Lead-free energy storage ceramic material with core-shell structure as well as preparation method and application of lead-free energy storage ceramic material

Abstract

The invention belongs to the technical field of dielectric energy storage ceramic materials, and particularly relates to a lead-free energy storage ceramic material with a core-shell structure as well as a preparation method and application of the lead-free energy storage ceramic material. The core-shell structure exists in the lead-free energy storage ceramic material with the core-shell structure, so that internal stress and local electric field concentration of crystal grains can be relieved, dielectric distribution and polarization response are optimized, and breakdown resistance, energy storage density, energy storage efficiency and charge and discharge characteristics are improved; the lead-free energy storage ceramic material with the core-shell structure has high energy storage density and high energy storage efficiency, the effective energy storage density Wrec reaches up to 11.1 J / cm < 3 > and the energy storage efficiency eta reaches up to 89.1% under a breakdown electric field of 860 kV / cm, meanwhile, the lead-free energy storage ceramic material with the core-shell structure has the rapid charging and discharging characteristic, and the discharging time t0.9 is only 26.6 ns. The lead-free energy storage ceramic material with the core-shell structure provided by the invention has the performance, so that the lead-free energy storage ceramic material has extremely high application value in a pulse power system or an electronic and electric power system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of dielectric energy storage ceramic materials, and particularly relates to a core-shell structure lead-free energy storage ceramic material and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of new energy technology, the demand for high-efficiency energy storage devices is increasing. Dielectric energy storage ceramic materials have become an important direction of energy storage material research due to their high power density, fast charging and discharging characteristics, excellent thermal stability and safety. Dielectric energy storage ceramic materials can achieve high energy storage under high electric field conditions, and have good working frequency adaptability and long service life, and have high application value in hybrid electric vehicles, power electronic systems and pulse power equipment.

[0003] At present, lead-free perovskite ceramic systems, such as (Bi 0.5 Na 0.5 )TiO3-based materials, have attracted widespread attention due to their mature preparation process and good polarization performance. However, the existing dielectric energy storage ceramic materials still have obvious deficiencies in the synergistic optimization of energy storage density and charging and discharging characteristics, which limits their promotion in high-performance application fields.

[0004] Therefore, how to develop dielectric energy storage ceramic materials with high energy storage density and fast charging and discharging characteristics is a problem to be solved in the fields of material science and energy storage technology. SUMMARY

[0005] The purpose of the present application is to provide a core-shell structure lead-free energy storage ceramic material and a preparation method and application thereof. The core-shell structure lead-free energy storage ceramic material provided by the present application has high energy density, high energy storage efficiency and fast charging and discharging characteristics.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme: The present application provides a core-shell structure lead-free energy storage ceramic material, the chemical formula of which is x (Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)- y Ba(Mg 1 / 3 Ta 2 / 3 )O3; wherein, x and y are molar percentages, x + y= 100%, 50%≤ x<100%;the core-shell structure lead-free energy storage ceramic material comprises a core and a shell coated on the surface of the core; from the core to the shell, the Sr element shows a decreasing trend, and the Bi element and the Na element show an enrichment trend.

[0007] Preferably, the core-shell structure lead-free energy storage ceramic material comprises 85%-94% of the core. x y Preferably, the core-shell structure lead-free energy storage ceramic material comprises 6%-15% of the shell.

[0008] The application also provides a preparation method of the core-shell structure lead-free energy storage ceramic material. (1) according to the stoichiometric ratio of (Na x (Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)- y Ba(Mg 1 / 3 Ta 2 / 3 )O3, first ball milling is performed on element corresponding compound raw materials to obtain a slurry; the compound raw materials include one or more of oxides and carbonates; (2) the slurry is sequentially subjected to first drying, pre-sintering, second ball milling and second drying to obtain a powder; (3) the powder and a binder are mixed for granulation, and then sequentially subjected to first pressing, grinding and second pressing to obtain a green body; (4) the green body is sequentially subjected to plastic removal and sintering to obtain the core-shell structure lead-free energy storage ceramic material.

[0009] Preferably, the element corresponding compound raw materials include Bi2O3, La2O3, TiO2, MgO, Ta2O5, Na2CO3, SrCO3 and BaCO3.

[0010] Preferably, the sintering temperature is 1050-1150℃, and the holding time is 1-3 hours.

[0011] Preferably, the sintering further comprises a temperature rising before the sintering, and the temperature rising rate is 1-5℃ / min.

[0012] Preferably, the sintering further comprises a temperature falling after the sintering; the temperature falling comprises sequentially performing a first temperature falling stage and a second temperature falling stage; the first temperature falling stage has a temperature falling rate of 3-10℃ / min; the end temperature of the first temperature falling stage is 300-800℃; and the second temperature falling stage is natural cooling.

[0013] Preferably, the pre-sintering temperature is 800-900℃, and the holding time is 1-5 hours.

[0014] ​Preferably, the binder is a polyvinyl alcohol solution; the mass concentration of the polyvinyl alcohol solution is 3%-10%; and the mass ratio of the powder and the binder is 100:1-10.

[0015] The application further provides application of the core-shell structure lead-free energy storage ceramic material in the energy storage field.

[0016] The application provides a core-shell structure lead-free energy storage ceramic material. 2+ The diffusion energy barrier of Sr is the highest, so Sr is more likely to stay and enrich in the core region during sintering, which significantly weakens the long-distance diffusion ability, and thus becomes the main thermodynamic factor for forming the core-shell structure. (1) The core-shell structure of the core-shell structure lead-free energy storage ceramic material can relieve the internal stress and local electric field concentration of the grain, optimize the dielectric distribution and polarization response, and thus improve the breakdown resistance, energy storage density, energy storage efficiency and fast charging and discharging characteristics. (2) The core-shell structure lead-free energy storage ceramic material has high energy storage density and high energy storage efficiency, and the effective energy storage density (recoverable energy storage density) W of the material is up to 11.1 J / cm rec under a breakdown electric field of 860 kV / cm, the energy storage efficiency η is up to 89.1%, and the material has superfast charging and discharging characteristics, and the discharge time t is only 26.6 ns. 3 0.9 (3) The core-shell structure lead-free energy storage ceramic material has good breakdown resistance under the conditions of high energy density and high energy storage efficiency.

[0017] The application further provides a preparation method of the core-shell structure lead-free energy storage ceramic material.

[0018] ​​This invention also provides the application of the core-shell structured lead-free energy storage ceramic material described in the above-described scheme or the core-shell structured lead-free energy storage ceramic material prepared by the above-described scheme in the field of energy storage. The core-shell structured lead-free energy storage ceramic material provided by this invention exhibits good breakdown resistance and fast charge-discharge characteristics under high energy density and high energy storage efficiency conditions, making it suitable for the field of energy storage, especially for hybrid electric vehicles, pulse power systems, or electronic and power systems. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a bright-field transmission electron microscope image of the core-shell structured lead-free energy storage ceramic material prepared in Example 3; Figure 2 The diagram shows the unipolar hysteresis loops of the core-shell structured lead-free energy storage ceramic materials prepared in Examples 1-4. Figure 3 Weber distribution and breakdown electric field diagrams of the core-shell structured lead-free energy storage ceramic materials prepared in Examples 1-4; Figure 4 The diagram shows the recoverable energy storage density and energy storage efficiency of the core-shell structured lead-free energy storage ceramic materials prepared in Examples 1-4. Figure 5 The diagram shows the overdamped discharge characteristics of the core-shell structured lead-free energy storage ceramic material prepared in Example 3. Detailed Implementation

[0021] This invention provides a core-shell structured lead-free energy storage ceramic material, with the chemical formula being [chemical formula missing]. x (Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)- y Ba(Mg 1 / 3 Ta 2 / 3 O3, of which, x and y Per mole percentage x + y= 100%, 50%≤ x <100%; The core-shell structured lead-free energy storage ceramic material includes a core and a shell covering the surface of the core; from the core to the shell, Sr element shows a decreasing trend, while Bi and Na elements show an enrichment trend.

[0022] In the present application, the x Preferably 85%~94%, more preferably 88%~92%, further preferably 90%; the y Preferably 6%~15%, more preferably 8%~12%, further preferably 10%.

[0023] The present application also provides a preparation method of the core-shell structure lead-free energy storage ceramic material described in the above scheme, comprising the following steps: (1) According to the stoichiometric ratio of (Na x (Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)- y Ba(Mg 1 / 3 Ta 2 / 3 )O3, take the corresponding compound raw materials of elements to carry out the first ball milling to obtain the slurry; the compound raw materials include one or several of oxides and carbonates; (2) The slurry is sequentially subjected to first drying, pre-sintering, second ball milling and second drying to obtain a powder; (3) The powder and the binder are mixed for granulation, and then sequentially subjected to first pressing, grinding and second pressing to obtain a green body; (4) The green body is sequentially subjected to plastic arrangement and sintering to obtain the core-shell structure lead-free energy storage ceramic material.

[0024] According to the stoichiometric ratio of (Na x (Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)- y Ba(Mg 1 / 3 Ta 2 / 3 )O3, take the corresponding compound raw materials of elements to carry out the first ball milling to obtain the slurry; the corresponding compound raw materials of elements include the corresponding oxides of elements or the corresponding carbonates of elements.

[0025] In the present application, the corresponding compound raw materials of elements preferably include Bi2O3, La2O3, TiO2, MgO, Ta2O5, Na2CO3, SrCO3 and BaCO3.

[0026] In the present application, the ball milling medium used in the first ball milling is preferably anhydrous ethanol; the mass ratio of the corresponding compound raw materials of elements to anhydrous ethanol is preferably 1:1~2, more preferably 1:1.5.

[0027] In the present application, the grinding ball used in the first ball milling is preferably zirconium oxide grinding ball; the mass ratio of the compound raw material corresponding to the element and the zirconium oxide grinding ball is preferably 1:2-3, more preferably 1:2.5.

[0028] In the present application, the time of the first ball milling is preferably 18-24 hours, more preferably 20-22 hours; the equipment of the first ball milling is preferably planetary ball mill.

[0029] After obtaining the slurry, the present application sequentially carries out first drying, pre-sintering, second ball milling and second drying on the slurry to obtain powder. In the present application, the temperature of the first drying is preferably 60-100℃, more preferably 80℃, and the holding time is preferably 3-8 hours, more preferably 5 hours.

[0030] In the present application, the temperature of the pre-sintering is preferably 800-900℃, more preferably 830-860℃, and the holding time is preferably 1-5 hours, more preferably 2-3 hours; the pre-sintering preferably further comprises temperature rising (denoted as first temperature rising); the temperature rising rate of the first temperature rising is preferably 3-5 o C / min, more preferably 3 o C / min.

[0031] In the present application, the ball milling medium used in the second ball milling is preferably anhydrous ethanol; the mass ratio of the compound raw material corresponding to the element and the anhydrous ethanol is preferably 1:1-2, more preferably 1:1.5.

[0032] In the present application, the grinding ball used in the second ball milling is preferably zirconium oxide grinding ball; the mass ratio of the compound raw material corresponding to the element and the zirconium oxide grinding ball is preferably 1:2-3, more preferably 1:2.5.

[0033] In the present application, the time of the second ball milling is preferably 18-24 hours, more preferably 20-22 hours; the equipment of the first ball milling is preferably planetary ball mill.

[0034] In the present application, the temperature of the second drying is preferably 60-100℃, more preferably 80℃, and the holding time is preferably 3-8 hours, more preferably 5 hours.

[0035] After obtaining the powder, the present application mixes the powder and a binder to carry out granulation and then sequentially carries out first pressing, grinding and second pressing to obtain green body. In the present application, the binder is preferably polyvinyl alcohol solution; the mass concentration of the polyvinyl alcohol solution is preferably 3%-10%, more preferably 8%.

[0036] In the present application, the mass ratio of the powder and the binder is preferably 100:1-10, more preferably 100:5.

[0037] In the present application, the granulation is preferably followed by sieving the obtained granules (denoted as first sieving) ; the mesh size of the sieve used in the first sieving is preferably 100-150 mesh, more preferably 120 mesh.

[0038] In the present application, the pressure of the first pressing is preferably 2-8 MPa, more preferably 5 MPa.

[0039] In the present application, the grinding is preferably followed by sieving the obtained product (denoted as second sieving) ; the mesh size of the sieve used in the second sieving is preferably 160-250 mesh, more preferably 200 mesh.

[0040] In the present application, the pressure of the second pressing is preferably 2-8 MPa, more preferably 2.5 MPa.

[0041] In the present application, the green body preferably has a shape of a round sheet; the diameter of the round sheet is preferably 6-12 mm, more preferably 10 mm, and the thickness is preferably 0.5-2 mm, more preferably 1 mm.

[0042] After obtaining the green body, the green body is subjected to plastic removal and sintering in sequence to obtain the core-shell structure energy storage ceramic material. In the present application, the plastic removal preferably comprises the following steps: heating (denoted as third heating) to 600℃ for 6 h and then cooling; the rate of the third heating is preferably 1℃ / min; the cooling is preferably natural cooling.

[0043] In the present application, the sintering is preferably preceded by heating (denoted as second heating), and the rate of the second heating is preferably 1-5℃ / min, more preferably 3℃ / min.

[0044] In the present application, the temperature of the sintering is preferably 1050-1150℃, more preferably 1100℃, and the holding time is preferably 1-3 hours, more preferably 2 hours.

[0045] In the present application, the sintering is preferably followed by cooling; the cooling preferably comprises first cooling stage and second cooling stage in sequence; the rate of the first cooling stage is preferably 3-10℃ / min, more preferably 5℃ / min; the end temperature of the first cooling stage is preferably 300-800℃, more preferably 500℃; the second cooling stage is preferably natural cooling; the end temperature of the second cooling stage is preferably 18-25℃, more preferably 20℃.

[0046] The present application also provides the use of the core-shell structure lead-free energy storage ceramic material described in the above-mentioned scheme or the core-shell structure lead-free energy storage ceramic material obtained by the preparation method described in the above-mentioned scheme in the field of energy storage.

[0047] The core-shell structure lead-free energy storage ceramic material provided by the application has good breakdown resistance and fast charge and discharge characteristics under the conditions of high energy density and high energy storage efficiency, and is suitable for the energy storage field, and is especially suitable for hybrid electric vehicles, pulse power systems or electronic and power systems.

[0048] In order to further illustrate the application, the scheme of the application is described in detail below in combination with the drawings and examples, but they cannot be understood as limiting the protection scope of the application.

[0049] Example 1 In this example, a core-shell structure lead-free energy storage ceramic material is prepared, and the specific steps of the preparation method are as follows: (1) 6.0171 g of Bi2O3, 0.4906 g of La2O3, 6.0123 g of TiO2, 0.0645 g of MgO, 0.7106 g of Ta2O5, 1.1980 g of Na2CO3, 3.1101 g of SrCO3 and 0.9474 g of BaCO3 are mixed according to the stoichiometric ratio of 0.94(Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)-0.06Ba(Mg 1 / 3 Ta 2 / 3 )O3, and anhydrous ethanol and zirconia balls are added as ball milling media, the mass of the anhydrous ethanol and the zirconia balls is 28 g and 46 g respectively, a planetary ball mill is used for ball milling, the ball milling time is 22 h, and a slurry is obtained; (2) The slurry obtained in step (1) is dried at a temperature of 80 DEG C for 5 h, and then the dried powder is placed in a box furnace and precalcined at 850 DEG C for 3 h; the precalcined powder is added to anhydrous ethanol and zirconia balls for secondary ball milling, the secondary ball milling time is 24 h, and secondary drying is performed, the secondary drying temperature is 80 DEG C, and the secondary drying time is 5 h, to obtain a powder; (3) 10 g of the powder prepared in step (2) is added to 0.5 g of a polyvinyl alcohol solution with a mass concentration of 8% for granulation, and after being ground, the powder is passed through a 120 mesh screen, the powder is pressed into a block under a pressure of 5 MPa to ensure uniform diffusion of the polyvinyl alcohol solution, and then the block is ground and passed through a 200 mesh screen, and then a die with a diameter of 10 mm is used to press under a pressure of 2.5 MPa to obtain a green compact disc with a thickness of 1 mm; (4) the green disc obtained in step (3) is placed in a box furnace, and heated to 600 ℃ at a rate of 1 ℃ / min, and kept for 6 h, and then naturally cooled; the green disc is sintered in the box furnace, heated to 1150 ℃ at a rate of 3 ℃ / min, kept for 2 h, then cooled to 500 ℃ at a rate of 5 ℃ / min, and then naturally cooled to room temperature, to obtain a lead-free energy storage ceramic material with core-shell structure.

[0050] Example 2 The preparation method of this example is the same as that of Example 1, except that in step (1), 5.7610 g of Bi2O3, 0.4697 g of La2O3, 5.7565 g of TiO2, 0.1075 g of MgO, 1.1843 g of Ta2O5, 1.1470 g of Na2CO3, 2.9778 g of SrCO3 and 1.5789 g of BaCO3 are mixed according to the stoichiometric ratio of 0.90(Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)-0.10Ba(Mg 1 / 3 Ta 2 / 3 )O3, the mass of anhydrous ethanol and zirconium oxide balls added is 28 g and 47 g respectively; in step (4), the temperature is increased to 1100 ℃ at a rate of 3 ℃ / min.

[0051] Example 3 The preparation method of this example is the same as that of Example 1, except that in step (1), 5.7610 g of Bi2O3, 0.4697 g of La2O3, 5.7565 g of TiO2, 0.1075 g of MgO, 1.1843 g of Ta2O5, 1.1470 g of Na2CO3, 2.9778 g of SrCO3 and 1.5789 g of BaCO3 are mixed according to the stoichiometric ratio of 0.90(Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)-0.10Ba(Mg 1 / 3 Ta 2 / 3 )O3, the mass of anhydrous ethanol and zirconium oxide balls added is 28 g and 47 g respectively; in step (4), the temperature is increased to 1100 ℃ at a rate of 3 ℃ / min.

[0052] Example 4 The preparation method of this example is the same as that of Example 1, except that in step (1), 5.7610 g of Bi2O3, 0.4697 g of La2O3, 5.7565 g of TiO2, 0.1075 g of MgO, 1.1843 g of Ta2O5, 1.1470 g of Na2CO3, 2.9778 g of SrCO3 and 1.5789 g of BaCO3 are mixed according to the stoichiometric ratio of 0.90(Na 0.30 Bi 0.34 Sr0.28 La 0.04 TiO3)-0.15Ba(Mg 1 / 3 Ta 2 / 3 The stoichiometric ratio of O3 was determined by mixing 5.4410 g of Bi2O3, 0.4436 g of La2O3, 5.4367 g of TiO2, 0.1613 g of MgO, 1.7765 g of Ta2O5, 1.0833 g of Na2CO3, 2.8123 g of SrCO3, and 2.3684 g of BaCO3. The mass of anhydrous ethanol and zirconium oxide balls added were 29 g and 49 g, respectively. In step (4), the temperature was increased to 1100℃ at a rate of 3℃ / min.

[0053] Test Example 1 The structure of the core-shell lead-free energy storage ceramic material prepared in Example 3 was tested using transmission electron microscopy, and the results are as follows: Figure 1 As shown. According to Figure 1 It can be seen that a core-shell structure was detected in the core-shell structured lead-free energy storage ceramic material prepared in Example 3.

[0054] Test Example 2 The breakdown electric field (E0) of the core-shell structured lead-free energy storage ceramic materials prepared in Examples 1-4 was analyzed using a ferroelectric analyzer. b For each embodiment, 8 samples were prepared for testing, and the hysteresis loop was as follows: Figure 2 As shown. From Figure 2 It can be seen that the core-shell structured lead-free energy storage ceramic materials prepared in all embodiments exhibit a fine hysteresis curve, i.e., a large Pm-Pr, and all core-shell structured lead-free energy storage ceramic materials prepared in all embodiments have a high breakdown electric field. Such characteristic hysteresis curves can achieve high energy storage density. Based on the Weber distribution analysis of the breakdown electric field of the core-shell structured lead-free energy storage ceramic materials of each embodiment, the theoretical maximum breakdown electric field E of the core-shell structured lead-free energy storage ceramic materials prepared in Examples 1-4 is obtained from the Weber distribution diagram. b Value, result as Figure 3 As shown.

[0055] according to Figure 3 It can be seen that the theoretical maximum breakdown electric field E of the core-shell structured lead-free energy storage ceramic material prepared in Example 3 is [missing information]. b The highest value was 863 kV / cm.

[0056] Test Example 3 The recyclable energy storage density W of the core-shell structured lead-free energy storage ceramic materials prepared in Examples 1-4 was calculated using formulas (1) and (2), respectively. rec And energy storage efficiency η: (1); (2); Among them, P m For the maximum polarization intensity, P r Where E is the remanent polarization intensity, and W is the electric field intensity. rec For recoverable energy storage density, W total This represents the total energy storage density.

[0057] The recyclable energy storage density W of the core-shell structured lead-free energy storage ceramic materials prepared in Examples 1-4 rec The calculation results of energy storage efficiency η are as follows Figure 4 As shown. According to Figure 4 It can be seen that the effective energy storage density W of the core-shell structured lead-free energy storage ceramic material prepared in Example 3 is [data missing]. rec Up to 11.1 J / cm 3 The energy storage efficiency η is 89.1%.

[0058] Test Example 4 The overdamping characteristics of the core-shell structured lead-free energy storage ceramic material prepared in Example 3 were tested using a dielectric charge-discharge testing system. The results are as follows: Figure 5 As shown. According to Figure 5 It can be seen that the core-shell structured lead-free energy storage ceramic material prepared in Example 3 has a faster discharge rate and a shorter discharge time t. 0.9 It is only 26.6 ns.

[0059] As can be seen from the above embodiments, the core-shell structured lead-free energy storage ceramic material provided by the present invention has both high energy storage density and fast charge / discharge characteristics, and can recover energy storage density W. rec Up to 11.1 J / cm 3 The energy storage efficiency η is as high as 89.1%, and the discharge time is only 26.6 ns.

[0060] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative intent, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A core-shell structured lead-free energy storage ceramic material, characterized in that, Chemical formula is x (Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)- y Ba(Mg 1 / 3 Ta 2 / 3 O3, of which, x and y Per mole percentage x + y= 100%, 50%≤ x <100%; The core-shell structured lead-free energy storage ceramic material includes a core and a shell covering the surface of the core; from the core to the shell, Sr element shows a decreasing trend, while Bi and Na elements show an enrichment trend.

2. The core-shell structured lead-free energy storage ceramic material according to claim 1, characterized in that, The x It is 85%~94%. y It ranges from 6% to 15%.

3. The method for preparing the core-shell structured lead-free energy storage ceramic material according to any one of claims 1 to 2, characterized in that, Includes the following steps: (1) According to x (Na 0.30 Bi 0.34 Sr 0.28 La 0.04 TiO3)- y Ba(Mg 1 / 3 Ta 2 / 3 The stoichiometric ratio of O3 is used to first ball mill the corresponding compound raw materials to obtain a slurry; the compound raw materials include one or more of oxides and carbonates. (2) The slurry is subjected to a first drying, a pre-calcination, a second ball milling, and a second drying in sequence to obtain powder; (3) The powder and binder are mixed and granulated, and then subjected to first pressing, grinding and second pressing in sequence to obtain a green body; (4) The green body is sequentially subjected to plasticizing and sintering to obtain the core-shell structure lead-free energy storage ceramic material.

4. The preparation method according to claim 3, characterized in that, The compound raw materials corresponding to the elements include Bi2O3, La2O3, TiO2, MgO, Ta2O5, Na2CO3, SrCO3 and BaCO3.

5. The preparation method according to claim 3, characterized in that, The sintering temperature is 1050~1150℃, and the holding time is 1~3 hours.

6. The preparation method according to claim 3 or 5, characterized in that, The process before sintering also includes heating, with a heating rate of 1~5℃ / min.

7. The preparation method according to claim 3 or 5, characterized in that, The sintering process further includes cooling; the cooling process includes a first cooling stage and a second cooling stage in sequence; the cooling rate of the first cooling stage is 3~10℃ / min; the end temperature of the first cooling stage is 300~800℃; the second cooling stage is natural cooling.

8. The preparation method according to claim 3, characterized in that, The preheating temperature is 800~900℃, and the holding time is 1~5 hours.

9. The preparation method according to claim 3, characterized in that, The binder is a polyvinyl alcohol solution; the mass concentration of the polyvinyl alcohol solution is 3%~10%; the mass ratio of the powder to the binder is 100:1~10.

10. The application of the core-shell structured lead-free energy storage ceramic material according to any one of claims 1 to 2 or the core-shell structured lead-free energy storage ceramic material obtained by the preparation method according to any one of claims 3 to 9 in the field of energy storage.

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