A lead-free relaxor-type antiferroelectric ceramic material, its preparation method and application

Abstract

This invention discloses a lead-free relaxor-type antiferroelectric ceramic material, its preparation method, and its applications. The chemical formula of this material is Ba. 1‑1.5x Bi x Ti 0.93 Li 0.07 O 2.895 Where 0.07≤x≤0.10; high-purity raw materials BaCO3, Li2CO3, Bi2O3 and TiO2 are weighed according to stoichiometric ratio, and the mixed raw materials are ball-milled, dried and sieved in sequence, and then sealed and calcined to obtain calcined ceramic powder; the ceramic powder is ball-milled, dried and sieved in sequence, and then granulated and aged in sequence to obtain ceramic green body; the ceramic green body is heated to remove the polyvinyl alcohol added during granulation; the heated ceramic green body is buried in the calcined ceramic powder for sintering, and cooled to room temperature in the furnace to obtain the product; this invention successfully prepares lead-free relaxor antiferroelectric ceramic materials by solid-state method, which have double hysteresis characteristics similar to antiferroelectrics, and have high dielectric constant and energy conversion efficiency, low dielectric loss and polarization hysteresis, simple preparation process, low material cost and environmental friendliness.

Description

Technical Field

[0001] This invention belongs to the field of lead-free ferroelectric materials technology, and particularly relates to a lead-free relaxor-type antiferroelectric ceramic material, its preparation method and application. Background Technology

[0002] With the rapid development of society, economy, and high technology, antiferroelectric materials are increasingly demonstrating their application value in high-pulse power energy storage capacitors, high-strain actuators, and transducer sensors due to their unique antiferroelectric-ferroelectric phase transition characteristics. For example, the double hysteresis loop characteristic of antiferroelectric materials can significantly improve the energy storage density of ferroelectric capacitors; electric field-induced antiferroelectric-ferroelectric phase transitions can be applied in high-strain actuators; and stress-induced antiferroelectric-ferroelectric phase transitions can be applied in the field of explosive energy conversion. Currently reported antiferroelectric materials with high saturation polarization and near-zero remanent polarization are mainly lead-based materials such as PbZrO3, which have great application value in high-pulse power energy storage capacitors, high-strain actuators, and transducer sensors. However, the raw materials of lead-containing antiferroelectric materials such as PbZrO3 contain a large amount of lead oxide, and the heavy metal lead oxide is highly volatile at high temperatures. During preparation, use, and post-processing, it not only endangers human health and safety but also causes serious environmental pollution problems.

[0003] L. Zhao et al. (L. Zhao, Q. Liu, J. Gao, et al. Lead ~ free antiferroelectric silverniobate tantalate with high energy storage performance. Adv. Mater., 2017, 29: 1701824.) used Ta 5+ Replacing part of the Nb in AgNbO3 5+ Elements that enhance the antiferroelectricity of AgNbO3; N. Luo et al. (N. Luo, K. Han, F. Zhuo, et al. Aliovalent A-site engineered AgNbO3 lead-free antiferroelectric ceramics toward superior energy storage density. J. Mater. Chem. A, 2019, 7: 14118-14128) used Sm 3+Heterovalent doping of AgNbO3 enhances its antiferroelectric properties. Since the free energy of the antiferroelectric phase of NaNbO3 at room temperature is very close to that of the ferroelectric phase, it is difficult to observe the double hysteresis loop characteristic of antiferroelectrics in NaNbO3 prepared by conventional methods. Therefore, the antiferroelectricity of NaNbO3 ceramics is stabilized by enhancing electronegativity and reducing the tolerance factor. Z. Liu et al. (Z. Liu, J. Lu, Y. Mao, et al. Energy storage properties of NaNbO3-CaZrO3 ceramics with coexistence offerroelectric and antiferroelectric phases. J. Eur. Ceram. Soc., 2018, 38: 4939-4945.) observed the double hysteresis loop characteristic by adding a certain amount of CaZrO3 to NaNbO3.

[0004] Although antiferroelectric double hysteresis loops have been observed in AgNbO3 and NaNbO3-based lead-free materials in recent years, these materials require expensive raw materials and have demanding preparation conditions. They also suffer from drawbacks such as high residual polarization, significant hysteresis loss, and low energy conversion efficiency, which severely limit their practical application needs. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a lead-free relaxor-type antiferroelectric ceramic material, its preparation method and application. The lead-free relaxor-type antiferroelectric ceramic material is prepared by solid-state method, which has double hysteresis loop characteristics similar to antiferroelectrics, and has high dielectric constant and energy conversion efficiency, low dielectric loss and polarization hysteresis, simple preparation process, low material cost and environmental friendliness.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A lead-free relaxor-type antiferroelectric ceramic material, wherein the general chemical formula of the material is Ba. 1- 1.5x Bi x Ti 0.93 Li 0.07 O 2.895 , where 0.07≤x≤0.10.

[0008] The lead-free relaxor-type antiferroelectric ceramic material has a perovskite structure and exhibits defect dipole characteristics.

[0009] A method for preparing lead-free relaxor-type antiferroelectric ceramic materials as described above includes the following steps:

[0010] Step 1: According to Ba 1-1.5x Bi x Ti 0.93 Li 0.07 O 2.895 High-purity raw materials BaCO3, Li2CO3, Bi2O3 and TiO2 were weighed according to the stoichiometric ratio to obtain a mixed raw material;

[0011] Step 2: Mix the weighed raw materials from Step 1 with zirconium oxide balls and anhydrous ethanol, and then ball mill, dry, and sieve them in sequence to obtain a mixed raw material with a sieve mesh size of 60-120 mesh.

[0012] Step 3: Place the sieved mixed raw material from Step 2 into a sealed alumina or zirconium oxide crucible and calcine it at 750-850℃ for 2-4 hours to obtain calcined ceramic powder.

[0013] Step 4: The calcined ceramic powder from Step 3 is mixed with zirconium oxide balls and anhydrous ethanol, and then ball-milled, dried, and sieved to obtain ceramic powder with a sieve mesh size of 60-120 mesh.

[0014] Step 5: Add polyvinyl alcohol (PVA) solution to the ceramic powder obtained in step 4 for granulation, and then press it into a ceramic green body after aging for 24-48 hours.

[0015] Step 6: Heat the ceramic green body obtained in Step 5 to completely remove polyvinyl alcohol (PVA);

[0016] Step 7: The ceramic green body from which polyvinyl alcohol (PVA) was removed in Step 6 is embedded in the ceramic powder obtained in Step 4 for sintering. After cooling to room temperature in the furnace, lead-free relaxor antiferroelectric ceramic material is obtained.

[0017] The purity of the raw materials BaCO3, Li2CO3, Bi2O3 and TiO2 in step 1 is ≥98%.

[0018] In step 2, the mass ratio of the mixed raw materials, zirconium oxide balls, and anhydrous ethanol is 1:2:(1-1.5); the ball milling speed is 400-450 rpm, the ball milling time is 12-24 h; the drying temperature is 90-100℃, and the drying time is at least 6 h.

[0019] In step 4, the mass ratio of ceramic powder, zirconia balls, and anhydrous ethanol is 1:2:(1-1.5); the ball milling speed is 420-450 rpm, the ball milling time is 12-15 h; the drying temperature is 90-100℃, and the drying time is at least 6 h.

[0020] In step 5, the mass concentration of the polyvinyl alcohol (PVA) solution is 6-8%; the amount of polyvinyl alcohol (PVA) solution added accounts for 2-3% of the mass of the ceramic powder obtained in step 4.

[0021] The specific heating operation in step 6 is as follows: heat to 550-650℃ at a heating rate of 1-3℃ / min and keep at that temperature for 8-12 hours.

[0022] The sintering operation in step 7 is as follows: heat to 1130-1150℃ at a heating rate of 2-4℃ / min and hold for 2-3 hours.

[0023] Applications of lead-free relaxor antiferroelectric ceramic materials as described above, or lead-free relaxor antiferroelectric ceramic materials prepared by the above methods, in high-pulse power energy storage capacitors, high-strain actuators, and transducer sensors.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. This invention successfully prepared lead-free relaxor antiferroelectric ceramic materials using a solid-state method. The preparation process is stable and reliable. Compared with the AgNbO3 and NaNbO3-based lead-free materials in the prior art, the sintering temperature range in step 7 of this invention is wider, the process is more operable, and it is suitable for industrial-scale mass production.

[0026] 2. The raw materials used in this invention are low in cost, and the introduced Bi2O3 and Li2CO3 can both reduce the sintering temperature and reduce energy consumption.

[0027] 3. The lead-free relaxor-like antiferroelectric ceramic material prepared by the present invention can help form various types of defect dipoles by introducing different valence Bi and Li elements, which can regulate the response of the electric domains inside the ferroelectric material to the applied electric field, so that it exhibits a double hysteresis loop similar to an antiferroelectric material on a macroscopic scale.

[0028] 4. The lead-free relaxor-type antiferroelectric ceramic material prepared by this invention does not contain lead, which pollutes the environment. It exhibits significant relaxation phenomena and the characteristic double hysteresis loop of an antiferroelectric material. Its dielectric constant is higher than 1000 in the temperature range of 20–320℃ and the kHz range of 1–1000, while its dielectric loss is less than 0.18. The lead-free relaxor-type antiferroelectric ceramic material prepared by this invention has high dielectric constant and polarization intensity, low dielectric loss and polarization hysteresis, and high energy storage efficiency, reaching 93.55%. It has advantages in environmental protection, technology, and economy compared to lead-based antiferroelectric materials and AgNbO3 and NaNbO3-based lead-free antiferroelectric materials.

[0029] In summary, this invention prepares lead-free relaxor-like antiferroelectric ceramic materials via a solid-state method. These materials not only exhibit obvious relaxation phenomena and the double hysteresis loop characteristics of antiferroelectric materials, but also possess high saturation polarization intensity and dielectric constant, low hysteresis loss, simple preparation process, low cost, and environmental friendliness. They are expected to become an important candidate material that is both technically and economically superior to lead-based antiferroelectric materials. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the defect structure of the lead-free relaxor-type antiferroelectric ceramic material provided by the present invention.

[0031] Figure 2 This is a SEM image of the lead-free relaxor-type antiferroelectric ceramic material of Embodiment 1 of the present invention.

[0032] Figure 3 The image shows the XRD pattern of the lead-free relaxor-type antiferroelectric ceramic material of Embodiment 1 of the present invention.

[0033] Figure 4 The dielectric temperature spectrum of the lead-free relaxor antiferroelectric ceramic material of Example 1 of the present invention at different temperatures is shown.

[0034] Figure 5 This is a bipolar hysteresis loop diagram of the lead-free relaxor antiferroelectric ceramic material of Embodiment 1 of the present invention under different electric field strengths.

[0035] Figure 6 This is a unipolar hysteresis loop diagram of the lead-free relaxor antiferroelectric ceramic material of Embodiment 1 of the present invention under an electric field strength of 300 kV / cm. Detailed Implementation

[0036] The technical solution of the present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0037] like Figure 1 As shown, a lead-free relaxor-type antiferroelectric ceramic material, wherein the general chemical formula of the lead-free relaxor-type antiferroelectric ceramic material is Ba. 1-1.5x Bi x Ti 0.93 Li 0.07 O 2.895 Where 0.07 ≤ x ≤ 0.10; the lead-free relaxor-type antiferroelectric ceramic material has defect dipole characteristics and a perovskite structure. Introducing heterovalent Bi and Li elements helps to form various positively and negatively charged point defects, such as Li' T " i , V Ba , These point defects, carrying positive and negative charges, readily form defect dipole pairs, which can modulate the response of the electric domains within the ferroelectric material to an applied electric field, resulting in a macroscopically antiferroelectric-like double hysteresis loop while maintaining a large dielectric constant and polarization intensity. Meanwhile, for the chemical formula Ba within the stoichiometric range of this invention... 1-1.5x Bi x Ti 0.93 Li 0.07 O 2.895 The defective dipole formed does not weaken the improvement of the breakdown electric field due to leakage current, and the maximum test electric field strength can reach 300kV / cm.

[0038] A method for preparing a lead-free relaxor-type antiferroelectric ceramic material includes the following steps:

[0039] Step 1: According to Ba 1-1.5x Bi x Ti 0.93 Li 0.07 O 2.895 High-purity raw materials BaCO3, Li2CO3, Bi2O3 and TiO2 were weighed according to the stoichiometric ratio to obtain a mixed raw material; the purity of BaCO3, Li2CO3, Bi2O3 and TiO2 is ≥98%;

[0040] Step 2: Mix the weighed raw materials from Step 1 with zirconia balls and anhydrous ethanol, and ball mill at 400-450 rpm for 12-24 hours to obtain a mixed slurry; dry the mixed slurry at 90-100℃ for at least 6 hours, and then sieve the dried mixed powder to obtain a mixed raw material with a sieve mesh size of 60-120 mesh; the mass ratio of the mixed raw material, zirconia balls and anhydrous ethanol is 1:2:(1-1.5);

[0041] Step 3: Place the sieved mixed raw material from Step 2 into a sealed alumina or zirconium oxide crucible and calcine it at 750-850℃ for 2-4 hours to obtain calcined ceramic powder.

[0042] Step 4: Mix the calcined ceramic powder from Step 3 with zirconia balls and anhydrous ethanol, and ball mill at 420-450 rpm for 12-15 hours. Then dry at 90-100℃ for at least 6 hours. Finally, sieve the dried ceramic powder to obtain ceramic powder with a sieve mesh size of 60-120 mesh. The mass ratio of the ceramic powder, zirconia balls and anhydrous ethanol is 1:2:(1-1.5).

[0043] Step 5: Add a 6-8% polyvinyl alcohol (PVA) solution to the ceramic powder obtained in Step 4 for granulation. After aging for 24-48 hours, press it into a ceramic green body with a diameter of 10-12 mm. The amount of polyvinyl alcohol (PVA) solution added accounts for 2-3% of the mass of the ceramic powder obtained in Step 4.

[0044] Step 6: Heat the ceramic green body obtained in Step 5 to 550-650℃ at a heating rate of 1-3℃ / min and hold for 8-12 hours to completely remove polyvinyl alcohol (PVA).

[0045] Step 7: The ceramic green body from which polyvinyl alcohol (PVA) was removed in Step 6 is embedded in the ceramic powder obtained in Step 4 to avoid the volatilization loss of elements Bi and Li at high temperature. Then, it is heated to 1130-1150℃ at a heating rate of 2-4℃ / min for sintering and held at that temperature for 2-3 hours. After cooling to room temperature in the furnace, lead-free relaxor antiferroelectric ceramic material is obtained.

[0046] Example 1

[0047] A lead-free relaxor-type antiferroelectric ceramic material, with the chemical formula:

[0048] Ba 0.865 Bi 0.09 Ti 0.93 Li 0.07 O 2.895 The material was prepared using the following steps:

[0049] Step 1: According to Ba 0.865 Bi 0.09 Ti 0.93 Li 0.07 O 2.895 High-purity raw materials BaCO3, Li2CO3, Bi2O3 and TiO2 were weighed according to the stoichiometric ratio to obtain a mixed raw material;

[0050] Step 2: Mix 60g of the mixed raw material with 120g of zirconia balls and 90g of anhydrous ethanol, and then ball mill at 400 rpm for 12 hours. After that, dry at 100℃ for 6 hours and sieve to obtain a mixed raw material with a sieve mesh size of 60 mesh.

[0051] Step 3: Place the sieved mixed raw material from Step 2 into a sealed alumina crucible and calcine it at 800℃ for 4 hours to obtain calcined ceramic powder.

[0052] Step 4: Mix 30g of calcined ceramic powder, 60g of zirconia balls and 30g of anhydrous ethanol, and ball mill at 450 rpm for 15 hours. Then dry at 90℃ for 8 hours. Finally, sieve the dried ceramic powder to obtain ceramic powder with a sieve mesh size of 120 mesh.

[0053] Step 5: Add 8% polyvinyl alcohol (PVA) solution to 15g of sieved ceramic powder for granulation, and after aging for 24h, press it into a ceramic green body with a diameter of 10mm; the amount of polyvinyl alcohol (PVA) solution added is 0.3g;

[0054] Step 6: Heat the ceramic green body obtained in Step 5 to 650℃ at a heating rate of 1℃ / min and hold for 8 hours to completely remove the added polyvinyl alcohol (PVA).

[0055] Step 7: The ceramic green body from which polyvinyl alcohol (PVA) was removed in Step 6 is embedded in the ceramic powder obtained in Step 4, heated to 1150℃ at a heating rate of 3℃ / min for sintering and held at that temperature for 2 hours. After cooling to room temperature in the furnace, lead-free relaxor antiferroelectric ceramic material is obtained.

[0056] Example 2

[0057] A lead-free relaxor-type antiferroelectric ceramic material, with the chemical formula:

[0058] Ba 0.895 Bi 0.07 Ti 0.93 Li 0.07 O 2.895 The material was prepared using the following steps:

[0059] Step 1: According to Ba 0.895 Bi 0.07 Ti 0.93 Li 0.07 O 2.895 High-purity raw materials BaCO3, Li2CO3, Bi2O3 and TiO2 were weighed according to the stoichiometric ratio to obtain a mixed raw material;

[0060] Step 2: Mix 80g of the mixed raw material with 160g of zirconia balls and 80g of anhydrous ethanol, and then ball mill at 450 rpm for 24 hours. After that, dry at 90℃ for 8 hours and sieve to obtain a mixed raw material with a sieve mesh size of 120 mesh.

[0061] Step 3: Place the sieved mixed raw material from Step 2 into a sealed zirconium oxide crucible and calcine it at 850°C for 2 hours to obtain calcined ceramic powder.

[0062] Step 4: Mix 50g of calcined ceramic powder, 100g of zirconia balls and 75g of anhydrous ethanol, and ball mill at 420 rpm for 12 hours. Then dry at 100℃ for 6 hours. Finally, sieve the dried ceramic powder to obtain ceramic powder with a sieve mesh size of 60 mesh.

[0063] Step 5: Add a 6% polyvinyl alcohol (PVA) solution to 20g of sieved ceramic powder for granulation. After aging for 48h, press it into a ceramic green body with a diameter of 12mm. The amount of polyvinyl alcohol (PVA) solution added is 0.6g.

[0064] Step 6: Heat the ceramic green body obtained in Step 5 to 550℃ at a heating rate of 3℃ / min and hold for 12h to completely remove the added polyvinyl alcohol (PVA).

[0065] Step 7: The ceramic green body from which polyvinyl alcohol (PVA) was removed in Step 6 is embedded in the ceramic powder obtained in Step 4, heated to 1140℃ at a heating rate of 2℃ / min for sintering and held at that temperature for 3 hours. After cooling to room temperature in the furnace, lead-free relaxor antiferroelectric ceramic material is obtained.

[0066] Example 3

[0067] A lead-free relaxor-type antiferroelectric ceramic material, with the chemical formula:

[0068] Ba 0.85 Bi 0.10 Ti 0.93 Li 0.07 O 2.895 The material was prepared using the following steps:

[0069] Step 1: According to Ba 0.85 Bi 0.10 Ti 0.93 Li 0.07 O 2.895 High-purity raw materials BaCO3, Li2CO3, Bi2O3 and TiO2 were weighed according to the stoichiometric ratio to obtain a mixed raw material;

[0070] Step 2: Mix 70g of the mixed raw material with 140g of zirconia balls and 90g of anhydrous ethanol, and then ball mill at 420 rpm for 18 hours. After that, dry at 95℃ for 9 hours and sieve to obtain a mixed raw material with a sieve mesh size of 80 mesh.

[0071] Step 3: Place the sieved mixture from Step 2 into a sealed alumina crucible and calcine it at 750°C for 4 hours to obtain calcined ceramic powder.

[0072] Step 4: Mix 50g of calcined ceramic powder, 100g of zirconia balls and 60g of anhydrous ethanol, and ball mill at 430 rpm for 14 hours. Then dry at 100℃ for 8 hours. Finally, sieve the dried ceramic powder to obtain ceramic powder with a sieve mesh size of 80 mesh.

[0073] Step 5: Add a 7% polyvinyl alcohol (PVA) solution to 15g of sieved ceramic powder for granulation. After aging for 35h, press it into a ceramic green body with a diameter of 11mm. The amount of polyvinyl alcohol (PVA) solution added is 0.39g.

[0074] Step 6: Heat the ceramic green body obtained in Step 5 to 600℃ at a heating rate of 2℃ / min and hold for 10h to completely remove the added polyvinyl alcohol (PVA).

[0075] Step 7: The ceramic green body from which polyvinyl alcohol (PVA) was removed in Step 6 is embedded in the ceramic powder obtained in Step 4, heated to 1130℃ at a heating rate of 4℃ / min for sintering and held at that temperature for 3 hours. After cooling to room temperature in the furnace, lead-free relaxor antiferroelectric ceramic material is obtained.

[0076] To test the phase structure and electrical properties, the surface of the lead-free relaxor-type antiferroelectric ceramic material prepared in this invention was polished with 8000-grit sandpaper, then cleaned in an ultrasonic cleaner for 10 minutes. The cleaned ceramic sample was then placed in a resistance furnace and heated to 1080℃ at a heating rate of 3℃ / min and held for 30 minutes. After cooling to room temperature with the furnace, its surface was observed using a scanning electron microscope. The surface of the lead-free relaxor-type antiferroelectric ceramic material prepared in this invention was cleaned and ground into a powder without any graininess. Its phase composition was characterized using X-ray diffraction. The lead-free relaxor-type antiferroelectric ceramic material prepared in this invention was polished until the ceramic thickness reached 0 mm. The ceramic sample was then placed in an ultrasonic cleaner for 10 minutes. A silver electrode with a diameter of 6 mm was imprinted on the cleaned ceramic sample surface. The sample was heated to 600°C at a heating rate of 3°C / min and held for 20 minutes. After cooling to room temperature in the furnace, dielectric temperature spectrum testing was performed. The lead-free relaxor antiferroelectric ceramic material prepared in this invention was polished until the ceramic thickness reached 0.07 mm. The sample was then placed in an ultrasonic cleaner for 5 minutes. A gold electrode with a diameter of 2 mm was sputtered on the cleaned ceramic sample surface. The sample was heated to 300°C at a heating rate of 5°C / min and held for 30 minutes. After cooling to room temperature in the furnace, hysteresis loop testing was performed using a ferroelectric analyzer.

[0077] Figure 2 The image shows a scanning electron microscope image of the lead-free relaxor antiferroelectric ceramic material of Embodiment 1 of the present invention. It can be clearly observed from the image that the ceramic material is sintered relatively densely and there are no obvious pores.

[0078] Figure 3 The X-ray diffraction pattern of the lead-free relaxor antiferroelectric ceramic material of Example 1 of the present invention shows that the ceramic material has a pure perovskite structure and no obvious second phase.

[0079] Figure 4 The figure shows the dielectric constant and dielectric loss curves of the lead-free relaxor antiferroelectric ceramic material of Example 1 of the present invention as a function of temperature. It can be observed from the figure that the maximum value of the dielectric constant shifts towards higher temperatures as the test frequency increases, showing obvious dielectric relaxation characteristics. Furthermore, the dielectric constant is higher than 1000 in the range of 20-320℃ and 1-1000kHz, while the dielectric loss is less than 0.18.

[0080] Figure 5 The bipolar hysteresis loops of the lead-free relaxor antiferroelectric ceramic material in Example 1 of this invention were measured at electric field strengths of 40 kV / cm, 80 kV / cm, and 120 kV / cm. The waisted bipolar hysteresis loops of the antiferroelectric material can be clearly observed in the figure, showing a large saturation polarization intensity, a small residual polarization intensity, and polarization hysteresis.

[0081] Figure 6 The effective energy storage density (W) was calculated from the unipolar hysteresis loop of the lead-free relaxor antiferroelectric ceramic material in Example 1 of this invention, measured under an electric field strength of 300 kV / cm. rec The energy storage efficiency (η) is 2.03 J / cm³. 3 With a lead storage efficiency of 93.55%, compared with the lead-free AgNbO3 and NaNbO3-based materials in the prior art, the lead-free relaxor antiferroelectric ceramic material prepared by this invention has a significantly improved energy storage efficiency.

Claims

1. A lead-free relaxor-type antiferroelectric ceramic material, characterized in that: The chemical formula of the material is Ba. 1- 1.5x Bi x Ti 0.93 Li 0.07 O 2.895 Where 0.07≤x≤0.10; the lead-free relaxor antiferroelectric ceramic material has a perovskite structure and has defect dipole characteristics.

2. A method for preparing a lead-free relaxor-type antiferroelectric ceramic material, characterized in that, Includes the following steps: Step 1: According to Ba 1-1.5x Bi x Ti 0.93 Li 0.07 O 2.895 High-purity raw materials BaCO3, Li2CO3, Bi2O3, and TiO2 were weighed according to their stoichiometric ratios to obtain a mixed raw material; wherein 0.07≤x≤0.10; Step 2: Mix the weighed raw materials from Step 1 with zirconium oxide balls and anhydrous ethanol, and then ball mill, dry, and sieve them in sequence to obtain a mixed raw material with a sieve mesh size of 60~120 mesh. Step 3: Place the sieved mixed raw material from Step 2 into a sealed alumina or zirconium oxide crucible and calcine it at 750~850℃ for 2~4 hours to obtain calcined ceramic powder. Step 4: Mix the calcined ceramic powder from Step 3 with zirconium oxide balls and anhydrous ethanol, then ball mill, dry, and sieve sequentially to obtain ceramic powder with a sieve mesh size of 60-120 mesh. Step 5: Add polyvinyl alcohol solution to the ceramic powder obtained in step 4 for granulation, and after aging for 24-48 hours, press it into a ceramic green body; Step 6: Heat the ceramic green body obtained in Step 5 to completely remove polyvinyl alcohol; Step 7: The ceramic green body after removing polyvinyl alcohol in step 6 is embedded in the ceramic powder obtained in step 4 for sintering, and then cooled to room temperature in the furnace to obtain lead-free relaxor antiferroelectric ceramic material.

3. The method for preparing a lead-free relaxor-type antiferroelectric ceramic material according to claim 2, characterized in that: The purity of the raw materials BaCO3, Li2CO3, Bi2O3 and TiO2 in step 1 is ≥98%.

4. The method for preparing a lead-free relaxor-type antiferroelectric ceramic material according to claim 2, characterized in that: In step 2, the mass ratio of the mixed raw materials, zirconium oxide balls, and anhydrous ethanol is 1:2:(1~1.5); the ball milling speed is 400~450 rpm, the ball milling time is 12~24 h; the drying temperature is 90~100℃, and the drying time is at least 6 h.

5. The method for preparing a lead-free relaxor-type antiferroelectric ceramic material according to claim 2, characterized in that: In step 4, the mass ratio of ceramic powder, zirconia balls, and anhydrous ethanol is 1:2:(1~1.5); the ball milling speed is 420~450 rpm, the ball milling time is 12~15 h; the drying temperature is 90~100℃, and the drying time is at least 6 h.

6. The method for preparing a lead-free relaxor-type antiferroelectric ceramic material according to claim 2, characterized in that: In step 5, the mass concentration of the polyvinyl alcohol solution is 6-8%; the amount of polyvinyl alcohol solution added accounts for 2-3% of the mass of the ceramic powder obtained in step 4.

7. The method for preparing a lead-free relaxor-type antiferroelectric ceramic material according to claim 2, characterized in that, The specific heating operation in step 6 is as follows: heat to 550-650℃ at a heating rate of 1-3℃ / min and keep warm for 8-12 hours.

8. The method for preparing a lead-free relaxor-type antiferroelectric ceramic material according to claim 2, characterized in that, The sintering operation in step 7 is as follows: heat to 1130~1150℃ at a heating rate of 2~4℃ / min and hold for 2~3 hours.

9. The application of a lead-free relaxor antiferroelectric ceramic material as described in claim 1, or a lead-free relaxor antiferroelectric ceramic material obtained by the preparation method according to any one of claims 2-8, in high-pulse power energy storage capacitors, high-strain actuators, and transducer sensors.

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