A barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage characteristics, a preparation method and application thereof

Abstract

The present invention relates to a high-energy storage barium titanate-silver niobate relaxor ferroelectric ceramic, a preparation method, and applications thereof. The chemical composition of the high-energy storage barium titanate-silver niobate relaxor ferroelectric ceramic is (1-x)BaTiO3-xAgNbO3; wherein 0.06≤x≤0.08.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of functional ceramics, and particularly relates to a barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage characteristics and a preparation method and application thereof. BACKGROUND

[0002] In recent years, with the rapid development of electric vehicles, aerospace industry and portable electronic products, the demand for integrated, compact and efficient electronic systems has increased dramatically. Ceramic capacitors, as key components of pulse power systems, can provide high power density, fast charge and discharge speed, high breakdown strength and high stability in a wide temperature range. However, compared with electrochemical energy storage devices, the low energy density of ceramic capacitors limits their application. Lead-based ceramics are still the mainstream of current commercial pulse capacitors, which have serious harm to the environment and human body in raw material mining, device preparation and recycling, and their use has been restricted by various countries. The low energy storage density of current lead-free dielectric materials poses a huge challenge to the integration, lightweight and miniaturization of pulse power systems. Therefore, it is urgent to develop lead-free ceramic materials with high energy storage density.

[0003] BaTiO3 has become the most widely used dielectric material due to its high dielectric constant, low production cost and stable chemical structure. However, the long-range ordered dipole arrangement in unmodified BaTiO3 ceramic materials can lead to high remnant polarization, and the polarization loss in A-site can result in low saturation polarization, which greatly hinders the enhancement of energy storage performance. Relaxation design can reduce the remnant polarization of ferroelectric materials and improve the breakdown field strength, so it is considered as an effective measure to improve the energy storage performance of ferroelectric materials.

[0004] Currently, there have been a large number of reports on improving the energy storage characteristics of barium titanate-based ceramic materials. For example, (Ba 0.8 Bi 0.2 )(Ti 0.58 Zr 0.14 Sc 0.18 Mg 0.04 Nb 0.05 Ta 0.01 )O3 ceramic achieved a recoverable energy density of 5.18 J / cm 3 (reference: J.Alloy.Compd.2024, 970, 8.); 0.85(0.9BaTiO3-0.1Bi(Mg 2 / 3 Ta 1 / 3 )O3-0.15NaTaO3 ceramic can achieve 6.02 J / cm 3(Ref: J. Eur. Ceram. Soc. 2024, 44, 3916.). However, the large reduction of the saturation polarization of the modified barium titanate-based ceramics in the above studies (18 μC / cm 2 , 27 μC / cm 2 at 640 kV / cm and 718 kV / cm electric field, respectively) also limited the improvement of the energy storage properties of the barium titanate-based ceramics. SUMMARY

[0005] In view of the above technical problems, the present application aims to provide a barium titanate-silver niobate relaxor ferroelectric ceramic with high polarization and high energy storage properties, a preparation method and application thereof. The ceramic material provided by the present application has excellent performance, is lead-free and environmentally friendly, is simple to prepare, and has the characteristics of high breakdown field strength, high energy storage density and efficiency, thereby providing a high-performance alternative energy storage material for devices such as pulse capacitors.

[0006] In a first aspect, the present application provides a barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage properties, wherein the chemical composition of the barium titanate-silver niobate relaxor ferroelectric ceramic is (1-x) BaTiO3-x AgNbO3; and 0.06≤x≤0.08.

[0007] Preferably, the breakdown field strength of the barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage properties is 554-665 kV / cm, the recoverable energy density is 4.02-6.04 J / cm 3 , and the energy storage efficiency is 81.9-86.8%.

[0008] In a second aspect, the present application provides a preparation method of the above barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage properties, which comprises the following steps:

[0009] (1) The barium carbonate powder, titanium dioxide powder, silver oxide powder and niobium pentoxide powder are weighed according to the stoichiometric ratio in the chemical formula (1-x) BaTiO3-x AgNbO3, mixed as raw materials, calcined in an oxygen atmosphere, finely ground and sieved to obtain ceramic powder;

[0010] (2) A binder is added to the ceramic powder, granulated, sieved and molded to obtain a green ceramic body;

[0011] (3) The green ceramic body is arranged and sintered in an oxygen atmosphere to obtain the barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage properties.

[0012] Preferably, in step (1), the purity of the raw material powder is at least 99%.

[0013] The mixing method is planetary ball milling, and the mixing parameters include: the medium of the ball milling is anhydrous ethanol, the grinding balls are zirconia balls and zirconia columns, the rotating speed of the ball milling is 200-240 r / min, and the ball milling time is 4-6 h; preferably, the particle size of the zirconia balls is 6 mm, the size of the zirconia columns is 10 mm in diameter and 10 mm in height, the mass of the zirconia balls and the zirconia columns in the grinding balls is each half, and the ball milling time is 4 h.

[0014] Preferably, in step (1), the calcination temperature is 1270-1330℃, and the calcination time is 2-3 h, preferably 3 h.

[0015] The screen mesh number of the fine grinding is 40 meshes.

[0016] Preferably, in step (2), the binder is a polyvinyl alcohol aqueous solution with a concentration of 6-7 wt.%, and the adding amount is 6-7 wt.% of the mass of the ceramic powder; and the screen mesh number of the granulation is 40 meshes.

[0017] Preferably, in step (3), the plastic removal process is: heating at a rate of 2-4℃ / min to 600-800℃ and maintaining for 2-3 h; preferably, heating at a rate of 2℃ / min to 800℃ and maintaining for 2 h.

[0018] Preferably, in step (3), the sintering process is: heating at a rate of 2-4℃ / min to 1000℃, and then heating at a rate of 2℃ / min to 1220-1280℃, and maintaining for 2-3 h.

[0019] In a third aspect, the present application provides an energy storage ceramic device, which comprises the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic and electrodes distributed on the surface of the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic.

[0020] In a fourth aspect, the present application provides an application of the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic in a multilayer ceramic capacitor and a pulse power device.

[0021] Advantages

[0022] Silver niobate has high polarizability due to its short covalent Ag-O bond, the present application will have high spontaneous polarizability of antiferroelectric material silver niobate solid solution into barium titanate, on the basis of induced relaxation, the introduction of silver niobate in barium titanate ceramic constructs a new A-O coupling, thereby compensating for the polarization loss in the relaxation process of barium titanate ceramic, the relaxed barium titanate-silver niobate relaxor ferroelectric ceramic shows high polarization response under an applied electric field, while the breakdown field strength of the ceramic is significantly improved (554-665 kV / cm), and finally the energy storage performance of the ceramic is significantly improved, the recoverable energy density of the ceramic is 4.02-6.04 J / cm 3 , and the energy efficiency is 81.9-86.8%;

[0023] The preparation process of the present application is simple, reliable, environmentally friendly, and has great application potential in the field of high-power pulse capacitors. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 X-ray diffraction images of barium titanate-silver niobate ceramic materials prepared in Examples 1, 2 and Comparative Examples 1-3;

[0025] Figure 2 、 3 Surface morphology images of high energy storage property barium titanate-silver niobate relaxor ferroelectric ceramics prepared in Examples 1 and 2;

[0026] Figure 4 、 5 Monopolar hysteresis loop diagrams of high energy storage property barium titanate-silver niobate relaxor ferroelectric ceramics prepared in Examples 1 and 2;

[0027] Figure 6 、 7 , 8 Monopolar hysteresis loop diagrams of barium titanate-silver niobate ferroelectric ceramics prepared in Comparative Examples 1-3;

[0028] Figure 9 Performance comparison diagrams of barium titanate-silver niobate ceramics with different components prepared in Examples 1 and 2 and Comparative Examples 1-3;

[0029] Figure 10 Dielectric temperature spectrum diagrams of barium titanate-silver niobate ceramics with different components prepared in Examples 1 and 2 and Comparative Examples 1-3 at a frequency of 1 kHz;

[0030] Figure 11 、 12 Monopolar hysteresis loop diagrams and performance change diagrams of barium titanate-silver niobate ceramics prepared in Example 2 at different temperatures. DETAILED DESCRIPTION

[0031] The present invention is further described below through the following embodiments. It should be understood that the following embodiments are only used to illustrate the present invention, rather than to limit the present invention.

[0032] First, the present invention provides a barium titanate-silver niobate relaxor ferroelectric ceramic with high polarization and high energy storage properties. The chemical composition of the barium titanate-silver niobate relaxor ferroelectric ceramic can be: (1-x)BaTiO3-xAgNbO3, 0.06≤x≤0.08.

[0033] The present invention selects a polarization intensity of up to 52μC / cm 2 The high polarization antiferroelectric material silver niobate (AgNbO3) is dissolved in barium titanate, and the A position Ag + 、Ba 2+ and B-position Nb 5+ 、Ti 4+ The differences in ionic radius and charge induce localized heterostructures and electric fields in the ceramic, refining the ferroelectric domains into polar nanodomains, which promotes the induction of relaxation behavior and the reduction of remanent polarization. Simultaneously, the introduction of silver niobate compensates for the polarization loss of the A site in BaTiO3 and the interruption of the BO coupling by constructing a new AO coupling, thereby maintaining the saturation polarization of the barium titanate-based ceramic. The induced lattice distortion refines the grains, ultimately resulting in a ceramic material with significantly improved breakdown field strength and energy storage density.

[0034] Compared with the introduction of other highly polarizable materials such as NaNbO3, the introduction of silver niobate in the present invention has a more significant effect on inducing the relaxation behavior of ceramics, and the prepared barium titanate-silver niobate has a higher polarization intensity under an external electric field. In addition, silver niobate is usually used as a matrix material in the field of ceramic energy storage. Although it has a high saturation polarization intensity, due to the inherent properties of silver niobate itself, the modified silver niobate-based ceramic material still exhibits a relatively wide hysteresis loop, that is, low energy storage efficiency. The present invention introduces silver niobate as a relaxation end member into the barium titanate matrix, while increasing the energy storage density by increasing the polarization intensity, it also maintains high efficiency. The present invention introduces silver niobate, which is usually a matrix material, as a relaxation end member into the barium titanate matrix, and increases the polarization intensity by constructing a new Ag-O coupling therein, while increasing the energy storage density, it also maintains high efficiency.

[0035] Specifically, the present invention modulates the ceramic's relaxation behavior by introducing varying amounts of AgNbO₃ into barium titanate, resulting in ceramics with excellent energy storage performance and reliability. When the value of x is small, the ceramic exhibits pronounced ferroelectricity, resulting in low energy storage performance. Excessively large values ​​of x lead to the formation of a second phase, significantly reducing the breakdown field and, consequently, lowering energy storage performance.

[0036] In some embodiments, the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic has a breakdown field strength of 554-665 kV / cm, a recoverable energy density (energy storage density) of 4.02-6.04 J / cm3, and an energy storage efficiency of 81.9-86.8%. 3

[0037] Hereinafter, the preparation method of the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic provided by the present application is exemplarily described. The preparation method can include the following steps:

[0038] (1) The barium carbonate powder, titanium dioxide powder, silver oxide powder, and niobium pentoxide powder are weighed according to the stoichiometric ratio of the elements in the chemical formula (1-x)BaTiO3-xAgNbO3, mixed as raw materials, calcined in an oxygen atmosphere, finely ground and sieved to obtain ceramic powder;

[0039] (2) A binder is added to the ceramic powder, granulated, sieved, and molded into a green body;

[0040] (3) The ceramic green body is arranged and sintered in an oxygen atmosphere to obtain the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic.

[0041] In some embodiments, in step (1), the purity of all raw material powders is at least 99%; the mixing method is planetary ball milling, and the mixing parameters include: the ball milling medium is anhydrous ethanol, the milling balls are zirconia balls and zirconia columns, the ball milling speed is 200-240 r / min, and the ball milling time is 4-6 h; preferably, the particle size of the zirconia balls is 6 mm, the size of the zirconia columns is 10 mm in diameter and 10 mm in height, the mass of the zirconia balls and the zirconia columns in the milling balls is each half, and the ball milling time is 4 h.

[0042] In some embodiments, in step (1), the calcination temperature can be 1270-1330 ℃, the calcination time can be 2-3 h, and preferably 3 h; and the mesh size of the fine grinding and sieving can be 40 mesh. Calcination in an oxygen atmosphere can prevent the precipitation of Ag during calcination; too low a calcination temperature can result in incomplete reaction of the raw materials, making it impossible to synthesize pure phase (1-x)BaTiO3-xAgNbO3 powder; and too high a calcination temperature can change the properties of the powder, causing a significant decrease in performance.

[0043] In some embodiments, in step (2), the binder can be a polyvinyl alcohol aqueous solution with a concentration of 6-7 wt.%, and the addition amount can be 6-7 wt.% of the mass of the ceramic powder; and the mesh size of the granulation and sieving can be 40 mesh.

[0044] ​In some embodiments, in step (3), the process of plasticizing can be: heating to 600-800℃ at a rate of 2-4℃ / min and holding for 2-3h; preferably, heating to 800℃ at a rate of 2℃ / min and holding for 2h.

[0045] In some embodiments, in step (3), the process of sintering can be: heating to 1000℃ at a rate of 2-4℃ / min (preferably 3-4℃ / min), and then heating to 1220-1280℃ (preferably 1260-1280℃) at a rate of 2℃ / min, and holding for 2-3h.

[0046] In addition, the present application also provides an energy storage ceramic element. The high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic is processed into a desired size, and after being coated with an electrode, an energy storage ceramic element is obtained. That is, the energy storage ceramic element comprises the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic and an electrode distributed on the surface of the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic.

[0047] The high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic prepared by the preparation method provided by the present application can be applied in multilayer ceramic capacitors and pulse power devices (such as high-power pulse capacitors).

[0048] The following examples are further provided to illustrate the present application in detail. It should also be understood that the following examples are only used to further illustrate the present application, and cannot be understood as limiting the scope of protection of the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present application all belong to the protection scope of the present application. The specific process parameters in the following examples are only one example in the appropriate range, i.e. those skilled in the art can select within the appropriate range according to the description herein, and are not limited to the specific values in the following examples. If not specifically indicated, the technical means used in the examples are conventional means known to those skilled in the art.

[0049] Example 1

[0050] The preparation method of the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic (x=0.06) provided by the present embodiment comprises the following steps:

[0051] (1) According to the stoichiometric ratio of chemical elements in the formula 0.94BaTiO3-0.06AgNbO3, the raw materials are weighed, including barium carbonate powder (purity 99.95%), titanium dioxide powder (purity 99.9%), silver oxide powder (purity 99.7%), and niobium pentoxide powder (purity 99.99%), with a weighing accuracy of 0.001 g; the weighed raw materials are mixed and placed in a nylon tank, not more than 2 / 3 of the tank height of anhydrous ethanol is added to the tank, zirconium oxide balls with a particle size of 6 mm and zirconium oxide columns with a diameter of 10 mm x height of 10 mm are used as grinding balls, with a mass of half each, the nylon tank is placed on a planetary ball mill and ball milled for 4 hours at a speed of 200 r / min, then poured into a glass plate, dried in an oven at 80°C, and then sieved with a 40 mesh sieve to obtain a fully mixed powder; the above-mentioned powder is pressed into a cylinder with a size of diameter 65 mm x height 20 mm on a press, calcined at 1290°C in an oxygen atmosphere for 3h, then crushed and sieved through a 40 mesh sieve to obtain ceramic powder;

[0052] (2) A 6wt% polyvinyl alcohol aqueous solution is added to the above-mentioned ceramic powder as a binder, the mass of the polyvinyl alcohol aqueous solution added is 7% of the mass of the ceramic powder, then the mixture is thoroughly ground, granulated, sieved, and molded to obtain a ceramic green body; the mesh number of the sieve used is 40 mesh, and the ceramic green body is a small cylinder with a diameter of 13 mm x height of 1 mm;

[0053] (3) The above-mentioned ceramic green body is heated to 800°C at a rate of 2°C / min in an oxygen atmosphere and held for 2h to remove plastic, obtaining a plastic-removed ceramic green body; the above-mentioned plastic-removed ceramic green body is heated to 1000°C at a rate of 4°C / min in an oxygen atmosphere, then heated to 1260°C at a rate of 2°C / min and held for 3h, and then taken out after natural cooling to room temperature to obtain a sintered ceramic bulk body, thereby obtaining the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic.

[0054] Example 2

[0055] The preparation method of the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic provided in this example refers to Example 1, the main difference being that (1) x = 0.08; (2) the calcination temperature is 1280°C.

[0056] Comparative Example 1

[0057] The preparation method of the barium titanate-silver niobate ceramic provided in this comparative example refers to Example 1, the main difference being that (1) x = 0.02.

[0058] Comparative Example 2

[0059] The preparation method of the barium titanate-silver niobate ceramic provided in this comparative example refers to Example 1, the main difference being that (1) x = 0.04.

[0060] Comparative Example 3

[0061] The preparation method of barium titanate-silver niobate ceramic provided by Comparative Example 3 refers to Example 1, the main difference being that (1) x = 0.10; (2) the calcination temperature is 1280°C.

[0062] Figure 1 The X-ray diffraction images of the barium titanate-silver niobate ceramic materials prepared in Examples 1 and 2 and Comparative Examples 1-3 are shown in the figure. As can be seen from the figure, after AgNbO3 is solid-solved into BaTiO3, all the barium titanate-silver niobate ceramics exhibit a perovskite structure, proving the successful preparation of the barium titanate-silver niobate ceramic.

[0063] The surface morphology of the ceramic bulk was observed by field emission scanning electron microscopy. Figure 2 、 3 The surface morphology images of the barium titanate-silver niobate relaxor ferroelectric ceramics with high energy storage properties prepared in Examples 1 and 2 are shown in the figure. As can be seen from the figure, the surface grains of the barium titanate-silver niobate relaxor ferroelectric ceramics prepared in Examples 1 and 2 are well developed, small and dense.

[0064] The middle part of the ceramic double-sided thinning was taken, gold electrodes were sputtered, and the energy storage performance was tested. Figure 4 、 5 The unipolar electric hysteresis loop images of the barium titanate-silver niobate relaxor ferroelectric ceramics with high energy storage properties prepared in Examples 1 and 2 are shown in the figure. As can be seen from the figure, the electric hysteresis loops of Examples 1 and 2 are slender, and at the same time, a high saturation polarization strength is maintained, thereby obtaining high energy storage performance.

[0065] Figure 6 、 7 The unipolar electric hysteresis loop images of the barium titanate-silver niobate ferroelectric ceramics prepared in Comparative Examples 1-3 are shown in the figure. As can be seen from the figure, the barium titanate-silver niobate ceramics prepared in Comparative Examples 1-2 still have strong ferroelectricity, the barium titanate-silver niobate ceramic prepared in Comparative Example 1 has a breakdown field strength of only 324 kV / cm, an energy storage density of only 1.95 J / cm 3 , and an energy storage efficiency of 70.7%, the barium titanate-silver niobate ceramic prepared in Comparative Example 2 has a breakdown field strength of only 398 kV / cm, an energy storage density of 2.57 J / cm 3 , and an energy storage efficiency of 77.7%, and the barium titanate-silver niobate ceramic prepared in Comparative Example 3 has a breakdown field strength of only 417 kV / cm, an energy storage density of 3.20 J / cm 3 , and an energy storage efficiency of 83.3%.

[0066] Figure 9The figure is the performance comparison of different components of barium titanate-silver niobate ceramics prepared in Examples 1, 2 and Comparative Examples 1-3. As can be seen from the figure, the solid solution of silver niobate can improve the energy storage density and efficiency of the barium titanate-based ceramics, but when the amount of silver niobate introduced is too high, the energy storage performance will decrease, so reasonable control of the solid solution amount of silver niobate can obtain the best energy storage performance.

[0067] Figure 10 The figure is the dielectric temperature spectrum of different components of barium titanate-silver niobate ceramics prepared in Examples 1, 2 and Comparative Examples 1-3 at a frequency of 1 kHz. As can be seen from the figure, the barium titanate-silver niobate ceramic prepared in Example 1 has a breakdown field strength of 554 kV / cm, an energy storage density of 4.02 J / cm 3 , and an energy storage efficiency of 81.9%, the barium titanate-silver niobate ceramic prepared in Example 2 has a breakdown field strength of 665 kV / cm, an energy storage density of 6.04 J / cm 3 , and an energy storage efficiency of 86.8%, the solid solution of AgNbO3 reduces the Curie temperature of the ceramic, and the dielectric peak broadens and the frequency dispersion becomes more and more obvious, indicating that the ceramic changes from a ferroelectric to a relaxor ferroelectric.

[0068] Figure 11 、 12 The figure is the unipolar hysteresis loop and performance change of the barium titanate-silver niobate ceramic prepared in Example 2 at different temperatures. As can be seen from the figure, the ceramic prepared in Example 2 has small performance fluctuations in the temperature range of -40-120℃, indicating its superior temperature stability.

[0069] Table 1 below is a comparison of the performance parameters of the high energy storage characteristic barium titanate-silver niobate relaxor ferroelectric ceramic prepared in the present application:

[0070] x Recyclable energy storage density (J / cm 3 ) Energy storage efficiency / % Breakdown field (kV / cm) Example 1 0.06 4.02 81.9％ 554 Example 2 0.08 6.04 86.8％ 665 Comparative Example 1 0.02 1.95 70.7％ 324 Comparative Example 2 0.04 2.57 77.7％ 398 Comparative Example 3 0.10 3.20 83.3％ 417

[0071] As can be seen from Table 1, the solid solution of AgNbO3 continuously enhances the energy storage performance of the ceramic, the breakdown field strength of Examples 1 and 2 is high, and the energy storage performance is superior.

[0072] In summary, in the present disclosure, the inventors studied the preparation of different AgNbO3 solid solution contents (x=0.02, 0.04, 0.06, 0.08, 0.10) ceramics and their effects on performance based on the problem of significant decrease in the saturation polarization of the ceramic during the induction of relaxor behavior. The solid solution of AgNbO3 effectively induces the relaxor behavior of the BaTiO3-based ceramic, but the saturation polarization intensity of each component ceramic basically remains at the same level (~34 μC / cm 2 ). Combined with the improvement of the breakdown field strength, the energy storage performance of the ceramic is continuously enhanced, but too much AgNbO3 will lead to a decrease in the breakdown field strength and energy storage performance, only when the AgNbO3 is appropriate, can high energy storage characteristics be achieved.

[0073] While the application has been described in detail by reference to preferred embodiments thereof, it is to be understood that the description is not to be construed as limiting the scope of the application. Various modifications and changes can occur to those skilled in the art, once they learn of the basic concept of the application. Therefore, the scope of the application is to be defined by the appended claims, rather than by the description of the preferred embodiments.

Claims

1. A barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage properties, characterized in that: The chemical composition of the barium titanate-silver niobate relaxor ferroelectric ceramic is: (1-x)BaTiO3-xAgNbO3; wherein 0.06≤x<0.08; The high energy storage property barium titanate-silver niobate relaxor ferroelectric ceramic has a breakdown field strength of 554-665 kV / cm and a recoverable energy density of 4.02-6.04 J / cm 3 , the energy storage efficiency is 81.9% to 86.8%.

2. A method for preparing the barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage characteristics according to claim 1, characterized in that: The preparation method comprises the following steps: (1) According to the stoichiometric ratio of elements in the chemical formula (1-x)BaTiO3-xAgNbO3, barium carbonate powder, titanium dioxide powder, silver oxide powder, and niobium pentoxide powder are weighed as raw materials, mixed, calcined in an oxygen atmosphere, and then finely ground and sieved to obtain ceramic powder; (2) adding a binder to the ceramic powder, granulating, screening and molding to obtain a ceramic green body; (3) The ceramic green body is molded and sintered in an oxygen atmosphere to obtain the barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage characteristics.

3. The preparation method according to claim 2, characterized in that In step (1), the purity of the raw material powder is at least 99%; The mixing method is planetary ball milling, and the mixing parameters include: the ball milling medium is anhydrous ethanol, the grinding balls are zirconia balls and zirconia columns, the ball milling speed is 200-240 r / min, and the ball milling time is 4-6 hours; the particle size of the zirconia balls is 6 mm, the size of the zirconia columns is 10 mm in diameter × 10 mm in height, and the mass of the zirconia balls and zirconia columns in the grinding balls each accounts for half.

4. The preparation method according to claim 2, characterized in that In step (1), the calcination temperature is 1270-1330° C., and the calcination time is 2-3 hours; The mesh number of the fine grinding and sieving is 40 meshes.

5. The preparation method according to claim 2, characterized in that In step (2), the binder is a polyvinyl alcohol aqueous solution with a concentration of 6 to 7 wt.%, and the added amount is 6 to 7 wt.% of the mass of the ceramic powder; the mesh number of the granulation screening is 40 mesh.

6. The preparation method according to claim 2, characterized in that In step (3), the process of plastic removal is: heating to 600-800°C at a rate of 2-4°C / min and keeping the temperature for 2-3h.

7. The preparation method according to claim 2, characterized in that In step (3), the sintering process is: heating to 1000°C at a heating rate of 2-4°C / min, then heating to 1220-1280°C at a heating rate of 2°C / min, and holding time is 2-3h.

8. An energy storage ceramic element, characterized in that: The energy storage ceramic element comprises: the barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage characteristics as claimed in claim 1, and electrodes distributed on the surface of the barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage characteristics.

9. Use of the barium titanate-silver niobate relaxor ferroelectric ceramic with high energy storage characteristics according to claim 1 in multilayer ceramic capacitors and pulse power devices.

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