阅读说明：本技术 一种高能量低损耗的BNT-SBT-xSMN陶瓷材料及其制备方法 (High-energy low-loss BNT-SBT-xSMN ceramic material and preparation method thereof ) 是由 夏卫民 赵梦洁 刘亿铭 曹从军 梁艳楠 于 2021-08-27 设计创作，主要内容包括：本发明提供一种高能量低损耗的BNT-SBT-xSMN陶瓷材料及其制备方法,化学式为：0.35(Sr-(0.7)+Bi-(0.2))TiO-(3)-0.65(Bi-(0.5)Na-(0.5))TiO-(3)-xSr(Mg-(1/3)Nb-(2/3))O-(3),其中0<x≤0.1。通过掺杂的方法,在0.35(Sr-(0.7)+Bi-(0.2))TiO-(3)-0.65(Bi-(0.5)Na-(0.5))TiO-(3)基陶瓷中引入第三组元Sr(Mg-(1/3)Nb-(2/3))O-(3),使得B位引入Mg～(2+)、Nb～(5+),形成无铅三元系统陶瓷,从而改善原有钙钛矿陶瓷的微观特征,很好地改善储能特性,在BNT-SBT基陶瓷的基础上提升了储能效率,有望实现更广泛的电子器件应用。(The invention provides a high-energy low-loss BNT-SBT-xSMN ceramic material and a preparation method thereof, wherein the chemical formula is as follows: 0.35 (Sr) 0.7 +Bi 0.2 )TiO 3 ‑0.65(Bi 0.5 Na 0.5 )TiO 3 ‑xSr(Mg 1/3 Nb 2/3 )O 3 Wherein 0 is<x is less than or equal to 0.1. By doping method, at 0.35 (Sr) 0.7 +Bi 0.2 )TiO 3 ‑0.65(Bi 0.5 Na 0.5 )TiO 3 The third component Sr (Mg) is introduced into the base ceramic 1/3 Nb 2/3 )O 3 So that the B site introduces Mg 2+ 、Nb 5+ The lead-free ternary system ceramic is formed, so that the microscopic characteristics of the original perovskite ceramic are improved, the energy storage characteristic is well improved, the energy storage efficiency is improved on the basis of the BNT-SBT-based ceramic, and the lead-free ternary system ceramic is expected to realize wider application of electronic devices.)

1. A high-energy low-loss BNT-SBT-xSMN ceramic material is characterized by having the chemical formula as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein 0 is<x≤0.1。

2. The method for preparing the high energy, low loss BNT-SBT-xSMN ceramic material according to claim 1, comprising:

(1) according to 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Taking raw material Bi according to the stoichiometric ratio shown in the chemical formula₂O₃、Na₂CO₃、TiO₂、SrCO₃MgO and Nb₂O₅Mixing the raw materials, performing wet ball milling, and drying to obtain mixed powder;

(2) grinding the mixed powder, heating to 800-900 ℃, and presintering at 800-900 ℃ for 2-4 h to obtain ceramic powder;

(3) carrying out wet ball milling on the ceramic powder to obtain mixed slurry;

(4) drying the mixed slurry, adding an adhesive, grinding, and granulating to obtain a ceramic precursor;

(5) pressing the ceramic precursor into a sheet, and then carrying out glue discharging treatment to obtain a sample;

(6) sintering the sample obtained by the glue discharging treatment in the step 5 at 1050-1150 ℃ for 2-4 h to obtain a ceramic sample;

(7) and (3) carrying out silver firing treatment on the ceramic sample to obtain the high-energy low-loss BNT-SBT-xSMN ceramic material.

3. The method for preparing the BNT-SBT-xSMN ceramic material with high energy and low loss as claimed in claim 2, wherein in the step (1) and the step (3), the ball milling medium used in the wet ball milling is absolute ethyl alcohol.

4. The method for preparing the BNT-SBT-xSMN ceramic material with high energy and low loss as claimed in claim 2, wherein the wet ball milling time in step (1) is 11-13 h.

5. The method for preparing BNT-SBT-xSMN ceramic material with high energy and low loss as claimed in claim 2, wherein in step (2), the temperature rise rate is controlled to 3 ℃ min^-1。

6. The method for preparing the BNT-SBT-xSMN ceramic material with high energy and low loss as claimed in claim 2, wherein in the step (3), the wet ball milling time is 3-5 h.

7. The method for preparing a high-energy low-loss BNT-SBT-xSMN ceramic material according to claim 2, wherein in step (4), the binder is PVA.

8. The method for preparing a BNT-SBT-xSMN ceramic material with high energy and low loss as claimed in claim 2, wherein in the step (6), after sintering, the front and back surfaces of the ceramic sample are polished by sand paper using deionized water as a medium and then polished by water polishing using a polishing machine to obtain the ceramic sample.

9. The method for preparing the BNT-SBT-xSMN ceramic material with high energy and low loss as claimed in claim 2, wherein the silver firing treatment comprises: and brushing silver on the ceramic sample, and then drying to obtain the high-energy low-loss BNT-SBT-xSMN ceramic material.

Technical Field

The invention relates to a ceramic material, in particular to 0.35 (Sr) with high energy and low loss_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃(BNT-SBT-xSMN) ceramic material and a preparation method thereof.

Background

Ceramics have excellent energy density properties and efficiency as popular materials studied in recent years. Although perovskite-structured ceramics such as PZT, PZLT and PLZST, which have high saturation polarization, have excellent piezoelectric, dielectric and ferroelectric properties recently and are widely used in transducers, energy storage devices and oscillators, lead-based ceramics mainly contain lead oxide (with a content of 60-70%), which causes serious damage to human beings and ecological environments. Thus, some environmentally friendly ceramics, especially Bi-based ABO₃Perovskite materials with structures attract attention in the field of electronic device research, and research and development of the perovskite materials are also subjects with important scientific significance and urgent market demands. In these lead-free Bi-based ABOs₃In the ceramic, Bi_0.5Na_0.5TiO₃The (BNT) group has been reported to be one of the most promising candidates for high energy density applications.

BNT has excellent Curie temperature (320 ℃), residual polarization (32. mu.C. cm)^-2) And coercive field (-73 kV · cm)^-1) However, it is difficult to directly burn a compact sample, so that it has certain defects in practical application, such as: high conductivity, difficult polarization, low breakdown field strength, etc., which results in poor energy storage performance. Researchers often improve the deficiency by doping other elements to form A, B ion substitution, and the like, and hope to obtain higher energy storage density and performance. At present, although researchers form BNT-SBT ceramics by doping to obtain good energy storage characteristics, the energy storage efficiency has great progress space.

Disclosure of Invention

In view of the above-mentioned deficiencies in the prior art, the present invention aims to provide a high-energy low-loss BNT-SBT-xSMN ceramic material and a preparation method thereof. SMN with different components is doped in the BNT-SBT-based ceramic, so that the properties of the BNT-SBT-based ceramic such as microstructure and the like are improved, and good energy storage efficiency and density are obtained.

A high-energy low-loss BNT-SBT-xSMN ceramic material has a chemical formula as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein 0 is<x≤0.1。

The preparation method of the high-energy low-loss BNT-SBT-xSMN ceramic material comprises the following steps:

(1) according to 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Taking raw material Bi according to the stoichiometric ratio shown in the chemical formula₂O₃、Na₂CO₃、TiO₂、SrCO₃MgO and Nb₂O₅Mixing the raw materials, performing wet ball milling, and drying to obtain mixed powder;

(2) grinding the mixed powder, heating to 800-900 ℃, and presintering at 800-900 ℃ for 2-4 h to obtain ceramic powder;

(3) carrying out wet ball milling on the ceramic powder to obtain mixed slurry;

(4) drying the mixed slurry, adding an adhesive, grinding, and granulating to obtain a ceramic precursor;

(5) pressing the ceramic precursor into a sheet, and then carrying out glue discharging treatment to obtain a sample;

(6) sintering the sample obtained by the glue discharging treatment in the step 5 at 1050-1150 ℃ for 2-4 h to obtain a ceramic sample;

(7) and (3) carrying out silver firing treatment on the ceramic sample to obtain the high-energy low-loss BNT-SBT-xSMN ceramic material.

Preferably, in the step (1) and the step (3), the ball milling medium adopted by the wet ball milling is absolute ethyl alcohol.

Preferably, in the step (1), the wet ball milling time is 11-13 h.

Preferably, in the step (2), the temperature increase rate is controlled to 3 ℃ min^-1。

Preferably, in the step (3), the wet ball milling time is 3-5 h.

Preferably, in step (4), the binder is PVA.

Preferably, in the step (6), after sintering, the front and back surfaces of the ceramic sample are polished by using sand paper with deionized water as a medium, and then are polished by using a polishing machine to obtain the ceramic sample.

Preferably, the silver firing treatment specifically comprises: and brushing silver on the ceramic sample, and then drying to obtain the high-energy low-loss BNT-SBT-xSMN ceramic material.

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

material 0.35 (Sr) of the invention_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Introducing a third component Sr (Mg) into the BNT-SBT-based ceramic by a doping method_1/3Nb_2/3)O₃(SMN) so that Mg is introduced into the B site²⁺、Nb⁵⁺To form lead-free ternary system ceramic, thereby improving the microscopic characteristics of the original perovskite ceramic and reducing the degradation temperature (T) of the material_d) So that the antiferroelectric phase originally existing in the high-temperature section can be shown at room temperature. Since the grain size of the ceramic is related to the magnitude of the breakdown field intensity, which is closely related to the energy storage density and efficiency, the energy storage characteristics can be improved well by increasing the compactness of the grains. By controlling the SMN doping amount, the grain size of the ceramic is obviously changed, the grain size reaches the minimum when x is 0.01, and meanwhile, the energy storage efficiency reaches 80.70 percent, so that the defect of poor compactness of the original BNT-based ceramic is overcome, meanwhile, the energy storage efficiency is improved on the basis of the BNT-SBT-based ceramic, and the wider application of electronic devices is expected to be realized.

The preparation method is simple, high in yield, low in cost and easy to implement.

Drawings

FIG. 1 is provided in examples 1-8 of the present invention: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃XRD pattern of ceramic material;

FIG. 2 is provided in examples 1 to 8 of the present invention: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃A dielectric spectrum of the ceramic material;

FIG. 3 is provided in examples 1-8 of the present invention: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃A dielectric thermogram of a ceramic material;

FIG. 4 is provided in examples 1-8 of the present invention: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃SEM image of ceramic material;

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

The high-energy low-loss BNT-SBT-xSMN ceramic material has the chemical formula as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein 0 is<x≤0.1。

The preparation method of the high-energy low-loss BNT-SBT-xSMN ceramic material comprises the following steps:

(1) ingredients

According to 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Respectively weighing raw material Bi by chemical formula₂O₃、Na₂CO₃、TiO₂、SrCO₃、MgO、Nb₂O₅Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, performing ball milling for 11-13 h, and drying to obtain mixed powder.

(2) Pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortar, putting the ground mixed powder into a crucible for presintering for 2-4 h at 800-900 ℃, and controlling the heating rate to be 3 ℃ per minute^-1And obtaining the ceramic powder.

(3) Secondary ball milling

And (3) ball-milling the ceramic powder obtained in the step (2) on a planetary ball mill for 3-5 hours to obtain fine and uniform particles, so as to obtain mixed slurry. Wherein anhydrous ethanol is also used as a ball milling medium.

(4) Granulating

And (3) drying the mixed slurry obtained in the step (3), adding a PVA adhesive with the mass fraction of 1.5%, grinding, sieving with an 80-mesh sieve, and granulating to obtain powder.

(5) Tabletting and binder removal

And (4) pressing the powder obtained in the step (4) into tablets under the pressure of 60-80 MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain the sample.

(6) Sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is increased to 1050-1150 ℃ at the temperature increasing rate, and the ceramic sample is obtained after sintering for 2-4 hours. And grinding the front surface and the back surface of the sintered ceramic by using deionized water as a medium by using sand paper, and then performing water grinding and polishing by using a polishing machine.

(7) Silver firing

And (4) brushing silver on the sample subjected to the glue removing treatment in the step (6) twice, and drying in an oven at the temperature of 70-90 ℃ for 1-2 hours to obtain a final sample.

The purity of the raw materials adopted in the step 1 is more than 99.8 percent.

The sample prepared in step 4 has a thickness of 1.5mm and a diameter of 10 mm.

Comparative example 1

The chemical formula of the ceramic material of the embodiment is as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein x is 0. The preparation method comprises the following steps:

(1) ingredients

According to 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Respectively weighing raw material Bi according to the chemical formula of x ═ 0₂O₃、Na₂CO₃、TiO₂、SrCO₃Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, and drying the mixture after ball milling for 12 hours;

(2) pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortar, putting the ground mixed powder into a crucible, presintering the crucible for 3 hours at 850 ℃, and controlling the heating rate to be 3 ℃ for min^-1；

(3) Secondary ball milling

And (3) ball-milling the ceramic powder obtained in the step (2) for 4 hours on a planetary ball mill to obtain fine and uniform particles. Wherein, the absolute ethyl alcohol is also used as a ball milling medium;

(4) granulating

Drying the mixed slurry obtained in the step (3), adding 1.5% by mass of PVA (polyvinyl alcohol) adhesive, grinding, and sieving with an 80-mesh sieve for granulation;

(5) tabletting and binder removal

Pressing the powder obtained in the step (4) into tablets under the pressure of 50MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain a sample;

(6) sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is raised to 1120 ℃ at the temperature raising rate, and the ceramic sample is obtained after sintering for 3 hours. Grinding the front surface and the back surface of the sintered ceramic by using deionized water as a medium by using sand paper, and then performing water grinding and polishing by using a polishing machine;

(7) coating silver paste with high conductivity on two sides of the polished ceramic sample, and drying in an oven at 80 ℃ for 1h to prepare the silver electrode.

The ceramic material obtained was subjected to X-ray diffraction testing, as shown in fig. 1.

The ferroelectric property of the prepared ceramic material is tested at normal temperature and 1kHz frequency. The dielectric properties of the ceramic material of this example at room temperature are shown in Table 1; the dielectric constant and dielectric loss of the ceramic at room temperature are shown in a regular dielectric spectrogram of the ceramic along with the change of frequency in figure 2; the dielectric constant and dielectric loss of the ceramic are shown in the regular dielectric thermogram of the ceramic with the temperature change in figure 3.

And performing SEM test characterization on the prepared ceramic material to obtain the surface micro-morphology, as shown in figure 4.

The prepared ceramic material is subjected to energy storage characteristic calculation, and the electric field is 100kV cm^-1To obtain the energy storage density W_recEnergy loss density W_lossThe energy storage efficiency eta is shown in table 2.

Example 1

The chemical formula of the ceramic material of the embodiment is as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein x is 0.005.

The preparation method comprises the following steps:

(1) ingredients

According to 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃The raw material Bi is weighed according to the chemical formula of 0.005₂O₃、Na₂CO₃、TiO₂、SrCO₃、MgO、Nb₂O₅Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, and drying the mixture after ball milling for 12 hours;

(2) pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortar, putting the ground mixed powder into a crucible, presintering the crucible for 3 hours at 850 ℃, and controlling the heating rate to be 3 ℃ for min^-1；

(3) Secondary ball milling

And (3) ball-milling the ceramic powder obtained in the step (2) on a planetary ball mill for 3 hours to obtain fine and uniform particles. Wherein, the absolute ethyl alcohol is also used as a ball milling medium;

(4) granulating

Drying the mixed slurry obtained in the step (3), adding 1.5% by mass of PVA (polyvinyl alcohol) adhesive, grinding, and sieving with an 80-mesh sieve for granulation;

(5) tabletting and binder removal

Pressing the powder obtained in the step (4) into tablets under the pressure of 50MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain a sample;

(6) sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is raised to 1120 ℃ at the temperature raising rate, and the ceramic sample is obtained after sintering for 3 hours. Grinding the front surface and the back surface of the sintered ceramic by using deionized water as a medium by using sand paper, and then performing water grinding and polishing by using a polishing machine;

(7) coating silver paste with high conductivity on two sides of the polished ceramic sample, and drying in an oven at 80 ℃ for 1h to prepare the silver electrode. .

The XRD profile of the ceramic material of this example is shown in FIG. 1.

The dielectric properties of the ceramic materials of this example at room temperature are shown in Table 1; the dielectric constant at room temperature and the regular dielectric spectrogram of the dielectric loss along with the frequency change are shown in figure 2; the dielectric constant and dielectric loss are shown in the chart 3 along with the temperature change.

The SEM test of this example shows the surface microtopography as shown in FIG. 4.

Energy storage Density W of the ceramic Material of this example_recEnergy loss density W_lossThe energy storage efficiency eta is shown in table 2.

Example 2

The chemical formula of the ceramic material of the embodiment is as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein x is 0.01.

The preparation method comprises the following steps:

(1) ingredients

According to 0.35(Sr0.7+ Bi)_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃The raw material Bi is weighed according to the chemical formula of x being 0.01₂O₃、Na₂CO₃、TiO₂、SrCO₃、MgO、Nb₂O₅Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, and drying the mixture after ball milling for 12 hours;

(2) pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortarPre-burning the ground mixture in a crucible at 850 deg.c for 3 hr at a heating rate of 3 deg.c/min^-1；

(3) Secondary ball milling

And (3) ball-milling the ceramic powder obtained in the step (2) for 4 hours on a planetary ball mill to obtain fine and uniform particles. Wherein, the absolute ethyl alcohol is also used as a ball milling medium;

(4) granulating

Drying the mixed slurry obtained in the step (3), adding 1.5% by mass of PVA (polyvinyl alcohol) adhesive, grinding, and sieving with an 80-mesh sieve for granulation;

(5) tabletting and binder removal

Pressing the powder obtained in the step (4) into tablets under the pressure of 50MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain a sample;

(6) sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is increased to 1100 ℃ at the temperature rising rate, and the ceramic sample is obtained after sintering for 3 hours. Grinding the front surface and the back surface of the sintered ceramic by using deionized water as a medium by using sand paper, and then performing water grinding and polishing by using a polishing machine;

(7) coating silver paste with high conductivity on two sides of the polished ceramic sample, and drying in an oven at 80 ℃ for 1h to prepare the silver electrode.

The XRD curve of the ceramic material of the present example is shown in figure 1; SEM test characterization gave the surface microtopography as shown in FIG. 4.

The dielectric properties of the ceramic materials of this example at room temperature are shown in Table 1; the dielectric constant at room temperature and the regular dielectric spectrogram of the dielectric loss along with the frequency change are shown in figure 2; the dielectric constant and dielectric loss are shown in the chart 3 along with the temperature change.

Energy storage Density W of the ceramic Material of this example_recEnergy loss density W_lossThe energy storage efficiency eta is shown in table 2.

Example 3

The chemical formula of the ceramic material of the embodiment is as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein x is 0.015.

The preparation method comprises the following steps:

(1) ingredients

According to 0.35(Sr0.7+ Bi)_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃The raw material Bi is weighed according to the chemical formula of 0.015₂O₃、Na₂CO₃、TiO₂、SrCO₃、MgO、Nb₂O₅Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, and drying the mixture after ball milling for 12 hours;

(2) pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortar, putting the ground mixed powder into a crucible, presintering the crucible for 3 hours at 850 ℃, and controlling the heating rate to be 3 ℃ for min^-1；

(3) Secondary ball milling

And (3) ball-milling the ceramic powder obtained in the step (2) for 5 hours on a planetary ball mill to obtain fine and uniform particles. Wherein, the absolute ethyl alcohol is also used as a ball milling medium;

(4) granulating

Drying the mixed slurry obtained in the step (3), adding 1.5% by mass of PVA (polyvinyl alcohol) adhesive, grinding, and sieving with an 80-mesh sieve for granulation;

(5) tabletting and binder removal

Pressing the powder obtained in the step (4) into tablets under the pressure of 50MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain a sample;

(6) sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is increased to 1100 ℃ at the temperature rising rate, and the ceramic sample is obtained after sintering for 3 hours. Grinding the front surface and the back surface of the sintered ceramic by using deionized water as a medium by using sand paper, and then performing water grinding and polishing by using a polishing machine;

(7) coating silver paste with high conductivity on two sides of the polished ceramic sample, and drying in an oven at 80 ℃ for 1h to prepare the silver electrode.

The XRD profile of the ceramic material of this example is shown in FIG. 1.

The dielectric properties of the ceramic materials of this example at room temperature are shown in Table 1; the dielectric constant at room temperature and the regular dielectric spectrogram of the dielectric loss along with the frequency change are shown in figure 2; the dielectric constant and dielectric loss are shown in the chart 3 along with the temperature change.

The SEM test of this example shows the surface microtopography as shown in FIG. 4.

Energy storage Density W of the ceramic Material of this example_recEnergy loss density W_lossThe energy storage efficiency eta is shown in table 2.

Example 4

The chemical formula of the ceramic material of the embodiment is as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein x is 0.02.

The preparation method comprises the following steps:

(1) ingredients

According to 0.35(Sr0.7+ Bi)_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃The raw material Bi is weighed according to the chemical formula of x being 0.02₂O₃、Na₂CO₃、TiO₂、SrCO₃、MgO、Nb₂O₅Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, and drying the mixture after ball milling for 11 hours;

(2) pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortar, putting the ground mixed powder into a crucible, presintering the ground mixed powder for 2 hours at 800 ℃, and controlling the heating rate to be 3 ℃ for min^-1；

(3) Secondary ball milling

And (3) ball-milling the ceramic powder obtained in the step (2) on a planetary ball mill for 3 hours to obtain fine and uniform particles. Wherein, the absolute ethyl alcohol is also used as a ball milling medium;

(4) granulating

Drying the mixed slurry obtained in the step (3), adding 1.5% by mass of PVA (polyvinyl alcohol) adhesive, grinding, and sieving with an 80-mesh sieve for granulation;

(5) tabletting and binder removal

Pressing the powder obtained in the step (4) into tablets under the pressure of 50MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain a sample;

(6) sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is raised to 1050 ℃ at the temperature raising rate, and the ceramic sample is obtained after sintering for 2 hours. Grinding the front surface and the back surface of the sintered ceramic by using deionized water as a medium by using sand paper, and then performing water grinding and polishing by using a polishing machine;

(7) coating silver paste with high conductivity on two sides of the polished ceramic sample, and drying in an oven at 80 ℃ for 1h to prepare the silver electrode.

The XRD profile of the ceramic material of this example is shown in FIG. 1.

The dielectric properties of the ceramic materials of this example at room temperature are shown in Table 1; the dielectric constant at room temperature and the regular dielectric spectrogram of the dielectric loss along with the frequency change are shown in figure 2; the dielectric constant and dielectric loss are shown in the chart 3 along with the temperature change.

The SEM test of this example shows the surface microtopography as shown in FIG. 4.

Energy storage Density W of the ceramic Material of this example_recEnergy loss density W_lossThe energy storage efficiency eta is shown in table 2.

Example 5

The chemical formula of the ceramic material of the embodiment is as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein x is 0.04.

The preparation method comprises the following steps:

(1) ingredients

According to 0.35(Sr0.7+ Bi)_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃The raw material Bi is weighed according to the chemical formula of x being 0.04₂O₃、Na₂CO₃、TiO₂、SrCO₃、MgO、Nb₂O₅Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, and drying the mixture after ball milling for 11 hours;

(2) pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortar, putting the ground mixed powder into a crucible, presintering the ground mixed powder for 2 hours at 800 ℃, and controlling the heating rate to be 3 ℃ for min^-1；

(3) Secondary ball milling

And (3) ball-milling the ceramic powder obtained in the step (2) for 4 hours on a planetary ball mill to obtain fine and uniform particles. Wherein, the absolute ethyl alcohol is also used as a ball milling medium;

(4) granulating

Drying the mixed slurry obtained in the step (3), adding 1.5% by mass of PVA (polyvinyl alcohol) adhesive, grinding, and sieving with an 80-mesh sieve for granulation;

(5) tabletting and binder removal

Pressing the powder obtained in the step (4) into tablets under the pressure of 50MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain a sample;

(6) sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is raised to 1050 ℃ at the temperature raising rate, and the ceramic sample is obtained after sintering for 2 hours. Grinding the front surface and the back surface of the sintered ceramic by using deionized water as a medium by using sand paper, and then performing water grinding and polishing by using a polishing machine;

(7) coating silver paste with high conductivity on two sides of the polished ceramic sample, and drying in an oven at 80 ℃ for 1h to prepare the silver electrode.

The XRD profile of the ceramic material of this example is shown in FIG. 1.

The dielectric properties of the ceramic materials of this example at room temperature are shown in Table 1; the dielectric constant at room temperature and the regular dielectric spectrogram of the dielectric loss along with the frequency change are shown in figure 2; the dielectric constant and dielectric loss are shown in the chart 3 along with the temperature change.

The SEM test of this example shows the surface microtopography as shown in FIG. 4.

Energy storage Density W of the ceramic Material of this example_recEnergy loss density W_lossThe energy storage efficiency eta is shown in table 2.

Example 6

The chemical formula of the ceramic material of the embodiment is as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein x is 0.06.

The preparation method comprises the following steps:

(1) ingredients

According to 0.35(Sr0.7+ Bi)_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Respectively weighing raw material Bi according to the chemical formula of 0.06₂O₃、Na₂CO₃、TiO₂、SrCO₃、MgO、Nb₂O₅Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, and drying the mixture after ball milling for 13 hours;

(2) pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortar, putting the ground mixed powder into a crucible to presintered for 4 hours at 900 ℃, and controlling the heating rate to be 3 ℃ for min^-1；

(3) Secondary ball milling

And (3) putting the ceramic powder obtained in the step (2) on a planetary ball mill for 5 hours to obtain fine and uniform particles. Wherein, the absolute ethyl alcohol is also used as a ball milling medium;

(4) granulating

Drying the mixed slurry obtained in the step (3), adding 1.5% by mass of PVA (polyvinyl alcohol) adhesive, grinding, and sieving with an 80-mesh sieve for granulation;

(5) tabletting and binder removal

Pressing the powder obtained in the step (4) into tablets under the pressure of 50MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain a sample;

(6) sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is increased to 1150 ℃ at the temperature increasing rate, and the ceramic sample is obtained after sintering for 4 hours. Deionized water is added on the front and back surfaces of the sintered ceramicFirstly, grinding a medium by using sand paper and then performing water grinding and polishing by using a polishing machine;

(7) coating silver paste with high conductivity on two sides of the polished ceramic sample, and drying in an oven at 80 ℃ for 1h to prepare the silver electrode.

The XRD profile of the ceramic material of this example is shown in FIG. 1.

The dielectric properties of the ceramic materials of this example at room temperature are shown in Table 1; the dielectric constant at room temperature and the regular dielectric spectrogram of the dielectric loss along with the frequency change are shown in figure 2; the dielectric constant and dielectric loss are shown in the chart 3 along with the temperature change.

The SEM test of this example shows the surface microtopography as shown in FIG. 4.

Energy storage Density W of the ceramic Material of this example_recEnergy loss density W_lossThe energy storage efficiency eta is shown in table 2.

Example 7

The chemical formula of the ceramic material of the embodiment is as follows: 0.35 (Sr)_0.7+Bi_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃Wherein x is 0.1.

The preparation method comprises the following steps:

(1) ingredients

According to 0.35(Sr0.7+ Bi)_0.2)TiO₃-0.65(Bi_0.5Na_0.5)TiO₃-xSr(Mg_1/3Nb_2/3)O₃The raw material Bi is weighed according to the chemical formula of 0.005₂O₃、Na₂CO₃、TiO₂、SrCO₃、MgO、Nb₂O₅Mixing the raw materials, putting the mixture into a nylon tank, adding absolute ethyl alcohol as a ball milling medium, and drying the mixture after ball milling for 13 hours;

(2) pre-firing

Grinding the mixed powder obtained in the step 1 in an agate mortar, putting the ground mixed powder into a crucible to presintered for 4 hours at 900 ℃, and controlling the heating rate to be 3 ℃ for min^-1；

(3) Secondary ball milling

And (3) ball-milling the ceramic powder obtained in the step (2) for 4 hours on a planetary ball mill to obtain fine and uniform particles. Wherein, the absolute ethyl alcohol is also used as a ball milling medium;

(4) granulating

Drying the mixed slurry obtained in the step (3), adding 1.5% by mass of PVA (polyvinyl alcohol) adhesive, grinding, and sieving with an 80-mesh sieve for granulation;

(5) tabletting and binder removal

Pressing the powder obtained in the step (4) into tablets under the pressure of 50MPa to obtain ceramic material green body tablets, and then carrying out glue removal treatment to obtain a sample;

(6) sintering and polishing

The sample after the glue discharging treatment in the step 5 is processed at the temperature of 3 ℃ for min^-1The temperature is increased to 1150 ℃ at the temperature increasing rate, and the ceramic sample is obtained after sintering for 4 hours. Grinding the front surface and the back surface of the sintered ceramic by using deionized water as a medium by using sand paper, and then performing water grinding and polishing by using a polishing machine;

(7) coating silver paste with high conductivity on two sides of the polished ceramic sample, and drying in an oven at 80 ℃ for 1h to prepare the silver electrode.

The XRD profile of the ceramic material of this example is shown in FIG. 1.

The dielectric properties of the ceramic materials of this example at room temperature are shown in Table 1; the dielectric constant at room temperature and the regular dielectric spectrogram of the dielectric loss along with the frequency change are shown in figure 2; the dielectric constant and dielectric loss are shown in the chart 3 along with the temperature change.

The SEM test of this example shows the surface microtopography as shown in FIG. 4.

The ceramic material of this embodiment has an energy storage density W_recEnergy loss density W_lossThe energy storage efficiency eta is shown in table 2.

TABLE 1 dielectric characteristics of the ceramic materials of the examples

As can be seen from Table 1, as the SMN content increases, the dielectric constant and dielectric loss of the ceramic material of the present invention decrease, indicating that Mg doping is used²⁺、Nb⁵⁺A reduction in dielectric constant and dielectric loss results.

TABLE 2 energy storage Properties of the ceramic materials of the examples

As can be seen from Table 2, as the SMN content increases, W_lossThe eta is obviously improved from 77.90% to 94.80%, high energy storage density and energy storage efficiency can be obtained under a certain SMN doping amount, and when x is 0.01, the energy storage density can reach 1.32 J.min^-3The efficiency was 80.70%.

As can be seen from the XRD pattern of FIG. 1, the ceramic material obtained by the present invention has a pure perovskite structure, no other second phase exists, and three-way or four-way lattice distortion does not exist in the XRD result, which indicates that the doped Mg is²⁺、Nb⁵⁺Smoothly enter a main body crystal lattice to form a solid solution with the BNT-SBT ceramic.

As can be seen from the dielectric spectrum diagram of fig. 2, the dielectric constant is decreased with the increase of frequency, which shows the characteristics of the standard ferroelectric. Since there is a certain time difference between the polarization generated inside the sample and the external polarization during this process, the dielectric loss increases.

As can be seen from the dielectric thermogram of FIG. 3, T increases with the SMN content_mDecrease of T_sIncreasing the dielectric constant at room temperature decreases because doping can damage the ferroelectric lattice, deforming the local lattice.

As can be seen from the SEM image of fig. 4, the size of the crystal grains is somewhat changed by controlling the doping amount of SMN. When x is less than or equal to 0.01, the average grain size of the BNT-SBT-xSMN ceramic slightly decreases with increasing SMN concentration. When x is 0.01, the crystal grain is the smallest, about 0.6 μm, and since the storage of the crystal grain directly affects the magnitude of the breakdown strength, the smaller crystal grain size ensures the breakdown strength of the ceramic, thereby obtaining excellent energy storage characteristics. While as the concentration continues to increase, the grain size increases slightly due to the excess doping, resulting in grain distortion.