A high-temperature stable high-entropy ceramic material with excellent energy storage performance and a preparation method thereof

Abstract

This invention discloses a high-temperature stable high-entropy ceramic material with excellent energy storage performance and its preparation method. First, according to (Ba 0.3 Sr 0.7 TiO3, (Na) 0.5 Bi 0.5 TiO3 and (K 0.5 Bi 0.5 The chemical formula of TiO3 is given by the following molar ratio: raw materials, anhydrous ethanol, and zirconium oxide spheroids are ball-milled and mixed, then dried and calcined separately to obtain (Ba 0.3 Sr 0.7 TiO3, (Na) 0.5 Bi 0.5 TiO3 and (K 0.5 Bi 0.5 TiO3 powder, the three powders obtained are processed according to (Ba 0.12 Sr 0.28 K 0.3‑x Bi 0.3 Na x TiO3 (0.125≤x≤0.2) was ball-milled and dried to obtain the final material powder. The powder was pre-pressed using a mold, then cold isostatically pressed and sintered at 1220–1250℃ for 4 hours to obtain high-entropy perovskite ceramic. This high-entropy ceramic achieved W0 under a low electric field of 210 kV / cm. rec =2.07J / cm 3 η = 84.5%, W in the range of 40–140℃ rec With good energy storage performance, the changes in η are less than 4.9% and 2.0% respectively, within the range of 42–317℃, and Δε r / ε 150℃ Excellent high-temperature dielectric stability of ≤±15%, high dielectric constant of ~3259 at 150℃, and ultra-low dielectric loss of ~0.002.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, and relates to high-entropy ceramic materials, specifically to a high-temperature stable high-entropy ceramic material with excellent energy storage performance and its preparation method. Background Technology

[0002] In recent years, with the continuous development of the electronics industry, the market demands for ceramic capacitors have become increasingly stringent, requiring miniaturization, integration, and increasingly demanding operating environments (high temperature, low electric field, etc.). However, the relatively low energy density and poor high-temperature stability of ceramic capacitors make it difficult to meet the further requirements of practical applications in high-temperature environments. For example, in the automotive industry, components near the engine and braking system must withstand temperatures up to 200°C to operate normally. In the aerospace industry, electronic equipment operating near the engine must withstand ambient temperatures of 200–300°C.

[0003] Increase breakdown strength (E) b ) and polarization difference (ΔP=P max -P r High energy density dielectric ceramics can be obtained. Most ceramic dielectrics increase their energy density through high breakdown field strength, for example: (Na...) 0.5 Bi 0.5 TiO3-based ceramics can rapidly increase energy storage density by utilizing high breakdown electric field strength, typically requiring a field strength above 300 kV / cm. However, high electric field strength places extremely high demands on the insulation system of electronic devices, and high E... b In practical applications, the lifespan of capacitors is affected, which to some extent limits the miniaturization and integration of energy storage materials and related devices. Furthermore, for some electronic devices operating under low electric fields, the low electric field restricts the use of ceramic capacitors with excellent high-field excitation performance. Therefore, designing and fabricating dielectric ceramics with excellent stability at high temperatures and good energy storage performance under low electric fields (300 kV / cm) is a highly significant undertaking. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a high-temperature stable high-entropy ceramic material with excellent energy storage performance and its preparation method. The prepared high-entropy ceramic material achieves good energy storage density and energy storage efficiency under low electric field, and has excellent high-temperature stability. The preparation process is simple and the material cost is low.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A high-temperature stable high-entropy ceramic material with excellent energy storage performance, stoichiometric formula (Ba 0.12 Sr 0.28 K0.3- x Bi 0.3 Na x TiO3, where 0.125≤x≤0.2, and x is the mole percentage.

[0007] This invention also protects a method for preparing a high-temperature stable high-entropy ceramic material with excellent energy storage performance as described above, comprising the following steps:

[0008] Step 1: Based on the stoichiometric formula (Ba 0.3 Sr 0.7 TiO3, BaCO3, SrCO3 and TiO2 are mixed to obtain a mixture, the mixture is ball-milled, dried and then ground and sieved to obtain a pre-made powder, the pre-made powder is pre-calcined at 900℃ to obtain a block solid, the block solid is crushed to obtain solid powder A;

[0009] According to the stoichiometry (Na) 0.5 Bi 0.5 TiO3, Na2CO3, Bi2O3 and TiO2 are mixed to obtain a mixture, the mixture is ball-milled, dried and then ground and sieved to obtain a pre-made powder, the pre-made powder is pre-calcined at 850℃ to obtain a block solid, the block solid is crushed to obtain solid powder B;

[0010] According to the stoichiometry (K) 0.5 Bi 0.5 TiO3, K2CO3, Bi2O3 and TiO2 are mixed to obtain a mixture, the mixture is ball-milled, dried and then ground and sieved to obtain a pre-made powder, the pre-made powder is pre-calcined at 850℃ to obtain a block solid, the block solid is crushed to obtain solid powder C;

[0011] The three solid powders obtained above were stoichiometrically formulated according to the stoichiometric formula (Ba). 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x TiO3, 0.125≤x≤0.2, was taken and mixed to obtain a mixture, which was then ball-milled, dried and sieved to obtain the final material powder;

[0012] Step 2: After pouring the material powder into the mold and pressing it into shape, it is then densified by cold isostatic pressing. The ceramic green body is then sintered at 1220–1250℃ to obtain (Ba). 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x TiO3 (0.125≤x≤0.2) is a high-entropy ceramic material.

[0013] Preferably, the auxiliary materials and media for ball milling in step one are zirconia balls and anhydrous ethanol, and the mass ratio of the mixture, zirconia balls and anhydrous ethanol is 1:2:2, and the ball milling regime is 550 r / min for 8 h.

[0014] Preferably, the drying temperature in step one is 80-90°C and the drying time is 12 hours.

[0015] Preferably, the pre-firing process described in step one is as follows: the temperature is increased from room temperature to the pre-firing temperature at a rate of 5°C / min and held for 4 hours, then the temperature is decreased to 500°C at a rate of 5°C / min and cooled to room temperature with the furnace.

[0016] Preferably, the pressure applied during the compression molding process in step two is 550–650 N.

[0017] Preferably, the cold isostatic pressing densification in step two involves placing the material in a cold isostatic press and holding it under pressure of 250–350 MPa for 3 minutes.

[0018] Preferably, the sintering process described in step two is as follows: the ceramic green body is buried with the same mass of green body powder, placed in a sealed crucible, placed in a furnace, heated from room temperature to the pre-firing temperature at 5℃ / min and held for 4 hours, and then cooled to 500℃ at 3℃ / min and cooled to room temperature with the furnace.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] The (Ba) prepared by this invention 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x TiO3 high-entropy ceramics select low P r of (Ba 0.3 Sr 0.7 TiO3 and complex phase transitions, high P max of (Na 0.5 Bi 0.5 TiO3 and high Curie temperature (K) 0.5 Bi 0.5A novel perovskite ceramic was prepared using a solid-state method with a designed ratio of TiO3. Firstly, the high-entropy effect broadens the solubility limits between components, promoting the formation of a complete solid solution. Secondly, the presence of multiple elements in the same lattice leads to compositional fluctuations and structural phase transitions, broadening the dielectric constant peak and improving temperature stability. Thirdly, the hysteresis diffusion effect slows down the diffusion rate of elements, hindering grain growth and resulting in a more uniform and fine microstructure, thus improving the material's resistivity. Fourthly, the lattice distortion effect causes structural distortion of the ceramic structure by ions with different valence states and radii, increasing the material's polarization and thus improving energy storage performance. Fifthly, the cocktail effect further enhances the performance of multi-component ceramic materials compared to single-component ceramic materials, achieving a 1+1>2 effect. The (Ba)3 prepared in this invention... 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x TiO3 (0.125≤x≤0.2) high-entropy ceramics exhibit a high dielectric constant of ~3259 at 150℃ and an ultra-low dielectric loss of ~0.002, and a high Δε at 42~317℃. r / ε 150℃ Excellent dielectric stability ≤±15%; W was obtained at a low electric field of 210kV / cm. rec =2.07J / cm 3 It exhibits a good energy storage density and efficiency of η = 84.5%, and W within the temperature range of 40–140℃. rec It exhibits excellent high-temperature stability with changes in η of less than 4.9% and 2.0% respectively; demonstrating outstanding comprehensive performance, it can adapt to the needs of different working scenarios such as low electric field and high temperature, and has great application potential;

[0021] In the sample preparation process of this invention, a more advanced cold isostatic pressing (CIP) technology is adopted, which avoids sample waste and the addition of binders, saves production costs, speeds up the production cycle, and avoids the possibility of binder contamination of the sample. In subsequent steps, the steps of removing binders are reduced, reducing the waste of resources and production time. In addition, since CIP technology uses liquid to transmit pressure, compared with traditional single-direction pressing, CIP allows the sample to be subjected to pressure from all directions, and the pressure is relatively greater, resulting in a denser green body, which lays the foundation for excellent experimental results in the next step.

[0022] Furthermore, the raw materials used in this invention do not contain heavy metals such as lead, making them environmentally friendly and ensuring that the preparation process does not cause environmental damage. The materials prepared by this invention have uniform grain size, and the samples are dense with no obvious pores, guaranteeing the (Ba) 0.12 Sr0.28 K 0.3-x Bi 0.3 Na x The excellent dielectric and ferroelectric properties of TiO3 high-entropy perovskite ceramic materials have very important practical significance and economic benefits.

[0023] Because high-entropy materials are composed of diverse elements with varying physical properties, they are prone to problems such as difficulty in densification, deformation, warping, bulging, and element volatilization during ceramic preparation. The present invention employs buried firing, a sealed space, and a slowed cooling rate during sintering to ensure that the sintered ceramic has the advantages of intact shape, high crystal density, and low element volatilization. Attached Figure Description

[0024] Figure 1 The graphs show the configurational entropy and tolerance factor of the high-entropy ceramic materials prepared in Examples 1-4 as a function of x.

[0025] Figure 2 The XRD patterns of the high-entropy ceramic materials prepared in Examples 1-4 are shown.

[0026] Figure 3 The graphs show the changes in dielectric constant and dielectric loss of the high-entropy ceramic materials prepared in Examples 1-4 as a function of temperature.

[0027] Figure 4 The temperature change rate curves of the high-entropy ceramic materials prepared in Examples 1-4 are shown.

[0028] Figure 5 SEM images of the high-entropy ceramic materials prepared in Examples 1-4;

[0029] Figure 6 The PE loop of the high-entropy ceramic materials prepared in Examples 1-4 under the breakdown electric field;

[0030] Figure 7 The curves showing the changes in energy storage density and energy storage efficiency as a function of x for the high-entropy ceramic materials prepared in Examples 1-4 are shown.

[0031] Figure 8 The PE hysteresis loops of the high-entropy ceramic materials prepared in Examples 1-4 at different temperatures under 100 kV / cm.

[0032] Figure 9 The energy storage density and energy storage efficiency of the high-entropy ceramic materials prepared in Examples 1-4 at different temperatures under 100 kV / cm. Detailed Implementation

[0033] The specific content of the present invention will be further explained in detail below with reference to the embodiments.

[0034] Example 1

[0035] A method for preparing a high-temperature stable high-entropy ceramic material with excellent energy storage performance includes the following steps:

[0036] Step 1: Prepare material powder:

[0037] According to the chemical formula (Ba 0.3 Sr 0.7 TiO3 was prepared by mixing BaCO3, SrCO3, and TiO2. The mixture was then mixed with zirconia balls and anhydrous ethanol in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 80°C for 12 hours. After grinding, it was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 900°C at a rate of 5°C / min and held for 4 hours. Then, it was cooled to 500°C at a rate of 5°C / min and cooled with the furnace. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder A.

[0038] According to the chemical formula (Na) 0.5 Bi 0.5 TiO3 was prepared by mixing Na2CO3, Bi2O3, and TiO2. The mixture was then mixed with zirconia balls and anhydrous ethanol in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 80°C for 12 hours. After grinding, it was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 850°C at a rate of 5°C / min and held for 4 hours. Then, it was cooled to 500°C at a rate of 5°C / min and cooled with the furnace. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder B.

[0039] According to the chemical formula (K) 0.5 Bi 0.5 TiO3 was prepared by mixing K2CO3, Bi2O3, and TiO2. The mixture, along with zirconia balls and anhydrous ethanol, was then ball-milled for 8 hours. The milled mixture was then placed in an electric heating drying oven and dried at 80℃ for 12 hours, followed by grinding. The resulting powder was then passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 850℃ (5℃ / min) and held for 4 hours. Then, it was cooled to 500℃ (5℃ / min) and cooled in the furnace. The pre-calcined powder yielded a blocky solid, which was then pulverized to obtain solid powder C.

[0040] The three solid powders obtained above are based on the chemical formula (Ba 0.12 Sr 0.28 K 0.175 Bi 0.3 Na 0.125 TiO3, mixed in a molar ratio to obtain a mixture, namely (Ba 0.12Sr 0.28 K 0.3-x Bi 0.3 Na x In TiO3, x = 0.125, (Ba 0.3 Sr 0.7 TiO3, (Na) 0.5 Bi 0.5 TiO3 and (K 0.5 Bi 0.5 The mass percentages of TiO3 were 40%, 25%, and 35%, respectively. The mixture, zirconium oxide balls, and anhydrous ethanol were mixed in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 80°C for 12 hours. After grinding, the mixture was passed through a 200-mesh sieve to obtain the material powder.

[0041] Step 2: Pour 4.0g of material powder into a mold and press it under a pressure of 550N. Place the molded sample into a cold isostatic press and hold it under a pressure of 250Mpa for 3min to press the ceramic green body. Cover the ceramic green body with an equal mass of green body powder, place it in a sealed crucible, and place it in a furnace. Heat the crucible from room temperature to 1220℃ at a rate of 5℃ / min and hold it for 4h. Then cool it down to 500℃ at a rate of 3℃ / min and let it cool to room temperature in the furnace to obtain (Ba 0.12 Sr 0.28 K 0.175 Bi 0.3 Na 0.125 TiO3 high-entropy ceramic materials.

[0042] Example 2

[0043] A method for preparing a high-temperature stable high-entropy ceramic material with excellent energy storage performance includes the following steps:

[0044] Step 1: Prepare material powder:

[0045] According to the chemical formula (Ba 0.3 Sr 0.7 TiO3 was prepared by mixing BaCO3, SrCO3, and TiO2. The mixture was then mixed with zirconia balls and anhydrous ethanol in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 85°C for 12 hours. After grinding, it was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 900°C at a rate of 5°C / min and held for 4 hours. Then, it was cooled to 500°C at a rate of 5°C / min and cooled with the furnace. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder A.

[0046] According to the chemical formula (Na) 0.5 Bi 0.5TiO3 was prepared by mixing Na2CO3, Bi2O3, and TiO2. The mixture was then mixed with zirconia balls and anhydrous ethanol in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 85°C for 12 hours. After grinding, it was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 850°C at a rate of 5°C / min and held for 4 hours. Then, it was cooled to 500°C at a rate of 5°C / min and cooled with the furnace. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder B.

[0047] According to the chemical formula (K) 0.5 Bi 0.5 TiO3 was prepared by mixing K2CO3, Bi2O3, and TiO2. The mixture was then mixed with zirconia balls and anhydrous ethanol in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 85°C for 12 hours. After grinding, it was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 850°C at a rate of 5°C / min and held for 4 hours. Then, it was cooled to 500°C at a rate of 5°C / min and cooled with the furnace. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder C.

[0048] The three solid powders obtained above are based on the chemical formula (Ba 0.12 Sr 0.28 K 0.15 Bi 0.3 Na 0.15 The mixture is obtained by mixing TiO3 in a certain molar ratio, namely (Ba 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x In TiO3, x = 0.15, (Ba 0.3 Sr 0.7 TiO3, (Na) 0.5 Bi 0.5 TiO3 and (K 0.5 Bi 0.5 The mass percentages of TiO3 were 40%, 30%, and 30%, respectively. The mixture, zirconium oxide balls, and anhydrous ethanol were mixed in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 85°C for 12 hours. After grinding, the mixture was passed through a 200-mesh sieve to obtain material powder D.

[0049] Step 2: Pour 4.0g of material powder into a mold and press it under a pressure of 650N. Place the molded sample into a cold isostatic press and hold it under a pressure of 350Mpa for 3min to press the ceramic green body. Cover the ceramic green body with an equal mass of green body powder, place it in a sealed crucible, and place it in a furnace. Heat the crucible from room temperature to 1230℃ at a rate of 5℃ / min and hold it for 4h. Then cool it down to 500℃ at a rate of 3℃ / min and let it cool to room temperature in the furnace to obtain (Ba 0.12 Sr 0.28 K 0.175 Bi 0.3 Na 0.125 TiO3 high-entropy ceramic materials.

[0050] Example 3

[0051] A method for preparing a high-temperature stable high-entropy ceramic material with excellent energy storage performance includes the following steps:

[0052] Step 1: Prepare material powder:

[0053] According to the chemical formula (Ba 0.3 Sr 0.7 TiO3 was prepared by mixing BaCO3, SrCO3, and TiO2. The mixture was then mixed with zirconia balls and anhydrous ethanol in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 90°C for 12 hours. After grinding, it was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 900°C at a rate of 5°C / min and held for 4 hours. Then, it was cooled to 500°C at a rate of 5°C / min and cooled with the furnace. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder A.

[0054] According to the chemical formula (Na) 0.5 Bi 0.5 TiO3 was prepared by mixing Na2CO3, Bi2O3, and TiO2. The mixture, along with zirconia balls and anhydrous ethanol, was then ball-milled for 8 hours. The milled mixture was placed in an electrically heated drying oven and dried at 90°C for 12 hours. After further grinding, the powder was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. This pre-formed powder was pre-calcined at 850°C at a rate of 5°C / min, held for 4 hours, and then cooled to 500°C at a rate of 5°C / min. The pre-calcined powder yielded a blocky solid. This blocky solid was then pulverized to obtain solid powder B.

[0055] According to the chemical formula (K) 0.5 Bi 0.5 TiO3, a mixture of K2CO3, Bi2O3 and TiO2 is obtained, (Ba 0.3 Sr 0.7 TiO3, (Na)0.5 Bi 0.5 TiO3 and (K 0.5 Bi 0.5 The mass percentages of TiO3 were 40%, 35%, and 25%, respectively. The mixture, zirconia balls, and anhydrous ethanol were mixed in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 90°C for 12 hours. After grinding, it was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 850°C at a rate of 5°C / min, held at that temperature for 4 hours, and then cooled to 500°C at a rate of 5°C / min. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder C.

[0056] The three solid powders obtained above are based on the chemical formula (Ba 0.12 Sr 0.28 K 0.125 Bi 0.3 Na 0.175 The mixture is obtained by mixing TiO3 in a certain molar ratio, namely (Ba 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x In TiO3, x = 0.175, (Ba 0.3 Sr 0.7 TiO3, (Na) 0.5 Bi 0.5 TiO3 and (K 0.5 Bi 0.5 The mass percentages of TiO3 were 40%, 35%, and 25%, respectively. The mixture, zirconia balls, and anhydrous ethanol were mixed in a mass ratio of 1:2:2 and then ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 90°C for 12 hours. After grinding, the mixture was passed through a 200-mesh sieve to obtain material powder D.

[0057] Step 2: Pour 4.0g of material powder into a mold and press it under a pressure of 600N. Place the molded sample into a cold isostatic press and hold it under a pressure of 300MPa for 3 minutes to press the ceramic green body. Cover the ceramic green body with an equal mass of green body powder, place it in a sealed crucible, and place it in a furnace. Heat the crucible from room temperature to 1240℃ at a rate of 5℃ / min and hold it for 4 hours. Then cool it down to 500℃ at a rate of 3℃ / min and let it cool to room temperature in the furnace to obtain (Ba 0.12 Sr 0.28 K 0.175 Bi 0.3 Na 0.125 TiO3 high-entropy ceramic materials.

[0058] Example 4

[0059] A method for preparing a high-temperature stable high-entropy ceramic material with excellent energy storage performance includes the following steps:

[0060] Step 1: Prepare material powder:

[0061] According to the chemical formula (Ba 0.3 Sr 0.7 TiO3 was prepared by mixing BaCO3, SrCO3, and TiO2. The mixture was then mixed with zirconia balls and anhydrous ethanol in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 80°C for 12 hours. After grinding, it was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 900°C at a rate of 5°C / min and held for 4 hours. Then, it was cooled to 500°C at a rate of 5°C / min and cooled with the furnace. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder A.

[0062] According to the chemical formula (Na) 0.5 Bi 0.5 TiO3 was prepared by mixing Na2CO3, Bi2O3, and TiO2. The mixture, along with zirconia balls and anhydrous ethanol, was then ball-milled for 8 hours. The milled mixture was placed in an electrically heated drying oven and dried at 80°C for 12 hours. After further grinding, the powder was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. This pre-formed powder was pre-calcined at 850°C at a rate of 5°C / min, held for 4 hours, and then cooled to 500°C at a rate of 5°C / min. The pre-calcined powder yielded a blocky solid. This blocky solid was then pulverized to obtain solid powder B.

[0063] According to the chemical formula (K) 0.5 Bi 0.5 TiO3 was prepared by mixing K2CO3, Bi2O3, and TiO2. The mixture was then mixed with zirconia balls and anhydrous ethanol in a mass ratio of 1:2:2 and ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 80°C for 12 hours. After grinding, the mixture was passed through a 120-mesh sieve to obtain a uniform pre-formed powder. The pre-formed powder was pre-calcined at 850°C at a rate of 5°C / min and held for 4 hours. Then, it was cooled to 500°C at a rate of 5°C / min and cooled with the furnace. After pre-calcination, a blocky solid was obtained. The blocky solid was then crushed to obtain solid powder C.

[0064] The three solid powders obtained above are based on the chemical formula (Ba 0.12 Sr 0.28 K 0.1 Bi 0.3 Na 0.2 The mixture is obtained by mixing TiO3 in a certain molar ratio, namely (Ba 0.12 Sr 0.28K 0.3-x Bi 0.3 Na x In TiO3, x = 0.20, (Ba 0.3 Sr 0.7 TiO3, (Na) 0.5 Bi 0.5 TiO3 and (K 0.5 Bi 0.5 The mass percentages of TiO3 were 40%, 40%, and 20%, respectively. The mixture, zirconia balls, and anhydrous ethanol were mixed in a mass ratio of 1:2:2 and then ball-milled for 8 hours. The ball-milled mixture was then placed in an electric heating drying oven and dried at 80°C for 12 hours. After grinding, the mixture was passed through a 200-mesh sieve to obtain material powder D.

[0065] Step 2: Pour 4.0g of material powder into a mold and press it under a pressure of 600N. Place the molded sample into a cold isostatic press and hold it under a pressure of 300Mpa for 3min to press the ceramic green body. Cover the ceramic green body with an equal mass of green body powder, place it in a sealed crucible, and place it in a furnace. Heat the crucible from room temperature to 1250℃ at a rate of 5℃ / min and hold it for 4h. Then cool it down to 500℃ at a rate of 3℃ / min and let it cool to room temperature in the furnace to obtain (Ba 0.12 Sr 0.28 K 0.175 Bi 0.3 Na 0.125 TiO3 high-entropy ceramic materials.

[0066] The samples from Examples 1 to 4 were tested.

[0067] The high-entropy ceramic materials prepared in Examples 1-4 were polished and cleaned, and then silver electrodes were uniformly coated on both sides of the ceramic materials. Afterwards, they were heat-treated at 550°C for 25 minutes to obtain test ceramic materials. The performance of the test ceramic materials prepared from the ceramic materials in Examples 1-4 was tested, and the specific results are as follows: Figures 1-9 As shown.

[0068] Reference Figure 1 , Figure 1 The graph shows the variation of configuration entropy and tolerance factor of the samples prepared in Examples 1-4 as a function of x. The configuration entropy is minimum at x = 0.2, and is 1.52R, proving that all samples are high-entropy ceramics. The tolerance factor gradually decreases from 0.991 to 0.984, very close to 1, indicating that (Ba 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x TiO3 (0.125≤x≤0.2) high-entropy ceramics can obtain a stable perovskite structure.

[0069] Reference Figure 2 , Figure 2 The XRD curves of the samples prepared in Examples 1-4 are obtained from... Figure 2 It can be seen that (Ba) 0.12 Sr 0.28 K 0.3- x Bi 0.3 Na x The TiO3 ceramic samples with each component (x = 0.125, 0.15, 0.175, 0.5) exhibited a single-phase perovskite structure with no second phase formation.

[0070] Reference Figure 3 , Figure 3 The curves showing the dielectric constant and dielectric loss of the high-entropy ceramics prepared in Examples 1-4 as a function of temperature are shown respectively. It can be seen that the prepared high-entropy ceramics have obvious dispersion phase transition and frequency dispersion, and are typical relaxor ferroelectrics. The dielectric constants of all components are flat and broad, with peak values ​​all above 3000, and the dielectric loss is less than 0.025 at 78-330℃.

[0071] Reference Figure 4 , Figure 4 The graphs show the capacitive temperature change rate curves of the high-entropy ceramics used in Examples 1-4. Figure 4 It can be seen that when x = 0.15, the curve Δε is within the temperature range of 42–317℃. r / ε 150℃ It exhibits good high-temperature dielectric stability with a dielectric strength of ≤±15%.

[0072] Reference Figure 5 , Figure 5 The images shown are SEM images of the high-entropy ceramics used for testing obtained in Examples 1 to 4. It can be seen that all of them have good compactness and no obvious pores.

[0073] Reference Figure 6 and Figure 7 , Figure 6 The image shows the hysteresis loops of the samples prepared in Examples 1-4 under the breakdown electric field. Figure 7 It is based on Figure 6 A plot of the calculated data values. From the plot, it can be seen that when x = 0.15, it exhibits a thin hysteresis loop, and a larger P... max and smaller P r The breakdown electric field is 210 kV / cm, and the energy storage density is 2.07 J / cm². 3 The energy storage efficiency is 84.5%.

[0074] Reference Figure 8 and 9 , Figure 8The image shows the hysteresis loops of the sample prepared in Example 2 at different temperatures under 100 kV / cm. Figure 9 It is based on Figure 8 A plot of the calculated data values. From Figure 8 As can be seen, the hysteresis loop becomes thinner with increasing temperature, while P... r The changes gradually decrease. Between 40 and 140°C, the variations in energy storage density and energy storage efficiency are less than 4.9% and 2.0%, respectively.

Claims

1. A high-temperature stable high-entropy ceramic material having excellent energy storage performance, characterized by comprising: stoichiometric formula is (Ba 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x )TiO3, where 0.125≤ x ≤0.2, x is the molar percentage.

2. The method for producing a high-temperature stable high-entropy ceramic material having excellent energy storage performance according to claim 1, characterized by, Includes the following steps: Step 1: Based on the stoichiometric formula (Ba 0.3 Sr 0.7 TiO3, BaCO3, SrCO3 and TiO2 are mixed to obtain a mixture, the mixture is ball-milled, dried and then ground and sieved to obtain a pre-made powder, the pre-made powder is pre-calcined at 900 ℃ to obtain a block solid, the block solid is crushed to obtain solid powder A; According to the stoichiometry (Na) 0.5 Bi 0.5 TiO3, Na2CO3, Bi2O3 and TiO2 are mixed to obtain a mixture, the mixture is ball-milled, dried and then ground and sieved to obtain a pre-made powder, the pre-made powder is pre-calcined at 850 ℃ to obtain a block solid, the block solid is crushed to obtain solid powder B; According to the stoichiometry (K) 0.5 Bi 0.5 TiO3, K2CO3, Bi2O3 and TiO2 are mixed to obtain a mixture, the mixture is ball-milled, dried and then ground and sieved to obtain a pre-made powder, the pre-made powder is pre-calcined at 850 ℃ to obtain a block solid, the block solid is crushed to obtain solid powder C; The three solid powders obtained above were stoichiometrically formulated according to the stoichiometric formula (Ba). 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x TiO3, 0.125≤ x ≤0.2 The material is mixed to obtain a mixture, which is then ball-milled, dried and sieved to obtain the final material powder; Step 2: After pouring the material powder into the mold and pressing it into shape, it is then densified by cold isostatic pressing. The ceramic green body is then sintered at 1220-1250 ℃ to obtain (Ba). 0.12 Sr 0.28 K 0.3-x Bi 0.3 Na x TiO3 high-entropy ceramic materials, where 0.125≤ x ≤0.

2.

3. The method for preparing the high-temperature stable high-entropy ceramic material with excellent energy storage performance as described in claim 2, characterized in that, The auxiliary materials and media for ball milling mentioned in step one are zirconia balls and anhydrous ethanol, and the mass ratio of the mixture, zirconia balls and anhydrous ethanol is 1:2:

2. The ball milling regime is 550 r / min for 8 h.

4. The method of claim 2, wherein the high-entropy ceramic material has high energy storage performance and high-temperature stability. The drying temperature described in step one is 80~90℃, and the drying time is 12 hours.

5. The method of claim 2, wherein the high-entropy ceramic material has high energy storage performance and high-temperature stability. The pre-firing process described in step one is as follows: the temperature is increased from room temperature to the pre-firing temperature at a rate of 5 °C / min and held for 4 hours, then the temperature is decreased to 500 °C at a rate of 5 °C / min and cooled to room temperature with the furnace.

6. The method for preparing a high-temperature stable high-entropy ceramic material with excellent energy storage performance as described in claim 2, characterized in that, The pressure applied during the compression molding process in step two is 550~650 N.

7. The method for preparing a high-temperature stable high-entropy ceramic material with excellent energy storage performance as described in claim 2, characterized in that, The cold isostatic pressing densification process described in step two involves placing the material in a cold isostatic press and holding it under pressure of 250-350 MPa for 3 minutes.

8. The method for preparing a high-temperature stable high-entropy ceramic material with excellent energy storage performance as described in claim 2, characterized in that, The sintering process described in step two is as follows: the ceramic green body is buried with the same mass of green body powder, placed in a sealed crucible, and placed in a furnace. The temperature is increased from room temperature to the pre-firing temperature at 5 ℃ / min and held for 4 h. Then the temperature is decreased to 500℃ at 3℃ / min and cooled to room temperature with the furnace.

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