fired powder to the zirconia balls and ethanol is preferably 1:(2.5 - 3):(1.5 - 2).

[0056] In the present invention, the rotation speed of the secondary ball milling is preferably 450 - 500 r / min; the time of the secondary ball milling is preferably 12 - 20 h. By controlling the process parameters of the secondary ball milling, the present invention can make the material mix evenly.

[0057] After the secondary ball milling is completed, the present invention preferably dries and hand-grinds the product obtained from the secondary ball milling in sequence to obtain a precursor powder.

[0058] In the present invention, the drying temperature is preferably 80 - 90 °C; the drying time is preferably 12 - 24 h.

[0059] The present invention does not have a special limitation on the operation of the hand-grinding, and the operations well-known to those skilled in the art can be used.

[0060] After obtaining the ceramic powder, the present invention compresses the ceramic powder into a green body.

[0061] In the present invention, the compression molding preferably includes pre-pressing and cold isostatic pressing carried out in sequence.

[0062] The present invention does not have a special limitation on the operation of the pre-pressing, and the operations well-known to those skilled in the art can be used.

[0063] In the present invention, the temperature of the cold isostatic pressing is preferably room temperature; the pressure of the cold isostatic pressing is preferably 200 - 250 MPa, more preferably 200 - 220 MPa; the time of the cold isostatic pressing is preferably 2 - 5 min, more preferably 2 - 3 min.

[0064] After obtaining the green body, the present invention sinters the green body to obtain a sodium bismuth titanate-based high-entropy energy storage ceramic material.

[0065] In the present invention, the sintering temperature is preferably 1220 - 1250 °C, more preferably 1230 - 1240 °C; the sintering time is preferably 3 - 5 h; the sintering is preferably carried out in an air atmosphere.

[0066] After the sintering is completed, the present invention preferably cools the product obtained from the sintering in the furnace to obtain a sodium bismuth titanate-based high-entropy energy storage ceramic material.

[0067] The present invention has no special limitation on the operation of furnace cooling, and the operation well-known to those skilled in the art can be adopted.

[0068] The present invention adopts the solid-phase reaction method for preparation. The preparation method is simple, which can effectively reduce the sintering temperature during preparation, reduce element volatilization, improve the microstructure of ceramics, and obtain ceramics with good densification; the prepared ceramics have the characteristics of high breakdown strength, slender P-E curve, and excellent frequency and temperature stability, meeting the industrial requirements of dielectric energy storage ceramics.

[0069] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0070] Example 1

[0071] The chemical composition of the sodium bismuth titanate-based high-entropy energy storage ceramic material is: (Bi 0.5 Na 0.5 ) x (Ba 0.25 La 0.25 Sr 0.25 K 0.25 ) (1-x) TiO3, where x is 0.15, denoted as 15BNSLBKT, and its entropy value can be calculated according to Equation I:

[0072]

[0073] In the formula, R is the gas constant, and x i is the molar fraction of any i component; through the above formula, the entropy value can be obtained as 1.71R;

[0074] The preparation method comprises the following steps:

[0075] (1) Using analytical pure Na2CO3 powder, K2CO3 powder, SrCO3 powder, BaCO3 powder, Bi2O3 powder, La2O3 powder, and TiO2 powder as raw materials, weighing the raw materials according to the above chemical formula for stoichiometry, mixing them, then loading the mixed powder into a nylon ball milling tank, adding zirconia balls and ethanol, placing it in a planetary ball mill for primary ball milling, then placing it in a drying oven, drying at 80 °C for 12 h, and then manually grinding in a mortar to obtain a precursor powder; wherein, the mass ratio of the mixed powder: zirconia balls: ethanol is 1:3:1.5; the rotation speed of the primary ball milling is 450 r / min; the time of the primary ball milling is 12 h;

[0076] (2) Compact the precursor powder obtained in step (1) in an alumina crucible, cover it, heat it from room temperature to 850 °C at a heating rate of 5 °C / min, hold for 3 h for pre-sintering, then cool it to room temperature with the furnace and open the furnace, and obtain the pre-sintered powder after manual grinding in a mortar;

[0077] (3) Load the pre-sintered powder obtained in step (2) into a nylon ball milling jar, add zirconia balls and ethanol, place it in a planetary ball mill for secondary ball milling, then place it in a drying oven, dry it at 80 °C for 12 h, and then manually grind it in a mortar to obtain ceramic powder; among them, the mass ratio of pre-sintered powder: zirconia balls: ethanol is 1:3:1.5; the rotation speed of secondary ball milling is 450 r / min; the time of secondary ball milling is 12 h;

[0078] (4) Place the ceramic powder obtained in step (3) in a mold for pre-pressing to make a disc-shaped sample, then put it into a cold isostatic press, hold the pressure at 200 MPa at room temperature for 2 min and then take it out to obtain a green body;

[0079] (5) Put the green body obtained in step (4) into a crucible and place it in a muffle furnace, sinter it in an air atmosphere at 1250 °C for 3 h, cool it to room temperature with the furnace and open the furnace to obtain a sodium bismuth titanate-based high-entropy energy storage ceramic material.

[0080] The Weibull distribution diagrams of the sodium bismuth titanate-based high-entropy energy storage ceramic materials prepared in Examples 1 to 3 are as Figure 1 shown, and the breakdown strength of the prepared sodium bismuth titanate-based high-entropy ceramics can be predicted through the Weibull distribution diagram.

[0081] Figure 2 is the single-pole P-E hysteresis loop diagram of the sodium bismuth titanate-based high-entropy energy storage ceramic materials prepared in Examples 1 to 3 under the breakdown strength.

[0082] Grind the two sides of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 1 smoothly, then coat it with gold and silver electrodes by ion sputtering and test its electrical properties at room temperature. Use a ferroelectric analyzer Polyk to test the single-pole P-E hysteresis loop, obtain the maximum polarization intensity and the remanent polarization intensity values through the P-E hysteresis loop, and calculate the energy storage performance through the following equation:

[0083]

[0084]

[0085]

[0086] In the formula, W total , W rec, η represents the total energy storage density, recoverable energy storage density, and energy storage efficiency of the dielectric material; P max , P r , E represent the maximum polarization intensity, remanent polarization intensity, and external electric field intensity of the dielectric material, respectively. Among them, the breakdown strength of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 1 is 350 kV / cm, and the recoverable energy storage density is 2.23 J / cm 3 , and the energy storage efficiency is 73%.

[0087] The energy storage performance of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 1 is shown in Table 1.

[0088] Table 1 Energy storage performance of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 1

[0089] Breakdown strength / kV / cm <![CDATA[Total energy storage density / J / cm 3 > <![CDATA[Recoverable density / J / cm 3 > Energy storage efficiency / % 350 3.05 2.23 73

[0090] Example 2

[0091] The chemical composition of the sodium bismuth titanate-based high-entropy energy storage ceramic material is: (Bi 0.5 Na 0.5 ) x (Ba 0.25 La 0.25 Sr 0.25 K 0.25 ) (1-x) TiO3, where x is 0.2, denoted as 20BNSLBKT. According to Equation I, its entropy value is 1.75R;

[0092] The preparation method is the same as that of Example 1.

[0093] The two sides of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 were polished flat, and then gold-silver electrodes were deposited by ion sputtering. The electrical properties were tested at room temperature. The single-pole P-E hysteresis loop was measured using a ferroelectric analyzer Polyk as Figure 2 shown. The maximum breakdown strength of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 can reach 510 kV / cm, and the recoverable energy storage density can reach 4.68 J / cm 3 , and the energy storage efficiency is 85%.

[0094] The energy storage performance of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 is shown in Table 2.

[0095] Table 2 Energy storage performance of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2

[0096] Breakdown strength / kV / cm <![CDATA[Total energy storage density / J / cm 3 > <![CDATA[Recoverable density / J / cm 3 > Energy storage efficiency / % 510 5.5 4.68 85

[0097] The relationship curves between the recoverable energy storage density and energy storage efficiency of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 and the electric field are as Figure 3 shown.

[0098] From Figure 3 it can be seen that the recoverable energy storage density (W rec ) of the sodium bismuth titanate-based high-entropy ceramic gradually increases with the increase of the electric field strength, while its energy storage efficiency (η) changes little with the increase of the electric field strength.

[0099] The single-stage P-E hysteresis loop diagrams of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 at different temperatures are as Figure 4 shown; the relationship curves between the recoverable energy storage density and energy storage efficiency of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 and the temperature are as Figure 5 shown.

[0100] From Figure 4 and 5 it can be seen that the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in the present invention has good temperature stability.

[0101] The single-stage P-E hysteresis loop diagrams of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 at different frequencies are as Figure 6 shown; the relationship curves between the recoverable energy storage density and energy storage efficiency of the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in Example 2 and the frequency are as Figure 7 shown.

[0102] From Figure 6 and 7 it can be seen that the sodium bismuth titanate-based high-entropy energy storage ceramic material prepared in the present invention has good frequency stability.

[0103] Example 3

[0104] The chemical composition of the sodium bismuth titanate-based high-entropy energy storage ceramic material is: (Bi 0.5 Na 0.5 ) x (Ba 0.25 La 0.25 Sr 0.25 K 0.25 ) (1-x) TiO3, x is 0.25, denoted as 25BNSLBKT, and according to Equation I, its entropy value is 1.78R;

[0105] On the basis of the preparation method of Example 1, the sintering temperature was modified to 1220 °C, and other conditions remained unchanged.

[0106] The bismuth sodium titanate-based high-entropy energy storage ceramic material prepared in Example 3 was polished on both sides until flat, and then silver-gold electrodes were deposited on it by ion sputtering, and its electrical properties were tested at room temperature. The single-polar P-E hysteresis loop was tested using a ferroelectric analyzer Polyk as shown in Figure 2 shown. The maximum breakdown strength of the bismuth sodium titanate-based high-entropy energy storage ceramic material prepared in Example 3 can reach 300 kV / cm, and the recoverable energy storage density can reach 1.83 J / cm 3 , and the energy storage efficiency is 62%.

[0107] The energy storage performance of the bismuth sodium titanate-based high-entropy energy storage ceramic material prepared in Example 3 is shown in Table 3.

[0108] Table 3 Energy storage performance of the bismuth sodium titanate-based high-entropy energy storage ceramic material prepared in Example 3

[0109] Breakdown strength / kV / cm <![CDATA[Total energy storage density / J / cm 3 > <![CDATA[Recoverable density / J / cm 3 > Energy storage efficiency / % 300 2.94 1.83 62

[0110] As can be seen from the above examples, the bismuth sodium titanate-based high-entropy energy storage ceramic material provided by the present invention has an extremely high breakdown strength and a slender P-E hysteresis loop, greatly improving the energy storage density and energy storage efficiency.

[0111] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A sodium bismuth titanate-based high-entropy energy storage ceramic material, and the chemical composition of the sodium bismuth titanate-based high-entropy energy storage ceramic material is: (Bi 0.5 Na 0.5 ) x (Ba 0.25 La 0.25 Sr 0.25 K 0.25 ) (1-x) TiO3, where x is 0.1 to 0.

25.

2. The sodium bismuth titanate-based high-entropy energy storage ceramic material according to claim 1, wherein x is 0.15 to 0.

2.

3. The preparation method of the sodium bismuth titanate-based high-entropy energy storage ceramic material according to claim 1 or 2, comprising the following steps: (1) Mix Na2CO3, K2CO3, SrCO3, BaCO3, Bi2O3, La2O3 and TiO2, and perform primary ball milling to obtain a precursor powder; (2) Pre-calcine the precursor powder obtained in step (1) to obtain a pre-calcined powder; (3) Perform secondary ball milling on the pre-calcined powder obtained in step (2) to obtain a ceramic powder; (4) Press and form the ceramic powder obtained in step (3) to obtain a green body; (5) Sinter the green body obtained in step (4) to obtain a sodium bismuth titanate-based high-entropy energy storage ceramic material.

4. The preparation method according to claim 3, characterized in that, In step (1), the rotation speed of the primary ball milling is 450 to 500 r / min, and the time of the primary ball milling is 12 to 20 h.

5. The preparation method according to claim 3, characterized in that, In step (2), the pre-calcination temperature is 850 to 900 °C, and the pre-calcination time is 3 to 6 h.

6. The preparation method according to claim 5, wherein The heating rate to the pre-calcination temperature is 3 to 5 °C / min.

7. The preparation method according to claim 3, characterized in that, In step (3), the rotation speed of the secondary ball milling is 450 to 500 r / min, and the time of the secondary ball milling is 12 to 20 h.

8. The preparation method according to claim 3, characterized in that, The press forming in step (4) includes pre-pressing and cold isostatic pressing performed in sequence.

9. The preparation method according to claim 8, characterized in that, The temperature of the cold isostatic pressing is room temperature, the pressure of the cold isostatic pressing is 200 to 250 MPa, and the time of the cold isostatic pressing is 2 to 5 min.

10. The preparation method according to claim 3, characterized in that, In step (5), the sintering temperature is 1220 to 1250 °C, and the sintering time is 3 to 5 h.

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