Preparation method of defect-regulated barium titanate composite material

Abstract

The invention belongs to the technical field of preparation of barium titanate, and particularly relates to a preparation method of a defect-regulating barium titanate composite material, which comprises the following preparation steps: S1, adding a proper amount of barium carbonate, titanium dioxide, nickel oxide and dopant mixed powder into a ball milling tank for ball milling to obtain initial barium titanate composite particles; s2, dispersing the initial barium titanate composite particles obtained in the step S1 into an aqueous solution of a growth inhibitor for reaction to form modified barium titanate composite powder; and S3, mixing the barium titanate composite powder obtained in the step S2 with an adhesive polyvinyl butyral, pressing into a biscuit, performing cold isostatic pressing, sintering, annealing in a nitrogen atmosphere, and performing heat preservation to obtain the defect-regulated barium titanate composite material.

Description

Technical Field

[0001] This invention belongs to the field of barium titanate preparation technology, and specifically relates to a method for preparing defect-controlled barium titanate composite materials. Background Technology

[0002] Barium titanate, as a core raw material for titanate electronic ceramics, occupies a pivotal position in the field of electronic ceramics. Its excellent dielectric properties, including high dielectric constant and low dielectric loss, as well as its superior ferroelectric, piezoelectric, withstand voltage, and insulating characteristics, make barium titanate highly effective in manufacturing ceramic sensitive components. Barium titanate is crucial in the field of electronic ceramics due to its excellent dielectric and ferroelectric properties. It plays an indispensable role, particularly in PTC thermistors, multilayer ceramic capacitors (MLCCs), grain boundary layer capacitors, thermoelectric elements, piezoelectric ceramics, sonar, sensors, electro-optical displays, polymer-based composite materials, and coatings. Traditional solid-state methods involve high-temperature calcination of a mixture of barium carbonate and titanium dioxide. The resulting powder particles are typically in the micrometer range and prone to agglomeration, leading to difficulties in subsequent processing.

[0003] Barium titanate (BaTiO3) is an important electronic material, and its crystal structure is crucial for understanding its properties and applications. Variations in the BaTiO3 crystal structure directly affect its electrical properties, and specific properties of BaTiO3 can be prepared by controlling the particle size. Therefore, in-depth research into its crystal structure is necessary to better understand its unique physical and chemical properties, thereby providing strong support for its application in electronic components. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a defect-controlled barium titanate composite material, which has the advantage of convenient opening and closing.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a method for preparing a defect-modified barium titanate composite material, comprising the following preparation steps:

[0006] S1: Add appropriate amounts of barium carbonate, titanium dioxide, nickel oxide, and dopant mixed powder into a ball mill jar, add zirconium oxide grinding balls, use ethanol as the ball milling solvent, and ball mill for 20-25 hours. Then dry the wet material at 80℃ for 12 hours, then sieve it, and then calcine the uniformly mixed powder in a muffle furnace at 800-1000℃ for 2-3 hours to obtain the initial barium titanate composite particles.

[0007] S2: The initial barium titanate composite particles obtained in step S1 are dispersed in an aqueous solution of growth inhibitor, heated and stirred in a water bath at 150-200℃ for 4 hours, and then washed, dried and ground to obtain modified barium titanate composite powder.

[0008] S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then cold isostatically pressed and sintered at 1300-1400℃ for 4-5 hours. The annealing temperature under nitrogen atmosphere is 1250-1270℃ for 20-30 minutes to obtain the defect-controlled barium titanate composite material.

[0009] By employing the above technical solution, this invention prepares a barium titanate composite ceramic dielectric through special chemical material construction and optimized sintering process. By introducing dopants, it exhibits good dielectric properties, energy storage temperature stability, and high energy storage efficiency. Furthermore, the modified barium titanate in this invention, after nitrogen annealing, possesses localized 90° domain structures and wedge-shaped domain structures. Nitrogen annealing is beneficial for "soft" properties. This not only restores the "soft" properties of the nitrogen-annealed sample but also imparts "hard" characteristics, thereby achieving excellent comprehensive piezoelectric performance. Simultaneously, it exhibits good resonant or anti-resonant characteristics and sufficient phase reversal.

[0010] Meanwhile, the valence states of nickel were studied using X-ray photoelectron spectroscopy, revealing that nickel exists in two valence states, namely Ni in the NiO lattice. 2+ It is easily oxidized to Ni 3+ Since the valence states of Ti and Bi are stable, Ni 2+ and Ni 3+ Coexistence will inevitably create oxygen vacancies to balance the charge, which may contribute to the increase in grain size.

[0011] A further feature of the present invention is that the dopant is Bi(Zr) 0.25 Sn 0.5 )O3.

[0012] A further provision of the present invention is that the dopant is prepared by the following method: (1) Bismuth trioxide, zirconium dioxide, and tin dioxide are thoroughly mixed in a mass ratio of 1:0.5:1 and ball-milled in ethanol medium for 15-18 hours; (2) the slurry is sieved and dried, and then sintered at 900-1000℃ for 3 hours to allow the raw material powder to undergo a chemical reaction and remove CO2. After sintering, it is ball-milled again for 12 hours to obtain Bi(Zr) 0.25 Sn 0.5 O3 dopant.

[0013] By employing the above technical solution, the dopant forms polar nanoregions by disrupting polarization coupling, inducing relaxation behavior in the material, significantly improving microstructural stability and reducing polarization losses in alternating electric fields, thereby increasing energy storage efficiency. This demonstrates that Bi 3+ Zr 4+and Sn 4+ The random occupancy of A / B sites leads to an increase in ionic disorder within the ceramic, causing relaxation behavior due to short-range polarization mismatch. After the introduction of dopants, barium titanate ceramics exhibit good relaxation behavior, which helps to achieve a fast response under an applied electric field, reduce polarization loss, and improve energy storage efficiency. Under a high electric field, it can be transformed into a long-range ferroelectric ordered structure, and after the electric field is removed, it almost returns to its original state, which is conducive to achieving high polarization intensity and low residual polarization intensity, thereby improving energy storage density and energy storage efficiency. At the same time, the increase in ionic disorder caused by doping leads to the disruption of long-range dipole interactions, which is crucial for improving energy storage density and energy storage efficiency. Oxygen vacancy defects in barium titanate ceramics are the key factor limiting further improvement in their breakdown strength.

[0014] A further provision of the present invention is that the growth inhibitor comprises one of sodium stearate, barium acetylacetonate, and glucose.

[0015] By adopting the above technical solution,

[0016] A further provision of the present invention is as follows: The specific preparation method of step S2 is as follows: an appropriate amount of water, initial barium titanate composite particles, and growth inhibitor are stirred and mixed for 30-50 minutes, and then reacted in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, modified barium titanate composite powder is obtained.

[0017] A further setting of the present invention is that the volumetric mass concentration of the water, the initial barium titanate composite particles, and the growth inhibitor is 15-20 mL: 1 g: 0.01 g.

[0018] A further provision of the present invention is that the molar ratio of barium carbonate, titanium oxide, and dopant mixed powder in step S1 is 1:1-1.1:0.9-1.

[0019] By employing the above-mentioned technical solution, carbon-coated barium titanate materials were prepared through hydrothermal coating. The carbon coating layer acts as a growth inhibitor, limiting particle growth at high temperatures, and also serves as an interlayer separator, preventing the barium titanate particles from fusing and growing together at high temperatures. Simultaneously, the carbon coating layer can be effectively removed during high-temperature calcination. Due to the growth inhibitor effect, the powder dispersibility and uniformity are improved, resulting in the preparation of dense barium titanate composite powder at a lower temperature, with a reduced agglomeration coefficient and an increased dielectric constant.

[0020] A further provision of the present invention is that the mass ratio of titanium dioxide to nickel oxide is 1:0.3-0.6.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention prepares an environmentally friendly barium titanate ceramic dielectric through special chemical material construction and optimized sintering process. By introducing dopants, it exhibits good dielectric properties, energy storage temperature stability, and high energy storage efficiency. Furthermore, the modified barium titanate in this invention, after nitrogen annealing, possesses localized 90° domain structures and wedge-shaped domain structures. Nitrogen annealing is beneficial for "soft" properties. It not only restores the "soft" properties of the sample after nitrogen annealing but also imparts "hard" characteristics, thus achieving excellent comprehensive piezoelectric properties. Simultaneously, it exhibits good resonant or anti-resonant characteristics and sufficient phase reversal.

[0023] 2. Dopants disrupt polarization coupling to form polar nanoregions, inducing relaxation behavior in the material, significantly improving microstructural stability and reducing polarization losses in alternating electric fields, thereby increasing energy storage efficiency. This indicates that Bi... 3+ Zr 4+ and Sn 4 + The random occupancy of A / B sites leads to an increase in ionic disorder within the ceramic, causing relaxation behavior due to short-range polarization mismatch. After the introduction of dopants, barium titanate ceramics exhibit good relaxation behavior, which helps to achieve a fast response under an applied electric field, reduce polarization loss, and improve energy storage efficiency. Under a high electric field, it can be transformed into a long-range ferroelectric ordered structure, and after the electric field is removed, it almost returns to its original state, which is conducive to achieving high polarization intensity and low residual polarization intensity, thereby improving energy storage density and energy storage efficiency. At the same time, the increase in ionic disorder caused by doping leads to the disruption of long-range dipole interactions, which is crucial for improving energy storage density and energy storage efficiency. Oxygen vacancy defects in barium titanate ceramics are the key factor limiting further improvement in their breakdown strength.

[0024] 3. This invention prepares carbon-coated barium titanate material through a hydrothermal coating method. The carbon coating layer acts as a growth inhibitor, limiting particle growth at high temperatures. It also acts as an interlayer separator, preventing the barium titanate particles from fusing and growing together at high temperatures. Simultaneously, the carbon coating layer can be effectively removed during high-temperature calcination. Due to the growth inhibitor effect, the powder dispersibility and uniformity are improved, resulting in a dense barium titanate composite powder prepared at a lower temperature. This process reduces the agglomeration coefficient and increases the dielectric constant. Detailed Implementation

[0025] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] A method for preparing a defect-modified barium titanate composite material includes the following preparation steps:

[0028] S1: The molar ratio of barium carbonate, titanium dioxide, nickel oxide, and Bi(Zr) is 1:1-1.1:0.3-0.6:0.9-1. 0.25 Sn 0.5 O3 mixed powder was added to a ball mill jar, along with zirconium oxide grinding balls and ethanol as the ball milling solvent. The mixture was ball milled for 20-25 hours. The wet material was then dried at 80°C for 12 hours, sieved, and the uniformly mixed powder was calcined in a muffle furnace at 800-1000°C for 2-3 hours to obtain the initial barium titanate composite particles.

[0029] S2: Mix appropriate amounts of water, initial barium titanate composite particles, and sodium stearate for 30-50 minutes, then react in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, the modified barium titanate composite powder is obtained. The volumetric mass concentration of water, initial barium titanate composite particles, and sodium stearate is 15-20 mL: 1 g: 0.01 g.

[0030] S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then cold isostatically pressed and sintered at 1350℃ for 4-5 hours. The annealing temperature is 1250-1270℃ under a nitrogen atmosphere, and the holding time is 20-30 minutes. The defect-controlled barium titanate composite material is obtained.

[0031] Example 2

[0032] A method for preparing a defect-modified barium titanate composite material includes the following preparation steps:

[0033] S1: The molar ratio of barium carbonate, titanium dioxide, nickel oxide, and Bi(Zr) is 1:1-1.1:0.3-0.6:0.9-1. 0.25 Sn 0.5 O3 mixed powder was added to a ball mill jar, along with zirconium oxide grinding balls and ethanol as the ball milling solvent. The mixture was ball milled for 20-25 hours. The wet material was then dried at 80°C for 12 hours, sieved, and the uniformly mixed powder was calcined in a muffle furnace at 800-1000°C for 2-3 hours to obtain the initial barium titanate composite particles.

[0034] S2: Mix appropriate amounts of water, initial barium titanate composite particles, and barium acetylacetonate for 30-50 minutes, then react in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, the modified barium titanate composite powder is obtained. The volumetric mass concentration of water, initial barium titanate composite particles, and barium acetylacetonate is 15-20 mL: 1 g: 0.01 g.

[0035] S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then cold isostatically pressed and sintered at 1350℃ for 4-5 hours. The annealing temperature is 1250-1270℃ under a nitrogen atmosphere, and the holding time is 20-30 minutes. The defect-controlled barium titanate composite material is obtained.

[0036] Example 3

[0037] A method for preparing a defect-modified barium titanate composite material includes the following preparation steps:

[0038] S1: The molar ratio of barium carbonate, titanium dioxide, nickel oxide, and Bi(Zr) is 1:1-1.1:0.3-0.6:0.9-1. 0.25 Sn 0.5 O3 mixed powder was added to a ball mill jar, along with zirconium oxide grinding balls and ethanol as the ball milling solvent. The mixture was ball milled for 20-25 hours. The wet material was then dried at 80°C for 12 hours, sieved, and the uniformly mixed powder was calcined in a muffle furnace at 800-1000°C for 2-3 hours to obtain the initial barium titanate composite particles.

[0039] S2: Mix appropriate amounts of water, initial barium titanate composite particles, and glucose for 30-50 minutes, then react in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, the modified barium titanate composite powder is obtained. The volumetric mass concentration of water, initial barium titanate composite particles, and glucose is 15-20 mL: 1 g: 0.01 g.

[0040] S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then cold isostatically pressed and sintered at 1350℃ for 4-5 hours. The annealing temperature is 1250-1270℃ under a nitrogen atmosphere, and the holding time is 20-30 minutes. The defect-controlled barium titanate composite material is obtained.

[0041] Example 4

[0042] A method for preparing a defect-modified barium titanate composite material includes the following preparation steps:

[0043] S1: Add barium carbonate and titanium dioxide mixed powder with a molar ratio of 1:1-1.1 to a ball mill jar, add zirconium oxide grinding balls, use ethanol as the ball milling solvent, and ball mill for 20-25 hours. Then dry the wet material at 80℃ for 12 hours, then sieve it, and then calcine the uniformly mixed powder in a muffle furnace at 800-1000℃ for 2-3 hours to obtain the initial barium titanate composite particles.

[0044] S2: Mix appropriate amounts of water, initial barium titanate composite particles, and glucose for 30-50 minutes, then react in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, the modified barium titanate composite powder is obtained. The volumetric mass concentration of water, initial barium titanate composite particles, and glucose is 15-20 mL: 1 g: 0.01 g.

[0045] S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then cold isostatically pressed and sintered at 1350℃ for 4-5 hours. The annealing temperature is 1250-1270℃ under a nitrogen atmosphere, and the holding time is 20-30 minutes. The defect-controlled barium titanate composite material is obtained.

[0046] Example 5

[0047] A method for preparing a defect-modified barium titanate composite material includes the following preparation steps:

[0048] S1: Add a mixture of barium carbonate, titanium dioxide, and nickel oxide powder in a molar ratio of 1:1-1.1:0.3-0.6 to a ball mill jar, add zirconium oxide grinding balls, and use ethanol as the ball milling solvent. Ball mill for 20-25 hours, then dry the wet material at 80℃ for 12 hours, then sieve it, and finally calcine the uniformly mixed powder in a muffle furnace at 800-1000℃ for 2-3 hours to obtain the initial barium titanate composite particles.

[0049] S2: Mix appropriate amounts of water, initial barium titanate composite particles, and glucose for 30-50 minutes, then react in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, the modified barium titanate composite powder is obtained. The volumetric mass concentration of water, initial barium titanate composite particles, and glucose is 15-20 mL: 1 g: 0.01 g.

[0050] S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then cold isostatically pressed and sintered at 1350℃ for 4-5 hours. The annealing temperature is 1250-1270℃ under a nitrogen atmosphere, and the holding time is 20-30 minutes. The defect-controlled barium titanate composite material is obtained.

[0051] Example 6

[0052] A method for preparing a defect-modified barium titanate composite material includes the following preparation steps:

[0053] S1: Barium carbonate, titanium dioxide, and Bi(Zr) in a molar ratio of 1:1-1.1:0.9-1 0.25 Sn 0.5 O3 mixed powder was added to a ball mill jar, along with zirconium oxide grinding balls and ethanol as the ball milling solvent. The mixture was ball milled for 20-25 hours. The wet material was then dried at 80°C for 12 hours, sieved, and the uniformly mixed powder was calcined in a muffle furnace at 800-1000°C for 2-3 hours to obtain the initial barium titanate composite particles.

[0054] S2: Mix appropriate amounts of water, initial barium titanate composite particles, and glucose for 30-50 minutes, then react in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, the modified barium titanate composite powder is obtained. The volumetric mass concentration of water, initial barium titanate composite particles, and glucose is 15-20 mL: 1 g: 0.01 g.

[0055] S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then cold isostatically pressed and sintered at 1350℃ for 4-5 hours. The annealing temperature is 1250-1270℃ under a nitrogen atmosphere, and the holding time is 20-30 minutes. The defect-controlled barium titanate composite material is obtained.

[0056] Example 7

[0057] A method for preparing a defect-modified barium titanate composite material includes the following preparation steps:

[0058] S1: The molar ratio of barium carbonate, titanium dioxide, nickel oxide, and Bi(Zr) is 1:1-1.1:0.3-0.6:0.9-1. 0.25 Sn 0.5 O3 mixed powder was added to a ball mill jar, along with zirconium oxide grinding balls and ethanol as the ball milling solvent. The mixture was ball milled for 20-25 hours. The wet material was then dried at 80°C for 12 hours, sieved, and the uniformly mixed powder was calcined in a muffle furnace at 800-1000°C for 2-3 hours to obtain the initial barium titanate composite particles.

[0059] S2: Mix appropriate amounts of water, initial barium titanate composite particles, and glucose for 30-50 minutes, then react in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, the modified barium titanate composite powder is obtained. The volumetric mass concentration of water, initial barium titanate composite particles, and glucose is 15-20 mL: 1 g: 0.01 g.

[0060] S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then subjected to cold isostatic pressing, and the sintering temperature is increased to 1350℃. The sintering time is 4-5 hours. After cooling, the defect-controlled barium titanate composite material is obtained.

[0061] Example 8

[0062] A method for preparing a defect-modified barium titanate composite material includes the following preparation steps:

[0063] S1: The molar ratio of barium carbonate, titanium dioxide, nickel oxide, and Bi(Zr) is 1:1-1.1:0.3-0.6:0.9-1. 0.25 Sn 0.5 O3 mixed powder was added to a ball mill jar, along with zirconium oxide grinding balls and ethanol as the ball milling solvent. The mixture was ball milled for 20-25 hours. The wet material was then dried at 80°C for 12 hours, sieved, and the uniformly mixed powder was calcined in a muffle furnace at 800-1000°C for 2-3 hours to obtain the initial barium titanate composite particles.

[0064] S2: The initial barium titanate composite particles obtained in step S1 are mixed with the binder polyvinyl butyral and pressed into a green blank. The green blank is then cold isostatically pressed and sintered at 1350℃ for 4-5 hours. The annealing temperature is 1250-1270℃ under a nitrogen atmosphere, and the holding time is 20-30 minutes. The defect-controlled barium titanate composite material is obtained.

[0065] Comparative Example 1

[0066] A method for preparing barium titanate includes the following preparation steps:

[0067] S1: Add barium carbonate and titanium dioxide mixed powder with a molar ratio of 1:1-1.1 to a ball mill jar, add zirconium oxide grinding balls, use ethanol as the ball milling solvent, and ball mill for 20-25 hours. Then dry the wet material at 80℃ for 12 hours, then sieve it, and then calcine the uniformly mixed powder in a muffle furnace at 800-1000℃ for 2-3 hours to obtain the initial barium titanate composite particles.

[0068] S2: The initial barium titanate composite particles obtained in step S1 are mixed with the binder polyvinyl butyral and pressed into a green blank. The green blank is then cold isostatically pressed and sintered at 1350℃ for 4-5 hours. After cooling, the defect-controlled barium titanate composite material is obtained.

[0069] The performance of the defect-modified barium titanate composite materials obtained in Comparative Example 1 and Examples 1-8 was tested, and the results are shown in Table 1.

[0070] <![CDATA[Ceramic density / g / cm 3 > Dielectric constant Grain size / μm Aggregation coefficient Example 1 6.02 3036 1.44 1.105 Example 2 6.08 3041 1.46 1.092 Example 3 6.12 3058 1.51 1.046 Example 4 5.71 2848 1.28 1.134 Example 5 5.78 2854 1.35 1.126 Example 6 5.87 2861 1.27 1.112 Example 7 5.94 2942 1.55 1.092 Example 8 5.63 2743 1.76 1.38 Comparative Example 1 5.17 2651 5.8 1.64

[0071] As can be seen from the table above, Examples 1-3 all exhibit high ceramic density and dielectric constant, and low agglomeration coefficient. This is because a barium titanate composite ceramic dielectric was prepared through special chemical material construction and optimized sintering process. The introduction of dopants gave it good dielectric properties, energy storage temperature stability, and high energy storage efficiency. Carbon-coated barium titanate materials were prepared using a hydrothermal coating method. The carbon coating layer acts as a growth inhibitor, limiting particle growth at high temperatures, and also acts as an isolation layer between particles, preventing the barium titanate particles from fusing and growing at high temperatures, thus increasing grain uniformity.

Claims

1. A method for preparing a defect-modified barium titanate composite material, characterized in that: The preparation steps include the following: S1: Add appropriate amounts of barium carbonate, titanium dioxide, nickel oxide, and dopant mixed powder into a ball mill jar, add zirconium oxide grinding balls, use ethanol as the ball milling solvent, and ball mill for 20-25 hours. Then dry the wet material at 80℃ for 12 hours, then sieve it, and then calcine the uniformly mixed powder in a muffle furnace at 800-1000℃ for 2-3 hours to obtain the initial barium titanate composite particles. S2: The initial barium titanate composite particles obtained in step S1 are dispersed in an aqueous solution of growth inhibitor, heated and stirred in a water bath at 150-200℃ for 4 hours, and then washed, dried and ground to obtain modified barium titanate composite powder. S3: The barium titanate composite powder obtained in step S2 is mixed with the binder polyvinyl butyral and pressed into a green blank. It is then cold isostatically pressed and sintered at 1300-1400℃ for 4-5 hours. The annealing temperature under nitrogen atmosphere is 1250-1270℃ for 20-30 minutes to obtain the defect-controlled barium titanate composite material.

2. The method for preparing a defect-controlled barium titanate composite material according to claim 1, characterized in that: The dopant is Bi(Zr) 0.25 Sn 0.5 )O3.

3. The method for preparing a defect-controlled barium titanate composite material according to claim 2, characterized in that: The dopant is prepared by the following method: (1) Bismuth trioxide, zirconium dioxide, and tin dioxide are thoroughly mixed in a mass ratio of 1:0.5:1 and ball-milled in ethanol medium for 15-18 hours; (2) The slurry is sieved and dried, and then sintered at 900-1000℃ for 3 hours to allow the raw material powder to undergo a chemical reaction and remove CO2. After sintering, it is ball-milled again for 12 hours to obtain Bi(Zr) 0.25 Sn 0.5 O3 dopant.

4. The method for preparing a defect-controlled barium titanate composite material according to claim 1, characterized in that: The growth inhibitors include one of sodium stearate, barium acetylacetonate, and glucose.

5. The method for preparing a defect-controlled barium titanate composite material according to claim 1, characterized in that: The specific preparation method of step S2 is as follows: an appropriate amount of water, initial barium titanate composite particles, and growth inhibitor are stirred and mixed for 30-50 minutes, and then reacted in a hydrothermal reactor at 180-200℃ for 5-6 hours. After washing, drying, and grinding, modified barium titanate composite powder is obtained.

6. The method for preparing a defect-controlled barium titanate composite material according to claim 5, characterized in that: The volumetric mass concentration of the water, initial barium titanate composite particles, and growth inhibitor is 15-20 mL: 1 g: 0.01 g.

7. The method for preparing a defect-controlled barium titanate composite material according to claim 1, characterized in that: In step S1, the molar ratio of barium carbonate, titanium oxide, and dopant mixed powder is 1:1-1.1:0.9-1.

8. The method for preparing a defect-controlled barium titanate composite material according to claim 1, characterized in that: The mass ratio of titanium dioxide to nickel oxide is 1:0.3-0.6.