High-entropy perovskite ceramic material, preparation method thereof and capacitor

Abstract

This invention relates to a high-entropy perovskite ceramic material, its preparation method, and a capacitor, belonging to the technical field of perovskite ceramic materials. The high-entropy perovskite ceramic material of this invention has a chemical composition of (Bi... 0.4‑ x Ln x Na 0.2 K 0.2 Ba 0.2 TiO3, wherein the lanthanide element Ln includes at least one of La, Ce, Pr, Nd, Sm, Eu, and Gd;

Description

Technical Field

[0001] This invention belongs to the technical field of perovskite ceramic materials, specifically relating to a high-entropy perovskite ceramic material, its preparation method, and a capacitor. Background Technology

[0002] Since Rost et al. introduced the concept of high entropy in the field of oxide materials in 2015, high entropy oxides with various crystal structures have been developed, including high entropy rock salt oxides, fluorite oxides, spinel oxides, and perovskite oxides. Among them, high entropy perovskite oxides have attracted increasing attention due to their potential multifunctionality, such as high ferroelectric relaxation, low thermal conductivity, high catalytic activity, thermal and chemical stability, proton conductivity, and significant oxygen permeability. Summary of the Invention

[0003] This invention provides a high-entropy perovskite ceramic material, its preparation method, and a capacitor. This invention provides a novel high-entropy perovskite ceramic material system, obtaining a series of new high-entropy perovskite ceramics with high releasable energy storage density and energy storage efficiency through lanthanide element Ln doping. Furthermore, the high-energy-density lead-free high-entropy perovskite ceramic provided by this invention does not contain harmful lead elements and is environmentally friendly.

[0004] To this end, the present invention provides the following technical solution.

[0005] In a first aspect, the present invention provides a high-entropy perovskite ceramic material with a chemical composition of (Bi) 0.4- x Ln x Na 0.2 K 0.2 Ba 0.2 TiO3, wherein the lanthanide element Ln includes at least one of La, Ce, Pr, Nd, Sm, Eu, and Gd; <x≤0.20。

[0006] Preferably, 0.04 <x≤0.16。

[0007] Secondly, this invention provides a method for preparing high-entropy perovskite ceramic materials, comprising the following steps:

[0008] Step 1, press (Bi) 0.4-x Ln x Na 0.2 K 0.2 Ba 0.2 The TiO3 formulation involves mixing Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Ln oxides to obtain a mixed powder.

[0009] Step 2: Pre-fire and pulverize the mixed powder to obtain ceramic powder;

[0010] Step 3: Use the ceramic powder to form a ceramic blank;

[0011] Step 4: Sinter the ceramic blank to obtain the high-entropy perovskite ceramic material.

[0012] Preferably, before mixing in step 1, the oxides of the raw materials Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Ln are dried. More preferably, the raw material powder is dried in a vacuum drying oven at 100–180°C for 8–24 hours.

[0013] Preferably, step 1 includes: mixing the raw material powders and then ball milling, drying, and sieving to obtain a mixed powder.

[0014] Preferably, the ball milling includes: using zirconia balls and anhydrous ethanol as the milling medium for 8 to 24 hours.

[0015] Furthermore, in step 1, the oxide of Ln includes La2O3, CeO2, and Pr6O. 11 At least one of Nd2O3, Sm2O3, Eu2O3 and Gd2O3.

[0016] Furthermore, step 2 satisfies at least one of the following conditions:

[0017] (1) The pre-calcination includes: keeping the mixed powder at 800-1050°C for 2-6 hours; preferably, the pre-calcination is completed and then naturally cooled to room temperature;

[0018] (2) After crushing, the powder is ball-milled a second time, dried, and then sieved to obtain ceramic powder.

[0019] A second ball milling process was performed using zirconia balls and anhydrous ethanol as the milling medium. Optionally, the conditions for the second ball milling were the same as those for the first ball milling.

[0020] Furthermore, the preheating temperature is increased to 800-1050°C at a rate of 2-5°C / min.

[0021] Furthermore, step 3 includes:

[0022] Step 301: Granulate the ceramic powder;

[0023] Step 302: The granulated ceramic powder is shaped to obtain the ceramic green body.

[0024] Furthermore, step 3 satisfies at least one of the following conditions:

[0025] (1) In step 301, the ceramic powder is mixed with a binder and granulated using a granulator;

[0026] More preferably, the binder is PVB or PVA;

[0027] More preferably, the addition amount of the binder is 1 - 5 wt% of the mass of the ceramic powder;

[0028] (2) In step 302, the granulated ceramic powder is added to a dry pressing mold and pressed into shape under the condition of 20 - 100 MPa to obtain the ceramic green body;

[0029] Preferably, step 302 further includes cold isostatic pressing; more preferably, the pressure of cold isostatic pressing is 150 - 250 Mpa and the time is 5 - 10 min.

[0030] Furthermore, step 4 includes:

[0031] Step 401: Heat the ceramic green body to 400 - 600 °C and keep it warm for 1 - 6 hours for debinding;

[0032] Step 402: Raise the temperature of the debound ceramic green body to 1000 - 1200 °C and keep it warm for 3 - 6 hours to obtain the high-entropy perovskite ceramic material.

[0033] Preferably, in step 401 and step 402, the heating rate is 1 - 5 °C / min.

[0034] When Ln is La, preferably, 0.04 < x ≤ 0.10, the pre-sintering temperature is 825 - 875 °C, the time is 3 - 6 h; the sintering temperature is 1100 - 1140 °C, the time is 3 - 6 h;

[0035] When Ln is Ce, preferably, 0.06 < x ≤ 0.12, the pre-sintering temperature is 825 - 900 °C, the time is 3 - 6 h; the sintering temperature is 1100 - 1180 °C, the time is 3 - 6 h;

[0036] When Ln is Pr, preferably, 0.06 < x ≤ 0.14, the pre-sintering temperature is 825 - 900 °C, the time is 3 - 6 h; the sintering temperature is 1120 - 1180 °C, the time is 3 - 6 h;

[0037] When Ln is Nd, preferably, 0.06 < x ≤ 0.16, the pre-sintering temperature is 825 - 900 °C, the time is 3 - 6 h; the sintering temperature is 1120 - 1180 °C, the time is 3 - 6 h;

[0038] When Ln is Sm, preferably, 0.04 < x ≤ 0.10, the pre-sintering temperature is 800 - 900 °C, and the time is 3 - 6 h; the sintering temperature is 1090 - 1150 °C, and the time is 3 - 6 h;

[0039] When Ln is Eu, preferably, 0.04 < x ≤ 0.12, the pre-sintering temperature is 825 - 900 °C, and the time is 3 - 6 h; the sintering temperature is 1110 - 1160 °C, and the time is 3 - 6 h;

[0040] When Ln is Gd, preferably, 0.04 < x ≤ 0.12, the pre-sintering temperature is 800 - 900 °C, and the time is 2 - 6 h; the sintering temperature is 1100 - 1140 °C, and the time is 3 - 6 h.

[0041] In a third aspect, the present invention provides a capacitor, comprising a high-entropy perovskite ceramic material or a high-entropy perovskite ceramic material prepared according to the method, and a silver electrode is provided on its surface.

[0042] The technical solution of the present invention has the following advantages:

[0043] 1. The chemical composition of the high-entropy perovskite ceramic material of the present invention is (Bi 0.4-x Ln x Na 0.2 K 0.2 Ba 0.2 )TiO3, where the lanthanide element Ln includes at least one of La, Ce, Pr, Nd, Sm, Eu, Gd; 0 < x ≤ 0.20.

[0044] The present invention introduces the lanthanide element, Ln 3+ equivalently replaces a part of Bi 3+ , making the configuration of cations in the perovskite structure more complex. Due to the differences in valence states and ionic radii of various cations, the lattice distortion and oxygen octahedron distortion are more serious, resulting in enhanced relaxation behavior of the ceramic and promoting the formation of smaller-sized polar nano-domains, which is beneficial to obtaining multi-domain polar nano-domains. Finally, the ceramic has a slender polarization-electric field curve, which is beneficial to obtaining good energy storage efficiency. At the same time, the addition of Ln series elements will cause the phase transition point to decrease, adjust the phase transition point closer to room temperature, and increase the room temperature dielectric constant, thereby increasing the energy storage density.

[0045] In addition, the high-entropy perovskite ceramic material provided by the present invention has a high recoverable energy storage density and energy storage efficiency under a low electric field.

[0046] 2. The preparation method of the high-entropy perovskite ceramic material of the present invention adopts the solid-phase reaction method. The solid-phase reaction method for preparing ceramics has the advantages of simple process, low cost, and easy large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative work, other drawings can be obtained based on these drawings.

[0048] Figure 1 XRD patterns of the ceramics obtained in Examples 1-7 of the present invention;

[0049] Figure 2 Variation curves of the dielectric constants of the ceramics obtained in Examples 1-8 and Comparative Example 1 with the test temperature;

[0050] Figure 3 Single-pole ferroelectric hysteresis loops of the test samples obtained in Examples 1-8 and Comparative Example 1 of the present invention. Specific embodiments

[0051] The following embodiments are provided to better further understand the present invention. It is not limited to the best embodiment, and does not limit the content and protection scope of the present invention. Any product that is the same or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior art features falls within the protection scope of the present invention.

[0052] For those not specifying specific experimental steps or conditions in the embodiments, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments not indicating the manufacturer, they are all conventional reagent products that can be obtained through commercial purchase.

[0053] The preparation method of the high-entropy perovskite ceramic material of the present invention includes the following steps:

[0054] 1. Powders of commercially available Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and oxides of lanthanide elements Ln (at least one of La2O3, CeO2, Pr6O 11 , Nd2O3, Sm2O3, Eu2O3 and Gd2O3) are dried in a vacuum drying oven at 100-180 °C for 8-24 hours.

[0055] 2. Weigh the dried raw materials and mix them according to the formula (Bi 0.4-x Ln x Na 0.2 K 0.2 Ba 0.2 )TiO3, where 0 < x ≤ 0.20. After ball milling, drying and sieving, a mixed powder is obtained;

[0056] Specifically, the mixture is ball-milled for 8–24 hours using zirconia balls and anhydrous ethanol as the milling medium. The slurry is then dried and sieved to obtain the mixed powder.

[0057] 3. Place the mixed powder into an alumina crucible and heat it to 800-1050°C in a box furnace at a heating rate of 2-5°C / min, and keep it at that temperature for 2-6 hours. After the holding time is over, allow it to cool naturally to room temperature and pulverize it. Then, use zirconia balls and anhydrous ethanol as the ball milling medium for secondary ball milling. After drying, sieve the powder to obtain the ceramic powder.

[0058] 4. Add 1-5 wt% binder to the ceramic powder and granulate it using a granulator.

[0059] The granulated ceramic powder is added into a dry pressing mold and pressurized under pressure of 20–100 MPa to obtain the ceramic green body. For example, the pressurization can be uniaxial pressing.

[0060] Preferably, the obtained ceramic green body is subjected to cold isostatic pressing at a pressure of 150–250 MPa. Cold isostatic pressing can further improve the density of the ceramic green body.

[0061] 5. Heat the ceramic blank to 400-600℃ and hold for 1-6 hours to remove the binder; after removing the binder, continue to heat to 1000-1200℃ and hold for 3-6 hours to sinter, thereby obtaining high-entropy perovskite relaxor ferroelectric ceramic, wherein the heating rate is 1-5℃ / min.

[0062] Example 1

[0063] This embodiment provides (Bi) 0.32 La 0.08 Na 0.2 K 0.2 Ba 0.2 The preparation method of TiO3 high-entropy perovskite ceramic material includes the following steps:

[0064] 1. Place the commercially available Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and La2O3 powders in a vacuum drying oven and dry them at 140℃ for 8 hours.

[0065] 2. According to the chemical formula (Bi) 0.32 La 0.08 Na 0.2 K 0.2 Ba 0.2TiO3 was prepared by weighing Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and La2O3, placing them in a nylon ball mill jar, and ball milling for 12 hours to grind and mix them evenly. After drying, the mixture was passed through a 40-mesh sieve to obtain a mixed powder.

[0066] 3. The obtained mixed powder is placed in an alumina crucible and placed in a box furnace. It is heated to 850°C at a heating rate of 5°C / min and calcined at 850°C for 3 hours. Then it is naturally cooled to room temperature. The calcined block is broken up and ball-milled a second time using zirconia balls and anhydrous ethanol as the ball milling medium. The slurry is then dried and passed through a 200-mesh sieve to obtain fine ceramic powder.

[0067] 4. Mix the ceramic powder obtained in step 3 with 2 wt% PVB binder. Let the uniformly mixed binder powder stand for at least 12 hours, and then granulate it using a granulator. Place the granulated granules into a cylindrical mold and press the powder into a ceramic green body under a uniaxial pressure of approximately 100 MPa. Then, cold isostatically press the dry-pressed ceramic green body at 200 MPa for 20 minutes.

[0068] 5. The cold isostatically pressed ceramic green body is placed in a box furnace and heated to 550℃ at a rate of 5℃ / min. It is then heat-treated at 550℃ for 3 hours to remove the binder and organic matter. The debinded ceramic green body is then placed on an alumina firing plate and heated to 1130℃ at a rate of 5℃ / min. It is then sintered at 1130℃ for 3 hours to finally obtain a disc-shaped (Bi) ceramic green body. 0.32 La 0.08 Na 0.2 K 0.2 Ba 0.2 TiO3 high-entropy perovskite ceramics.

[0069] 6. The disc-shaped high-entropy perovskite ceramic obtained in step 5 is processed into two samples with thicknesses of 1 mm and 0.10 mm. After cleaning, drying, printing silver paste, and drying again, the temperature is raised to 600℃ at a heating rate of 2℃ / min and held for 30 minutes to obtain ceramic components.

[0070] Example 2

[0071] This embodiment provides (Bi) 0.32 Ce 0.08 Na 0.2 K 0.2 Ba 0.2 The preparation method of TiO3 high-entropy perovskite ceramic material includes the following steps:

[0072] 1. Place the commercially available Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and CeO2 powders in a vacuum drying oven and dry them at 180℃ for 12 hours.

[0073] 2. According to the chemical formula (Bi) 0.32 Ce 0.08 Na 0.2 K 0.2 Ba 0.2 TiO3 was prepared by weighing Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and CeO2, placing them in a nylon ball mill jar, and ball milling for 24 hours to grind and mix them evenly. After drying, the mixture was passed through a 60-mesh sieve to obtain a mixed powder.

[0074] 3. The obtained mixed powder is placed in an alumina crucible and placed in a muffle furnace. It is heated to 850°C at a heating rate of 4°C / min and calcined at 850°C for 3 hours. Then it is naturally cooled to room temperature. The calcined block is crushed and ball-milled a second time using zirconia balls and anhydrous ethanol as the ball milling medium. The slurry is then dried and passed through a 200-mesh sieve to obtain fine ceramic powder.

[0075] 4. Mix the ceramic powder obtained in step 3 with 2 wt% PVB binder. Let the uniformly mixed binder powder stand for at least 12 hours, and then granulate it using a granulator. Place the granulated granules into a cylindrical mold and press the powder into a ceramic green body under a uniaxial pressure of approximately 100 MPa. Then, cold isostatically press the dry-pressed ceramic green body at 200 MPa for 20 minutes.

[0076] 5. The cold isostatically pressed ceramic green body is placed in a muffle furnace and heated to 550℃ at a rate of 2℃ / min. It is held at 550℃ for 3 hours to remove the binder and organic matter. Then, the debinded ceramic green body is placed in a sealed crucible and sintered at 1120℃ for 3 hours to finally obtain a disc-shaped (Bi) ceramic green body. 0.32 Ce 0.08 Na 0.2 K 0.2 Ba 0.2 TiO3 high-entropy perovskite ceramics.

[0077] 6. The disc-shaped high-entropy perovskite ceramic obtained in step 5 is processed into two samples with thicknesses of 1 mm and 0.10 mm. After cleaning, drying, printing silver paste, and drying again, the temperature is raised to 600℃ at a heating rate of 2℃ / min and held for 30 minutes to obtain ceramic components.

[0078] Example 3

[0079] This embodiment provides (Bi) 0.28 Pr0.12 Na 0.2 K 0.2 Ba 0.2 The preparation method of TiO3 high-entropy perovskite ceramic material includes the following steps:

[0080] 1. Mix commercially available Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Pr6O 11 The powder was placed in a vacuum drying oven and dried at 150°C for 24 hours.

[0081] 2. According to the chemical formula (Bi) 0.28 Pr 0.12 Na 0.2 K 0.2 Ba 0.2 Prepare a mixture of TiO3, weighing out Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Pr6O. 11 The mixture is placed in a nylon ball mill jar and ball-milled for 12 hours to grind and mix it evenly. After that, it is dried and passed through a 60-mesh sieve to obtain a mixed powder.

[0082] 3. The obtained mixed powder is placed in an alumina crucible and placed in a box furnace. It is heated to 850°C at a heating rate of 5°C / min and calcined at 850°C for 3 hours. Then it is naturally cooled to room temperature. The calcined block is broken up and ball-milled a second time using zirconia balls and anhydrous ethanol as the ball milling medium. The slurry is then dried and passed through a 200-mesh sieve to obtain fine ceramic powder.

[0083] 4. Mix the ceramic powder obtained in step 3 with 3 wt% PVB binder. Let the uniformly mixed binder powder stand for at least 12 hours, and then granulate it using a granulator. Place the granulated granules into a cylindrical mold and press the powder into a ceramic green body under a uniaxial pressure of approximately 100 MPa. Then, cold isostatically press the dry-pressed ceramic green body at 200 MPa for 20 minutes.

[0084] 5. The cold isostatically pressed ceramic green body is placed in a box furnace and heated to 550℃ at a rate of 2℃ / min. It is then heat-treated at 550℃ for 3 hours to remove the binder and organic matter. The debinded ceramic green body is then placed on an alumina firing plate and heated to 1130℃ at a rate of 5℃ / min. It is then sintered at 1130℃ for 3 hours to finally obtain a disc-shaped (Bi) ceramic green body. 0.28 Pr 0.12 Na 0.2 K 0.2 Ba 0.2 TiO3 high-entropy perovskite ceramics.

[0085] 6. The disc-shaped high-entropy perovskite ceramic obtained in step 5 is processed into two samples with thicknesses of 1 mm and 0.10 mm. After cleaning, drying, printing silver paste, and drying again, the temperature is raised to 600℃ at a heating rate of 2℃ / min and held for 30 minutes to obtain ceramic components.

[0086] Example 4

[0087] This embodiment provides (Bi) 0.28 Nd 0.12 Na 0.2 K 0.2 Ba 0.2 The preparation method of TiO3 high-entropy perovskite ceramic material includes the following steps:

[0088] 1. Place the commercially available Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and Nd2O3 powders in a vacuum drying oven and dry them at 140℃ for 8 hours.

[0089] 2. According to (Bi) 0.28 Nd 0.12 Na 0.2 K 0.2 Ba 0.2 To determine the stoichiometric ratio of TiO3 ceramics, weigh out Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Nd2O3, place them in a nylon ball mill jar, and ball mill for 12 hours to grind them finely and mix them evenly. Then dry them and pass them through a 60-mesh sieve to obtain the mixed powder.

[0090] 3. The obtained mixed powder is placed in an alumina crucible and placed in a box furnace. It is heated to 850°C at a heating rate of 4°C / min and calcined at 850°C for 3 hours. Then it is naturally cooled to room temperature. The calcined block is broken up and ball-milled a second time using zirconia balls and anhydrous ethanol as the ball milling medium. The slurry is then dried and passed through a 200-mesh sieve to obtain fine ceramic powder.

[0091] 4. Mix the ceramic powder obtained in step 3 with 4 wt% PVB binder. Let the uniformly mixed binder powder stand for at least 12 hours, and then granulate it using a granulator. Place the granulated granules into a cylindrical mold and press the powder into a ceramic green body under a uniaxial pressure of approximately 100 MPa. Then, cold isostatically press the dry-pressed ceramic green body at 200 MPa for 20 minutes.

[0092] 5. The cold isostatically pressed ceramic green body is placed in a box furnace and heated to 550℃ at a rate of 3℃ / min. It is then heat-treated at 550℃ for 3 hours to remove the binder and organic matter. The debinded ceramic green body is then placed on an alumina firing plate and heated to 1140℃ at a rate of 5℃ / min. It is then sintered at 1140℃ for 3 hours to finally obtain a disc-shaped (Bi) ceramic green body. 0.28 Nd 0.12 Na 0.2 K 0.2 Ba 0.2 TiO3 high-entropy perovskite ceramics.

[0093] 6. The disc-shaped high-entropy perovskite ceramic obtained in step 5 is processed into two samples with thicknesses of 1 mm and 0.10 mm. After cleaning, drying, printing silver paste, and drying again, the temperature is raised to 600℃ at a heating rate of 2℃ / min and held for 30 minutes to obtain ceramic components.

[0094] Example 5

[0095] This embodiment provides (Bi) 0.32 Sm 0.08 Na 0.2 K 0.2 Ba 0.2 The preparation method of TiO3 high-entropy perovskite ceramic material includes the following steps:

[0096] 1. Place the commercially available Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and Sm2O3 powders in a vacuum drying oven and dry them at 120℃ for 24 hours.

[0097] 2. According to (Bi) 0.32 Sm 0.08 Na 0.2 K 0.2 Ba 0.2 To determine the stoichiometric ratio of TiO3 ceramics, weigh out Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Sm2O3, place them in a nylon ball mill jar, and ball mill for 12 hours to grind them finely and mix them evenly. Then dry them and pass them through a 40-mesh sieve to obtain the mixed powder.

[0098] 3. The mixed powder is placed in an alumina crucible and placed in a box furnace. It is heated to 850°C at a heating rate of 5°C / min and calcined at 850°C for 3 hours. Then it is allowed to cool naturally to room temperature. The calcined lumps are broken up and ball-milled a second time using zirconia balls and anhydrous ethanol as the ball milling medium. The slurry is then dried and passed through a 200-mesh sieve to obtain fine ceramic powder.

[0099] 4. Mix the ceramic powder obtained in step 3 with 4 wt% PVB binder. Let the uniformly mixed binder powder stand for at least 12 hours, and then granulate it using a granulator. Place the granulated granules into a cylindrical mold and press the powder into a ceramic green body under a uniaxial pressure of approximately 100 MPa. Then, cold isostatically press the dry-pressed ceramic green body at 200 MPa for 20 minutes.

[0100] 5. The cold isostatically pressed ceramic green body is placed in a muffle furnace and heated to 550℃ at a rate of 1℃ / min. It is held at 550℃ for 3 hours to remove the binder and organic matter. The debinded ceramic sheet is then placed on an alumina sintering plate and heated to 1110℃ at a rate of 5℃ / min. It is then sintered at 1110℃ for 4 hours to finally obtain a round (Bi) sheet. 0.32 Sm 0.08 Na 0.2 K 0.2 Ba 0.2 TiO3 high-entropy perovskite ceramics.

[0101] 6. The disc-shaped high-entropy perovskite ceramic obtained in step 5 is processed into two samples with thicknesses of 1 mm and 0.10 mm. After cleaning, drying, printing silver paste, and drying again, the temperature is raised to 600℃ at a heating rate of 3℃ / min and held for 30 minutes to obtain ceramic components.

[0102] Example 6

[0103] This embodiment provides (Bi) 0.28 Eu 0.12 Na 0.2 K 0.2 Ba 0.2 The preparation method of TiO3 high-entropy perovskite ceramic material includes the following steps:

[0104] 1. Place the commercially available Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and Eu2O3 powders in a vacuum drying oven and dry them at 130℃ for 16 hours.

[0105] 2. According to (Bi) 0.28 Eu 0.12 Na 0.2 K 0.2 Ba 0.2 To determine the stoichiometric ratio of TiO3 ceramics, weigh out Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Eu2O3, place them in a nylon ball mill jar, and ball mill for 12 hours to grind them finely and mix them evenly. Then dry them and pass them through a 40-mesh sieve to obtain the mixed powder.

[0106] 3. The mixed powder is placed in an alumina crucible and placed in a box furnace. It is heated to 850°C at a heating rate of 5°C / min and calcined at 850°C for 3 hours. Then it is allowed to cool naturally to room temperature. The calcined lumps are broken up and ball-milled a second time using zirconia balls and anhydrous ethanol as the ball milling medium. The slurry is then dried and passed through a 200-mesh sieve to obtain fine ceramic powder.

[0107] 4. Mix the ceramic powder obtained in step 3 with 4 wt% PVB binder. Let the uniformly mixed binder powder stand for at least 12 hours, and then granulate it using a granulator. Place the granulated granules into a cylindrical mold and press the powder into a ceramic green body under a uniaxial pressure of approximately 100 MPa. Then, cold isostatically press the dry-pressed ceramic green body at 200 MPa for 20 minutes.

[0108] 5. The cold isostatically pressed ceramic green body is placed in a muffle furnace and heated to 550℃ at a rate of 2℃ / min. It is held at 550℃ for 3 hours to remove the binder and organic matter. The debinded ceramic sheet is then placed in a sealed crucible and heated to 1120℃ at a rate of 5℃ / min. It is sintered at 1120℃ for 3 hours to finally obtain a circular (Bi) sheet. 0.28 Eu 0.12 Na 0.2 K 0.2 Ba 0.2 TiO3 high-entropy perovskite ceramics.

[0109] 6. The disc-shaped high-entropy perovskite ceramic obtained in step 5 is processed into two samples with thicknesses of 1 mm and 0.10 mm. After cleaning, drying, printing silver paste, and drying again, the temperature is raised to 600℃ at a heating rate of 2℃ / min and held for 30 minutes to obtain ceramic components.

[0110] Example 7

[0111] This embodiment provides (Bi) 0.32 Gd 0.08 Na 0.2 K 0.2 Ba 0.2 The preparation method of TiO3 high-entropy perovskite ceramic material includes the following steps:

[0112] 1. Place the commercially available Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2 and Gd2O3 powders in a vacuum drying oven and dry them at 160℃ for 8 hours.

[0113] 2. According to (Bi) 0.32 Gd 0.08 Na 0.2 K 0.2 Ba0.2 To determine the stoichiometric ratio of TiO3 ceramics, weigh out Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Gd2O3, place them in a nylon ball mill jar, and ball mill for 12 hours to grind them finely and mix them evenly. Then dry them and pass them through a 40-mesh sieve to obtain the mixed powder.

[0114] 3. The mixed powder is placed in an alumina crucible and placed in a box furnace. It is heated to 850°C at a heating rate of 4°C / min and calcined at 850°C for 3 hours. Then it is allowed to cool naturally to room temperature. The calcined lumps are broken up and ball-milled a second time using zirconia balls and anhydrous ethanol as the ball milling medium. The slurry is then dried and passed through a 200-mesh sieve to obtain fine ceramic powder.

[0115] 4. Mix the ceramic powder obtained in step 3 with 4 wt% PVB binder. Let the uniformly mixed binder powder stand for at least 12 hours, and then granulate it using a granulator. Place the granulated granules into a cylindrical mold and press the powder into a ceramic green body under a uniaxial pressure of approximately 100 MPa. Then, cold isostatically press the dry-pressed ceramic green body at 200 MPa for 20 minutes.

[0116] 5. The cold isostatically pressed ceramic green body is placed in a muffle furnace and heated to 550℃ at a rate of 3℃ / min. It is held at 550℃ for 3 hours to remove organic matter through a debinding process. The debinded ceramic sheet is then placed in a sealed crucible and heated to 1120℃ at a rate of 3℃ / min. It is then sintered at 1120℃ for 3 hours to finally obtain a circular (Bi) sheet. 0.32 Gd 0.08 Na 0.2 K 0.2 Ba 0.2 TiO3 high-entropy perovskite ceramics.

[0117] 6. The disc-shaped high-entropy perovskite ceramic obtained in step 5 is processed into two samples with thicknesses of 1 mm and 0.10 μm. After cleaning, drying, printing silver paste, and drying again, the temperature is raised to 600°C at a heating rate of 2°C / min and held for 30 minutes to obtain ceramic components.

[0118] Example 8

[0119] This embodiment is basically the same as embodiment 5, except that the ceramic green body prepared in this embodiment is not subjected to cold isostatic pressing.

[0120] Comparative Example 1

[0121] This comparative example is basically the same as Example 5, except that Ln element Sm was not added in this comparative example, and (Bi) was obtained. 0.4 Na 0.2 K0.2 Ba 0.2 TiO3 perovskite ceramics.

[0122] Test case

[0123] 1. The crystal structure of the high-entropy perovskite ceramics was determined using X-ray diffraction analysis. The XRD patterns of the ceramics prepared in Examples 1-7 are shown below. Figure 1 .Depend on Figure 1 It can be seen that all samples are pure perovskite phase, that is, they are all high-entropy perovskite.

[0124] 2. The dielectric properties of the 1 mm thick perovskite ceramics prepared in Examples 1-8 and Comparative Example 1 were tested using a dielectric impedance spectrometer. The test results are shown in [Figure number missing]. Figure 2 .

[0125] Depend on Figure 2 It can be seen that, compared with Comparative Example 1, the samples prepared in Examples 1-8 have a smaller change in dielectric constant with temperature, and a larger dielectric constant at room temperature, resulting in better energy storage performance and temperature stability.

[0126] 3. The single-phase hysteresis loops of the perovskite ceramics with a thickness of 0.1 mm prepared in Examples 1-8 and Comparative Example 1 were tested using a TF-2000 ferroelectric analyzer. The test results are shown in [Figure number missing]. Figure 3 .

[0127] Depend on Figure 3 It can be seen that the polarization intensity of the examples is significantly higher than that of Comparative Example 1. Comparing the energy storage performance of the samples prepared in Example 5 and Example 8, it can be seen that cold isostatic pressing helps to improve the energy storage performance.

[0128] Table 1. Energy storage performance of high-entropy perovskite ceramics prepared in the examples and comparative examples.

[0129]

[0130]

[0131] As shown in Table 1, the high-entropy perovskite ceramics prepared by this invention have significantly improved releasable energy storage density and energy storage efficiency.

[0132] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A high-entropy perovskite ceramic material, characterized in that, The chemical composition is (Bi) 0.4-x Ln x Na 0.2 K 0.2 Ba 0.2 TiO3, wherein the lanthanide element Ln includes at least one of La, Ce, Pr, Nd, Sm, Eu, and Gd; 0.04 < x ≤0.

16.

2. The high-entropy perovskite ceramic material according to claim 1, characterized in that, The Ln is La, 0.04 < x ≤0.10; or The Ln is Ce, 0.06 <x≤0.12; or Ln is Pr, 0.06 <x≤0.14; or The Ln is Nd, 0.06 < x ≤0.16; or The Ln is Sm, 0.04 < x ≤0.10; or The Ln is Eu, 0.04 < x ≤0.12; or The Ln is Gd, 0.04 < x ≤0.

12.

3. A method for preparing the high-entropy perovskite ceramic material according to claim 1 or 2, characterized in that, Includes the following steps: Step 1, press (Bi) 0.4-x Ln x Na 0.2 K 0.2 Ba 0.2 The TiO3 formulation involves mixing Bi2O3, Na2CO3, K2CO3, BaCO3, TiO2, and Ln oxides to obtain a mixed powder. Step 2: Pre-fire and pulverize the mixed powder to obtain ceramic powder; Step 3: Use the ceramic powder to form a ceramic blank; Step 4: Sinter the ceramic blank to obtain the high-entropy perovskite ceramic material.

4. The method for preparing high-entropy perovskite ceramic materials according to claim 3, characterized in that, In step 1, the oxides of Ln include La2O3, CeO2, and Pr6O. 11 At least one of Nd2O3, Sm2O3, Eu2O3 and Gd2O3.

5. The method for preparing high-entropy perovskite ceramic materials according to claim 3 or 4, characterized in that, Step 2 satisfies at least one of the following conditions: (1) The pre-calcination includes: keeping the mixed powder at 800~1050℃ for 2~6h; (2) After crushing, the powder is ball-milled a second time, dried, and then sieved to obtain ceramic powder.

6. The method for preparing high-entropy perovskite ceramic material according to claim 5, characterized in that, The preheating process involves raising the temperature to 800-1050°C at a rate of 2-5°C / min.

7. The method for preparing high-entropy perovskite ceramic material according to claim 3, characterized in that, Ln is La, the pre-firing temperature is 825~875℃, the time is 3~6h; the sintering temperature is 1100~1140℃, the time is 3~6h; or Ln is Ce, the pre-firing temperature is 825~900℃, the time is 3~6h; the sintering temperature is 1100~1180℃, the time is 3~6h; or Ln is Pr, the pre-firing temperature is 825~900℃, the time is 3~6h; the sintering temperature is 1120~1180℃, the time is 3~6h; or Ln is Nd, the pre-firing temperature is 825~900℃, the time is 3~6h; the sintering temperature is 1120~1180℃, the time is 3~6h; or Ln is Sm, the pre-firing temperature is 800~900℃, the time is 3~6h; the sintering temperature is 1090~1150℃, the time is 3~6h; or Ln is Eu, the pre-firing temperature is 825~900℃, the time is 3~6h; the sintering temperature is 1110~1160℃, the time is 3~6h; or Ln is Gd, the pre-firing temperature is 800~900℃, the time is 2~6h; the sintering temperature is 1100~1140℃, the time is 3~6h.

8. The method for preparing high-entropy perovskite ceramic materials according to claim 3 or 4, characterized in that, Step 3 includes: Step 301: Granulate the ceramic powder; Step 302: The granulated ceramic powder is shaped to obtain the ceramic green body.

9. The method for preparing high-entropy perovskite ceramic material according to claim 8, characterized in that, Step 3 satisfies at least one of the following conditions: (1) In step 301, the ceramic powder is mixed with the binder and granulated using a granulator; the amount of binder added is 1-5 wt% of the mass of the ceramic powder. (2) In step 302, the granulated ceramic powder is added into a dry pressing mold and pressed under pressure at 20~100MPa to obtain the ceramic blank.

10. The method for preparing high-entropy perovskite ceramic material according to claim 8, characterized in that, Step 302 further includes cold isostatic pressing of the ceramic blank; the pressure of cold isostatic pressing is 150~250 MPa, and the time is 5~10 min.

11. A capacitor, characterized in that, The material includes the high-entropy perovskite ceramic material as described in claim 1 or 2, or the high-entropy perovskite ceramic material prepared by the method according to any one of claims 3-8, and has a silver electrode disposed on its surface.

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