A bismuth-based perovskite ceramic with a self-absorption doping strategy and a preparation method thereof

Abstract

The application belongs to the technical field of dielectric materials, and provides a bismuth-based perovskite ceramic with a self-absorption doping strategy and a preparation method.The chemical formula of the bismuth-based perovskite ceramic is (1-x)(0.7BiFeO3-0.3SrTiO3)-xBi2Ti2O7, wherein 0x≤0.08.In the embodiment of the application, Bi2Ti2O7 (BTO) secondary phase which is prone to appear in bismuth-based perovskite is used as a doping component to improve the dielectric breakdown strength of BiFeO3-SrTiO3 (BFST) solid solution ceramic.After twice solid-phase sintering, the BFST-BTO solid solution ceramic is formed by mixing and sintering again, and the incorporation of BTO improves the dielectric breakdown strength and energy storage density of the BFST-based ceramic, thereby providing a new strategy for improving the dielectric breakdown strength without introducing new elements, and having potential application value for improving the energy storage performance of other bismuth-based ceramics.

Description

Technical Field

[0001] This invention belongs to the field of dielectric materials technology, and particularly relates to a bismuth-based perovskite ceramic with a self-absorption doping strategy and its preparation method. Background Technology

[0002] Ceramic dielectric capacitors have become a research hotspot due to their high power density and excellent fast charge / discharge performance. However, compared with traditional energy storage devices such as batteries and electrochemical capacitors, their relatively low energy density restricts the industrial-scale application of this technology. Therefore, developing new dielectric materials that combine high energy density and high energy storage efficiency has become a key issue that urgently needs to be addressed in the current energy storage field. Modifying ceramics using doping strategies is an important method to optimize the energy storage performance of ferroelectric ceramics: bismuth-based perovskites, such as BiFeO3-based lead-free ceramics (BFO), have high spontaneous polarization (P0). s Approximately 90 μC / cm 2 ) and higher Curie temperature (T c (≈ 830℃), considered one of the most promising fundamental materials for designing high-performance energy storage dielectrics; however, pure BFO suffers from problems such as high leakage current, which greatly limits its breakdown strength (E). b To compensate for the inherent defects of BFO (BioFocus of the Oxide-Based Fiber) and energy storage efficiency (η), linear dielectric strontium titanate (SrTiO3, ST) is incorporated into BFO ceramics to synthesize BiFeO3-SrTiO3 ceramics (BFST). ST has the advantages of wide bandgap and low dielectric loss, which can form a synergistic effect with BFO, but there is still room for improvement in its energy storage density and breakdown strength.

[0003] Bi2Ti2O7 (BTO) is a linear dielectric material with high breakdown strength and low leakage current. It is a common second phase in the preparation of Bi-based perovskite ceramics. Studies have shown that the presence of the BTO second phase can improve the energy storage performance of ceramics. However, the dielectric constant of BTO is significantly lower than that of the matrix phase. When a voltage is applied to the capacitor, the local electric field will concentrate in the second phase with low dielectric constant. In addition, the content and microstructure of the second phase are difficult to control. Although the second phase itself has a high dielectric breakdown strength, there are defects such as pores and oxygen vacancies at the interface between the second phase and the matrix phase. This makes it easy for dielectric breakdown weak points to appear at the heterogeneous interface between the second phase and the matrix phase, which will affect the uniformity of ceramic properties and dielectric breakdown strength [Cai, Ziming; Feng, Peizhong; Zhu, Chaoqiong; Wang, Xiaohui;Dielectric breakdown behavior of ferroelectric ceramics: The role of pores,Journal of the European Ceramic Society, 2021, 41 (4), p. 2533-2538]. It can be seen that the current doping technology may increase the complexity of the composition and pose a risk of reduced composition uniformity. Summary of the Invention

[0004] The purpose of this invention is to provide a bismuth-based perovskite ceramic with a self-absorption doping strategy, aiming to solve the problems mentioned in the background art.

[0005] The present invention is implemented as follows: a bismuth-based perovskite ceramic with a self-absorption doping strategy, wherein the chemical formula of the bismuth-based perovskite ceramic is (1-x)(0.7BiFeO3-0.3SrTiO3)-xBi2Ti2O7, where 0<x≤0.08.

[0006] Another objective of this invention is to provide a method for preparing bismuth-based perovskite ceramics using a self-absorption doping strategy, comprising the following steps:

[0007] (1) Ingredients: Bismuth oxide, ferric oxide, strontium carbonate and titanium oxide are mixed in a molar ratio of 0.7BiFeO3-0.3SrTiO3 to obtain a mixture. The weighed raw materials are placed in an oven to dry.

[0008] (2) Mixing: Add anhydrous ethanol to the mixture and continue ball milling to mix the powder evenly to form a slurry;

[0009] (3) Drying: Dry the slurry at a constant temperature to remove ethanol, and grind it to obtain a uniformly mixed powder;

[0010] (4) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed into shape, and the shaped block is placed in a solid-phase reaction furnace for solid-phase reaction;

[0011] (5) Ball milling: After the solid reaction, the material blocks are crushed and ground to obtain ceramic powder. Anhydrous ethanol is added to the ceramic powder and ball milling is continued to make the powder mix evenly to form a slurry.

[0012] (6) Drying: The slurry is dried at a constant temperature to remove ethanol and then ground to obtain a uniformly mixed 0.7BiFeO3-0.3SrTiO3 ceramic powder;

[0013] (7) Ingredients: Sodium bismuthate and titanium oxide are mixed in a molar ratio according to the chemical formula Bi2Ti2O7 to obtain a mixture, which is then dried;

[0014] (8) Mixing: Add anhydrous ethanol to the mixture and continue ball milling to mix the powder evenly to form a slurry;

[0015] (9) Drying: Dry the slurry at a constant temperature to remove ethanol, and grind it to obtain a uniformly mixed powder;

[0016] (10) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed into shape, and the shaped block is placed in a solid-phase reaction furnace for solid-phase reaction;

[0017] (11) Ball milling: After the solid reaction, the material blocks are crushed and ground to obtain ceramic powder. Anhydrous ethanol is added to the ceramic powder and ball milling is continued to make the powder mix evenly to form a slurry.

[0018] (12) Drying: The slurry is dried at a constant temperature to remove ethanol and then ground to obtain a uniformly mixed Bi2Ti2O7 ceramic powder;

[0019] (13) Batching: The ceramic powders obtained in steps (6) and (12) are mixed according to the molar ratio of (1-x)(0.7BiFeO3-0.3SrTiO3)-xBi2Ti2O7, wherein... 0 < x ≤ 0.08, a mixture is obtained. The weighed raw materials are placed in an oven and dried.

[0020] (14) Mixing: Add anhydrous ethanol to the mixture and continue ball milling to mix the powder evenly to form a slurry;

[0021] (15) Drying: Dry the slurry at a constant temperature to remove ethanol, and grind it to obtain a uniformly mixed powder;

[0022] (16) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed into shape, and the shaped block is placed in a solid-phase reaction furnace for solid-phase reaction;

[0023] (17) Ball milling: After the solid reaction, the material blocks are crushed and ground to obtain ceramic powder. Anhydrous ethanol is added to the obtained ceramic powder and ball milling is continued to make the powder mix evenly to form a slurry.

[0024] (18) Drying: Dry the slurry at a constant temperature to remove ethanol, and grind it to obtain a uniformly mixed ceramic powder;

[0025] (19) Granulation and molding: The ceramic powder is sieved, then PVA solution is added to it, it is ground and sieved again, then the powder particles are placed in the mold and pressed into shape, and then isostatic pressing is performed to form a ceramic green body.

[0026] (20) Removal of PVA: The PVA in the ceramic green body is removed to obtain the ceramic body;

[0027] (21) Sintering: The ceramic blank is sintered and cooled to obtain bismuth-based perovskite ceramics with the chemical formula (1-x)(0.7BiFeO3-0.3SrTiO3)-xBi2Ti2O7 using a self-absorption doping strategy.

[0028] This invention employs a design that selects the Bi₂Ti₂O₇ (BTO) second phase, which is readily found in bismuth-based perovskites, as a dopant to improve the dielectric breakdown strength of BiFeO₃-SrTiO₃ (BFST) solid solution ceramics. After two solid-state sintering processes, a second mixing and sintering process is performed to form BFST-BTO solid solution ceramics. The incorporation of BTO enhances the dielectric breakdown strength and energy density of the BFST-based ceramics. Specifically, after BTO doping, BTO is completely dissolved into the perovskite lattice, and the grain size decreases with increasing BTO doping concentration. Low dielectric loss is achieved in the BFST-BTO ceramics, and the dielectric breakdown strength and energy density of all ceramics are improved. Specifically, when x=0.04, the dielectric breakdown strength reaches 420 kV / cm, and when x=0.08, the energy density reaches 3.38 J / cm². 3 ;

[0029] The embodiments of the present invention provide a new strategy for improving dielectric breakdown strength without introducing new elements, which has potential application value for improving the energy storage performance of other bismuth-based ceramics. Attached Figure Description

[0030] Figure 1 A flowchart illustrating a method for preparing bismuth-based perovskite ceramics using a self-absorption doping strategy, as provided in an embodiment of the present invention.

[0031] Figure 2 Here is a SEM image of the ceramic from Embodiment 1 of the present invention;

[0032] Figure 3The XRD pattern of the ceramic in Example 1 of this invention;

[0033] Figure 4 The hysteresis loop of the ceramic in Embodiment 1 of the present invention;

[0034] Figure 5 The dielectric constant and dielectric loss of the ceramic in Example 1 of this invention are shown as curves of temperature variation.

[0035] Figure 6 Here is a SEM image of the ceramic from Embodiment 2 of the present invention;

[0036] Figure 7 The XRD pattern of the ceramic in Example 2 of this invention;

[0037] Figure 8 The hysteresis loop of the ceramic in Embodiment 2 of the present invention;

[0038] Figure 9 The dielectric constant and dielectric loss of the ceramic in Example 2 of this invention are curves showing the change with temperature.

[0039] Figure 10 Here is a SEM image of the ceramic from Example 3 of this invention;

[0040] Figure 11 The XRD pattern of the ceramic in Example 3 of this invention;

[0041] Figure 12 The hysteresis loop of the ceramic in Embodiment 3 of the present invention;

[0042] Figure 13 The dielectric constant and dielectric loss of the ceramic in Example 3 of this invention are curves showing the change with temperature.

[0043] Figure 14 This is a SEM image of the ceramic in Example 4 of the present invention;

[0044] Figure 15 The XRD pattern of the ceramic in Example 4 of this invention;

[0045] Figure 16 The hysteresis loop of the ceramic in Embodiment 4 of the present invention;

[0046] Figure 17 The dielectric constant and dielectric loss of the ceramic in Example 4 of this invention are curves showing the change of temperature.

[0047] Figure 18 This is a SEM image of the ceramic from Example 5 of the present invention;

[0048] Figure 19 The image shown is the XRD pattern of the ceramic in Example 5 of this invention.

[0049] Figure 20The hysteresis loop of the ceramic in Embodiment 5 of the present invention;

[0050] Figure 21 The curves showing the dielectric constant and dielectric loss of the ceramic in Example 5 of the present invention as a function of temperature are shown. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0053] Example 1: A ferroelectric ceramic (0.7BiFeO3-0.3SrTiO3), the preparation method of which includes the following steps:

[0054] (1) Ingredients: Bismuth oxide, ferric oxide, strontium carbonate and titanium oxide are mixed in a molar ratio of 0.7BiFeO3-0.3SrTiO3 to obtain a mixture. The weighed raw materials are placed in an oven and dried at 120 °C for 2 h.

[0055] (2) Mixing: Add 1.5 times the mass of anhydrous ethanol to the mixture and continue ball milling for 1 hour to make the powder mix evenly to form a slurry;

[0056] (3) Drying: Place the slurry in a 120℃ oven to dry at a constant temperature to remove ethanol, and grind it with a mortar and pestle to obtain a uniformly mixed powder;

[0057] (4) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed for 3 minutes. The molded block is placed in a solid-phase reaction furnace and kept at 800°C for 3 hours to carry out a solid-phase reaction.

[0058] (5) Ball milling: After the solid reaction, the material block is crushed and ground in a mortar to obtain ceramic powder. Add 2 times the mass of anhydrous ethanol to the obtained ceramic powder and continue ball milling for 8 hours to make the powder evenly mixed to form a slurry.

[0059] (6) Drying: The slurry was placed in a 120℃ oven for constant temperature drying to remove ethanol, and then ground with a mortar and pestle to obtain a uniformly mixed 0.7BiFeO3-0.3SrTiO3 ceramic powder;

[0060] (7) Granulation and molding: Ceramic powder is passed through a 150-mesh sieve, and then a 3% PVA solution is added to it. After grinding, it is passed through a 150-mesh sieve to make the PVA evenly mixed in the ceramic powder. The powder particles are placed in a mold and pressed into shape, and then isostatically pressed at 250MPa to form a ceramic green body.

[0061] (8) Removal of adhesive: Keep warm at 500℃ for 0.5 hours to remove PVA from the ceramic green body and obtain the ceramic green body;

[0062] (9) Sintering: The ceramic blank is sintered at 1000℃ for 2 hours and then cooled to obtain ferroelectric ceramic of 0.7BiFeO3-0.3SrTiO3.

[0063] Example 2: A bismuth-based perovskite ceramic (0.98(0.7BiFeO3-0.3SrTiO3)-0.02Bi2Ti2O7) prepared using a self-absorption doping strategy, the preparation process of which is as follows: Figure 1 As shown, the specific steps include:

[0064] Steps (1) to (6) are the same as in Example 1;

[0065] (7) Ingredients: Sodium bismuthate and titanium oxide are mixed in the molar ratio of the chemical formula Bi2Ti2O7 to obtain a mixture. The weighed raw materials are placed in an oven and dried at 120 °C for 2 h.

[0066] (8) Mixing: Add 1.5 times the mass of anhydrous ethanol to the mixture and continue ball milling for 1 hour to make the powder mix evenly to form a slurry;

[0067] (9) Drying: Place the slurry in a 120℃ oven to dry at a constant temperature to remove ethanol, and grind it with a mortar and pestle to obtain a uniformly mixed powder;

[0068] (10) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed for 3 minutes. The molded block is placed in a solid-phase reaction furnace and kept at 900°C for 3 hours to carry out a solid-phase reaction.

[0069] (11) Ball milling: After the solid reaction, the material block is crushed and ground in a mortar to obtain ceramic powder. Add 2 times the mass of anhydrous ethanol to the obtained ceramic powder and continue ball milling for 8 hours to make the powder evenly mixed to form a slurry.

[0070] (12) Drying: The slurry was placed in a 120℃ oven for constant temperature drying to remove ethanol, and then ground with a mortar and pestle to obtain a uniformly mixed Bi2Ti2O7 ceramic powder.

[0071] (13) Batching: The ceramic powder obtained above is mixed in a molar ratio of 0.98 (0.7BiFeO3-0.3SrTiO3)-0.02Bi2Ti2O7 to obtain a mixture. The weighed raw materials are placed in an oven and dried at 120 °C for 2 hours.

[0072] (14) Mixing: Add 1.5 times the mass of anhydrous ethanol to the mixture and continue ball milling for 1 hour to make the powder mix evenly to form a slurry;

[0073] (15) Drying: Place the slurry in a 120℃ oven to dry at a constant temperature to remove ethanol, and grind it with a mortar and pestle to obtain a uniformly mixed powder.

[0074] (16) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed for 3 minutes. The molded block is placed in a solid-phase reaction furnace and kept at 800°C for 3 hours to carry out a solid-phase reaction.

[0075] (17) Ball milling: After the solid reaction, the material block is crushed and ground in a mortar to obtain ceramic powder. Add 2 times the mass of anhydrous ethanol to the obtained ceramic powder and continue ball milling for 8 hours to make the powder evenly mixed to form a slurry.

[0076] (18) Drying: Place the slurry in a 120℃ oven to dry at a constant temperature to remove ethanol, and grind it with a mortar and pestle to obtain a uniformly mixed ceramic powder;

[0077] (19) Granulation and molding: Ceramic powder is passed through a 150-mesh sieve, and then a 3% PVA solution is added to it. After grinding, it is passed through a 150-mesh sieve to make the PVA evenly mixed in the ceramic powder. The powder particles are placed in a mold and pressed into shape, and then isostatically pressed at 250 MPa to form a ceramic green body.

[0078] (20) Removal of PVA: Keep warm at 500℃ for 0.5 hours to remove PVA from the ceramic green body and obtain the ceramic green body;

[0079] (21) Sintering: The ceramic blank was sintered at 1000℃ for 2 hours and cooled to obtain ferroelectric ceramics of 0.98(0.7BiFeO3-0.3SrTiO3)-0.02Bi2Ti2O7.

[0080] Example 3: Compared with Example 2, the only difference is that in step (13), the ceramic powder is mixed in a molar ratio of 0.96(0.7BiFeO3-0.3SrTiO3)-0.04Bi2Ti2O7 to finally prepare ferroelectric ceramic of 0.96(0.7BiFeO3-0.3SrTiO3)-0.04Bi2Ti2O7.

[0081] Example 4: Compared with Example 2, the only difference is that in step (13), the ceramic powder is mixed in a molar ratio of 0.94(0.7BiFeO3-0.3SrTiO3)-0.06Bi2Ti2O7 to finally prepare ferroelectric ceramic of 0.94(0.7BiFeO3-0.3SrTiO3)-0.06Bi2Ti2O7.

[0082] Example 5: Compared with Example 2, the only difference is that in step (13), the ceramic powder is mixed in a molar ratio of 0.92(0.7BiFeO3-0.3SrTiO3)-0.08Bi2Ti2O7 to finally prepare ferroelectric ceramics of 0.92(0.7BiFeO3-0.3SrTiO3)-0.08Bi2Ti2O7.

[0083] The ferroelectric ceramics prepared in Examples 1-5 were observed, characterized, and their performance was tested.

[0084] The SEM images obtained in Example 1 are as follows: Figure 2 As shown, the average size of the ceramic grains is about 1.45 μm, and they are dense with no obvious pores.

[0085] XRD patterns as follows Figure 3 As shown, this indicates that the ceramic phase is a pure BFST phase;

[0086] Hysteresis loop, for example Figure 4 As shown, the breakdown strength of the ceramic can reach 140 kV / cm, and the energy storage density is 0.38 J / cm². 3 ;

[0087] The curves showing the changes in dielectric constant and dielectric loss with temperature are as follows: Figure 5 As shown, the relative permittivity of the ceramic at 30℃ is 480.48, and the dielectric loss is 0.47635.

[0088] The SEM images obtained in Example 2 are as follows: Figure 6 As shown, the average size of the ceramic grains is about 1.02 μm, and they are dense with no obvious pores.

[0089] XRD patterns as follows Figure 7 As shown, there is no second phase and no BTO phase, proving that BTO is completely dissolved in the perovskite lattice.

[0090] Hysteresis loop, for example Figure 8 As shown, the breakdown strength of the ceramic can reach 260 kV / cm, and the energy storage density is 1.02 J / cm². 3 ;

[0091] The curves showing the changes in dielectric constant and dielectric loss with temperature are as follows: Figure 9 As shown, the relative permittivity of the ceramic at 30℃ is 376.343, and the dielectric loss is 0.04069.

[0092] The SEM images obtained in Example 3 are as follows: Figure 10 As shown, the average size of the ceramic grains is about 0.96 μm, and they are dense with no obvious pores.

[0093] XRD patterns as follows Figure 11 As shown, there is no second phase and no BTO phase, proving that BTO is completely dissolved in the perovskite lattice.

[0094] Hysteresis loop, for example Figure 12 As shown, the breakdown strength of the ceramic can reach 420 kV / cm, and the energy storage density is 2.24 J / cm². 3 ;

[0095] The curves showing the changes in dielectric constant and dielectric loss with temperature are as follows: Figure 13 As shown, the relative permittivity of the ceramic at 30℃ is 397.662, and the dielectric loss is 0.03601.

[0096] The SEM images obtained in Example 4 are as follows: Figure 14 As shown, the average size of the ceramic grains is about 0.99 μm, and they are dense with no obvious pores.

[0097] XRD patterns as follows Figure 15 As shown, there is no second phase and no BTO phase, proving that BTO is completely dissolved in the perovskite lattice.

[0098] Hysteresis loop, for example Figure 16 As shown, the breakdown strength of the ceramic can reach 360 kV / cm, and the energy storage density is 2.18 J / cm². 3 ;

[0099] The curves showing the changes in dielectric constant and dielectric loss with temperature are as follows: Figure 17 As shown, the relative permittivity of the ceramic at 30℃ is 373.652, and the dielectric loss is 0.03537.

[0100] The SEM image obtained in Example 5 is as follows: Figure 18 As shown, the average size of the ceramic grains is about 1.14 μm, and they are dense with no obvious pores.

[0101] XRD patterns as follows Figure 19 As shown, there is no second phase and no BTO phase, proving that BTO is completely dissolved in the perovskite lattice.

[0102] Hysteresis loop, for example Figure 20 As shown, the breakdown strength of the ceramic can reach 400 kV / cm, and the energy storage density is 3.38 J / cm². 3 ;

[0103] The curves showing the changes in dielectric constant and dielectric loss with temperature are as follows: Figure 21 As shown, the relative permittivity of the ceramic at 30℃ is 363.429, and the dielectric loss is 0.03295.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bismuth-based perovskite ceramic with a self-absorption doping strategy, characterized in that, The chemical formula of the bismuth-based perovskite ceramic is (1-x)(0.7BiFeO3-0.3SrTiO3)-xBi2Ti2O7, where 0<x≤0.

08.

2. A method for preparing bismuth-based perovskite ceramics using the self-absorption doping strategy as described in claim 1, characterized in that, Includes the following steps: (1) Ingredients: Bismuth oxide, ferric oxide, strontium carbonate and titanium oxide are mixed in a molar ratio of 0.7BiFeO3-0.3SrTiO3 to obtain a mixture. The weighed raw materials are placed in an oven to dry. (2) Mixing: Add anhydrous ethanol to the mixture and continue ball milling to mix the powder evenly to form a slurry; (3) Drying: Dry the slurry at a constant temperature to remove ethanol, and grind it to obtain a uniformly mixed powder; (4) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed into shape, and the shaped block is placed in a solid-phase reaction furnace for solid-phase reaction; (5) Ball milling: After the solid reaction, the material blocks are crushed and ground to obtain ceramic powder. Anhydrous ethanol is added to the ceramic powder and ball milling is continued to make the powder mix evenly to form a slurry. (6) Drying: The slurry is dried at a constant temperature to remove ethanol and then ground to obtain a uniformly mixed 0.7BiFeO3-0.3SrTiO3 ceramic powder; (7) Ingredients: Sodium bismuthate and titanium oxide are mixed in a molar ratio according to the chemical formula Bi2Ti2O7 to obtain a mixture, which is then dried; (8) Mixing: Add anhydrous ethanol to the mixture and continue ball milling to mix the powder evenly to form a slurry; (9) Drying: Dry the slurry at a constant temperature to remove ethanol, and grind it to obtain a uniformly mixed powder; (10) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed into shape, and the shaped block is placed in a solid-phase reaction furnace for solid-phase reaction; (11) Ball milling: After the solid reaction, the material blocks are crushed and ground to obtain ceramic powder. Anhydrous ethanol is added to the ceramic powder and ball milling is continued to make the powder mix evenly to form a slurry. (12) Drying: The slurry is dried at a constant temperature to remove ethanol and then ground to obtain a uniformly mixed Bi2Ti2O7 ceramic powder; (13) Ingredients: The ceramic powders obtained in steps (6) and (12) are mixed in the molar ratio of (1-x)(0.7BiFeO3-0.3SrTiO3)-xBi2Ti2O7, where 0<x≤0.08, to obtain a mixture. The weighed raw materials are placed in an oven and dried. (14) Mixing: Add anhydrous ethanol to the mixture and continue ball milling to mix the powder evenly to form a slurry; (15) Drying: Dry the slurry at a constant temperature to remove ethanol, and grind it to obtain a uniformly mixed powder; (16) Solid-phase reaction: The uniformly mixed powder is placed in a mold and pressed into shape, and the shaped block is placed in a solid-phase reaction furnace for solid-phase reaction; (17) Ball milling: After the solid reaction, the material blocks are crushed and ground to obtain ceramic powder. Anhydrous ethanol is added to the obtained ceramic powder and ball milling is continued to make the powder mix evenly to form a slurry. (18) Drying: Dry the slurry at a constant temperature to remove ethanol, and grind it to obtain a uniformly mixed ceramic powder; (19) Granulation and molding: The ceramic powder is sieved, then PVA solution is added to it, it is ground and sieved again, then the powder particles are placed in the mold and pressed into shape, and then isostatic pressing is performed to form a ceramic green body. (20) Removal of PVA: The PVA in the ceramic green body is removed to obtain the ceramic body; (21) Sintering: The ceramic blank is sintered and cooled to obtain bismuth-based perovskite ceramics with the chemical formula (1-x)(0.7BiFeO3-0.3SrTiO3)-xBi2Ti2O7 using a self-absorption doping strategy.

3. The method for preparing bismuth-based perovskite ceramics using the self-absorption doping strategy according to claim 2, characterized in that, In step (4), the solid-phase reaction is carried out at a temperature of 800°C for 3 hours.

4. The method for preparing bismuth-based perovskite ceramics using the self-absorption doping strategy according to claim 2, characterized in that, In step (10), the solid-phase reaction is carried out at a temperature of 900°C for 3 hours.

5. The method for preparing bismuth-based perovskite ceramics using the self-absorption doping strategy according to claim 2, characterized in that, In step (16), the solid-phase reaction is carried out at a temperature of 800°C for 3 hours.

6. The method for preparing bismuth-based perovskite ceramics using the self-absorption doping strategy according to claim 2, characterized in that, In step (19), the mass concentration of the PVA solution is 3%, and the pressure of the static pressing is 250 MPa.

7. The method for preparing bismuth-based perovskite ceramics using the self-absorption doping strategy according to claim 2, characterized in that, In step (20), the specific operation of the glue removal is to keep it at 500℃ for 0.5 hours.

8. The method for preparing bismuth-based perovskite ceramics using the self-absorption doping strategy according to claim 2, characterized in that, In step (21), the sintering temperature is 1000℃ and the holding time is 2 hours.

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