阅读说明：本技术 一种陶瓷材料及其制备方法和用途 (Ceramic material and preparation method and application thereof ) 是由 姚武 施成 魏永起 闫非 翟继卫 于 2021-02-10 设计创作，主要内容包括：本发明属于材料领域,具体涉及一种陶瓷材料及其制备方法和用途。本发明中陶瓷材料的通式为(1-x)(Ba-(0.85)Ca-(0.15)Zr-(0.1)Ti-(0.9)O-3)x(Sr-(0.7)Bi-(0.2)TiO-3),其中0.1≤x≤0.4。本发明通过Sr-(0.7)Bi-(0.2)TiO-3对Ba-(0.85)Ca-(0.15)Zr-(0.1)Ti-(0.9)O-3进行适当改性,获得的陶瓷材料同时达到高储能密度和高储能效率,其中高储能效率能够有效避免存储的能量以热的形式释放,延长材料的使用寿命。(The invention belongs to the field of materials, and particularly relates to a ceramic material and a preparation method and application thereof. The general formula of the ceramic material in the invention is (1-x) (Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 )x(Sr 0.7 Bi 0.2 TiO 3 ) Wherein x is more than or equal to 0.1 and less than or equal to 0.4. By Sr 0.7 Bi 0.2 TiO 3 For Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 The ceramic material obtained by proper modification simultaneously achieves high energy storage density and high energy storage efficiency, wherein the high energy storage efficiency can effectively prevent the stored energy from being released in a thermal form, and the service life of the material is prolonged.)

1. A ceramic material, characterized in that the ceramic material has the formula:

(1-x)(Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃)x(Sr_0.7Bi_0.2TiO₃) Wherein x is more than or equal to 0.1 and less than or equal to 0.4.

2. The ceramic material of claim 1, wherein the average size of the grains in the ceramic material is 2.0 to 3.0 μm;

and/or the Curie temperature is between-60 and-7 ℃;

and/or the energy storage density is 1.81J/cm³～4.02J/cm³；

And/or the energy storage efficiency is 92.82% -94.74%.

3. A method for preparing the ceramic material according to any one of claims 1 to 2, comprising the steps of:

Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃powder and Sr_0.7Bi_0.2TiO₃And mixing the powder, and then performing ball milling, granulation, ageing, press forming, glue discharging and sintering in sequence to obtain the ceramic material.

4. The method according to claim 3, wherein said Ba is present in said Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃The preparation method of the powder comprises the following steps: according to the chemical formula Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Weighing stoichiometric BaCO₃、CaCO₃、ZrO₂And TiO₂Then ball milling, mixing and calcining are carried out to obtain the Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃And (3) powder.

5. The preparation method according to claim 4, wherein the calcination temperature is 1100-1200 ℃ and the calcination time is 4-6 h.

6. The method of claim 3Method characterized by said Sr_0.7Bi_0.2TiO₃The preparation method of the powder comprises the following steps: according to the chemical formula Sr_0.7Bi_0.2TiO₃Weighing stoichiometric SrCO₃、Bi₂O₃And TiO₂Then ball milling, mixing and calcining are carried out to obtain the Sr_0.7Bi_0.2TiO₃And (3) powder.

7. The preparation method according to claim 6, wherein the calcination temperature is 900-1000 ℃ and the calcination time is 4-6 h.

8. The method according to claim 3, wherein in the granulating step, wet granulation is performed using PVA as a binder;

and/or the step of discharging the rubber comprises processing for 4 to 6 hours at 500 to 600 ℃;

and/or, the sintering step comprises sintering at 1250-1450 ℃ for 2-3 h;

and/or, the ball milling adopts wet ball milling, and the screen allowance of the powder passing through a 120-mesh screen after ball milling is less than or equal to 5 percent;

and/or, the step of drying at 80-120 ℃ is also included after the ball milling.

9. Use of the ceramic material according to claim 1 or 2 as a dielectric in a capacitor.

10. The ceramic capacitor is characterized by comprising an electrode layer and a dielectric layer, wherein the outermost two sides of the ceramic capacitor are both the electrode layer; the dielectric layer is composed of the ceramic material of claim 1 or 2.

Technical Field

The invention belongs to the field of materials, and particularly relates to a ceramic material and a preparation method and application thereof.

Background

With the continuous development of information technology, the miniaturization and the multifunctionalization of devices, and the ceramic with high energy storage density and high energy storage efficiency is a key material for manufacturing small-sized, large-capacity and high-efficiency capacitors. The ceramic capacitor with high energy storage density has the advantages of high energy storage density, high charging and discharging speed, cyclic aging resistance, high mechanical strength, suitability for extreme environments such as high temperature and high pressure, stable performance and the like, meets the requirements of new energy development and utilization, and is widely applied to modern fields such as communication, computers, automobiles, electronic circuit equipment, military industry and the like. However, the existing energy storage medium materials have the problems of low energy storage density and energy storage efficiency, small discharge current, short service life, lead which is unfavorable to human health and pollutes the environment and the like, and are difficult to meet the requirements of the development of the contemporary society. Therefore, it is critical to develop a lead-free ceramic dielectric material having high energy storage density and high energy storage efficiency to improve the energy storage characteristics of the capacitor.

The dielectric materials of the energy storage capacitor are mainly linear ceramics, ferroelectric ceramics and antiferroelectric ceramics. At present, the linear ceramic systems used in energy storage are predominantly TiO₂A base ceramic; the ferroelectric ceramic system mainly comprises BaTiO₃A base ceramic; the antiferroelectric ceramic system mainly comprises PbZrO₃The base ceramic, but lead, which occupies a large specific gravity, has a large toxicity and causes serious pollution to the human body and the environment.

The performance of the energy storage ceramic mainly depends on two factors of the dielectric constant and the insulating performance of the energy storage ceramic, and the energy storage characteristic of the ceramic dielectric has a direct proportional relation with the product of the dielectric constant of the dielectric and the square of the working field intensity. Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃The ceramic is excellent BaTiO₃A base dielectric material having a high dielectric constant, low dielectric loss and high energy storage efficiency, but Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Breakdown of ceramicsThe field intensity is low, and the energy storage density is low, so that the application of the magnetic material in practical production is limited. Therefore, Ba is to be broadened_0.85Ca_0.15Zr_0.1Ti_0.9O₃The ceramic dielectric is applied to the field of energy storage.

Disclosure of Invention

In view of the technical problems in the prior art, the present invention aims to provide a ceramic material, a preparation method and a use thereof, wherein the ceramic material provided by the present invention has high energy storage density and high energy storage efficiency, and the preparation process is simple, can meet the requirements of different applications, and is suitable for industrial production.

To achieve the above objects and other related objects, the present invention is achieved by the following technical solutions.

One of the objects of the present invention is to provide a ceramic material having the general formula:

(1-x)(Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃)x(Sr_0.7Bi_0.2TiO₃) Wherein x is more than or equal to 0.1 and less than or equal to 0.4.

Preferably, x is 0.2 ≦ x ≦ 0.4.

In the present invention, x cannot be too high or too low. If x is too high, the remanent polarization of the ceramic material of the present invention is continuously reduced, the maximum strength is also reduced, and the energy storage density is reduced. If x is too low, the ceramic material of the present invention has too low a breakdown strength and too high a remanent polarization, resulting in a reduction in energy storage density and efficiency.

Preferably, the average size of crystal grains in the ceramic material is 2.0-3.0 μm.

Preferably, the ceramic material has a Curie temperature of-60 ℃ to-7 ℃.

Preferably, the energy storage density of the ceramic material is 1.81J/cm³～4.02J/cm³。

Preferably, the energy storage efficiency of the ceramic material is 92.82% -94.74%.

The invention also aims to provide a preparation method of the ceramic material, which comprises the following steps:

Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃powder and Sr_0.7Bi_0.2TiO₃And mixing the powder, and then performing ball milling, granulation, ageing, press forming, glue discharging and sintering in sequence to obtain the ceramic material.

Preferably, said Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃The residue of the powder passing through a 120-mesh sieve is less than or equal to 5 percent.

Preferably, said Sr_0.7Bi_0.2TiO₃The residue of the powder passing through a 120-mesh sieve is less than or equal to 5 percent.

Preferably, the ball milling adopts wet ball milling, and the residue of the powder passing through a 120-mesh sieve after ball milling is less than or equal to 5 percent. In the invention, the ball milling equipment adopts conventional equipment in the prior art, the ball milling medium is preferably absolute ethyl alcohol, the grinding ball is preferably zirconia ball, and the ball milling is carried out in a nylon tank.

Preferably, the rotation speed of the ball milling is 300 r/min-400 r/min, and the ball milling time is 10 h-12 h.

More preferably, during ball milling, the mass ratio of the absolute ethyl alcohol to the ball stone to the powder is 1: (1.5-3): 1.

preferably, the step of drying at 80-120 ℃ is further included after the ball milling.

Preferably, in the granulating step, PVA is used as a binder for wet granulation.

More preferably, in the wet granulation, Ba is added_0.85Ca_0.15Zr_0.1Ti_0.9O₃Powder and Sr_0.7Bi_0.2TiO₃Mixing and molding the powder and a PVA aqueous solution, wherein the concentration of the PVA aqueous solution is 5 wt% -8 wt%, and the mass of the PVA aqueous solution is Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Powder and Sr_0.7Bi_0.2TiO₃8 to 15 percent of the total mass of the powder.

Further preferably, the mass of the aqueous PVA solution is Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Powder and Sr_0.7Bi_0.2TiO₃10 to 15 percent of the total mass of the powder.

Preferably, the staling time is 24 to 30 hours.

More preferably, the staling time is 24 to 26 hours.

Preferably, the pressure in the compression molding process is 6MPa to 15MPa, and the pressure maintaining time is 30s to 60 s.

More preferably, the pressure in the compression molding process is 10MPa to 15MPa, and the pressure maintaining time is 40s to 60 s.

Preferably, the step of discharging the rubber comprises processing for 4 to 6 hours at 500 to 600 ℃.

More preferably, the step of discharging the rubber comprises processing for 5 to 6 hours at 550 to 600 ℃.

Preferably, the sintering step comprises sintering at 1250-1450 ℃ for 2-3 h.

More preferably, the sintering step comprises sintering at 1250 ℃ to 1300 ℃ for 2.5h to 3 h.

Preferably, said Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃The preparation method of the powder comprises the following steps: according to the chemical formula Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Weighing stoichiometric BaCO₃、CaCO₃、ZrO₂And TiO₂Then ball milling, mixing and calcining are carried out to obtain the Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃And (3) powder.

More preferably, the calcining temperature is 1100-1200 ℃, and the calcining time is 4-6 h.

More preferably, the rotation speed of the ball mill is 300 r/min-400 r/min, and the time is 10 h-12 h.

More preferably, the ball milling is performed by a wet ball milling method, absolute ethyl alcohol is used as a medium, zirconium oxide is used as a milling ball, and the mass ratio of the absolute ethyl alcohol to the zirconium ball to the powder is 2 (1-1.5): 1.

Preferably, said Sr_0.7Bi_0.2TiO₃The preparation method of the powder comprises the following steps: according to the chemical formula Sr_0.7Bi_0.2TiO₃By weighing in stoichiometric proportionsSrCO₃、Bi₂O₃And TiO₂Then ball milling, mixing and calcining are carried out to obtain the Sr_0.7Bi_0.2TiO₃And (3) powder.

More preferably, the calcining temperature is 900-1000 ℃, and the calcining time is 4-6 h.

More preferably, the rotation speed of the ball mill is 300-400 r/min, and the time is 10-12 h.

More preferably, the ball milling is performed by a wet ball milling method, absolute ethyl alcohol is used as a medium, zirconium oxide is used as a milling ball, and the mass ratio of the absolute ethyl alcohol to the zirconium ball to the powder is 1 (1-3): 1.

It is a further object of the present invention to provide the use of said ceramic material as a dielectric in a capacitor.

Preferably, the ceramic capacitor comprises an electrode layer and a dielectric layer, and both outermost sides are the electrode layers; the dielectric layer is composed of the ceramic material.

Preferably, the material of the electrode layer is gold.

Sr_0.7Bi_0.2TiO₃The material is a strong dielectric material, has high saturation polarization, and can show strong relaxation behavior and excellent phase transition temperature. The invention utilizes Sr_0.7Bi_0.2TiO₃For Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃The ferroelectric ceramic is modified to be converted into relaxation type ferroelectric ceramic, the breakdown field strength is improved to the maximum extent while high dielectric and low loss are maintained, and the residual polarization is reduced, so that the energy storage density and the energy storage efficiency are improved.

Compared with the prior art, the invention has the following beneficial effects:

1) the ceramic material provided by the invention has the advantages of simple preparation process, good stability and high density, can meet the requirements of different applications, and is suitable for industrial production.

2) By Sr_0.7Bi_0.2TiO₃For Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Can be modified properly and simultaneouslyHigh energy storage density and high energy storage efficiency are achieved, wherein the high energy storage efficiency can effectively prevent stored energy from being released in a thermal form, and the service life of the material is prolonged.

3) The ceramic material is obtained through chemical formula control and step-by-step sintering temperature control, the average grain size is about 2.0-3.0 mu m, and the energy storage density (W)_reco) Is 1.81J/cm³～4.02J/cm³The energy storage efficiency (eta) is 92.82-94.74%, and the ceramic material has high breakdown strength, can widen the bias range in the use process and shows great application potential. In addition, the Curie temperature of the ceramic material is in the range of-60 to-7 ℃, so that the dielectric property mutation caused by ferroelectric paraelectric phase change can be effectively avoided, and the material has better dielectric temperature stability.

Drawings

Fig. 1 shows an XRD pattern of the ceramic material obtained by the preparation of example 1 of the present invention.

Fig. 2 shows an XRD pattern of the ceramic material obtained by the preparation of example 2 of the present invention.

Fig. 3 shows XRD patterns of the ceramic material obtained by the preparation of example 3 of the present invention.

Fig. 4 shows XRD patterns of the ceramic material obtained by the preparation of example 4 of the present invention.

Fig. 5 shows XRD patterns of ceramic materials obtained by comparative example preparation of the present invention.

FIG. 6 is an SEM image of a ceramic material prepared in example 1 of the present invention.

FIG. 7 is a SEM image of a ceramic material prepared in example 2 of the present invention.

FIG. 8 is a SEM image of a ceramic material prepared in example 3 of the present invention.

FIG. 9 is a SEM image of a ceramic material prepared in example 4 of the present invention.

Fig. 10 shows an SEM image of a ceramic material prepared by a comparative example of the present invention.

FIG. 11 is a graph showing the hysteresis loop at a test frequency of 10Hz for the ceramic material prepared in example 1 of the present invention.

FIG. 12 is a graph showing the hysteresis loop at a test frequency of 10Hz for the ceramic material prepared in example 2 of the present invention.

FIG. 13 is a graph showing the hysteresis loop at a test frequency of 10Hz for the ceramic material prepared in example 3 of the present invention.

FIG. 14 is a graph showing the hysteresis loop at a test frequency of 10Hz for the ceramic material prepared in example 4 of the present invention.

FIG. 15 is a graph showing the hysteresis loop at a test frequency of 10Hz of a ceramic material prepared according to a comparative example of the present invention.

FIG. 16 shows the dielectric temperature spectrum of the ceramic material prepared in example 1 of the present invention at a test frequency of 10 kHz.

FIG. 17 shows the dielectric temperature spectrum of the ceramic material prepared in example 2 of the present invention at a test frequency of 10 kHz.

FIG. 18 shows the dielectric temperature spectrum of the ceramic material prepared in example 3 of the present invention at a test frequency of 10 kHz.

FIG. 19 shows the dielectric temperature spectrum of the ceramic material prepared in example 4 of the present invention at a test frequency of 10 kHz.

FIG. 20 shows the dielectric temperature spectrum of the ceramic material prepared by the comparative example of the present invention at the test frequency of 10 kHz.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure of the present specification.

Before the present embodiments are further described, it is to be understood that the scope of the invention is not limited to the particular embodiments described below; it is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the respective manufacturers.

When numerical ranges are given in the examples, it is understood that both endpoints of each of the numerical ranges and any value therebetween can be selected unless the invention otherwise indicated. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, and materials used in the examples, any methods, devices, and materials similar or equivalent to those described in the examples may be used in the practice of the invention in addition to the specific methods, devices, and materials used in the examples, in keeping with the knowledge of one skilled in the art and with the description of the invention.

The invention relates to a ceramic material, which has the following general formula:

(1-X)(Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃)X(Sr_0.7Bi_0.2TiO₃) Wherein X is more than or equal to 0.1 and less than or equal to 0.4.

Preferably, X is 0.2 ≦ X ≦ 0.4.

The average size of crystal grains in the ceramic material is 2.0-3.0 mu m; the Curie temperature is-60 to-7 ℃; the energy storage density is 1.81J/cm³～4.02J/cm³(ii) a The energy storage efficiency is 92.82% -94.74%.

The preparation method of the ceramic material comprises the following steps:

(1) according to the chemical formula Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Weighing stoichiometric analytically pure BaCO₃、CaCO₃、ZrO₂And TiO₂Proportioning, ball milling at 300-400 r/min for 10-12 hr, mixing, calcining at 1100-1200 deg.C for 4-6 hr to obtain Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Powder of Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃The residue of the powder passing through a 120-mesh sieve is less than or equal to 5 percent. The ball milling adopts wet ball milling, absolute ethyl alcohol is used as a medium, zirconium oxide is used as a milling ball, and the mass ratio of the absolute ethyl alcohol to the zirconium ball to the powder is 2 (1-1.5) to 1.

(2) According to the chemical formula Sr_0.7Bi_0.2TiO₃Weighing stoichiometric analytically pure SrCO₃、Bi₂O₃And TiO₂Burdening, ball milling for 10-12 h at the rotating speed of 300-400 r/min, mixing, calcining for 4-6 h at 900-1000 ℃ to obtain Sr_0.7Bi_0.2TiO₃Powder of Sr_0.7Bi_0.2TiO₃The residue of the powder passing through a 120-mesh sieve is less than or equal to 5 percent. The ball milling adopts wet ball milling, absolute ethyl alcohol is used as a medium, zirconium oxide is used as a milling ball, and the mass ratio of the absolute ethyl alcohol to the zirconium ball to the powder is 1 (1-3) to 1.

(3) The powder in the steps (1) and (2) is (1-x) (Ba) according to the chemical formula_0.85Ca_0.15Zr_0.1Ti_0.9O₃)x(Sr_0.7Bi_0.2TiO₃) Mixing the ingredients, ball-milling at a rotation speed of 300-400 r/min for 10-12 h, drying at 80-120 ℃, and sieving with a 120-mesh sieve to obtain a sieve residue of less than or equal to 5%. The ball milling adopts wet ball milling, absolute ethyl alcohol is used as a medium, zirconium oxide is used as a milling ball, and the mass ratio of the absolute ethyl alcohol to the zirconium ball to the powder is 1 (1-3) to 1.

(4) Adding a binder into the product obtained in the step (3) for granulation, preferably, the binder is PVA, and performing wet granulation, specifically: mix Ba with_0.85Ca_0.15Zr_0.1Ti_0.9O₃Powder and Sr_0.7Bi_0.2TiO₃Mixing and molding the powder and a PVA aqueous solution, wherein the concentration of the PVA aqueous solution is 5 wt% -8 wt%, and the mass of the PVA aqueous solution is Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Powder and Sr_0.7Bi_0.2TiO₃8 to 15 percent of the total mass of the powder. After granulation, ageing for 24-48 h, then maintaining the pressure for 30-60 s under the pressure of 6-15 MPa, pressing into wafers, and then treating for 4-6 h to discharge glue at the temperature of 500-600 ℃.

(5) And (4) sintering the product subjected to the rubber removal in the step (4) at 1250-1450 ℃ for 2-3 h to obtain the ceramic material.

(6) Processing the sintered ceramic material into a sheet with two smooth surfaces and a thickness of about 0.05-0.20 mm, plating gold on an electrode, testing the ferroelectric property at the frequency of 10Hz at room temperature, calculating the energy storage characteristic,energy storage Density (W)₁) And energy loss density (W)₂) The calculation formula of (2) is as follows:

wherein W₁And W₂Respectively representing the energy storage density and energy loss density, P_maxDenotes the maximum polarization, P_rIndicates remanent polarization, E indicates electric field intensity, and P indicates polarization.

In the embodiment of the application, wet ball milling is adopted, absolute ethyl alcohol is used as a medium, zirconium oxide is used as grinding balls, and the mass ratio of the absolute ethyl alcohol to the zirconium balls to the materials is 1:2: 1.

Example 1

In this example, the chemical formula of the ceramic material is shown as follows: 0.9 (Ba)_0.85Ca_0.15Zr_0.1Ti_0.9O₃)0.1(Sr_0.7Bi_0.2TiO₃) The preparation method comprises the following steps:

(1) according to the chemical formula Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Weighing stoichiometric BaCO₃、CaCO₃、ZrO₂And TiO₂Proportioning, ball-milling at 300r/min for 10h, mixing, calcining at 1100 deg.C for 4h, pulverizing, and sieving with 120 mesh sieve to obtain Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃And (3) powder.

(2) According to the chemical formula Sr_0.7Bi_0.2TiO₃Weighing stoichiometric SrCO₃、Bi₂O₃And TiO₂Proportioning, ball-milling at 350r/min for 12h, mixing, calcining at 900 deg.C for 4h, pulverizing, and sieving with 120 mesh sieve to obtain Sr_0.7Bi_0.2TiO₃And (3) powder.

(3) Will step withThe powders of steps (1) and (2) are represented by the chemical formula 0.9 (Ba)_0.85Ca_0.15Zr_0.1Ti_0.9O₃)0.1(Sr_0.7Bi_0.2TiO₃) Burdening to obtain a mixture, then ball-milling for 11h at the rotating speed of 400r/min, and drying at 100 ℃.

(4) Adding a PVA aqueous solution with the concentration of 8 wt% into the mixture obtained in the step (3) and granulating, wherein the mass of the added PVA aqueous solution is 15% of the mass of the mixture, ageing for 24h, maintaining the pressure for 30s under the pressure of 6MPa, pressing into a wafer, and then treating for 6h in a sintering furnace at 560 ℃ to discharge glue.

(5) And (4) sintering the product subjected to the rubber removal in the step (4) at 1450 ℃ for 2h to obtain the ceramic material.

(6) And (3) simply polishing the two sides of the ceramic material sintered in the step (5) until the thickness is about 0.1mm, then plating gold electrode (300 ℃, 30min) on the ceramic material, testing the ferroelectric property of the ceramic material at the frequency of 10Hz at room temperature, and calculating the energy storage characteristic.

Fig. 1 is an XRD pattern of the ceramic material prepared in this example 1, and it can be seen that the obtained ceramic material has a pure perovskite structure.

Fig. 6 is an SEM image of the ceramic material prepared in example 1, which shows that the obtained ceramic material has a dense structure and relatively uniform grain size, and the average grain size is 2 to 3 μm.

FIG. 11 is a hysteresis loop diagram of the ceramic material prepared in this example 1 at a test frequency of 10Hz, and it can be seen from the hysteresis loop diagram that the obtained ceramic material at the test frequency of 10Hz has a relatively long hysteresis loop, a small loop area, and a breakdown strength of 304kV/cm, and can be calculated from the energy storage characteristics, and the energy storage density of the ceramic material in this example is 1.81J/cm³The energy storage efficiency was 92.82%.

FIG. 16 is a graph of the dielectric temperature spectrum at 10kHz for the ceramic material prepared in this example 1, showing that the ceramic in this example 1 has a Curie temperature of about-7 ℃.

The performance index of the ceramic material obtained in example 1 is shown in table 1.

Example 2

In this example, the chemical formula of the ceramic material is shown as follows: 0.8 (Ba)_0.85Ca_0.15Zr_0.1Ti_0.9O₃)0.2(Sr_0.7Bi_0.2TiO₃) The preparation method comprises the following steps:

(1) according to the chemical formula Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Weighing stoichiometric BaCO₃、CaCO₃、ZrO₂And TiO₂Proportioning, ball-milling at 320r/min for 11h, mixing, calcining at 1100 deg.C for 5h, pulverizing, and sieving with 120 mesh sieve to obtain Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃And (3) powder.

(2) According to the chemical formula Sr_0.7Bi_0.2TiO₃Weighing stoichiometric SrCO₃、Bi₂O₃And TiO₂Proportioning, ball-milling at 320r/min for 11h, mixing, calcining at 960 deg.C for 5h, pulverizing, and sieving with 120 mesh sieve to obtain Sr_0.7Bi_0.2TiO₃And (3) powder.

(3) The powder obtained in the steps (1) and (2) is prepared according to the chemical formula of 0.8 (Ba)_0.85Ca_0.15Zr_0.1Ti_0.9O₃)0.2(Sr_0.7Bi_0.2TiO₃) Burdening to obtain a mixture, then ball-milling for 12 hours at the rotating speed of 320r/min, and drying at 100 ℃.

(4) And (3) adding a PVA aqueous solution with the concentration of 5 wt% into the mixture obtained in the step (3) and granulating, wherein the mass of the added PVA aqueous solution is 15% of the mass of the mixture, ageing for 24h, maintaining the pressure for 40s under the pressure of 10MPa, pressing into a wafer, and then treating for 6h in a sintering furnace at 500 ℃ to discharge glue.

(5) And (4) sintering the product subjected to the glue discharging in the step (4) at 1250 ℃ for 2h to obtain the ceramic material.

(6) And (3) simply polishing the two sides of the ceramic material sintered in the step (5) until the thickness is about 0.1mm, then plating gold electrodes (300 ℃ and 30min), then testing the ferroelectric property at the frequency of 10Hz at room temperature, and calculating the energy storage characteristic.

Fig. 2 is an XRD pattern of the ceramic material prepared in this example 2, and it can be seen that the obtained ceramic material has a pure perovskite structure.

Fig. 7 is an SEM image of the ceramic material prepared in example 2, which shows that the obtained ceramic material has a dense structure and relatively uniform grain size, and the average grain size is about 2 to 3 μm.

FIG. 12 is a hysteresis loop diagram of the ceramic material prepared in this example 2 at a test frequency of 10Hz, and it can be seen from the hysteresis loop diagram that the obtained ceramic material at the test frequency of 10Hz has a relatively long and thin hysteresis loop, a small loop area, and a breakdown strength of 422kV/cm, and can be calculated from the energy storage characteristics, and the energy storage density of the ceramic material in this example is 3.06J/cm³The energy storage efficiency was 94.74%.

FIG. 17 is a graph of the dielectric temperature spectrum of the ceramic material prepared in this example 2 at 10kHz, showing that the ceramic material in this example 2 has a Curie peak at about-40 ℃.

The performance index of the ceramic material obtained in example 2 is shown in table 1.

Example 3

In this example, the chemical formula of the ceramic material is shown as follows: 0.7 (Ba)_0.85Ca_0.15Zr_0.1Ti_0.9O₃)0.3(Sr_0.7Bi_0.2TiO₃) The preparation method comprises the following steps:

(1) according to the chemical formula Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Weighing stoichiometric BaCO₃、CaCO₃、ZrO₂And TiO₂Proportioning, ball-milling at 350r/min for 12h, mixing, calcining at 1200 deg.C for 6h, pulverizing, and sieving with 120 mesh sieve to obtain Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃And (3) powder.

(2) According to the chemical formula Sr_0.7Bi_0.2TiO₃Weighing stoichiometric SrCO₃、Bi₂O₃And TiO₂Proportioning, ball-milling at 350r/min for 10h, mixing, calcining at 900 deg.C for 4h, pulverizing, sieving with 120 mesh sieve,to obtain Sr_0.7Bi_0.2TiO₃And (3) powder.

(3) The powder obtained in the steps (1) and (2) is prepared according to the chemical formula of 0.7 (Ba)_0.85Ca_0.15Zr_0.1Ti_0.9O₃)0.3(Sr_0.7Bi_0.2TiO₃) Burdening to obtain a mixture, then ball-milling for 10 hours at the rotating speed of 350r/min, and drying at 80 ℃.

(4) Adding a PVA aqueous solution with the concentration of 6 wt% into the mixture obtained in the step (3) and granulating, wherein the mass of the added PVA aqueous solution is 12% of the mass of the mixture, ageing for 26h, maintaining the pressure for 50s under the pressure of 10MPa, pressing into a wafer, and then processing for 6h in a sintering furnace at 600 ℃ for glue discharging.

(5) And (4) sintering the product subjected to the glue discharging in the step (4) at 1275 ℃ for 3 hours to obtain the ceramic material.

(6) And (3) simply polishing the two sides of the ceramic material sintered in the step (5) until the thickness is about 0.1mm, then plating gold electrodes (300 ℃ and 30min), then testing the ferroelectric property at the frequency of 10Hz at room temperature, and calculating the energy storage characteristic.

Fig. 3 is an XRD pattern of the ceramic material prepared in this example 3, and it can be seen that the obtained ceramic material has a pure perovskite structure.

Fig. 8 is an SEM image of the ceramic material prepared in example 3, which shows that the obtained ceramic material has a dense structure and relatively uniform grain size, and the average grain size is about 2 to 3 μm.

FIG. 13 is a hysteresis loop diagram of the ceramic material prepared in this example 3 at a test frequency of 10Hz, and it can be seen from the graph that the obtained ceramic material has a relatively long hysteresis loop at the test frequency of 10Hz, a small loop area, a breakdown strength of 480kV/cm, and a calculated energy storage property, and the ceramic material of this example has an energy storage density of 4.02J/cm³The energy storage efficiency was 93.49%.

FIG. 18 is a graph of the dielectric temperature spectrum of the ceramic material prepared in this example 3 at 10kHz, showing that the ceramic material of this example has a Curie peak at about-50 ℃.

The performance index of the ceramic material obtained in this example 3 is shown in table 1.

Example 4

In this example, the chemical formula of the ceramic material is shown as follows: : 0.6 (Ba)_0.85Ca_0.15Zr_0.1Ti_0.9O₃)0.4(Sr_0.7Bi_0.2TiO₃) The preparation method comprises the following steps:

(1) according to the chemical formula Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Weighing stoichiometric BaCO₃、CaCO₃、ZrO₂And TiO₂Proportioning, ball-milling at 400r/min for 12h, mixing, calcining at 1050 deg.C for 5h, pulverizing, and sieving with 120 mesh sieve to obtain Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃And (3) powder.

(2) According to the chemical formula Sr_0.7Bi_0.2TiO₃Weighing stoichiometric SrCO₃、Bi₂O₃And TiO₂Proportioning, ball-milling at 400r/min for 10h, mixing, calcining at 1000 deg.C for 6h, pulverizing, and sieving with 120 mesh sieve to obtain Sr_0.7Bi_0.2TiO₃And (3) powder.

(3) The powder obtained in the steps (1) and (2) is prepared according to the chemical formula of 0.6 (Ba)_0.85Ca_0.15Zr_0.1Ti_0.9O₃)0.4(Sr_0.7Bi_0.2TiO₃) Burdening to obtain a mixture, then ball-milling for 12 hours at the rotating speed of 400r/min, and drying at 100 ℃.

(4) Adding a PVA aqueous solution with the concentration of 7 wt% into the mixture obtained in the step (3) and granulating, wherein the mass of the added PVA aqueous solution is 10% of the mass of the mixture, ageing for 30h, maintaining the pressure for 60s under the pressure of 10MPa, pressing into a wafer, and then processing for 4h in a sintering furnace at 500 ℃ to discharge glue.

(5) And (4) sintering the product subjected to the glue discharging in the step (4) at 1300 ℃ for 3h to obtain the ceramic material.

(6) And (3) simply polishing the two sides of the ceramic material sintered in the step (5) until the thickness is about 0.1mm, then plating gold electrodes (300 ℃ and 30min), then testing the ferroelectric property at the frequency of 10Hz at room temperature, and calculating the energy storage characteristic.

Fig. 4 is an XRD pattern of the ceramic material prepared in this example 4, and it can be seen that the obtained ceramic material has a pure perovskite structure.

FIG. 9 is an SEM image of the ceramic material prepared in this example 4, which shows that the obtained ceramic material has a compact structure and relatively uniform grain size, and the average grain size is about 2-3 μm.

FIG. 14 is a hysteresis loop diagram of the ceramic material prepared in this example 4 at a test frequency of 10Hz, and it can be seen from the graph that the obtained ceramic material has a relatively long hysteresis loop at the test frequency of 10Hz, a loop area is small, a breakdown strength is 388kV/cm, and the energy storage density of the ceramic material in this example is 3.12J/cm as calculated from the energy storage characteristics³The energy storage efficiency was 93.98%.

FIG. 19 is a graph of the dielectric temperature spectrum of the ceramic material prepared in this example 4 at 10kHz, showing that the ceramic material of this example has a Curie peak at about-60 ℃.

The performance index of the ceramic material obtained in example 4 is shown in table 1.

Comparative example

In this comparative example, the barium calcium zirconate titanate-based ceramic was not modified and was represented by the formula: : ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃The preparation method comprises the following steps:

(1) according to the chemical formula Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃Weighing stoichiometric BaCO₃、CaCO₃、ZrO₂And TiO₂Proportioning, ball-milling at 400r/min for 10h, mixing, sintering at 1200 deg.C for 6h, pulverizing, and sieving with 120 mesh sieve to obtain Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃And (3) powder.

(2) Adding a PVA aqueous solution with the concentration of 8 wt% into the mixture obtained in the step (1) and granulating, wherein the mass of the added PVA aqueous solution is Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃15 percent of the powder mass, aging for 30h, pressing into a wafer by unidirectional pressurization under the pressure of 10Mpa for 45s, and then processing for 6h in a sintering furnace at 560 ℃ for glue removal.

(3) And (3) sintering the product subjected to the glue discharge in the step (2) at 1450 ℃ for 2h to obtain the barium calcium zirconate titanate-based energy storage ceramic.

(4) And (4) simply polishing the two sides of the ceramic sintered in the step (3) to the thickness of about 0.1mm, and then plating gold on the electrodes (300 ℃ for 30 min). The prepared barium calcium zirconate titanate-based energy storage ceramic electrode is tested for ferroelectric performance at the frequency of 10Hz at room temperature, and energy storage characteristic calculation is carried out.

Fig. 5 is an XRD pattern of the barium calcium zirconate titanate-based ceramic prepared in the comparative example, and it can be seen that the obtained ceramic has a pure perovskite structure.

FIG. 10 is an SEM image of a barium calcium zirconate titanate-based ceramic prepared by a comparative example, and it can be seen that the obtained ceramic has a compact structure and relatively uniform grain size, and the average grain size is about 7-9 μm.

FIG. 15 is a hysteresis loop diagram of a barium calcium zirconate titanate-based ceramic prepared by a comparative example at a test frequency of 10Hz, and it can be seen from the diagram that the obtained ceramic material has a relatively long hysteresis loop at the test frequency of 10Hz, a small loop area, a breakdown strength of 190kV/cm, and is obtained by calculation of energy storage characteristics, and the energy storage density of the ceramic material of the comparative example is 0.51J/cm³The energy storage efficiency was 86.44%.

FIG. 20 is a dielectric temperature spectrum at 10kHz of the barium calcium zirconate titanate-based ceramic prepared by the comparative example, and the result shows that the Curie peak of the ceramic material in the comparative example is about 100 ℃.

The performance index of the ceramic material obtained in this comparative example is shown in table 1.

TABLE 1 energy storage characteristics of the ceramic materials of the examples and comparative examples

As can be seen from Table 1, Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃The ceramic material prepared from the powder has relatively low energy storage density. (1-x) (Ba) obtained by the present invention_0.85Ca_0.15Zr_0.1Ti_0.9O₃)x(Sr_0.7Bi_0.2TiO₃) Ceramic material, with modifier Sr_0.7Bi_0.2TiO₃The content is continuously increased, the breakdown strength of the ceramic material obtained by the method is continuously increased, the residual polarization strength is continuously reduced, the maximum polarization strength is continuously increased, and high energy storage density and energy storage efficiency can be obtained under a certain proportion. The energy storage density of the ceramic material is 1.81-4.02J/cm³And the energy storage efficiency is 92.82-94.74%. In addition, the Curie temperature of the ceramic material is adjustable within the range of-60 ℃ to-7 ℃, so that the dielectric property mutation caused by ferroelectric paraelectric phase change can be effectively avoided, and the ceramic has better dielectric temperature stability.

In practical applications, as an energy storage ceramic dielectric material, not only a high energy storage density but also a high energy storage efficiency should be achieved. Since if the energy storage efficiency is too low, most of the stored energy will be released as heat during the energy release process, the released heat will reduce the life and other properties of the material. Meanwhile, the energy storage ceramic dielectric material has higher breakdown strength, and can widen the bias voltage range in the use process.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.