Bczt-based energy storage ceramic material with high breakdown field strength and preparation method thereof

Abstract

The present invention discloses a BCZT-based energy storage ceramic material with high breakdown field strength and a preparation method thereof. The general composition formula of the BCZT-based energy storage ceramic material is: (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti0.90) 1‑x (Nb 0.5 La 0.5 ) x ]O3, among which, x =0.06~0.15; It is prepared by solid phase method, and the specific preparation method is: according to the stoichiometric ratio of the chemical formula, and then ball milled and pre-calcined to obtain (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1‑x (Nb 0.5 La 0.5 ) x ]O3 powder, finely grinding the powder and adding polyvinyl alcohol to granulate, pressing and molding to obtain a green body; removing organic matter from the green body at 500 ° C to obtain a green body; sintering the green body at 1400-1450 ° C to obtain the BCZT-based energy storage ceramic material. The preparation method of the BCZT-based energy storage ceramic material of the present invention is simple, has good repeatability, high yield, and has high energy storage density ( W rec =3.1 J / cm 3 ) and efficiency (86.7%), high breakdown field strength ( E b =410 kV / cm) and excellent fatigue resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic ceramics and devices, and particularly relates to a high-energy-density and high-efficiency energy storage ceramic with excellent breakdown field strength and anti-fatigue performance and a preparation method thereof. BACKGROUND

[0002] The high-energy-density ceramic has a wide application prospect in the electronic industry and new-generation information industrial technology fields such as artificial intelligence, Internet of Things and 5G due to its fast charging and discharging speed, strong anti-cycle aging ability, stable performance under extreme conditions such as high temperature and high pressure and the like.

[0003] There are four kinds of energy storage technologies, i.e., mechanical energy storage, electromagnetic energy storage, capacitor energy storage and electrochemical energy storage. Among them, the ceramic capacitor energy storage has become one of the most widely used energy storage devices in high-power pulse power systems due to its high energy storage density, fast energy storage speed and miniaturization and the like.

[0004] In 2009, scholars Liu and Ren prepared a new BCZT material, i.e., barium calcium titanate Ba(Ti 0.8 ZrO 0.2 )O3-(Ba 0.7 Ca 0.3 )TiO3 (BCZT), which does not contain volatile elements and thus can maintain a predetermined stoichiometric ratio after high-temperature calcination. Due to its excellent performance and environmental friendliness, the BCZT material has attracted extensive attention since its appearance and is considered to be able to replace the traditional lead-based perovskite material.

[0005] (Ba 0.85 Ca 0.15 )(Zr 0.1 Ti 0.9 )O3(BCZT) has a high d 33 However, the research on the energy storage of BCZT is less, and since the BCZT is in a ferroelectric phase at room temperature, the dielectric loss is large, the dielectric constant decreases with the increase of the electric field, and thus the energy storage density is only 0.20-0.30 J / cm 3 , and the energy storage efficiency is lower than 75%. SUMMARY

[0006] The application aims to provide a BCZT-based energy storage ceramic material with high energy storage density, high breakdown field strength and good anti-fatigue performance and a preparation method thereof.

[0007] To achieve the above object, the BCZT-based energy storage ceramic material provided by the application has a general formula of (Ba 0.85Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1-x (Nb 0.5 La 0.5 ) x ]O3, wherein, x is the number of moles, x is in the range of 0.06-0.15, preferably x is in the range of 0.12. The ceramic material is in a paraelectric phase at room temperature.

[0008] The preparation method of the BCZT-based energy storage ceramic material of the present application comprises the following steps:

[0009] Step 1: according to the stoichiometric ratio of (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1-x (Nb 0.5 La 0.5 ) x ]O3, BaCO3, CaCO3, ZrO2, TiO2, La2O3 and Nb2O5 with a purity of 99.00% or above are weighed respectively, and the weighed raw materials are mixed uniformly and then put into a planetary ball mill, with zirconium balls as grinding balls and anhydrous ethanol as ball milling medium, and then mixed and ball milled for 20-24 hours, and then dried at 60-80℃ for 20-24 hours to obtain a raw material mixture;

[0010] Step 2: the raw material mixture is pre-fired at 1200-1250℃ for 2-3 hours to obtain (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1-x (Nb 0.5 La 0.5 ) x ]O3 pre-fired powder;

[0011] Step 3: the (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1-x (Nb 0.5 La 0.5 ) x ]O3 pre-fired powder obtained in Step 2 is granulated, tabletted, and de-glued, and then sintered at 1400-1450℃ for 2-4 hours to prepare a BCZT-based energy storage ceramic material.

[0012] In the above step 2, the raw material mixture is preferably heated to 1200° C. at a heating rate of 3 to 5° C. / min and pre-calcined at the constant temperature for 2 hours.

[0013] In the above step 3, the tableting is first performed by using a powder tablet press to press the powder into a cylindrical green body at a pressure of 6 to 10 MPa, and then cold isostatically pressing the green body at a pressure of 210 to 230 MPa for 4 to 6 minutes.

[0014] In the above step 3, it is further preferred that the temperature be raised to 1440° C. at a rate of 3 to 5° C. / min and sintered at a constant temperature for 4 hours.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention is carried out by (Ba 0.85 Ca 0.15 )(Zr 0.1 Ti 0.9 )O3 ceramics (Nb 0.5 La 0.5 ) 4+ By modifying the BCZT by doping and regulating its Curie temperature to below room temperature, the material presents a paraelectric phase at room temperature, thereby improving the energy storage density and efficiency of the material. This results in an energy storage ceramic with high energy storage density and efficiency, high breakdown electric field strength, and good fatigue resistance. The breakdown electric field strength is above 310 kV / cm. Under a working electric field of 410 kV / cm, the energy storage density that can be released is 3.1 J / cm. 3 The energy storage efficiency is 86.7%, and the energy storage density can be released in 10 cycles. 5 The fluctuation after the test is no more than 3%, and the fluctuation of the releasable energy storage density in the frequency range of 1Hz to 150Hz does not exceed 11%.

[0017] 2. The ceramic material of the present invention is synthesized by the traditional solid-phase sintering method, which has a simple preparation process, low cost, good repeatability, and no toxic organic metal compounds are used in the preparation process, and no toxic additional products are produced. It meets the requirements of environmental friendliness and is suitable for industrial large-scale production.

[0018] 3. The energy storage ceramic material of the present invention can be used to manufacture energy storage multilayer ceramic capacitors, and expands the application field of barium calcium zirconate titanate-based ceramic materials in energy storage, which is conducive to promoting the application and development of high energy storage density ceramic technology and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is the XRD diffraction pattern of the BCZT-based energy storage ceramic material prepared in Examples 1 to 4.

[0020] Figure 2are surface SEM images of BCZT-based energy storage ceramic materials prepared in Examples 1-4, (a), (b), (c), (d) correspond to Examples 1, 2, 3, 4, respectively.

[0021] Figure 3 are hysteresis loop graphs of BCZT-based energy storage ceramic materials prepared in Examples 1-4 at critical breakdown field strength.

[0022] Figure 4 are corresponding energy storage density, polarization difference ΔP and energy storage efficiency of BCZT-based energy storage ceramic materials prepared in Examples 1-4 at critical breakdown field strength. P

[0023] Figure 5 are anti-fatigue test graph (a) and corresponding energy storage performance (b) of BCZT-based energy storage ceramic material prepared in Example 3. DETAILED DESCRIPTION

[0024] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with embodiments. It should be understood that the following embodiments are only used to illustrate but not limit the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of the present application. Example 1

[0025] The chemical formula of the BCZT-based energy storage ceramic material in this example is

[0026] (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 0.94 (Nb 0.5 La 0.5 ) 0.06 ]O3, and the preparation process is as follows:

[0027] Step 1: according to (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 0.94 (Nb 0.5 La 0.5 ) 0.06 ​The stoichiometric ratio of O3, respectively, BaCO3 12.4188 g, CaCO3 1.1005 g, ZrO2 0.8490 g, TiO2 4.9794 g, La2O3 0.3600 g, Nb2O5 0.2923 g with purity of 99.00% or above were weighed, and all the weighed raw materials were mixed uniformly and then put into a planetary ball mill with zirconium ball as the grinding ball and anhydrous ethanol as the ball milling medium. The ball milling power was 255 kW, the speed was 120 r / min, and the ball milling time was 24 h. After the powder was mixed uniformly, it was poured into a culture dish and dried in an 80 ℃ oven for 24 hours to obtain a raw material mixture.

[0028] Step 2: The raw material mixture was placed in an alumina crucible and compacted with a agate rod. The temperature was increased to 120 ℃ at a rate of 5 ℃ / min, and the temperature was kept for 2 h. The furnace was cooled down to obtain a perovskite structure (Ba 0.85 Ca 0.15 )(Zr 0.10 Ti 0.90 ) 0.94 (Nb 0.5 La 0.5 ) 0.06 O3 presintered body.

[0029] Step 3: 5% polyvinyl alcohol aqueous solution was added to the presintered body obtained in step 2. The amount of polyvinyl alcohol aqueous solution added was 5% of the mass of the presintered powder, and the polyvinyl alcohol aqueous solution was added in three times at 5-8 drops / g each time, and each time was ground for about half an hour. The powder was ground for 2 h. Then the obtained powder was pressed into a cylindrical blank with a diameter of 10 mm and a thickness of 1 mm by a powder tablet press at a pressure of 6 MPa for 3 min, and the cylindrical blank was placed in a cold isostatic pressing machine and pressed at a pressure of 200 MPa for 5 min for cold isostatic pressing. The obtained green compact was placed in a 500 ℃ oven for 3 h for plastic removal. The green compact after plastic removal was heated to 1420 ℃ at a heating rate of 5 ℃ / min, and kept for 4 h for sintering. The furnace was cooled down to obtain a BCZT-based energy storage ceramic material with a chemical formula of

[0030] (Ba 0.85 Ca 0.15 )(Zr 0.10 Ti 0.90 ) 0.94 (Nb 0.5 La 0.5 ) 0.06 O3. Example 2

[0031] In this embodiment, a BCZT-based energy storage ceramic material with a chemical formula of

[0032] (Ba 0.85 Ca 0.15[(Zr 0.10 Ti 0.90 ) 0.91 (Nb 0.5 La 0.5 ) 0.09 ]O3-based energy storage ceramic material, wherein in step 3, the green body after degassing is heated to 1430 ℃ at a heating rate of 5 ℃ / min, and sintered for 4 h. Example 3

[0033] In this example, the BCZT-based energy storage ceramic material of the chemical formula

[0034] (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 0.88 (Nb 0.5 La 0.5 ) 0.12 ]O3is prepared according to the method of Example 1, wherein in step 3, the green body after degassing is heated to 1440 ℃ at a heating rate of 5 ℃ / min, and sintered for 4 h. Example 4

[0035] In this example, the BCZT-based energy storage ceramic material of the chemical formula

[0036] (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 0.85 (Nb 0.5 La 0.5 ) 0.15 ]O3is prepared according to the method of Example 1, wherein in step 3, the green body after degassing is heated to 1450 ℃ at a heating rate of 5 ℃ / min, and sintered for 4 h.

[0037] The BCZT-based energy storage ceramic materials prepared in Examples 1-4 above are subjected to XRD testing, and the testing results are shown in Figure 1 . It can be seen from Figure 1 that (Nb 0.5 La 0.5 ) 4+ doping (Ba 0.85 Ca 0.15 )(Zr 0.10 Ti 0.90)O3 lattice, the crystal structure is pseudo cubic, and no second phase appears. The (200) peak near 44.8-45.6° is slightly split, and the main peaks of different components change. That is, with the increase of doping amount, the interplanar spacing changes, indicating that the lattice constant increases. This may be due to the increase of ionic radius (Nb 0.5 La 0.5 ) 4+ (0.0836 nm, Nb 5+ :0.064, La 3+ : 0.1032 nm, CN = 6) (Zr 0.10 Ti 0.90 ) 4+ (0.0665, Zr 4+ : 0.072 nm, CN = 6; Ti 4+ : 0.061 nm, CN = 6) is too large.

[0038] The surface SEM observation of the BCZT-based energy storage ceramic materials prepared in Examples 1 to 4 was carried out. Figure 2 It can be seen that Examples 1 to 4 have uniform grains, clear grain boundaries, fewer pores, and high ceramic density.

[0039] The BCZT-based energy storage ceramic materials prepared in Examples 1 to 4 were polished to 200 μm using 2000-mesh corundum and distilled water. After polishing, the samples were cleaned and sprayed with an electrode with a diameter of 2 mm in an ion sputtering instrument. The hysteresis loops were then measured at room temperature. The test results are shown in Table 1. Figure 3 .Depend on Figure 3 It can be seen that the breakdown electric field of the energy storage ceramic material of Example 1 reaches 310 kV / cm, the breakdown electric field of the energy storage ceramic material of Example 2 reaches 340 kV / cm, the breakdown electric field of the energy storage ceramic material of Example 3 reaches 410 kV / cm, and the breakdown electric field of the energy storage ceramic material of Example 4 reaches 340 kV / cm. Figure 4 Depend on Figure 3 It can be seen from the calculation that the Δ P Reached 23.26 μC / cm 2 , energy storage density up to 2.14 J / cm 3 ， While maintaining a large energy storage density, the efficiency is as high as 87.4%; Δ P Reached 22.27 μC / cm 2 , energy storage density up to 2.65 J / cm 3 , while maintaining a large energy storage density, the efficiency is as high as 86.2%; Example 3 Energy Storage Ceramic Material ΔP reached 19.81 μC / cm 2 , the energy storage density reached 3.11 J / cm 3 , and the efficiency was as high as 86.7% while maintaining a large energy storage density; the Δ P of the energy storage ceramic material of Example 4 reached 14.51 μC / cm 2 , and the energy storage density reached 2.02 J / cm 3 . Among them, the BCZT-based energy storage ceramic material prepared in Example 3 had E b an energy storage density of 410 kV / cm, the energy storage density reached the maximum (3.11 J / cm 3 ), and the energy storage efficiency was relatively high (86.7%).

[0040] The anti-fatigue test of the BCZT-based energy storage ceramic material prepared in Example 3 was carried out, and the test results are shown in Figure 5 , and the energy storage efficiency fluctuation was not more than 3% after 10 5 cycles.

Claims

1. A BCZT-based energy storage ceramic material with high breakdown field strength, characterized by: The general formula of the ceramic material is (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1-x (Nb 0.5 La 0.5 ) x ]O3, where x The value of is 0.06~0.15; the ceramic material is in paraelectric phase at room temperature; The ceramic material is prepared by the following steps: Step 1: Follow (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1-x (Nb 0.5 La 0.5 ) x ]O3 in a stoichiometric ratio, respectively weighing BaCO3, CaCO3, ZrO2, TiO2, La2O3 and Nb2O5 with a purity of more than 99.00%, mixing all the weighed raw materials evenly, placing them in a planetary ball mill using zirconium balls as grinding balls and anhydrous ethanol as ball milling medium, fully mixing and ball milling for 20 to 24 hours, and drying at 60 to 80°C for 20 to 24 hours to obtain a raw material mixture; Step 2: Pre-calcine the raw material mixture at 1200-1250°C for 2-3 hours to obtain (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1-x (Nb 0.5 La 0.5 ) x ]O3 pre-burned powder; Step 3: The (Ba 0.85 Ca 0.15 )[(Zr 0.10 Ti 0.90 ) 1-x (Nb 0.5 La 0.5 ) x ]After granulation, tableting and binder removal, the O3 pre-calcined powder is sintered at a constant temperature of 1400-1450 ℃ for 2-4 hours to prepare BCZT-based energy storage ceramic materials.

2. The BCZT-based energy storage ceramic material with high breakdown field strength according to claim 1, characterized in that: x The value of is 0.

12.

3. The BCZT-based energy storage ceramic material with high breakdown field strength according to claim 1, characterized in that: In step 2, the raw material mixture is heated to 1200° C. at a heating rate of 3 to 5° C. / min and pre-calcined at the constant temperature for 2 hours.

4. The BCZT-based energy storage ceramic material with high breakdown field strength according to claim 1, characterized in that: In step 3, the tableting is performed by using a powder tablet press to press the tablet into a cylindrical green body at a pressure of 6 to 10 MPa, and then cold isostatically pressing the green body at a pressure of 210 to 230 MPa for 4 to 6 minutes.

5. The BCZT-based energy storage ceramic material with high breakdown field strength according to claim 4, characterized in that: In step 3, the temperature is raised to 1440° C. at a rate of 3 to 5° C. / min and sintered at a constant temperature for 4 hours.

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