A sodium bismuth titanate-based lead-free antiferroelectric high-energy storage ceramic material and a preparation method thereof

Abstract

This invention provides a lead-free antiferroelectric high-energy-storage ceramic material based on sodium bismuth titanate and its preparation method, belonging to the field of dielectric energy-storage ceramic materials. Its key feature is that its chemical composition is (1-x)Bi. 0.5 Na 0.5 TiO3-xAgNbO3, where 0.15<x≤0.3. Utilizing the ferroelectric Bi... 0.5 Na 0.5 The advantages of TiO3 and antiferroelectric AgNbO3, with Bi having large spontaneous polarization 0.5 Na 0.5 Using TiO3 as the matrix, other perovskite components are added to it, and ions with different valence states and radii are introduced at the A and B sites to obtain a stable and reversible relaxor antiferroelectric phase structure. Finally, a sodium bismuth titanate-based lead-free antiferroelectric energy storage ceramic material with both high energy storage density and high energy storage efficiency is obtained, which can meet the practical application requirements in lead-free energy storage capacitors.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of dielectric energy storage ceramic materials, and particularly relates to a sodium bismuth titanate-based lead-free antiferroelectric high-energy storage ceramic material and a preparation method thereof. BACKGROUND

[0002] At present, with the increasing energy demand of people, non-renewable energy such as oil is consumed continuously, and the development and utilization of electric energy has become an important way to alleviate the current energy crisis, and it is necessary to find new materials and new processes for electric energy storage. Among them, the dielectric capacitor is a way of storing energy by using the action of electric field to cause dielectric polarization, which has the advantages of super-high power density, fast charging and discharging speed, long service life, mature technology and low cost, so that they can meet the application requirements in different aspects, and are the most widely used energy storage devices at present. In recent years, with the development of science and technology, the application in some fields such as pulse system requires energy storage materials to have the advantages of capacitors and high energy storage density. Therefore, under the premise of meeting the service life requirements, the maximum improvement of energy storage density is the goal of the research of high-performance pulse capacitors. At present, the research on high-energy storage density dielectric materials for preparing capacitors mainly focuses on three categories: polymers, polymer-ceramic composite materials and ceramics. Among them, ceramic materials have the advantages of high dielectric constant, high use temperature, good adjustability, high energy storage density, low loss and easy mass production, and are particularly suitable for use as dielectric materials of pulse power capacitors. In addition, ceramic materials are inorganic, have a long storage time, have a wide source and a variety of types, and the ceramic powder formula can be adjusted to meet different performance requirements.

[0003] As for the energy storage ceramic dielectric material, it can be mainly divided into three categories: linear ceramic dielectric, ferroelectric ceramic dielectric and antiferroelectric ceramic dielectric. Among them, the antiferroelectric material has the potential to obtain high energy storage characteristics due to its high saturation polarization strength and low residual polarization strength, but most of the current antiferroelectric materials such as lead zirconate material system contain lead element which is harmful to the environment and human body. Therefore, in view of the current human concern for environmental problems, it is of great practical significance to develop high-performance lead-free antiferroelectric energy storage ceramics for application in pulse capacitors. SUMMARY

[0004] In order to solve the above problems, the application provides a sodium bismuth titanate-based lead-free antiferroelectric high-energy storage ceramic material and a preparation method thereof, which utilizes the advantages of ferroelectric Bi 0.5 Na 0.5 TiO3 and antiferroelectric AgNbO3 to obtain Bi 0.5 Na 0.5The TiO3 is a matrix, other perovskite compositions are added to the matrix, ions with different valence and radius are introduced into A and B positions, a stable and reversible relaxor anti-ferroelectric phase structure is obtained, finally, a sodium bismuth titanate-based lead-free anti-ferroelectric high-energy storage ceramic material with high energy storage density and high energy storage efficiency is obtained, so that the material can meet the practical application requirements in lead-free energy storage capacitors.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a sodium bismuth titanate-based lead-free anti-ferroelectric high-energy storage ceramic material, which is applied to a pulse power capacitor, and has a chemical composition of (1-x)Bi 0.5 Na 0.5 TiO3-xAgNbO3, wherein 0.15 < x < 0.3.

[0007] Further, x = 0.2.

[0008] The present application provides a preparation method of the above-mentioned sodium bismuth titanate-based lead-free anti-ferroelectric high-energy storage ceramic material, which comprises the following steps: S1. raw materials of metal carbonates or oxides are weighed according to the stoichiometric ratio, mixed and subjected to primary calcination to obtain pre-synthesized powder; S2. the pre-synthesized powder is subjected to high-energy ball milling, mixed and granulated, and then subjected to sieving, tabletting and sintering to obtain a ceramic sample; and S3. the ceramic sample is polished, cleaned and dried, both end faces are coated with silver paste, and secondary calcination is performed.

[0009] Further, in the step S1, the mixing is performed by using alcohol or water as a medium, ball milling for 8-12 hours at a speed of 400-600 r / min, and then drying.

[0010] Further, the process parameters of the primary calcination are as follows: the dried mixed raw materials are calcined in an oxidizing environment, the synthesis temperature is 800-850 DEG C, and the temperature is maintained for 4-5 hours.

[0011] Further, in the step S2, the process parameters of the high-energy ball milling are as follows: the pre-synthesized powder is used as a medium, ball milling is performed for 8-12 hours at a speed of 500-700 r / min, and then drying is performed.

[0012] Further, after drying, the D50 particle size of the powder is 1.8-2.2 microns, and the D40 / D50 is 1.0-1.2.

[0013] Further, the dried powder is mixed with a binder to form granules, the granules are sieved through a 100-150 mesh sieve, and then cold-pressed into a ceramic green body under a pressure of 200-300 MPa.

[0014] Further, the ceramic ligand is sintered in an oxidation environment by a powder embedding method under normal pressure, heated to 500-600 DEG C at a heating rate of 2-4 DEG C / min, kept for 25-35 min, heated to 950-1050 DEG C at a heating rate of 4-6 DEG C / min, sintered for 2-3 h, and cooled down in the furnace after sintering.

[0015] Further, the process parameters of the secondary calcination are as follows: in an oxidation environment at 550-650 DEG C, silver is burned for 30-60 min.

[0016] The beneficial effects brought by the technical scheme provided by the embodiment of the present application include:

[0017] (1) The ceramic composition of the present application has high energy storage density and high energy storage efficiency, wherein the releasable energy storage density can reach 9.9 J / cm 3 , the energy storage efficiency is 77%, the ceramic silver content is low, the cost is low, and the application requirements of the pulse power capacitor are met.

[0018] (2) The present application uses the preparation technology of traditional piezoelectric ceramics and industrial raw materials, has practicability, and inhibits silver reduction by A-site vacancy method, has good process repeatability and good performance stability.

[0019] (3) The ceramic formula of the present application can effectively regulate the ceramic structure and energy storage performance, realize the transition from ferroelectric phase to relaxor anti-ferroelectric phase, and has extremely high structure and performance adjustability. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 The XRD pattern of 0.8Bi 0.5 Na 0.5 TiO3-0.2AgNbO3 prepared in the embodiment 1 of the present application;

[0022] Figure 2 The surface SEM morphology diagram of 0.8Bi 0.5 Na 0.5 TiO3-0.2AgNbO3 prepared in the embodiment 1 of the present application.

[0023] Figure 3 The energy storage performance diagram of 0.8Bi 0.5 Na 0.5 TiO3-0.2AgNbO3 prepared in the embodiment 1 of the present application. DETAILED DESCRIPTION

[0024] In order to make the objects, technical solutions and advantages of the present application clearer, the following further describes the present application in detail with reference to the accompanying drawings and specific embodiments.

[0025] The embodiment of the present application discloses a sodium bismuth titanate-based lead-free antiferroelectric high-energy storage ceramic material, which is applied to a pulse power capacitor, (1-x)Bi 0.5 Na 0.5 TiO3-xAgNbO3, wherein 0.15

[0026] Bi 0.5 Na 0.5 TiO3 has a large spontaneous polarization intensity (~ 38 mu C / cm 2 ) and a relatively high Curie temperature, so that it has a great advantage in the dielectric energy storage field. However, its large remanent polarization intensity causes large energy loss while obtaining high energy storage density, which is not conducive to its application as a dielectric energy storage material. In order to further improve the energy storage performance of the ceramic capacitor, antiferroelectric AgNbO3 is introduced into the ferroelectric Bi 0.5 Na 0.5 TiO3. Pure AgNbO3 has a high saturation polarization intensity (~ 52 mu C / cm 2 ) at room temperature, so that the AgNbO3 designed as a relaxor antiferroelectric will have more advantages than the NaNbO3-based relaxor antiferroelectric ceramic in energy storage performance. The introduction of AgNbO3 will stabilize the high-temperature antiferroelectric phase of Bi 0.5 Na 0.5 TiO3, and after the introduction of AgNbO3, the high-temperature antiferroelectric phase of Bi 0.5 Na 0.5 TiO3 will gradually approach room temperature, and finally the Bi 0.5 Na 0.5 TiO3 system gradually changes from a ferroelectric phase to an antiferroelectric phase at x = 0.2, which is at the phase boundary between a trigonal ferroelectric phase and a tetragonal antiferroelectric phase. On the one hand, the antiferroelectric-ferroelectric phase transition can improve the energy storage density; on the other hand, compared with other single-phase ferroelectric / antiferroelectric systems, the coexistence of two phases increases the polarization state, and due to the lower energy barrier, the domain deflection is easier under an applied electric field, which is conducive to obtaining high energy storage performance; in addition, by adding other perovskite components to the Bi 0.5 Na 0.5 TiO3 matrix, different valence and radius ions are introduced at A and B sites, so that stable and reversible relaxor ferroelectric and relaxor antiferroelectric phase structures can be obtained, and finally a sodium bismuth titanate-based lead-free antiferroelectric energy storage ceramic material with high energy storage density and high energy storage efficiency can be obtained, so that it can meet the practical application requirements in lead-free energy storage capacitors.

[0027] Preferably, x = 0.2.

[0028] The application also provides a preparation method of the above-mentioned sodium bismuth titanate-based lead-free antiferroelectric high-energy storage ceramic material, comprising the following steps:

[0029] S1. Raw materials of metal carbonates or oxides are weighed according to stoichiometric ratios, mixed and subjected to primary calcination to obtain pre-synthesized powders.

[0030] The mixing is as follows: the metal carbonates or oxides are ball milled in alcohol or water as a medium at a speed of 200-400 r / min for 8-12 h, and then dried; the process parameters of the primary calcination are as follows: the dried mixed raw materials are calcined in an oxidizing environment at a synthesis temperature of 800-850 ℃ for 4-5 h to obtain the pre-synthesized powders.

[0031] It should be pointed out that the application is directed to a material with a chemical composition of (1-x)Bi 0.5 Na 0.5 TiO3-xAgNbO3, and carbonates or oxides are selected as raw materials, for example, Bi2O3, Na2CO3, TiO2, Ag2O or NbO2; the alcohol is preferably anhydrous ethanol.

[0032] In order to improve the oxidation degree of the raw materials, the oxygen flow in the oxidizing environment is preferably 40-50 mL / min.

[0033] Preferably, the proportion of silver is reduced by 1-2% during batching to prevent silver reduction and precipitation.

[0034] S2. The pre-synthesized powders are subjected to high-energy ball milling, mixed and granulated, screened, and then pressed into tablets and sintered to obtain ceramic samples.

[0035] The process parameters of the high-energy ball milling are as follows: the pre-synthesized powders are ball milled in alcohol or water as a medium at a speed of 500-700 r / min for 8-12 h, and then dried. After drying, the D50 particle size of the powders is 1.8-2.2 μm, and the D40 / D50 is 1.0-1.2; the dried powders are mixed with a binder, granulated through a 100-150 mesh sieve, and then cold-pressed into ceramic green bodies at a pressure of 200-300 MPa; the ceramic green bodies are sintered in an oxidizing environment by the powder-embedding method at a constant pressure, heated to 500-600 ℃ at a heating rate of 2-4 ℃ / min and kept for 25-35 min, and then heated to 950-1050 ℃ at a heating rate of 4-6 ℃ / min and sintered for 2-3 h, and then cooled in the furnace after sintering to obtain the ceramic samples.

[0036] By controlling the high-energy ball milling process, the particle size of the powder is controlled within a certain range, so that the ceramic sample prepared subsequently has high density, the breakdown field strength is improved, thereby the ceramic sample has large energy storage density, and the organization and anti-ferroelectricity of the ceramic material are affected.

[0037] S3. The ceramic sample is polished, cleaned, dried, and then the two end faces are coated with silver paste and subjected to secondary calcination.

[0038] The process parameters of the secondary calcination are as follows: silver is burned for 30-60 min in an oxidation environment at 550-650 DEG C.

[0039] In order to better illustrate the embodiments of the present application, the present application is further described in detail through specific examples.

[0040] Example 1

[0041] The present application provides a preparation method of 0.8Bi 0.5 Na 0.5 TiO3-0.2AgNbO3, which comprises the following steps:

[0042] S1. The raw materials of metal carbonates or oxides are weighed according to the stoichiometric ratio, mixed, and subjected to primary calcination to obtain pre-synthesized powder. The metal carbonates or oxides are ball milled in alcohol or water as medium for 10 h at a speed of 300 r / min, and then dried. The process parameters of the primary calcination are as follows: the mixed raw materials after drying are calcined in an oxidation environment, the synthesis temperature is 850 DEG C, and the temperature is kept for 5 h, thereby obtaining the pre-synthesized powder.

[0043] S2. The pre-synthesized powder is subjected to high-energy ball milling, mixed and granulated, sieved, and then pressed into a tablet and subjected to sintering to obtain a ceramic sample. The process parameters of the high-energy ball milling are as follows: the pre-synthesized powder is ball milled in alcohol or water as medium for 10 h at a speed of 500 r / min, and then dried. After drying, the D50 particle size of the powder is 2.0 mu m, and the D40 / D50 is 1.1. The powder after drying is mixed with a binder, granulated through a 100-150 mesh sieve, and then cold-pressed into a ceramic body under a pressure of 200 MPa. The ceramic body is sintered in an oxidation environment by the powder-embedding method under normal pressure, the temperature is raised to 550 DEG C at a rate of 3 DEG C / min and kept for 30 min, the temperature is raised to 1000 DEG C at a rate of 5 DEG C / min, and sintering is performed for 3 h. After sintering is completed, the ceramic sample is cooled in the furnace.

[0044] S3. The ceramic sample is polished, cleaned, dried, and then the two end faces are coated with silver paste and subjected to secondary calcination.

[0045] The process parameters of the secondary calcination are: silver burning for 30 min in an oxidation environment at 550-650 DEG C.

[0046] Figure 1 0.8Bi 0.5 Na 0.5 The XRD pattern of 0.8Bi

[0047] Figure 2 0.8Bi 0.5 Na 0.5 The surface SEM morphology of 0.8Bi

[0048] Figure 3 0.8Bi 0.5 Na 0.5 The energy storage performance diagram of 0.8Bi

[0049] After measurement, the releasable energy storage density W rec 9.9 J / cm 3 , the energy storage efficiency η is 77%, the breakdown field strength E b is 556 kV / cm, the discharge time t 0.9 is 27 ns, the relative dielectric constant ε r is 1061, and the dielectric loss tan σ is 0.003.

[0050] Example 2

[0051] The embodiment of the application provides a preparation method of 0.8Bi 0.5 Na 0.5 TiO3-0.2AgNbO3, which comprises the following steps:

[0052] S1. The raw materials of metal carbonates or oxides are weighed according to the stoichiometric ratio, mixed and subjected to primary calcination to obtain pre-synthesized powder. The metal carbonates or oxides are ball milled in alcohol or water as medium at a rotating speed of 200 r / min for 8 h, and then dried; the process parameters of the primary calcination are that the mixed raw materials after drying are calcined in an oxidation environment, the synthesis temperature is 800 DEG C, and the heat preservation time is 4 h, so that the pre-synthesized powder is obtained.

[0053] S2. The pre-synthesized powder is subjected to high-energy ball milling, mixed granulation, sieving, tabletting, and sintering to obtain a ceramic sample. The process parameters of the high-energy ball milling are as follows: the pre-synthesized powder is ball milled for 8 h in alcohol or water as a medium at a rotation speed of 500 r / min, and then dried after the high-energy ball milling. After drying, the D50 particle size of the powder is 2.2 μm, and the D40 / D50 is 1.2; the dried powder is mixed with a binder to perform granulation, sieved through a 100-150 mesh sieve, and then cold-pressed into a ceramic green body under a pressure of 200 MPa; the ceramic ligand is sintered in an oxidizing environment by a powder-embedding method at a heating rate of 2 ℃ / min to 500 ℃ for 25 min, and then heated to 950 ℃ at a heating rate of 4 ℃ / min, and sintered for 2 h, and then cooled in the furnace after sintering to obtain the ceramic sample.

[0054] S3. The ceramic sample is polished, washed, dried, and then coated with silver paste on both end faces, and then subjected to secondary calcination.

[0055] The process parameters of the secondary calcination are as follows: the silver is calcined for 30 min in an oxidizing environment at 550-650 ℃.

[0056] The ceramic sample prepared in the embodiment has a pure perovskite structure, and does not have any other impurities, and has a dense microstructure. It is measured that the ceramic sample can release a stored energy density W rec of 7.8 J / cm 3 , a stored energy efficiency η of 76%, a breakdown field strength E b of 448 kV / cm, a discharge time t 0.9 of 29 ns, a relative dielectric constant ε r of 1073, and a dielectric loss tan σ of 0.005.

[0057] Embodiment 3

[0058] The embodiment of the present application provides a preparation method of 0.8Bi 0.5 Na 0.5 TiO3-0.2AgNbO3, which comprises the following steps:

[0059] S1. The raw materials of metal carbonates or oxides are weighed according to the stoichiometric ratio, mixed, and subjected to primary calcination to obtain a pre-synthesized powder. The metal carbonates or oxides are ball milled in alcohol or water as a medium for 12 h at a rotation speed of 400 r / min, and then dried after the ball milling; the process parameters of the primary calcination are as follows: the mixed raw materials after drying are calcined in an oxidizing environment at a synthesis temperature of 850 ℃ for 5 h to obtain the pre-synthesized powder.

[0060] S2. The pre-synthesized powder is subjected to high-energy ball milling, mixed and granulated, sieved, pressed into tablets, and sintered to obtain a ceramic sample. The process parameters for high-energy ball milling are as follows: the pre-synthesized powder is ball-milled for 12 hours with alcohol or water as the medium at a speed of 700 r / min, and then dried after high-energy ball milling. After drying, the D50 particle size of the powder is 1.8 μm, and the D40 / D50 ratio is 1.0. The dried powder is mixed with a binder and granulated, sieved through a 100-150 mesh sieve, and then cold-pressed under a pressure of 300 MPa to obtain a ceramic green body. The ceramic ligand is sintered in an oxidizing environment at normal pressure using a powder embedding method, heated to 600℃ at a heating rate of 4℃ / min and held for 35 min, then heated to 1050℃ at a heating rate of 6℃ / min and sintered for 3 hours. After sintering, the ceramic sample is obtained by furnace cooling.

[0061] S3. Polish the ceramic sample, clean and dry it, apply silver paste to both ends, and then calcine it a second time.

[0062] The process parameters for the secondary calcination are: calcining silver in an oxidizing environment at 550-650℃ for 60 minutes.

[0063] The ceramic sample prepared in this embodiment has a pure perovskite structure, free of any other impurities, and exhibits a dense microstructure. Measurements show that it can release a storage density W. rec It is 8.8 J / cm 3 The energy storage efficiency η is 77%, and the breakdown field strength E b The discharge voltage is 497 kV / cm, and the discharge time is t. 0.9 The relative permittivity is 28 ns, and the relative permittivity ε is 28 ns. r The value is 1065, and the dielectric loss tanσ is 0.004.

[0064] Example 4

[0065] Unlike Example 1, in this example, according to the chemical composition 0.84Bi 0.5 Na 0.5 TiO3-0.16AgNbO3 is used as the raw material.

[0066] The ceramic sample prepared in this embodiment has a pure perovskite structure, free of any other impurities, and exhibits a dense microstructure. Measurements show that it can release a storage density W. rec 8.5 J / cm 3 The energy storage efficiency η is 70%, and the breakdown field strength E b The discharge voltage is 488 kV / cm, and the discharge time is t. 0.9 The relative permittivity is 28 ns, and the relative permittivity ε is 28 ns. r The value is 980, and the dielectric loss tanσ is 0.005.

[0067] Example 5

[0068] Different from Example 1, in this example, the ceramic sample was prepared according to the chemical composition of 0.7Bi 0.5 Na 0.5 TiO3-0.3AgNbO3.

[0069] The ceramic sample prepared in this example was of pure perovskite structure, with few impurities and dense microstructure. It was measured that the releasable energy storage density W rec was 7.5 J / cm 3 , the energy storage efficiency η was 78%, the breakdown field strength E b was 465 kV / cm, the discharge time t 0.9 was 29 ns, the relative dielectric constant ε r was 1153, and the dielectric loss tanσ was 0.006.

[0070] Comparative Example 1

[0071] Different from Example 1, in this example, the ceramic sample was prepared according to the chemical composition of 0.68Bi 0.5 Na 0.5 TiO3-0.32AgNbO3.

[0072] The ceramic sample prepared in this example was of pure perovskite structure, with no other impurities and dense microstructure. It was measured that the releasable energy storage density W rec was 6.4 J / cm 3 , the energy storage efficiency η was 78%, the breakdown field strength E b was 368 kV / cm, the discharge time t 0.9 was 31 ns, the relative dielectric constant ε r was 1180, and the dielectric loss tanσ was 0.011.

[0073] Comparative Example 2

[0074] Different from Example 1, in this example, the ceramic sample was prepared according to the chemical composition of 0.85Bi 0.5 Na 0.5 TiO3-0.15AgNbO3.

[0075] The ceramic sample prepared in this example was of pure perovskite structure, with no other impurities and dense microstructure. It was measured that the releasable energy storage density W rec was 7.2 J / cm 3 , the energy storage efficiency η was 68%, the breakdown field strength E b was 435 kV / cm, the discharge time t 0.9 was 28 ns, the relative dielectric constant ε r was 971, and the dielectric loss tanσ was 0.006.

[0076] Comparative Example 3

[0077] Unlike Example 1, in this comparative example, the powder prepared in step S2 has a D50 particle size of 1.5 μm and a D40 / D50 ratio of 0.9.

[0078] The ceramic sample prepared in this comparative example has a pure perovskite structure, free of any other impurities, and exhibits a dense microstructure. Measurements show that its energy release density W... rec It is 9.3 J / cm 3 The energy storage efficiency η is 77%, and the breakdown field strength E b The voltage is 527 kV / cm, and the discharge time is t. 0.9 The relative permittivity is ε = 25 ns. r The value is 1071, and the dielectric loss tanσ is 0.004.

[0079] Comparative Example 4

[0080] Unlike Example 1, in this comparative example, the powder prepared in step S2 has a D50 particle size of 2.5 μm and a D40 / D50 ratio of 1.6.

[0081] The ceramic sample prepared in this comparative example has a pure perovskite structure, free of any other impurities, and exhibits a dense microstructure. Measurements show that its energy release density W... rec 9.0 J / cm 3 The energy storage efficiency η is 77%, and the breakdown field strength E b The discharge voltage is 510 kV / cm, and the discharge time is t. 0.9 The relative permittivity is 28 ns, and the relative permittivity ε is 28 ns. r The value is 1050, and the dielectric loss tanσ is 0.006.

[0082] By comparing Example 1, Comparative Examples 1 and 2, it can be seen that when (1-x)Bi 0.5 Na 0.5 When the value of x in TiO3-xAgNbO3 is outside the range of 0.15 < x ≤ 0.3, the performance of the prepared energy storage ceramic material deteriorates, mainly manifested in a significant decrease in energy storage density and breakdown strength, and an increase in dielectric loss. However, by comparing Examples 1, 3, and 4, it can be seen that by controlling the D50 particle size of the powder to 1.8-2.2 μm and the D40 / D50 ratio to 1.0-1.2, the energy storage density of the prepared energy storage ceramic can be improved, the breakdown field strength increased, and the stage loss reduced, thus improving the energy storage performance.

[0083] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sodium bismuth titanate-based lead-free antiferroelectric high energy storage ceramic material applied to pulse power capacitors, characterized in that, Chemical composition (1-x)Bi 0.5 Na 0.5 TiO3-xAgNbO3, where 0.2≤x≤0.

3.

2. A method of producing the sodium bismuth titanate-based lead-free antiferroelectric high energy storage ceramic material according to any one of claims 1, characterized in that, The method comprises the following steps: S1. Raw materials of metal carbonate or oxide are weighed according to stoichiometric ratio, mixed and once calcined to obtain pre-synthesized powder; S2. The pre-synthesized powder is high-energy ball milled, mixed, granulated, sieved, pressed into tablets and sintered to obtain ceramic samples; S3. The ceramic samples are polished, washed and dried, both ends are coated with silver paste and twice calcined.

3. The method of claim 2, wherein the method is characterized by: In the step S1, the mixing is as follows: the metal carbonate or oxide is ball milled in alcohol or water as medium at a rotating speed of 200-400 r / min for 8-12 h, and then dried.

4. The method of claim 3, wherein the method is characterized by: The process parameters of the once calcination are as follows: the dried mixed raw materials are calcined in an oxidizing environment at a synthesis temperature of 800-850 ℃ for 4-5 h.

5. The method of claim 2, wherein the method is characterized by: In the step S2, the process parameters of the high-energy ball milling are as follows: the pre-synthesized powder is ball milled in alcohol or water as medium at a rotating speed of 500-700 r / min for 8-12 h, and then dried.

6. The method of claim 5, wherein the method is characterized by: After drying, the D50 particle size of the powder is 1.8-2.2 μm, and the D40 / D50 is 1.0-1.

2.

7. The method of claim 5, wherein the method is characterized by: The dried powder is mixed with a binder, granulated, sieved through a 100-150 mesh sieve and cold-pressed into ceramic green bodies under a pressure of 200-300 MPa.

8. The method of claim 7, wherein the method is characterized by: The ceramic green bodies are sintered in an oxidizing environment by the powder embedding method under normal pressure, heated to 500-600 ℃ at a heating rate of 2-4 ℃ / min for 25-35 min, heated to 950-1050 ℃ at a heating rate of 4-6 ℃ / min, sintered for 2-3 h, and then cooled in the furnace after sintering.

9. The method of claim 2, wherein the method is characterized by: The process parameters of the twice calcination are as follows: silver is burned in an oxidizing environment at 550-650 ℃ for 30-60 min.

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