A high-energy-density strontium zirconate-doped sodium calcium cadmium titanate ceramic and its preparation method

Abstract

The present invention belongs to the technical field of energy storage materials, and discloses a sodium calcium cadmium copper titanate doped with strontium zirconate with high energy storage density and a preparation method thereof. The chemical general formula of the ceramic is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3, where x is the mass percentage of SrZrO3 in Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 , and 0 < x ≤ 0.1. First, the present invention synthesizes a high dielectric constant material, sodium calcium cadmium copper titanate, and obtains the Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3 ceramic by doping with strontium zirconate; uses strontium and zirconium ions to inhibit the abnormal growth of sodium calcium cadmium copper titanate grains, enhance the insulation of grain boundaries and the density of the material, improve the breakdown field strength, and at the same time has a high dielectric constant and breakdown field strength, and the energy storage density can reach 1.15 - 2.23 J / cm 3 .

Description

Technical Field

[0001] This invention belongs to the field of energy storage materials technology, specifically relating to a high energy storage density strontium zirconate-doped copper titanate sodium calcium cadmium ceramic and its preparation method. Background Technology

[0002] The development of information technology has demanded miniaturization and intelligence of electronic components, and dielectric materials with high dielectric constants and energy storage densities are key to solving this problem. In recent years, researchers have reported a series of high dielectric constant ceramic materials, but the relatively low breakdown field strength of these materials often leads to low energy storage densities. Calcium copper titanate (CaCu3Ti4O) is one such example. 12 CCTO (nonferroelectric dielectric ceramic) is a member of the ACTO family, and its ceramic dielectric constant is as high as 10. 4 It exhibits good temperature stability in the 100-600K range and has no structural phase transition, making it a promising candidate for widespread application in high-density energy storage and high-dielectric capacitors.

[0003] The energy storage density of ACTO-type dielectrics can be expressed as: Where ε0, ε r E b These represent the dielectric constant in vacuum, the relative dielectric constant, and the breakdown strength, respectively. From the above equation, it can be seen that the energy density is directly proportional to the dielectric constant and the breakdown strength; to maximize the charge that a capacitor can hold, the dielectric material needs to have a high dielectric constant and a high breakdown field strength. However, research shows that the dielectric constant and breakdown strength of a single material can only be enhanced at the cost of mutual sacrifice. Therefore, designing and developing dielectric materials with both high dielectric constant and high breakdown field strength is an effective way to achieve high energy density in dielectric materials. In 2020, Yang Zupei et al. from Shaanxi Normal University, through CdCu3Ti4O... 12 The addition of alumina improves the breakdown field strength of the ceramic, and its optimal energy storage density is 1.52 mJ / cm³. 3 (Z.Peng,J.Wang,X.Zhou,J.Zhu,X.Lei,P.Liang,X.Chao,Z.Yang,Grain engineering inducing high energy storage inCdCu3Ti4O 12 Ceramics, Ceramics International 46(2020)14425-14430); In 2022, they added silica to CdCu3Ti4O 12 In this study, the breakdown field strength of ceramic materials was improved, and the maximum energy storage density reached 1.77 mJ / cm³. 3(Z.Peng,J.Wang,F.Zhang,S.Xu,X.Lei,P.Liang,L.Wei,D.Wu,X.Chao,Z.Yang, High energy storage and colossal permittivity CdCu3Ti4O 12 Oxide ceramics, Ceramics International 48(2022)4255-4260). These results demonstrate the benefit and potential application value of conducting such research.

[0004] Currently, researchers are still exploring new high dielectric constant ceramic materials. However, the low breakdown field strength of such materials has become a key issue hindering the improvement of their energy storage density. Therefore, it is necessary to improve the breakdown field strength while developing high dielectric constant ceramic materials, so as to improve their energy storage density. Summary of the Invention

[0005] The purpose of this invention is to address the problem that the low breakdown field strength in existing technologies hinders the improvement of energy storage density, and to provide a high-energy-density strontium zirconate-doped sodium calcium cadmium copper titanate ceramic and its preparation method, thereby synthesizing sodium calcium cadmium copper titanate (Na₂C₃C₄) with a high dielectric constant occupying Ca sites, specifically addressing the issue that the low breakdown field strength in existing technologies hinders the improvement of energy storage density. 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 This method involves doping strontium zirconate (NCCCTO) ceramic materials with a second phase, strontium zirconate (SrZrO3), to improve the breakdown field strength. This ultimately yields a high-energy-density strontium zirconate-doped copper titanate (CTi) ceramic material. This method enhances the breakdown field strength while maintaining a high dielectric constant. The dielectric constant at 1 kHz is 6100–8300, the breakdown field strength is 56–82 kV / cm, and the energy density is 1.15–2.23 J / cm². 3 This results in a significant increase in energy storage density.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0007] The first objective of this invention is to provide a high-energy-density strontium zirconate-doped copper titanate sodium calcium cadmium ceramic, wherein the general chemical formula of the ceramic is Na. 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3, where x is the proportion of SrZrO3 in Na. 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12mass percentage, 0 <x≤0.1。

[0008] Preferably, 0.02 ≤ x ≤ 0.08.

[0009] A second objective of this invention is to provide a method for preparing the aforementioned high-energy-density strontium zirconate-doped sodium copper titanate ceramic, comprising the following steps:

[0010] S1. Select Na2CO3, CaCO3, CdO, CuO, TiO2, SrCO3, and ZrO2 as raw material powders, according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 The powders A and B were mixed with SrZrO3 and ground to obtain uniformly mixed powders.

[0011] S2. Sintering powder A to obtain Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Powder C; Sintering powder B to obtain SrZrO3 powder D; Powder C and powder D are processed according to the general chemical formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3 was mixed in proportion, ground, added binder and granulated, and then pressed into shape to obtain a ceramic body;

[0012] S3. First, remove the binder from the ceramic blank, then heat and hold it to obtain strontium zirconate-doped copper titanate sodium calcium cadmium ceramic.

[0013] Preferably, in S1, the grinding method is ball milling, and the time is 12 to 24 hours.

[0014] Preferably, in S2, the sintering temperature of powder A is 850-950℃, the holding time is 6-8h, and the heating rate is 2-3℃ / min.

[0015] Preferably, in S2, the sintering temperature of powder B is 1100-1200℃, the holding time is 3-4h, and the heating rate is 3-4℃ / min.

[0016] Preferably, in S2, the binder is polyvinyl alcohol, and the amount of polyvinyl alcohol added is 3 to 4 wt% of the mass of the ground powder.

[0017] Preferably, in S2, the pressing pressure is 200-250 MPa; the ceramic blank has a diameter of 1 cm and a thickness of 0.7-0.8 mm.

[0018] Preferably, in S3, the temperature of the glue discharge is 580-620℃, the holding time is 2-3h, and the heating rate is 2-3℃ / min. The temperature is raised to 1150℃, the holding time is 6-8h, and the heating rate is 3-5℃ / min.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) This invention synthesizes a novel high dielectric constant ceramic material, sodium copper titanate calcium cadmium (Na). 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 By doping with strontium zirconate (SrZrO3), the abnormal growth of sodium calcium cadmium copper titanate grains is suppressed by strontium and zirconium ions, enhancing the insulation of grain boundaries and the density of the material, significantly improving the breakdown field strength, and ultimately achieving strontium zirconate-doped sodium calcium cadmium copper titanate (Na... 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3) ceramics, which simultaneously possess high dielectric constant and breakdown field strength, with energy storage densities reaching 1.15–2.23 J / cm³. 3 .

[0021] (2) The preparation method of the ceramic material of the present invention is simple, low-cost, and highly reproducible, making it suitable for industrial production. When x = 0.05, the breakdown field strength of the ceramic is 82 kV / cm, the dielectric constant at 1 kHz is 7500, and the energy storage density is 2.23 J / cm³. 3 It has very important application value in fields such as high-density energy storage and high-dielectric capacitors. Attached Figure Description

[0022] Figure 1 XRD patterns of strontium zirconate-doped sodium calcium cadmium titanate ceramics prepared in this invention and Examples 1-5 and Comparative Example 1;

[0023] Figure 2 The Raman spectra of the strontium zirconate-doped sodium calcium cadmium titanate ceramics prepared in Examples 1-5 and Comparative Example 1 of this invention are shown below.

[0024] Figure 3 The dielectric constant of the strontium zirconate-doped copper sodium calcium cadmium titanate ceramics prepared in Examples 1-5 and Comparative Example 1 of this invention varies with frequency.

[0025] Figure 4 The graph shows the variation of nonlinear coefficient, breakdown field strength and energy storage density of the strontium zirconate-doped copper sodium calcium cadmium titanate ceramics prepared in Examples 1-5 and Comparative Example 1 of this invention. Detailed Implementation

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the data in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the protection scope of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be obtained through market purchases or prepared by existing methods.

[0028] A sodium-calcium-cadmium copper titanate ceramic doped with strontium zirconate with high energy storage density, the chemical general formula of the ceramic is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3, where 0 < x ≤ 0.1, preferably, 0.02 ≤ x ≤ 0.08.

[0029] By adding strontium zirconate, the abnormal growth of sodium-calcium-cadmium copper titanate grains is inhibited by strontium and zirconium ions, the insulation of grain boundaries and the density of the material are enhanced, and the breakdown field strength is significantly improved. Finally, the sodium-calcium-cadmium copper titanate ceramic doped with strontium zirconate has both a high dielectric constant and a breakdown field strength, achieving the purpose of improving its energy storage density. The dielectric constant of this ceramic material is 6100 - 8300 at 1 kHz, the breakdown field strength is 56 - 82 kV / cm, and the energy storage density is 1.15 - 2.23 J / cm 3 .

[0030] The preparation method of the above-mentioned sodium-calcium-cadmium copper titanate ceramic doped with strontium zirconate with high energy storage density includes the following steps:

[0031] S1. Select Na2CO3, CaCO3, CdO, CuO, TiO2, SrCO3 and ZrO2 as raw material powders, and formulate according to the composition general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 and SrZrO3, and after fully ball-milling for 12 - 24 h, obtain uniformly mixed powders A and B respectively;

[0032] S2. Heat powder A at a rate of 2 - 3 °C / min to 850 - 950 °C and sinter in an air atmosphere for 6 - 8 h to obtain Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O12 Powder C; Powder B is heated to 1100-1200℃ at 3-4℃ / min and sintered in air for 3-4 hours to obtain SrZrO3 powder D; Powder C and powder D are then processed according to the chemical formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3 was mixed in a certain proportion, ground, and then 3-4 wt% polyvinyl alcohol was added and granulated. The mixture was then pressed into a ceramic body with a diameter of 1 cm and a thickness of 0.7-0.8 mm under 200-250 MPa.

[0033] S3. The ceramic blank is heated to 580-620℃ at a rate of 2-3℃ / min, held for 2-3 hours, and then the binder is removed. The temperature is then increased to 1150℃ at a rate of 3-5℃ / min, held for 6-8 hours, and cooled in the furnace to obtain strontium zirconate-doped copper titanate sodium calcium cadmium ceramic.

[0034] The present invention will be further illustrated with examples below.

[0035] Example 1

[0036] A high-energy-density strontium zirconate-doped copper titanate sodium calcium cadmium ceramic, wherein the ceramic composition is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -0.05SrZrO3.

[0037] The preparation method of the above-mentioned high energy density strontium zirconate-doped sodium calcium cadmium copper titanate ceramic includes the following steps:

[0038] S1, according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Weigh 0.31797g Na2CO3, 0.40036g CaCO3, 1.2841g CdO, 4.773g CuO, and 5.1096g TiO2 and place them in a ball mill jar. Then, place the ball mill jar in a ball mill and grind thoroughly for 16 hours to obtain powder A. Weigh 1.4763g SrCO3 and 1.2322g ZrO2 according to the general formula SrZrO3 and place them in a ball mill jar. Then, place the ball mill jar in a ball mill and grind thoroughly for 16 hours to obtain powder B.

[0039] S2. Powder A is heated to 900℃ at a rate of 3℃ / min and sintered in air for 7 hours to obtain Na. 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12Powder C; Powder B was heated to 1150℃ at 4℃ / min and sintered in air for 4h to obtain SrZrO3 powder D; Powder D was then processed according to Na... 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -0.05% by mass of SrZrO3 chemical formula was added to powder C, and the powder was ground thoroughly for 18 hours. Then, 3 wt% of polyvinyl alcohol binder was added to the powder, and the powder was granulated and pressed into a ceramic blank with a diameter of 1 cm and a thickness of 0.8 mm under 220 MPa.

[0040] S3. The ceramic green body is heated to 600℃ at a rate of 2℃ / min, held at that temperature for 3 hours, and then the binder is removed. The temperature is then increased to 1150℃ at a rate of 5℃ / min, held for 8 hours, and cooled in the furnace to obtain Na. 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -0.05SrZrO3 ceramic.

[0041] The sintered ceramic sample was sanded to 200 μm. Silver paste was then applied to both the upper and lower surfaces of the ceramic for electrical performance testing. The obtained ceramic material exhibited a dielectric constant of 7500, a breakdown field strength of 82 kV / cm, and an energy density of 2.23 J / cm² at 1 kHz. 3 .

[0042] Example 2

[0043] A high-energy-density strontium zirconate-doped copper titanate sodium calcium cadmium ceramic, wherein the ceramic composition is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -0.02SrZrO3.

[0044] The preparation method is the same as in Example 1, except that: according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Weigh out 0.31797g Na2CO3, 0.40036g CaCO3, 1.2841g CdO, 4.773g CuO, and 5.1096g TiO2; according to the general formula SrZrO3, weigh out 0.59025g SrCO3 and 0.49288g ZrO2.

[0045] The sintered ceramic sample was sanded to 200 μm. Silver paste was then applied to both the upper and lower surfaces of the ceramic for electrical performance testing. The obtained ceramic material exhibited a dielectric constant of 8300, a breakdown field strength of 56 kV / cm, and an energy density of 1.15 J / cm² at 1 kHz.3 .

[0046] Example 3

[0047] A high-energy-density strontium zirconate-doped copper titanate sodium calcium cadmium ceramic, wherein the ceramic composition is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -0.08SrZrO3.

[0048] The preparation method is the same as in Example 1, except that: according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Weigh out 0.31797g Na2CO3, 0.40036g CaCO3, 1.2841g CdO, 4.773g CuO, and 5.1096g TiO2; according to the general formula SrZrO3, weigh out 2.36208g SrCO3 and 1.97152g ZrO2.

[0049] The sintered ceramic sample was sanded to 200 μm. Silver paste was then applied to both the upper and lower surfaces of the ceramic for electrical performance testing. The obtained ceramic material exhibited a dielectric constant of 6600, a breakdown field strength of 75 kV / cm, and an energy density of 1.64 J / cm² at 1 kHz. 3 .

[0050] Example 4

[0051] A high-energy-density strontium zirconate-doped copper titanate sodium calcium cadmium ceramic, wherein the ceramic composition is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -0.1SrZrO3.

[0052] The preparation method is the same as in Example 1, except that: according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Weigh out 0.31797g Na2CO3, 0.40036g CaCO3, 1.2841g CdO, 4.773g CuO, and 5.1096g TiO2; according to the general formula SrZrO3, weigh out 2.9526g SrCO3 and 2.4644g ZrO2.

[0053] The sintered ceramic sample was sanded to 200 μm. Silver paste was then applied to the top and bottom surfaces of the ceramic for electrical performance testing. The obtained ceramic material showed a dielectric constant of 6100, a breakdown field strength of 70 kV / cm, and an energy density of 1.32 J / cm at 1 kHz. 3 .

[0054] Example 5

[0055] A high-energy-density strontium zirconate-doped copper titanate sodium calcium cadmium ceramic, wherein the ceramic composition is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -0.03SrZrO3.

[0056] The preparation method is the same as in Example 1, except that: according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Weigh out 0.31797g Na2CO3, 0.40036g CaCO3, 1.2841g CdO, 4.773g CuO, and 5.1096g TiO2; according to the general formula SrZrO3, weigh out 0.88578g SrCO3 and 0.73932g ZrO2.

[0057] The sintered ceramic sample was sanded to 200 μm. Silver paste was then applied to both the upper and lower surfaces of the ceramic for electrical performance testing. The obtained ceramic material exhibited a dielectric constant of 7900, a breakdown field strength of 62 kV / cm, and an energy density of 1.34 J / cm² at 1 kHz. 3 .

[0058] Example 6

[0059] A high-energy-density strontium zirconate-doped copper titanate sodium calcium cadmium ceramic, wherein the ceramic composition is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -0.07SrZrO3.

[0060] The preparation method is the same as in Example 1, except that: according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Weigh out 0.31797g Na2CO3, 0.40036g CaCO3, 1.2841g CdO, 4.773g CuO, and 5.1096g TiO2; according to the general formula SrZrO3, weigh out 2.06682g SrCO3 and 1.72508g ZrO2.

[0061] The sintered ceramic sample was sanded to 200 μm. Silver paste was then applied to the upper and lower surfaces of the ceramic for electrical performance testing. The obtained ceramic material showed a dielectric constant of 6800, a breakdown field strength of 78 kV / cm, and an energy density of 1.83 J / cm at 1 kHz. 3 .

[0062] Comparative Example 1

[0063] A copper-sodium-calcium-cadmium titanate ceramic, wherein the ceramic composition is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 .

[0064] The preparation method of the above-mentioned sodium calcium cadmium titanate ceramic includes the following steps:

[0065] S1, according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Weigh 0.31797g Na2CO3, 0.40036g CaCO3, 1.2841g CdO, 4.773g CuO, and 5.1096g TiO2 and place them in a ball mill jar. Then place the ball mill jar in a ball mill and grind thoroughly for 16 hours to obtain powder A.

[0066] S2. Powder A is heated to 900℃ at a rate of 3℃ / min and sintered in air for 7 hours to obtain Na. 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 Powder C; after being fully ground for 18 hours, 3 wt% polyvinyl alcohol binder was added, granulated, and pressed into a ceramic blank with a diameter of 1 cm and a thickness of 0.8 mm under 220 MPa;

[0067] S3. The ceramic green body is heated to 600℃ at a rate of 2℃ / min, held at that temperature for 3 hours, and then the binder is removed. The temperature is then increased to 1150℃ at a rate of 5℃ / min, held for 8 hours, and cooled in the furnace to obtain Na. 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 ceramics.

[0068] The sintered ceramic sample was sanded to 200 μm. Silver paste was then applied to both the upper and lower surfaces of the ceramic for electrical performance testing. The obtained ceramic material exhibited a dielectric constant of 13800, a breakdown field strength of 5.7 kV / cm, and an energy density of 0.019 J / cm² at 1 kHz. 3 .

[0069] Silver electrodes were fabricated on the surface of the ceramic samples prepared in Examples 1-5 and Comparative Example 1 to test their electrical properties. The inventors used a SmartLab SE X-ray diffractometer (Japan), a Renishaw confocal laser Raman spectrometer (UK), an Agilent Technologies 4294A precision impedance analyzer (USA), and a Keithley 4200 testing system (USA) to characterize the crystal structure, microstructure, and electrical properties of the ceramic materials, and calculated the relevant performance parameters using the following formulas.

[0070] Dielectric constant: ε r =Cd / ε0A, where C is capacitance, d is sample thickness, and ε0 is vacuum permittivity (8.85 × 10⁻⁶ A). - 12 F / m), where A is the area of ​​the electrode.

[0071] Nonlinear coefficients: U1 and U2 are the voltages corresponding to I1 = 0.1mA and I2 = 1mA, respectively.

[0072] Energy storage density: The energy storage density of linear dielectric materials is determined by the dielectric constant and the breakdown field strength. Where ε0, ε r The dielectric constants in vacuum are 8.85 × 10⁻⁶ and 10⁻⁶ respectively. -12 F / m) and relative permittivity; breakdown field strength: U2 is the voltage when the current is 1mA, and d is the thickness of the ceramic sample.

[0073] Figure 1 The images show the XRD patterns of the strontium zirconate-doped sodium calcium cadmium titanate (NCT) ceramics prepared according to the present invention, Examples 1-5, and Comparative Example 1. Figure 1 It can be seen that the strontium zirconate-doped sodium calcium cadmium titanate ceramics prepared in Comparative Example 1 and Examples 1, 2, and 5 all have a single perovskite structure with no obvious second phase. However, as the doping amount of strontium zirconate increases, peaks of strontium zirconate appear, as seen in Examples 3 and 4.

[0074] Figure 2 The images show the Raman spectra of the strontium zirconate-doped sodium calcium cadmium titanate (NCT) ceramics prepared in Examples 1-5 and Comparative Example 1 of this invention. Figure 2 As shown, 441cm -1 507cm -1 572cm -1 These correspond to A in ACTO ceramics. g (1), A g (2) and F g (3) Module. Usually A g (1) and Ag (2) The mold corresponds to the rotational motion of TiO6, while F g (3) Originating from the reverse stretching atomic motion of O-Ti-O, in addition, the Raman spectrum of Example 4 is at 454 cm⁻¹. -1 607cm -1 The characteristic mode of strontium zirconate appeared, which corresponds to the largest doping amount of strontium zirconate. This is because the strontium zirconate doping amount in Example 4 is the largest, and therefore it will show obvious characteristic peaks.

[0075] Figure 3 The dielectric constant of the strontium zirconate-doped sodium calcium cadmium titanate ceramics prepared in Examples 1-5 and Comparative Example 1 varies with frequency. Figure 3 As shown, the dielectric constant of sodium calcium cadmium titanate (CCT) decreases after strontium zirconate doping, dropping from 13800 to 6100–8300 at 1 kHz. However, the dielectric constant remains relatively constant at frequencies above 10 kHz. 2 -10 6 Stability has been improved in the Hz range.

[0076] Figure 4 The graph shows the variations in nonlinear coefficient, breakdown field strength, and storage energy density of the strontium zirconate-doped sodium calcium cadmium titanate ceramics prepared in Examples 1-5 and Comparative Example 1 of this invention. Figure 4 It can be seen that strontium zirconate doping improves the nonlinear properties of sodium calcium cadmium titanate ceramic materials, such as the nonlinear coefficient and breakdown field strength, which is obviously beneficial to improving the energy storage density. In Comparative Example 1, the energy storage density of undoped sodium calcium cadmium titanate is only 0.019 J / cm³. 3 The energy densities of Examples 1-5 after strontium zirconate doping ranged from 1.15 to 2.23 J / cm². 3 In particular, in Example 1, Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 The energy density of -0.05SrZrO3 ceramics reaches 2.23 J / cm³. 3 The energy density is significantly higher than that of similar ceramic materials. Therefore, the strontium zirconate-doped copper titanate sodium calcium cadmium ceramic obtained in this invention has the advantages of high energy density, simple process, low cost, and good repeatability. This ceramic product has very important application prospects in high-density energy storage, high-dielectric capacitors, and other fields.

[0077] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the implementation examples, preferred implementation examples are described here to avoid redundancy. Although preferred implementation examples of this invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these implementation examples. Therefore, the appended claims are intended to be interpreted as including the preferred implementation examples as well as all changes and modifications falling within the scope of this invention.

[0078] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A strontium zirconate doped calcium sodium copper titanate ceramic with high energy storage density, characterized in that, The chemical general formula of the ceramic is Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3, wherein x is the mass percentage of SrZrO3 in Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 0.02≤x≤0.

08.

2. A method of producing a high energy density strontium zirconate doped calcium sodium copper titanate ceramic of claim 1, characterized by, The method comprises the following steps: S1, Na2CO3, CaCO3, CdO, CuO, TiO2, SrCO3 and ZrO2 are used as raw material powders, and the powders are compounded according to the general formula Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 and SrZrO3, and after grinding, mixed powders A and B are obtained respectively; S2, sintering powder A to obtain Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 powder C; sintering powder B to obtain SrZrO3 powder D; mixing powder C and powder D in a proportion of Na 0.3 Ca 0.2 Cd 0.5 Cu3Ti4O 12 -xSrZrO3, adding a binder and granulating after grinding, and pressing to obtain a ceramic green body; S3, the ceramic body is first degassed, then heated and kept to obtain a strontium zirconate doped calcium copper sodium titanate ceramic.

3. The method of producing a high energy density strontium zirconate doped calcium sodium copper titanate ceramic according to claim 2, characterized by, In S1, the grinding method is ball milling, and the time is 12-24 h.

4. The method of producing a high energy density strontium zirconate doped calcium sodium copper titanate ceramic according to claim 2, characterized by, In S2, the sintering temperature of the powder A is 850-950 ℃, the holding time is 6-8 h, and the heating rate is 2-3 ℃ / min.

5. The method of producing a high energy density strontium zirconate doped calcium sodium copper titanate ceramic according to claim 2, characterized by, In S2, the sintering temperature of the powder B is 1100-1200 ℃, the holding time is 3-4 h, and the heating rate is 3-4 ℃ / min.

6. The method of producing a high energy density strontium zirconate doped calcium sodium copper titanate ceramic according to claim 2, characterized by, In S2, the binder is polyvinyl alcohol, and the addition amount of polyvinyl alcohol is 3-4 wt% of the mass of the ground powder.

7. The method of producing a high energy density strontium zirconate doped calcium sodium copper titanate ceramic according to claim 2, characterized by, In S2, the pressing strength of the pressing forming is 200-250 MPa, the size of the ceramic body is 1 cm in diameter and 0.7-0.8 mm in thickness.

8. The method of producing a high energy density strontium zirconate doped calcium sodium copper titanate ceramic according to claim 2, characterized by, In S3, the degassing temperature is 580-620 ℃, the holding time is 2-3 h, the heating rate is 2-3 ℃ / min, the temperature is increased to 1150 ℃, the holding time is 6-8 h, and the heating rate is 3-5 ℃ / min.

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