A copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency and a preparation method thereof

Abstract

The application belongs to the field of energy storage ceramic materials, and specifically provides a copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency and a preparation method thereof. 0.97 Cu 0.03 )O3‑xNa(Nb 1‑y Ta y )O3(0.02≤x≤0.2, 0.05≤y≤0.2). Different valence ions are introduced into A sites and B sites of Ba(Ti 0.97 Cu 0.03 )O3 ceramics, thereby producing charge mismatch, Na + is introduced into the A sites to form Na + -Na + ion pairs and improve local polarization intensity, thereby improving energy storage density, Nb 5+ and Ta 5+ ions with different valences are introduced into the B sites to cause distortion of oxygen octahedrons and increase of displacement of B-site cations, thereby producing lattice distortion and improving energy storage efficiency and breakdown strength. The method is simple in steps, low in equipment requirement, and can be mass-produced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of energy storage ceramic materials, and particularly relates to a copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency and a preparation method thereof. BACKGROUND

[0002] Ship ballast water is water and suspended matter added to a ship to control the smooth and safe sailing of the ship in water. However, a large amount of organisms contained in the ship ballast water will enter a new environment along with the sailing of the ship, causing pollution of marine organisms. With the requirements of environmental protection and the promotion of the sustainable development strategy, a variety of methods for treating ballast water such as the shore discharge method, the chemical treatment method and the ultraviolet inactivation technology have been put into practical use, but these methods have problems such as regionalism, safety and poor sterilization effect.

[0003] In recent years, it has become an inevitable trend to use pulse power technology to solve the problem of ballast water pollution. This is because pulse power technology can produce a series of complex physical and chemical effects in a very short discharge process and form a high-temperature and high-pressure plasma channel, which can degrade organic matter in ballast water and quickly kill deadly microorganisms and larger algae in water without secondary pollution. Researchers use pulse arc liquid discharge to treat ballast water, and the effect of removing microorganisms reaches 99.8%, and the degradation rate of larger microalgae can reach 99.9%, which is about 2.90-5.14 times higher than that of commercial ultraviolet treatment of ballast water (J. Electrostat. 71 (2013) 728). However, with the continuous development of pulse devices towards miniaturization, lightness and multi-function, higher requirements are put forward for pulse power technology to solve the problem of ballast water pollution. As the core energy storage element of pulse technology, dielectric ceramic energy storage materials need to have higher energy storage density (>3 J / cm 3 ) and efficiency (>90%) at the same time.

[0004] At present, among lead-free functional ceramics, barium titanate ceramics have the advantages of high dielectric constant, low loss, small temperature change rate and fast response speed, and are potential pulse energy storage element materials. How to improve the energy storage density (<1 J / cm 3 ) of barium titanate ceramics is a technical bottleneck for its application in the field of pulse power. At present, the main method to improve the energy storage performance of barium titanate ceramics is to add Bi 0.5 Na 0.5TiO3, BiMeO3 (Me=Y, Al, Sc, etc.) and other systems form binary or ternary solid solutions (references: Ceram. Int., 2012, 38, S41-S44; J. Am. Ceram. Soc., 2009, 92, 110-118; Ceram. Int., 2021, 47, 12450-12458; Chem. Eng. J., 2021, 409, 128231). Although such solid solutions can obtain high energy storage performance to meet the requirements of pulse energy storage elements, the inevitable volatilization of metal elements such as Bi during the preparation process will cause the accumulation of internal electric charge, which seriously affects the average life, breakdown strength and stability of the material, and it is difficult to meet the requirements of pulse capacitors in fatigue resistance and temperature stability. SUMMARY

[0005] One of the purposes of the present application is to provide a copper barium titanate-based relaxor ferroelectric ceramic material capable of meeting the pulse energy storage element for treating ship ballast water, and having high energy storage density and high efficiency; the second purpose of the present application is to provide a design method of a bidirectional optimization strategy to obtain a ferroelectric ceramic material with high energy storage density and high efficiency.

[0006] In order to achieve the above-mentioned purposes, the present application provides the following technical solutions:

[0007] On the one hand, a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency for high-voltage pulse is provided, and the chemical formula of the copper barium titanate-based energy storage ceramic material is (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein 0.02≤x≤0.2, 0.05≤y≤0.2. The optimal value is obtained when x=0.10 and y=0.15, and the energy storage density thereof can reach 5.64 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency can be stabilized at more than 90%; in addition, the composition also has a uniform and dense microstructure, high breakdown strength and excellent cycle service life.

[0008] On the other hand, a design method of a bidirectional optimization strategy to obtain a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency is provided, that is, a bidirectional optimization strategy, Na(Nb 0.97 Cu 0.03 )O3 is added to Ba(Ti 1-y Ta y )O3 to introduce Na + -Na + ion pairs to the A site of the matrix to improve the local polarization strength and thus improve the energy storage density; at the same time, Na(Nb0.97 Cu 0.03 )O3 matrix, Nb and Ta ions are introduced into B site, which causes the distortion of oxygen octahedron and the increase of B site cation displacement, resulting in the lattice distortion, the thinning of hysteresis loop, the improvement of energy storage efficiency and breakdown strength. The preparation process comprises the following steps:

[0009] Step 1: (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3 stoichiometric ratio of the corresponding BaCO3, TiO2, CuO, Ta2O5, Nb2O5, Na2CO3 powder, then the obtained raw materials are ball milled in anhydrous ethanol as medium, uniformly mixed, dried in a drying oven, ground into powder, and the powder is obtained;

[0010] Step 2, the powder obtained in step 1 is sieved through an 80 mesh sieve and then pressed into a columnar block, pre-sintered at a temperature of 1050-1200℃, then naturally cooled to room temperature, and then ball milled again, dried and ground to obtain (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3 ceramic powder;

[0011] Step 3, the powder obtained in step 2 is sieved through a 120 mesh sieve, then 8wt.% polyvinyl alcohol aqueous solution is added, the mass ratio of polyvinyl alcohol aqueous solution to ceramic powder is 1:10, and then the mixture is uniformly mixed in a mortar and then placed in a mold and pressed into a green sheet under a pressure of 120 MPa;

[0012] Step 4, the green sheet obtained in step 3 is sintered with the same component powder as the embedding material to obtain a ceramic material.

[0013] Step 5, the sintered ceramic sample in step 4 is polished and ground to a thickness of 0.15-0.2mm, and then washed, dried and silver-coated to obtain a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency.

[0014] Further, the mass ratio of the raw material: zirconia ball: anhydrous ethanol during ball milling is equal to 1:2:4, the ball milling time is 20h, the rotation speed is 1500r / min, and the drying oven temperature is 80-110℃.

[0015] Further, in steps 1 and 2, the powder is placed in a high-purity alumina crucible during pre-sintering, the holding time is 4h, and the heating rate is 4℃ / min.

[0016] Further, the blank in step 3 is a cylindrical blank with a diameter of 12 mm and a thickness of 1-1.5 mm.

[0017] Further, the sintering in step 4 is specifically as follows: first, increase to 650 DEG C at a rate of 2 DEG C / min and keep for 4 h, then increase to 1050-1200 DEG C at a rate of 4 DEG C / min, increase to 1240-1300 DEG C at a rate of 2 DEG C / min and keep for 4 h, then decrease to 1050-1200 DEG C at a rate of 2 DEG C / min, and then naturally cool to room temperature.

[0018] Further, the same kind of powder in step 4 is the pre-sintered (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3 ceramic powder in step 2, and the mass ratio of the powder to the blank is 4:1.

[0019] The beneficial effects of the present application are as follows:

[0020] The technical scheme of the present application optimizes the substitution, and invents a copper barium titanate-based energy storage ceramic material which does not contain volatile substances and has high energy storage density, high power density and high efficiency, and the chemical formula is (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3. The present application uses a bidirectional optimization strategy, i.e., substituting Ba + -Na + ions in the A position of the Ba(Ti 0.97 Cu 0.03 )O3 matrix with Na(Nb 2+ Ta 2+ )O3, to improve the local polarization strength and thus improve the energy storage density; at the same time, introducing Nb and Ta heterovalent ions in the B position of the Ba(Ti 0.97 Cu 0.03 )O3 matrix causes the distortion of the oxygen octahedron and the increase of the B position cation displacement, produces lattice distortion, and makes the hysteresis loop thin, thereby improving the energy storage efficiency and breakdown strength. Moreover, the grain size of the component is small, and the density is high; the component does not contain volatile elements, which can reduce the cracks and defects in the crystal, and obtain a higher breakdown field strength. In addition, generally, materials will crack after several thousand cycles, but the material obtained by using this strategy can also improve the average service life. Through experimental verification, the energy storage density and efficiency of the ceramic system are 5.64 J / cm 3and 90.4%, which has exceeded the performance of most of the reported energy storage ceramics. In addition, the material is low in cost, simple in preparation method, friendly to the environment, long in service life, and can be mass-produced, which all indicate that the (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3 ceramic material can be applied in the field of pulse energy storage and meet the treatment of ship ballast water. At present, there is no report on the Ba(Ti 0.97 Cu 0.03 )O3-based relaxor ferroelectric ceramic which can simultaneously obtain high energy storage density and high efficiency without introducing volatile elements. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A surface scanning electron microscope structure map of the copper barium titanate-based energy storage ceramic material prepared in Example 3;

[0022] Figure 2 A hysteresis loop of the copper barium titanate-based energy storage ceramic material prepared in Example 3; the insert is a curve of the energy storage properties of the copper barium titanate-based relaxor ferroelectric ceramic prepared in Example 3 changing with the electric field intensity;

[0023] Figure 3 A pulse cycle curve of the copper barium titanate-based energy storage ceramic material prepared in Example 3; the insert is a corresponding change curve of the pulse discharge density;

[0024] Figure 4 A breakdown strength of the copper barium titanate-based energy storage ceramic material prepared in Examples 1-4;

[0025] Figure 5 A curve of the pulse discharge density of the ceramic material prepared in Examples 1-7 and Comparative Example 1 under different cycles. DETAILED DESCRIPTION

[0026] The application will be further described in detail below in combination with examples.

[0027] The application relates to a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency obtained by using a bidirectional optimization strategy and a preparation method thereof. 0.97 Cu 0.03 )O3 ceramic material as an object, Na + , Nb 5+ and Ta 5+ ions are introduced into the crystal lattice of the Ba(Ti 0.97 Cu 0.03 )O3 ceramic by a solid-phase sintering method, so that a chemical composition of (1-x)Ba(Ti 0.97 Cu0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein 0.02≤x≤0.2, 0.05≤y≤0.2, the sample has high energy storage density, high efficiency and excellent pulse cycle stability. The method comprises the following steps:

[0028] 1. Weighing raw materials: according to the stoichiometric ratio, the required raw materials are weighed: copper oxide with a purity of 99.5%, titanium dioxide with a purity of 99.8%, barium carbonate with a purity of 99.9%; sodium carbonate with a purity of 99.8%, niobium pentoxide with a purity of 99.5%, and tantalum pentoxide with a purity of 99.99%.

[0029] 2. Ball milling and drying: the weighed raw materials are put into a ball milling tank for ball milling and mixing, anhydrous ethanol is added to the tank, and the mass ratio of raw materials: agate balls: anhydrous ethanol is 1:2:4, the ball milling time is 20h (ball milling speed is 1500r / min), then the ball-milled raw materials are put into an oven and dried at 80℃.

[0030] 3. Pre-burning: after the ball-milled and dried powder is ground through an 80-mesh sieve, it is pressed into a columnar block, which is placed in a high-purity alumina crucible, and heated to 1050-1200℃ at a rate of 4℃ / min, and calcined for 4h, and then naturally cooled to room temperature.

[0031] 4. Granulation and tabletting: the pre-burned columnar block is put into a ball milling tank and ball-milled again under the same conditions as the first ball milling for 20h, then dried at 80℃, and then ground through a 120-mesh sieve to obtain fine ground powder. An appropriate amount of 8wt% polyvinyl alcohol aqueous solution (the mass ratio of polyvinyl alcohol aqueous solution to powder is 1:10) is added to the obtained fine ground ceramic powder for granulation, and after thorough mixing, the granulated powder is sieved through a 120-mesh sieve, and the granulated powder is molded under a pressure of 120MPa to obtain small cylindrical bodies with a size of 12mm in diameter and about 1mm in height.

[0032] 5. High-temperature sintering: the pressed cylindrical body is sintered with the same component (1-x) Ba(Ti 0.97 Cu 0.03 )-xNa(Nb 1- y Ta y )O3 powder as a buried material (the mass ratio of buried material to cylindrical body is 4:1), first heated to 650℃ at a rate of 2℃ / min and kept for 4h, then heated to 1050-1200℃ at a rate of 4℃ / min, then heated to 1240-1300℃ at a rate of 2℃ / min and kept for 4h, then cooled to 1050-1200℃ at a rate of 2℃ / min, and then naturally cooled to room temperature to obtain a ceramic material.

[0033] 6. Polish and grind the sintered ceramic material to a thickness of about 0.15mm, then clean, dry, and coat with electrodes to obtain barium copper titanate-based ceramic with both high energy storage density and high efficiency.

[0034] Unless otherwise specified, all methods in this invention are conventional methods. The raw material powders used in this invention were purchased from Sinopharm Chemical Reagent Co., Ltd. The breakdown strength data involved in this invention were obtained from measurements using the Shanghai Tongguo Insulation Withstand Voltage Tester; the energy density and energy efficiency data involved in this invention were calculated from polarization-electric field strength (PE) curves obtained using the Agilent Ferroelectric Comprehensive Analyzer.

[0035] Example 1

[0036] The chemical composition is (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y The O3 formula, where x = 0.06 and y = 0.15, involves weighing raw materials according to chemical proportions, ball milling for 20 hours, drying, grinding through an 80-mesh sieve, pressing into cylindrical blocks, placing the pressed cylindrical blocks in a sintering furnace for pre-sintering at 1150℃ for 4 hours at a heating rate of 4℃ / min, and then allowing them to cool naturally. The pre-sintered ceramic powder is then ball-milled a second time, dried, ground through a 120-mesh sieve to obtain finely ground powder, pressed into sheets, and placed in a sintering furnace for sintering. The temperature is first raised to 650℃ at a rate of 2℃ / min and held for 4 hours to remove the binder. Then, the temperature is raised to 1150℃ at a rate of 4℃ / min, then raised to 1270℃ at a rate of 2℃ / min and held for 4 hours. Finally, the temperature is lowered to 1150℃ at a rate of 2℃ / min and allowed to cool naturally to room temperature in the furnace to obtain the ceramic material. The sintered ceramic material was polished to a thickness of approximately 0.15 mm, then cleaned, dried, and silver-coated to obtain a barium copper titanate-based energy storage ceramic material with both high energy density and high efficiency. The breakdown strength of the barium copper titanate-based energy storage ceramic material prepared in this composition was tested with an insulation withstand voltage tester to be 447 kV / cm. Calculations using the polarization-electric field strength (PE) curve obtained from an Agilent ferroelectric comprehensive analyzer showed that the energy storage density reached 4.01 J / cm² under an electric field of 420 kV / cm. 3 The energy storage efficiency reaches 84.5%.

[0037] Example 2

[0038] The chemical composition is (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y)O3, wherein x = 0.08, y = 0.15, the raw materials are weighed in a stoichiometric ratio, ball-milled for 20 h, dried, ground through an 80-mesh sieve, and pressed into a cylindrical block. The pressed cylindrical block is placed in a sintering furnace for pre-sintering, raised to 1150°C at a rate of 4°C / min, and pre-sintered for 4 h, and then naturally cooled. The pre-sintered ceramic powder is dried after secondary ball-milling, ground through a 120-mesh sieve to obtain a finely ground powder, pressed into a disc, and sintered in a sintering furnace. The pressed disc is first raised to 650°C at a rate of 2°C / min, held for 4 h to remove glue, then raised to 1150°C at a rate of 4°C / min, raised to 1270°C at a rate of 2°C / min, and held for 4 h, then lowered to 1150°C at a rate of 2°C / min, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. Testing shows that the copper-barium titanate-based energy storage ceramic material prepared from this composition has a breakdown strength of 518 kV / cm, an energy storage density of 4.78 J / cm 3 at an electric field of 420 kV / cm, and an energy storage efficiency of 87.4%.

[0039] Example 3

[0040] A composition of (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein x = 0.10, y = 0.15, the raw materials are weighed in a stoichiometric ratio, ball-milled for 20 h, dried, ground through an 80-mesh sieve, and pressed into a cylindrical block. The pressed cylindrical block is placed in a sintering furnace for pre-sintering, raised to 1150°C at a rate of 4°C / min, and pre-sintered for 4 h, and then naturally cooled. The pre-sintered ceramic powder is dried after secondary ball-milling, ground through a 120-mesh sieve to obtain a finely ground powder, pressed into a disc, and sintered in a sintering furnace. The pressed disc is first raised to 650°C at a rate of 2°C / min, held for 4 h to remove glue, then raised to 1150°C at a rate of 4°C / min, raised to 1270°C at a rate of 2°C / min, and held for 4 h, then lowered to 1150°C at a rate of 2°C / min, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency.

[0041] Figure 1 A scanning electron microscope (SEM) image of the ceramic material prepared in Example 3 is shown, from which it can be seen that the ceramic material has a dense structure and a uniform grain size. Figure 1It can be seen from the figure that the ceramic material has a uniform and dense microstructure, and the grain size is about 1 μm. Figure 2 The monopolar electric hysteresis loop of the ceramic sample prepared in Example 3 was tested by an Agilent ferroelectric analyzer at room temperature, and the results are shown in Figure 2 It can be seen from the figure that the ceramic has an elongated electric hysteresis loop. Figure 2 The inset figure is the curve of the energy storage characteristics of the copper barium titanate-based energy storage ceramic material prepared in this example 3 with the change of electric field intensity, and it can be seen from the figure that the energy storage density of the ceramic can reach 5.64 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency can be stabilized at more than 90%. Figure 3 The pulse cycle curve of the copper barium titanate-based energy storage ceramic material prepared in Example 3 at 220 kV / cm; the prepared sample can still maintain stable pulse discharge after experiencing multiple cycles, and the inset figure is the corresponding change of pulse discharge density, and it can be seen from the figure that the change range is within 5%, indicating that it has excellent cycle service life.

[0042] Example 4

[0043] The chemical composition of (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein x=0.12, y=0.15, the raw materials are weighed according to the chemical ratio, ball milled for 20 h, dried, ground through an 80 mesh sieve, and then pressed into a columnar block. The pressed columnar block is placed in a sintering furnace for pre-sintering, and the temperature is raised to 1150℃ at a rate of 4℃ / min, and then pre-sintered for 4 h, and then naturally cooled. The pre-sintered ceramic powder is dried after secondary ball milling, ground through a 120 mesh sieve to obtain fine ground powder, and then pressed into a disc. The pressed disc is placed in a sintering furnace for sintering, and the temperature is first raised to 650℃ at a rate of 2℃ / min, and then held for 4 h to remove glue, and then raised to 1150℃ at a rate of 4℃ / min, and then raised to 1270℃ at a rate of 2℃ / min, and then held for 4 h, and then reduced to 1150℃ at a rate of 2℃ / min, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. The copper barium titanate-based energy storage ceramic material prepared from this component has a breakdown strength of 503 kV / cm, an energy storage density of 4.74 J / cm 3 at an electric field of 420 kV / cm, and an energy storage efficiency of 87.9%. The breakdown strength of the ceramic samples prepared in Comparative Examples 1-4 at room temperature is compared, and the results are shown in Figure 4As can be seen, the ceramic of Example 3 has the highest breakdown strength, which also means that the energy storage performance is optimal.

[0044] Example 5

[0045] A formula with a chemical composition of (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein x = 0.10 and y = 0.05, is prepared. Raw materials are weighed according to the chemical proportions, ball-milled for 20 h, dried, ground through an 80-mesh sieve, and pressed into a cylindrical block. The pressed cylindrical block is placed in a sintering furnace for pre-sintering, with a heating rate of 4°C / min to 1150°C, and pre-sintered for 4 h with natural cooling. The pre-sintered ceramic powder is ball-milled again, dried, ground through a 120-mesh sieve to obtain fine ground powder, pressed into a disc, and sintered in a sintering furnace. The pressed disc is first heated at a rate of 2°C / min to 650°C for 4 h to remove glue, then heated at a rate of 4°C / min to 1150°C, then heated at a rate of 2°C / min to 1270°C and held for 4 h, then heated at a rate of 2°C / min to 1150°C, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. Testing shows that the breakdown strength of the copper barium titanate-based energy storage ceramic material prepared from this composition is 443 kV / cm, the energy storage density reaches 4.21 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency reaches 85.5%.

[0046] Example 6

[0047] A formula with a chemical composition of (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y)O3 of which x = 0.10, y = 0.10, the raw materials are weighed according to the chemical proportion, ball-milled for 20h, dried, ground through an 80-mesh sieve, pressed into a cylindrical block, and pre-sintered in a sintering furnace at a heating rate of 4°C / min to 1150°C for 4h, and naturally cooled. The pre-sintered ceramic powder is secondarily ball-milled, dried, ground through a 120-mesh sieve to obtain fine ground powder, pressed into a disc, and sintered in a sintering furnace at a rate of 2°C / min to 650°C for 4h to remove glue, then at a rate of 4°C / min to 1150°C, at a rate of 2°C / min to 1270°C for 4h, at a rate of 2°C / min to 1150°C, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15mm, and then washed, dried, and coated with silver to obtain a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. The copper barium titanate-based energy storage ceramic material prepared from this composition has a breakdown strength of 523kV / cm, an energy storage density of 4.97J / cm 3 at an electric field of 420kV / cm, and an energy storage efficiency of 88.6%.

[0048] Example 7

[0049] A formula of (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3 of which x = 0.10, y = 0.20, the raw materials are weighed according to the chemical proportion, ball-milled for 20h, dried, ground through an 80-mesh sieve, pressed into a cylindrical block, and pre-sintered in a sintering furnace at a heating rate of 4°C / min to 1150°C for 4h, and naturally cooled. The pre-sintered ceramic powder is secondarily ball-milled, dried, ground through a 120-mesh sieve to obtain fine ground powder, pressed into a disc, and sintered in a sintering furnace at a rate of 2°C / min to 650°C for 4h to remove glue, then at a rate of 4°C / min to 1150°C, at a rate of 2°C / min to 1270°C for 4h, at a rate of 2°C / min to 1150°C, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15mm, and then washed, dried, and coated with silver to obtain a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. The copper barium titanate-based energy storage ceramic material prepared from this composition has a breakdown strength of 476kV / cm, an energy storage density of 4.53J / cm 3 at an electric field of 420kV / cm, and an energy storage efficiency of 87.9%.

[0050] Example 8

[0051] A formula of chemical composition of (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein x = 0.10, y = 0.15, raw materials are weighed in chemical proportions, ball-milled for 20 h, dried, ground through an 80-mesh screen, and pressed into a cylindrical block. The pressed cylindrical block is placed in a sintering furnace for pre-sintering, with a heating rate of 4°C / min to 1050°C, and pre-sintered for 4 h with natural cooling. The pre-sintered ceramic powder is secondarily ball-milled, dried, and ground through a 120-mesh screen to obtain a finely ground powder. The powder is pressed into a round sheet, which is placed in a sintering furnace for sintering. The round sheet is first heated at a rate of 2°C / min to 650°C, held for 4 h to remove glue, then heated at a rate of 4°C / min to 1050°C, then heated at a rate of 2°C / min to 1270°C, held for 4 h, then heated at a rate of 2°C / min to 1050°C, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. Testing shows that the energy storage density of the ceramic can reach 3.21 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency can be stabilized at 83%.

[0052] Example 9

[0053] A formula of chemical composition of (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y)O3, wherein x = 0.10, y = 0.15, the raw materials are weighed in a stoichiometric ratio, ball-milled for 20 h, dried, ground through an 80-mesh sieve, and pressed into a cylindrical block. The pressed cylindrical block is placed in a sintering furnace for pre-sintering, raised to 1100°C at a heating rate of 4°C / min, and pre-sintered for 4 h, and then naturally cooled. The pre-sintered ceramic powder is ball-milled again, dried, ground through a 120-mesh sieve to obtain a finely ground powder, pressed into a disc, and sintered in a sintering furnace. First, the pressed disc is raised to 650°C at a rate of 2°C / min, held for 4 h to remove glue, then raised to 1100°C at a rate of 4°C / min, raised to 1270°C at a rate of 2°C / min, and held for 4 h, then lowered to 1100°C at a rate of 2°C / min, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. Tests show that the energy storage density of the ceramic can reach 4.21 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency can be stabilized at 83%.

[0054] Example 10

[0055] A formula of (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein x = 0.10, y = 0.15, the raw materials are weighed in a stoichiometric ratio, ball-milled for 20 h, dried, ground through an 80-mesh sieve, and pressed into a cylindrical block. The pressed cylindrical block is placed in a sintering furnace for pre-sintering, raised to 1200°C at a heating rate of 4°C / min, and pre-sintered for 4 h, and then naturally cooled. The pre-sintered ceramic powder is ball-milled again, dried, ground through a 120-mesh sieve to obtain a finely ground powder, pressed into a disc, and sintered in a sintering furnace. First, the pressed disc is raised to 650°C at a rate of 2°C / min, held for 4 h to remove glue, then raised to 1200°C at a rate of 4°C / min, raised to 1270°C at a rate of 2°C / min, and held for 4 h, then lowered to 1200°C at a rate of 2°C / min, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. Tests show that the energy storage density of the ceramic can reach 4.75 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency can be stabilized at 86.4%.

[0056] Example 11

[0057] A ceramic material with high energy storage density and high efficiency is prepared by using a formula with a chemical composition of (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein x = 0.10 and y = 0.15, raw materials are weighed according to the chemical proportions, ball-milled for 20 h, dried, ground through an 80-mesh sieve, and pressed into a cylindrical block. The pressed cylindrical block is placed in a sintering furnace for pre-sintering, and is raised to 1150°C at a rate of 4°C / min, and is pre-sintered for 4 h, and is naturally cooled. The pre-sintered ceramic powder is ball-milled again, dried, ground through a 120-mesh sieve, and pressed into a disc. The pressed disc is placed in a sintering furnace for sintering, and is raised to 650°C at a rate of 2°C / min, and is held for 4 h to remove glue, and is then raised to 1150°C at a rate of 4°C / min, and is raised to 1240°C at a rate of 2°C / min, and is held for 4 h, and is then lowered to 1150°C at a rate of 2°C / min, and is naturally cooled to room temperature in the furnace. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and is then cleaned, dried, and coated with silver to obtain a copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. Testing shows that the energy storage density of the ceramic material can reach 5.23 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency can be stabilized at 87.1%.

[0058] Example 12

[0059] A ceramic material with high energy storage density and high efficiency is prepared by using a formula with a chemical composition of (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y)O3, wherein x = 0.10, y = 0.15, the raw materials are weighed according to the chemical proportion, ball-milled for 20 h, dried, ground through an 80-mesh sieve, and pressed into a columnar block. The pressed columnar block is placed in a sintering furnace for pre-sintering, raised to 1150°C at a heating rate of 4°C / min, and pre-sintered for 4 h, and then naturally cooled. The pre-sintered ceramic powder is ball-milled again, dried, ground through a 120-mesh sieve to obtain fine-milled powder, pressed into a disc, and sintered in a sintering furnace. The disc is first raised to 650°C at a rate of 2°C / min, held for 4 h to remove glue, then raised to 1150°C at a rate of 4°C / min, raised to 1300°C at a rate of 2°C / min, and held for 4 h, then reduced to 1150°C at a rate of 2°C / min, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic material is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency. Tests show that the energy storage density of the ceramic can reach 5.27 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency can be stabilized at 85.2%.

[0060] Comparative Example 1

[0061] A formula of Ba 1-x Na x (Ti 0.97 Cu 0.03 )O3, wherein x = 0.15, the raw materials are weighed according to the chemical proportion, ball-milled for 20 h, dried, ground through an 80-mesh sieve, and pressed into a columnar block. The pressed columnar block is placed in a sintering furnace for pre-sintering, raised to 1050°C at a heating rate of 4°C / min, and pre-sintered for 4 h, and then naturally cooled. The pre-sintered ceramic powder is ball-milled again, dried, ground through a 120-mesh sieve to obtain fine-milled powder, pressed into a disc, and sintered in a sintering furnace. The disc is first raised to 650°C at a rate of 2°C / min, held for 4 h to remove glue, then raised to 1050°C at a rate of 4°C / min, raised to 1250°C at a rate of 2°C / min, and held for 4 h, then reduced to 1050°C at a rate of 2°C / min, and then naturally cooled to room temperature in the furnace to obtain a ceramic material. The sintered ceramic sample is polished and ground to a thickness of about 0.15 mm, and then washed, dried, and coated with silver to obtain a barium titanate-based ceramic material. Tests show that the anti-breakdown strength of the copper-barium titanate-based ceramic material prepared from this component is 431 kV / cm, the energy storage density reaches 3.14 J / cm 3 at an electric field of 420 kV / cm, and the energy storage efficiency reaches 82.1%. Figure 5The pulse cycle curves of the copper barium titanate-based ceramic materials prepared in Examples 1-7 and Comparative Example 1 are shown in the figure. As can be seen from the figure, the pulse discharge of the ceramic prepared in Comparative Example 1 is slightly reduced after multiple cycles, while the ceramic obtained by using the optimization strategy can still maintain stability, with a change range of within 5%, indicating excellent cycle service life.

[0062] The energy storage performance test results of the ceramic materials prepared in Examples 1-7 are shown in Table 1.

[0063] Table 1 Energy storage performance of copper barium titanate-based ceramics prepared in Examples 1-7

[0064]

[0065]

[0066] By comparison, the results show that when x = 0.10 and y = 0.15, the ceramic has a higher energy storage density (5.64 J / cm 3 ) and energy storage efficiency (90.4%), i.e., can be used as a preferred composition, which shows that the copper barium titanate-based energy storage ceramic material obtained by using the bidirectional optimization strategy has high energy storage density and high efficiency, and is expected to become a very promising high-energy pulse power capacitor material.

[0067] The energy storage performance test results of the ceramic materials prepared in Examples 3 and 8-12 are shown in Table 2.

[0068] Table 2 Comparison of energy storage performance of copper barium titanate-based ceramics prepared in Example 3 and Examples 8-12

[0069]

[0070] By comparison, the results show that the ceramic has a higher energy storage density (5.64 J / cm 3 ) and energy storage efficiency (90.4%) when the pre-sintering temperature is 1150°C and the sintering temperature is 1270°C, which shows that excellent pre-sintering temperature and sintering temperature can obtain copper barium titanate-based energy storage ceramic material with high energy storage density and high efficiency.

[0071] The above only discloses a preferred embodiment of a barium titanate-based energy storage ceramic material and a preparation method thereof, and of course cannot limit the scope of the rights of the present application. Those skilled in the art can understand that all or part of the processes of the above embodiments are implemented, and equivalent changes made in accordance with the claims of the present application still belong to the scope covered by the present application.

Claims

1. A copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency, characterized in that, The chemical general formula of the copper barium titanate-based energy storage ceramic material is (1-x)Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3, wherein 0.02≤x≤0.2, 0.05≤y≤0.

2.

2. The method for preparing the copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency according to claim 1, characterized in that, The preparation method steps are as follows: Step 1, according to (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3 stoichiometric ratio BaCO3, TiO2, CuO, Ta2O5, Nb2O5, Na2CO3 powder, then the raw materials are added to absolute ethanol for ball milling, and then dried in a drying oven and ground into powder; Step 2, the powder obtained in step 1 is sieved, then pressed into a columnar block, then pre-sintered, and then naturally cooled to room temperature, after which it is again ball-mixed, dried, ground, to obtain (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1- y Ta y )O3 ceramic powder; Step 3, the ceramic powder obtained in step 2 is sieved and then added into a polyvinyl alcohol aqueous solution with a concentration of 8 wt.%, and the mass ratio of the polyvinyl alcohol aqueous solution to the ceramic powder is 1:10; after being uniformly mixed, the mixture is put into a mold and pressed into a green sheet with a thickness of 1-1.5 mm under a pressure of 120 MPa; Step 4, the green sheet obtained in step 3 is sintered with the same type of powder as the embedding material to obtain a ceramic material; Step 5, the sintered ceramic sample in step 4 is polished and ground to a thickness of 0.15-0.2 mm, and then washed, dried and silver-coated to obtain a copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency.

3. The method for preparing the copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency according to claim 2, characterized in that, In steps 1 and 2, the mass ratio of the raw materials: zirconia balls: anhydrous ethanol is equal to 1:2:4, the ball milling time is 20 h, the rotation speed is 1500 r / min, and the drying box temperature is 80-110℃.

4. The method for preparing the copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency according to claim 2, characterized in that, In step 2, the pre-sintering temperature is 1050-1200℃, the holding time is 4 h, and the heating rate is 4℃ / min.

5. The method for preparing the copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency according to claim 2, characterized in that, In step 4, the sintering specific steps are as follows: After being raised to 650℃ at a rate of 2℃ / min and holding for 4 h, it is then raised to 1050-1200℃ at a rate of 4℃ / min, and then raised to 1240-1300℃ at a rate of 2℃ / min and holding for 4 h, and then reduced to 1050-1200℃ at a rate of 2℃ / min, and then naturally cooled to room temperature.

6. The method for preparing the copper-barium titanate-based energy storage ceramic material with high energy storage density and high efficiency according to claim 2, characterized in that, The powder of the same component as described in Step 4 is the same component (1-x) Ba(Ti 0.97 Cu 0.03 )O3-xNa(Nb 1-y Ta y )O3 ceramic powder, and the mass ratio of the powder to the green sheet is 4:1.

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