A dielectric ceramic material with high breakdown strength and high energy storage density and its preparation method

Abstract

The present invention discloses a preparation method of a dielectric ceramic material with high breakdown strength and high energy storage density. The specific steps are as follows: Weigh BaCO3 with a weight percentage of 40 - 50%, B2O3 with a weight percentage of 5 - 10%, SiO2 with a weight percentage of 33 - 38%, and ZnO with a weight percentage of 5 - 10%. Ball mill, dry, melt, and quench the weighed reagents, and then ball mill the quenched glass into glass powder. Mix the prepared Ba 0.3 Sr 0.7 TiO3 powder and the glass powder to obtain a mixed powder, add a PVA reagent, spray dry, and obtain a green body after pressing. Sinter the green body to obtain a dielectric ceramic material with high breakdown strength and high energy storage density. The present invention also discloses a dielectric ceramic material with high breakdown strength and high energy storage density. The present invention significantly reduces the melting temperature of the glass and the sintering temperature of the ceramic dielectric, and improves the breakdown performance and energy storage characteristics of the base dielectric ceramic.

Description

Technical Field

[0001] The present invention relates to the field of high-performance dielectric ceramic materials, and particularly to a high breakdown strength and high energy storage density dielectric ceramic material and a preparation method thereof. Background Art

[0002] Dielectric ceramic materials with high energy storage density need to have relatively high dielectric constant and dielectric breakdown strength at the same time. However, there is an obvious competitive relationship between these two physical quantities in dielectric materials, which poses difficulties and challenges for the research and application of dielectric materials. Ferroelectric ceramic phases usually have relatively high polarization intensity, but the breakdown strength value is very low, which greatly limits their application in the field of energy storage dielectrics. Glass, as an amorphous phase, has the characteristics of few defects and high density, so it has a relatively high dielectric breakdown strength (10 3 kV / cm).

[0003] Combining the glass phase with the ceramic phase can not only improve the dielectric breakdown strength but also reduce its sintering temperature, and finally obtain a ceramic dielectric material with relatively balanced properties. However, the most crucial thing for ceramic dielectric materials lies in the interaction between the glass phase and the ceramic phase interface, and the second crystal phase precipitated in the dielectric will also be different. Generating different crystal phases with different structures will have different effects on the properties. In the prior art, the DBS of ceramics is improved by introducing glass additives into the ceramics, but its energy storage density and dielectric breakdown strength are difficult to meet the application requirements. Summary of the Invention

[0004] In order to overcome the deficiencies of the above prior art, the purpose of the present invention is to provide a preparation method of a high breakdown strength and high energy storage density dielectric ceramic material, so as to improve the energy storage density and dielectric breakdown strength of the dielectric ceramic material.

[0005] Another purpose of the present invention is to provide a high breakdown strength and high energy storage density dielectric ceramic material.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] A preparation method of a high breakdown strength and high energy storage density dielectric ceramic material, the specific steps are as follows:

[0008] (1) Prepare glass powder:

[0009] Weigh raw materials according to the weight percentages of the following components:

[0010]

[0011] Wet grind the weighed raw materials for 6 - 8 h, dry for 12 - 18 h, then melt at 1250 - 1350 °C for 2 - 3 h and quench with water, and grind the quenched glass into glass powder;

[0012] (2), Add Ba 0.3 Sr 0.7 TiO3 powder and the glass powder to obtain a mixed powder; wet grind the mixed powder for 3 - 5 h, then add PVA reagent, followed by spray drying, and obtain a green body after pressing; sinter the green body to obtain a high breakdown strength and high energy storage density dielectric ceramic material.

[0013] Preferably, in step (1), the weighed raw materials are wet ground for 6 - 8 h. The specific steps are as follows: add the weighed raw materials, anhydrous ethanol and zirconia milling beads and ball mill for 6 - 8 h.

[0014] Preferably, in step (1), during the ball milling process, deionized water is used as the medium.

[0015] Preferably, in step (2), the specific steps of the wet grinding are as follows:

[0016] Add deionized water and zirconia balls to the mixed powder and ball mill the mixture for 3 - 5 h.

[0017] Preferably, the particle size of the glass powder is 5 - 10 μm.

[0018] Preferably, the Ba 0.3 Sr 0.7 TiO3 powder is prepared by the following steps:

[0019] Weigh raw materials according to the weight percentages of the following components:

[0020] BaCO3 22 - 26%

[0021] SrCO3 40 - 45%

[0022] TiO2 30 - 35%

[0023] Wet grind the weighed raw materials for 6 - 8 h, dry for 12 - 18 h, and then calcine at 950 - 1000 °C to obtain Ba 0.3 Sr 0.7 TiO3 powder;

[0024] More preferably, the specific steps of the wet grinding are as follows:

[0025] Add deionized water and zirconia milling beads to the powder and wet grind for 6 - 8 h.

[0026] Preferably, in the mixed powder, the mass percentage of the glass powder is 3 - 18%;

[0027] More preferably, in the mixed powder, the mass percentage of the glass powder is 10 - 14%.

[0028] Preferably, the mass fraction of polyvinyl alcohol in the PVA reagent is 5-6 wt%.

[0029] Preferably, the specific steps of the press molding are as follows:

[0030] Uniaxially press into a mold with a diameter of 15-16 mm at 30-35 MPa.

[0031] Preferably, in step (2), during the wet grinding process, the mass ratio of the powder, water, and ball milling beads is 1.0: 1.5-2.0: 3.0-4.0.

[0032] Preferably, during the wet grinding process, the rotation speed of the ball mill is 400-480 r / min.

[0033] Preferably, the specific steps of the sintering are as follows:

[0034] Place the green body at 500-700 °C for 120-180 min to discharge the binder, and then raise the temperature to 1100-1300 °C for sintering, with the holding time being 120-180 min.

[0035] Preferably, the heating rate during the sintering process is 3-6 °C / min.

[0036] A high breakdown strength and high energy storage density dielectric ceramic material is prepared from glass powder and Ba 0.3 Sr 0.7 TiO3 powder, and the glass powder, by mass percentage, includes the following components:

[0037] BaCO3 40-50%;

[0038] B2O3 5-10%;

[0039] SiO2 33-38%;

[0040] ZnO 5-10%.

[0041] Preferably, the green body is a cylindrical green body with a thickness of 0.5 mm.

[0042] Preferably, the ball milling direction rotates clockwise.

[0043] Preferably, PVA is used as the binder.

[0044] The present invention has the following advantages and beneficial effects compared with the prior art:

[0045] (1), The melting point of ZnO is relatively low. Adding ZnO to the high breakdown strength and high energy storage density dielectric ceramic material can significantly reduce the melting temperature of the glass (1300 °C) and the sintering temperature of the ceramic dielectric. In addition, Zn 2+The ionic field strength is strong, which has a certain agglomeration effect on the glass structure, promotes the reaction between the glass and the main crystal phase to generate the second crystal phase Ba2TiSi2O8 (BTS), and the reaction equation is as follows: BaTiO3 + BaSi2O5 = Ba2TiSi2O8. Its microstructure changes significantly, and the large amount of precipitated short rod-shaped second crystal phase BTS greatly improves the breakdown performance and energy storage characteristics of the base dielectric ceramics.

[0046] (2) The present invention designs a new type of glass component (BBSZ). When it is used as an additive and compounded with barium strontium titanate (BST) ceramics, the glass can act as a flux during the ceramic sintering process, generate more liquid phases at a lower temperature, accelerate the rate of the solid-phase reaction, effectively reduce the sintering temperature of BST, and obtain a dense dielectric material with a lower grain size (less than 1 μm) at a lower firing temperature; the present invention is prepared by the solid-phase reaction method, and has the characteristics of lead-free environmental protection, simple process, low cost, etc. The glass phase, as an amorphous phase, has the advantages of fewer defects and higher density in the preparation of dielectric materials, and the breakdown strength of the glass is much higher than that of the ceramic phase. The introduction of BBSZ increases the content of the glass phase in the dielectric ceramics, and finally plays an effect of enhancing its voltage resistance characteristics. Brief Description of the Drawings

[0047] Figure 1 XRD patterns of BBSZ glass heat-treated at different temperatures.

[0048] Figure 2 XRD patterns of BBSZ-BST based dielectric ceramics of Examples 1-5 and Comparative Example 1.

[0049] Figure 3 SEM images of low-magnification BBSZ-BST based dielectric ceramics of Examples 1-5 and Comparative Example 1; where a is the SEM image of the BBSZ-BST based dielectric ceramic in Comparative Example 1, b is the SEM image of the BBSZ-BST based dielectric ceramic in Example 1, c is the SEM image of the BBSZ-BST based dielectric ceramic in Example 2, d is the SEM image of the BBSZ-BST based dielectric ceramic in Example 3, e is the SEM image of the BBSZ-BST based dielectric ceramic in Example 4, and f is the SEM image of the BBSZ-BST based dielectric ceramic in Example 5.

[0050] Figure 4SEM images of BBSZ-BST based dielectric ceramics for Examples 1-5 and Comparative Example 1; where a is the SEM image of the BBSZ-BST based dielectric ceramic in Comparative Example 1, b is the SEM image of the BBSZ-BST based dielectric ceramic in Example 1, c is the SEM image of the BBSZ-BST based dielectric ceramic in Example 2, d is the SEM image of the BBSZ-BST based dielectric ceramic in Example 3, e is the SEM image of the BBSZ-BST based dielectric ceramic in Example 4, and f is the SEM image of the BBSZ-BST based dielectric ceramic in Example 5.

[0051] Figure 5 Breakdown strength (E b ) Weibull distribution plot of the BBSZ-BST based dielectric ceramics for Examples 1-5 and Comparative Example 1.

[0052] Figure 6 Plots of the dielectric constant and dielectric loss of the BBSZ-BST based dielectric ceramics for Examples 1-5 and Comparative Example 1 versus frequency.

[0053] Figure 7 Electric hysteresis loop plots of the polarization intensity of the BBSZ-BST based dielectric ceramics for Examples 1-5 and Comparative Example 1 versus electric field. Detailed implementation manners

[0054] The invention objectives of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific examples. The examples cannot be elaborated one by one here, but the implementation manners of the present invention are not limited to the following examples.

[0055] Example 1

[0056] Weigh BaCO3 with a weight percentage of 46.18%, B2O3 with a weight percentage of 8.97%, SiO2 with a weight percentage of 35.87%, and ZnO with a weight percentage of 8.97%; use anhydrous ethanol as the medium and ball mill for 6-8 h. After ball milling, place it in an oven and dry for 12-18 h. Melt it in a corundum crucible at 1250-1350 °C for 2-3 h and then quench it with water. Ball mill the quenched glass into glass powder with a particle size of 5-10 μm using deionized water as the medium.

[0057] Weigh BaCO3 with a weight percentage of 24.5%, SrCO3 with a weight percentage of 42.5%, and TiO2 with a weight percentage of 33%. Add deionized water and zirconia ball milling beads to the powder and wet mill for 6-8 h. After drying in an oven for 12-18 h, calcine it at 1000 °C for 2-3 h to synthesize Ba 0.3 Sr 0.7 TiO3 powder.

[0058] Mix the glass powder with Ba 0.3 Sr0.7 Mix TiO3 powder, add the mixed reagent to deionized water and zirconia milling beads for ball milling, then add 5 wt% PVA and spray-dry the slurry. Uniaxially press the obtained mixed raw material into a mold with a diameter of 15 mm at 30 MPa to obtain a cylindrical green body with a thickness of 0.5 mm; keep the prepared cylindrical green body at 600 °C for 120 min to discharge the binder, and then sinter it at 1250 °C to obtain the fired ceramic sheet.

[0059] Example 2

[0060] Weigh BaCO3 with a weight percentage of 46.18%, B2O3 with a weight percentage of 8.97%, SiO2 with a weight percentage of 35.87%, and ZnO with a weight percentage of 8.97%; use absolute ethanol as the medium for ball milling for 6 - 8 h, after ball milling, place it in an oven to dry for 12 - 18 h, melt it in a corundum crucible at 1250 - 1350 °C for 2 - 3 h and then quench it with water, and ball mill the quenched glass into glass powder with a particle size of 5 - 10 μm using deionized water as the medium.

[0061] Weigh analytical grade reagents, BaCO3 with a weight percentage of 24.5%, SrCO3 with a weight percentage of 42.5%, TiO2 with a weight percentage of 33%, add deionized water and zirconia milling beads to the powder for wet ball milling for 6 - 8 h, place it in an oven to dry for 12 - 18 h and then calcine it at 1000 °C for 2 - 3 h to synthesize Ba 0.3 Sr 0.7 TiO3 powder.

[0062] Mix the glass powder with Ba 0.3 Sr 0.7 TiO3 powder at a weight percentage of 8%, add the mixed reagent to deionized water and zirconia milling beads for ball milling, then add 5 wt% PVA and spray-dry the slurry. Uniaxially press the obtained mixed raw material into a mold with a diameter of 15 mm at 30 MPa to obtain a cylindrical green body with a thickness of 0.5 mm; keep the prepared cylindrical green body at 600 °C for 120 min to discharge the binder, and then sinter it at 1200 °C to obtain the fired ceramic sheet.

[0063] Example 3

[0064] Weigh BaCO3 with a weight percentage of 46.18%, B2O3 with a weight percentage of 8.97%, SiO2 with a weight percentage of 35.87%, and ZnO with a weight percentage of 8.97%; use absolute ethanol as the medium for ball milling for 6 - 8 h, after ball milling, dry it in an oven for 12 - 18 h, melt it in a corundum crucible at 1250 - 1350 °C for 2 - 3 h and then quench it with water, and ball mill the quenched glass into glass powder with a particle size of 5 - 10 μm using deionized water as the medium.

[0065] Weigh analytical grade reagents, BaCO3 with a weight percentage of 24.5%, SrCO3 with a weight percentage of 42.5%, and TiO2 with a weight percentage of 33%. Add deionized water and zirconia milling beads to the powder and wet mill for 6 - 8 h. Place it in an oven to dry for 12 - 18 h and then calcine at 1000 °C for 2 - 3 h to synthesize Ba 0.3 Sr 0.7 TiO3 powder.

[0066] Mix the glass powder with Ba 0.3 Sr 0.7 TiO3 powder at a weight percentage of 12%. Add deionized water and zirconia milling beads to the mixed reagent for ball milling, and then add 5 wt% PVA and spray dry the slurry. Uniaxially press the obtained mixed raw material into a mold with a diameter of 15 mm at 30 MPa to obtain a cylindrical green body with a thickness of 0.5 mm; Keep the prepared cylindrical green body at 600 °C for 120 min to discharge the binder, and then sinter at 1100 °C to obtain a fired ceramic sheet.

[0067] Example 4

[0068] Weigh BaCO3 with a weight percentage of 46.18%, B2O3 with a weight percentage of 8.97%, SiO2 with a weight percentage of 35.87%, and ZnO with a weight percentage of 8.97%; Use absolute ethanol as the medium for ball milling for 6 - 8 h. After ball milling, dry it in an oven for 12 - 18 h, melt it in a corundum crucible at 1250 - 1350 °C for 2 - 3 h and then quench it with water. Ball mill the quenched glass into glass powder with a particle size of 5 - 10 μm using deionized water as the medium.

[0069] Weigh analytical grade reagents, BaCO3 with a weight percentage of 24.5%, SrCO3 with a weight percentage of 42.5%, and TiO2 with a weight percentage of 33%. Add deionized water and zirconia milling beads to the powder and wet mill for 6 - 8 h. Dry it in an oven for 12 - 18 h and then calcine at 1000 °C for 2 - 3 h to synthesize Ba 0.3 Sr 0.7 TiO3 powder.

[0070] Mix the glass powder with Ba 0.3 Sr 0.7Mix TiO3 powder. Add the mixed reagent to deionized water and zirconia milling beads for ball milling, then add 5 wt% PVA and spray-dry the slurry. Uniaxially press the obtained mixed raw material into a mold with a diameter of 15 mm at 30 MPa to obtain a cylindrical green body with a thickness of 0.5 mm; keep the prepared cylindrical green body at 600 °C for 120 min to discharge the binder, and then sinter it at 1100 °C to obtain a fired ceramic sheet.

[0071] Example 5

[0072] Weigh BaCO3 with a weight percentage of 46.18%, B2O3 with a weight percentage of 8.97%, SiO2 with a weight percentage of 35.87% and ZnO with a weight percentage of 8.97%; use absolute ethanol as the medium for ball milling for 6 - 8 h, dry in an oven for 12 - 18 h after ball milling, melt in a corundum crucible at 1250 - 1350 °C for 2 - 3 h and then quench with water, and ball mill the quenched glass into glass powder with a particle size of 5 - 10 μm using deionized water as the medium.

[0073] Weigh analytical grade reagents, BaCO3 with a weight percentage of 24.5%, SrCO3 with a weight percentage of 42.5%, and TiO2 with a weight percentage of 33%. Add deionized water and zirconia milling beads to the powder for wet ball milling for 6 - 8 h, dry in an oven for 12 - 18 h and then calcine at 1000 °C for 2 - 3 h to synthesize Ba 0.3 Sr 0.7 TiO3 powder.

[0074] Mix the glass powder with Ba 0.3 Sr 0.7 TiO3 powder at a weight percentage of 18%. Add the mixed reagent to deionized water and zirconia milling beads for ball milling, then add 5 wt% PVA and spray-dry the slurry. Uniaxially press the obtained mixed raw material into a mold with a diameter of 15 mm at 30 MPa to obtain a cylindrical green body with a thickness of 0.5 mm; keep the prepared cylindrical green body at 600 °C for 120 min to discharge the binder, and then sinter it at 1100 °C to obtain a fired ceramic sheet.

[0075] Comparative Example 1

[0076] Weigh analytical grade reagents, BaCO3 with a weight percentage of 24.5%, SrCO3 with a weight percentage of 42.5%, and TiO2 with a weight percentage of 33%. Add deionized water and zirconia milling beads to the powder for wet ball milling for 6 - 8 h, dry in an oven for 12 - 18 h and then calcine at 1000 °C for 2 - 3 h to synthesize Ba 0.3 Sr 0.7 TiO3 powder.

[0077] The calcined Ba 0.3 Sr 0.7 The TiO3 powder is added with 5wt% PVA, and then the slurry is spray-dried. The obtained mixed raw materials are uniaxially pressed into a mold with a diameter of 15 mm at 30 MPa to obtain a cylindrical green body with a thickness of 0.5 mm; the prepared cylindrical green body is kept at 600 °C for 120 min to discharge the binder, and then sintered at 1300 °C to obtain a fired ceramic sheet.

[0078] Table 1

[0079]

[0080] Table 2

[0081]

[0082] Table 3

[0083]

[0084] Table 1 shows the firing temperature and porosity of the glass composition. It can be seen from Table 1 that the introduction of the glass composition (BBSZ) significantly reduces the firing temperature of the ceramic dielectric. As the content of the glass composition increases, the porosity decreases, and thus the firing quality of the ceramic dielectric increases.

[0085] Table 2 shows the EDS results of the BBSZ-BST dielectric ceramic containing 12% glass in Example 3 (see Figure 3 regions 1 and 2 in d). Combining Figure 3 (d) and the results in Table 2, it can be seen that the fine grains with a grain size of 100-200 nm are barium strontium titanate Ba 0.3 Sr 0.7 TiO3, and the rod-shaped grains are mainly the second crystal phase BaTiSi2O8.

[0086] Table 3 shows the dielectric property parameters of the BBSZ-BST ceramic dielectric. The dielectric property parameters in Table 3 can be calculated according to the following formula:

[0087]

[0088] where U charge is the energy storage density value; ε0 is the vacuum permittivity (8.854×10 -12 F / m); ε r is the relative permittivity, and E b is the dielectric breakdown strength. It can be seen from Table 3 that the BST-BBSZ glass-ceramic dielectric material has a relatively high energy storage efficiency, which can basically be maintained at about 95%. The energy storage density value first increases and then decreases, and reaches the maximum value of 3.51 J / cm 3, which is 3.2 times higher than that of the comparative example, and the energy storage efficiency is as high as 96.4%.

[0089] Figure 1 XRD patterns of BBSZ glass heat-treated at different temperatures, from Figure 1 it can be seen that the glass phase will precipitate the crystal phase between 750 - 800 °C, and this crystal phase is mainly BaSi2O5.

[0090] Figure 2 XRD patterns of BBSZ - BST ceramics of different Examples 1 - 5 and Comparative Example 1. As the glass content (0 - 18%) gradually increases from bottom to top, the main BST crystal phase is significantly precipitated in the blank sample. With the increase of the glass content, the main crystal phase does not change, while the second crystal phase (Ba2TiSi2O8) gradually precipitates in the dielectric. Thus, it can be seen that after introducing the glass phase, the glass phase reacts with the ceramic phase to generate the second crystal phase (Ba2TiSi2O8).

[0091] Figure 3 SEM images of low - magnification BBSZ - BST - based dielectric ceramics of Examples 1 - 5 and Comparative Example 1, from Figure 3 it can be seen that there are significant differences in the surface morphologies between pores and other crystal structures, so the contrast in the morphology between pores and other crystal structures is very different, that is, the difference in brightness in the SEM photos. The porosity of the ceramic sample can be calculated by colorimetry. The Weka Segmentation plugin in ImageJ software can be used to identify the brightness of the photo, calculate the proportion of the pixels in the dark part to the total pixels of the whole picture, and finally obtain the porosity. The porosity results are shown in Table 1.

[0092] Figure 4 SEM images of BBSZ - BST - based dielectric ceramics of Examples 1 - 5 and Comparative Example 1, from Figure 4 it can be seen that a is the control diagram of the blank sample (Comparative Example 1). In a, the larger grain size of barium strontium titanate Ba 0.3 Sr 0.7 TiO3 is 4 - 5 μm, and the small grains are 1 - 2 μm. The grain size is not uniform, and the phenomenon of grain growth appears. With the increase of the glass content, the phenomenon of grain growth is inhibited, and the grain size is significantly reduced. With the significant increase of the glass phase content, some short - rod - shaped crystals are precipitated. Thus, it can be seen that the second crystal phase (Ba2TiSi2O8) precipitated after the reaction of the introduced glass phase with the main crystal phase is short - rod - shaped, and the ceramic material formed by the short - rod - shaped crystals has better strength.

[0093] Figure 5 Weibull distribution diagrams of the breakdown strength (E b ) of BBSZ - BST - based dielectric ceramics of Examples 1 - 5 and Comparative Example 1, from Figure 5It can be seen that with the increase of the glass content, the dielectric breakdown strength value increases significantly. Among them, the β value is the slope of the Weibull function curve, and its magnitude can represent the reliability of the results. Generally, the larger the β value, the higher the reliability of the breakdown strength results. Figure 5 The β values of the six dielectric materials in Figure 5 are all greater than 10, and the reliability of the breakdown strength results is relatively high.

[0094] Figure 6 FIG. is a graph showing the variation of the dielectric constant and dielectric loss of the BBSZ-BST-based dielectric ceramics of Examples 1 to 5 and Comparative Example 1 with frequency. From Figure 6 it can be seen that with the increase of the glass content, the dielectric constant gradually decreases because the dielectric constant of the glass phase is low, and the increase of the glass content will reduce the polarization intensity of the dielectric material. The variation of the dielectric loss value with the glass content has no obvious pattern, but generally speaking, the loss value of the BST-BBSZ glass ceramic is low (<0.02), which can meet the requirements of most dielectric materials. When the frequency reaches 5000 Hz and above, the stability of the dielectric constant and dielectric loss of this dielectric material is relatively high.

[0095] Figure 7 FIG. is a ferroelectric hysteresis loop diagram showing the variation of the polarization intensity of the BBSZ-BST-based dielectric ceramics of Examples 1 to 5 and Comparative Example 1 with the electric field. From Figure 7 it can be seen that the ceramics exhibit significant characteristics of linear dielectrics, and the energy storage density of this dielectric material can be calculated by the linear dielectric calculation formula.

[0096] The above specific embodiments are the preferred embodiments of the present invention and cannot limit the present invention. Any other changes or other equivalent replacement methods made without departing from the technical solution of the present invention are included in the protection scope of the present invention.

Claims

1. A preparation method of a dielectric ceramic material with high breakdown strength and high energy storage density, characterized in that, The specific steps are as follows: (1) Prepare glass powder: Weigh the raw materials according to the mass percentages of the following components: BaCO3 40 - 50% B2O3 5 - 10% SiO2 33 - 38% ZnO 5 - 10% Wet grind the weighed raw materials for 6 - 8 h, dry for 12 - 18 h, then melt at 1250 - 1350 °C for 2 - 3 h and quench with water. Grind the quenched glass beads into glass powder; (2)Mix Ba 0.3 Sr 0.7 TiO3 powder with the glass powder to obtain a mixed powder; wet-mill the mixed powder for 3 - 5 h, add PVA reagent, then perform spray drying, and obtain a green body after pressing; sinter the green body to obtain a dielectric ceramic material with high breakdown strength and high energy storage density; The specific steps of the sintering are as follows: Place the green body at 500 - 700 °C for heat preservation for 120 - 180 min to discharge the binder, then raise the temperature to 1100 - 1300 °C for sintering, and the heat preservation time is 120 - 180 min; In the high breakdown strength and high energy storage density dielectric ceramic material, there is a short rod-shaped second phase Ba2TiSi2O8; The said Ba 0.3 Sr 0.7 TiO3 powder is prepared by the following steps: Weigh the raw materials according to the weight percentages of the following components: Weigh BaCO3 with a weight percentage of 24.5%, SrCO3 with a weight percentage of 42.5%, and TiO2 with a weight percentage of 33%; The weighed raw materials are wet-milled for 6 to 8 h, dried for 12 to 18 h, and then calcined at 950 to 1000 °C to obtain Ba 0.3 Sr 0.7 TiO3 powder; In the mixed powder, the mass percentage of the glass powder is 12%.

2. The preparation method of a high breakdown strength and high energy storage density dielectric ceramic material according to claim 1, characterized in that, In the PVA reagent, the mass fraction of polyvinyl alcohol is 5 - 6 wt%.

3. The preparation method of a high breakdown strength and high energy storage density dielectric ceramic material according to claim 1, characterized in that, The specific steps of the press mold are as follows: Uniaxially press into a mold with a diameter of 15 - 16 mm at 30 - 35 MPa.

4. The preparation method of a high breakdown strength and high energy storage density dielectric ceramic material according to claim 1, wherein, In step (2), during the wet grinding process, the mass ratio of the powder, water and ball milling beads is 1.0:1.5 - 2.0:3.0 - 4.

0.

5. The preparation method of a high breakdown strength and high energy storage density dielectric ceramic material according to claim 1, characterized in that, During the wet grinding process, the rotation speed of the ball mill is 400 - 480 r / min.

6. The preparation method of a high breakdown strength and high energy storage density dielectric ceramic material according to claim 1, characterized in that The heating rate is 3 - 6 °C / min.

7. A high breakdown strength and high energy storage density dielectric ceramic material, characterized in that, Prepared by the preparation method of the high breakdown strength and high energy storage density dielectric ceramic material according to any one of claims 1 - 6.

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