Zirconium-tin composite ion modified sodium bismuth titanate-based dielectric energy storage ceramic material and preparation method thereof

Abstract

The invention discloses a zirconium-tin composite ion modified sodium bismuth titanate-based dielectric energy storage ceramic material and a preparation method thereof, the chemical general formula of the ceramic material is (Bi < 0.5 > Na < 0.5 >) < 0.65 > (Ba < 0.3 > Sr < 0.7 >) < 0.35 > Ti < 1-x > (Zr < 0.8 > Sn < 0.2 >) < x > O < 3 >, and x is greater than or equal to 0.01 and less than or equal to 0.10. The composite ion (Zr0. 8Sn0. 2) < 4 + > is introduced to equivalently replace Ti < 4 + > ions at the B site in (Bi0. 5Na0. 5) 0.65 (Ba0. 3Sr0. 7) 0.35 TiO3, so that the density of crystal grains is effectively improved, the breakdown field strength of the ceramic is remarkably improved, a slender ferroelectric hysteresis loop is obtained, and excellent energy storage performance and dielectric temperature stability are obtained under a low electric field. According to the invention, the difficulty of low energy storage density under a low electric field is broken through, the preparation process is simple and easy to operate, the performance stability is better, and the development requirements of miniaturization and integration of current electronic products are met.

Description

Technical Field

[0001] The present invention relates to the technical field of lead-free dielectric energy storage ceramic materials, and particularly relates to a zirconium-tin composite ion modified sodium bismuth titanate-based dielectric energy storage ceramic material and a preparation method thereof. Background Art

[0002] In order to promote the sustainable, green and high-quality development of energy utilization, many new power generation methods (such as tidal energy, wind energy, solar energy, etc.) have been developed so far. The new green energy not only meets the human demand for energy but also greatly reduces the impact on the environment. However, there are many problems in the utilization of this new energy, such as low conversion efficiency and inconvenient storage. Therefore, it is imperative to research and develop efficient energy storage technologies. Compared with other energy storage materials, such as batteries, electrochemical capacitors, and fuel cells, dielectric capacitors have unique characteristics of ultra-high power density and ultra-fast discharge rate, and have strong competitiveness compared with other energy storage devices in high-pulse power systems. Dielectric capacitors play an increasingly important role in electronic devices and power systems and have become a global hotspot. However, the relatively low energy storage density of dielectric capacitors hinders their wider application. Therefore, current research mainly focuses on developing dielectrics with higher energy storage density and good stability to meet the development requirements of miniaturization, integration, high capacity, and high reliability.

[0003] Na 0.5 Bi 0.5 TiO3 (BNT)-based lead-free ferroelectric materials have a high saturation polarization intensity P at room temperature due to the hybridization (i.e., lone pair effect) between Bi 6s and O 2p orbitals, forming lone electron pairs. s (>40μC / cm 2 ). Therefore, it is considered to be one of the most promising matrices for designing lead-free relaxor energy storage materials, but the large remanent polarization P r (38μC / cm 2 ) and the large coercive electric field (E c ) greatly reduce the recoverable energy storage density (W rec ) and energy storage efficiency (η).

[0004] The low breakdown field strength, high remanent polarization, and poor dielectric temperature stability greatly limit the application of BNT-based lead-free energy storage ceramics. Therefore, while increasing the breakdown field strength, maintaining a large polarization difference (P s -P r ) and having good temperature stability are of great significance for the wide application of lead-free energy storage ceramics. Summary of the Invention

[0005] The object of the present invention is to overcome the deficiencies of the prior art and provide a sodium bismuth titanate-based dielectric energy storage ceramic material modified by zirconium-tin composite ions. By using composite equivalent ions (Zr 0.8 Sn 0.2 ) 4+ to replace Ti 4+ ions for doping modification, the breakdown field strength of the ceramic is significantly improved, and excellent energy storage performance and dielectric temperature stability are obtained under low electric fields. Another object of the present invention is to provide a preparation method for the above-mentioned sodium bismuth titanate-based dielectric energy storage ceramic material modified by zirconium-tin composite ions.

[0006] The object of the present invention is achieved by the following technical solutions:

[0007] A sodium bismuth titanate-based dielectric energy storage ceramic material modified by zirconium-tin composite ions provided by the present invention uses composite equivalent ions (Zr 0.8 Sn 0.2 ) 4+ to replace Ti 0.5 ions at the B-site of (Bi 0.5 Na 0.65 )(Ba 0.3 Sr 0.7 ) 0.35 TiO3, forming a chemical general formula of (Bi 4+ Na 0.5 ) 0.5 (Ba 0.65 Sr 0.3 ) 0.7 Ti 0.35 (Zr (1-x) Sn 0.8 ) 0.2 ) x O3, where 0.01 ≤ x ≤ 0.10.

[0008] In the above solution, the effective energy storage density of the dielectric energy storage ceramic material of the present invention under a low electric field of 210 kV / cm ≥ 2.95 J / cm 3 , the energy storage efficiency ≥ 83.3%, and the dielectric constant in the temperature range of 20 - 249 °C is 2967 ± 15%.

[0009] Another object of the present invention is achieved by the following technical solutions:

[0010] The preparation method for the above-mentioned sodium bismuth titanate-based dielectric energy storage ceramic material modified by zirconium-tin composite ions provided by the present invention includes the following steps:

[0011] (1) Bi2O3, Na2CO3, TiO2, BaCO3, SrCO3, SnO2, and ZrO2 are used as raw materials, the ingredients are prepared according to the chemical formula, and then anhydrous ethanol is used as a ball milling medium for ball milling and mixing to obtain a slurry;

[0012] (2) The slurry is sieved, dried, pressed and shaped, and pre-fired at 750-900°C for 3-6 hours, cooled to room temperature, and ground to obtain pre-fired powder.

[0013] (3) subjecting the pre-sintered powder to a secondary ball milling treatment, followed by drying, grinding, granulating, aging, and pressing to obtain a ceramic body;

[0014] (4) After the ceramic body is subjected to a binder removal treatment, alumina is used as a calcining powder and calcined at a temperature of 1160 to 1280° C. for a holding time of 2 to 6 hours. After natural cooling, a zirconium-tin composite ion-modified sodium bismuth titanate-based dielectric energy storage ceramic material is obtained.

[0015] Furthermore, in the preparation method of the present invention, the rotation speed of the first ball milling in step (1) is 300-500 rpm, and the ball milling time is 10-24 hours. In step (2), the pressing molding is carried out under a pressure of 4-6 MPa. In step (3), the rotation speed of the second ball milling is 300-500 rpm, and the ball milling time is 12-36 hours; the pressing molding is carried out under a pressure of 100-200 MPa. In step (4), the debinding treatment is carried out at a temperature of 600-800°C.

[0016] The present invention has the following beneficial effects:

[0017] (1) The present invention is achieved by 0.5 Na 0.5 ) 0.65 (Ba 0.3 Sr 0.7 ) 0.35 TiO3 system (Zr 0.8 Sn 0.2 ) 4+ Replace Ti 4+ , effectively destroying the long-range ordered ferroelectric domains, delaying polarization saturation, improving relaxivity, effectively improving the density of grains, significantly improving the breakdown field strength, obtaining a slender hysteresis loop, and obtaining excellent energy storage density and energy storage efficiency under low electric field, and having excellent dielectric stability in an ultra-wide temperature range (20-249°C).

[0018] (2) The present invention overcomes the difficulties of the prior art, such as low energy storage density, low polarization difference, low energy storage efficiency, and poor dielectric temperature stability under low electric fields. Moreover, the process is simple and easy to prepare. All raw materials do not contain lead, are environmentally friendly, do not contain rare earth elements or precious metals, have a relatively low production cost, have good performance stability, are suitable for mass production, and can meet the development needs of the current miniaturization and integration of electronic products. Description of the Drawings

[0019] The present invention will be further described in detail below in conjunction with the embodiments and the drawings:

[0020] Figure 1 It is the XRD pattern of the dielectric energy storage ceramic materials prepared in the examples and comparative examples of the present invention. Detailed Embodiments

[0021] A preparation method of a zirconium-tin composite ion modified sodium bismuth titanate-based dielectric energy storage ceramic material according to an embodiment of the present invention comprises the following steps:

[0022] (1) Using Bi2O3 (purity 99.0%), Na2CO3 (purity 99.8%), TiO2 (purity 98.0%), BaCO3 (purity 99.0%), SrCO3 (purity 99.0%), SnO2 (purity 99.8%), and ZrO2 (purity 99.0%) as raw materials, after proportioning according to the stoichiometric ratio of the chemical general formula (Bi 0.5 Na 0.5 ) 0.65 (Ba 0.3 Sr 0.7 ) 0.35 Ti (1-x) (Zr 0.8 Sn 0.2 ) x O3, primary ball milling and mixing are carried out using zirconia ball mills with absolute ethanol as the ball milling medium. The ball milling speed is 500 revolutions per minute, and the ball milling time is 15 hours to obtain a slurry;

[0023] (2) After the above slurry is sieved, it is dried in an oven at 80 °C for 48 hours to fully volatilize ethanol, and then pressed into a mold under a pressure of 5 MPa, placed in a sealed crucible, and subjected to pre-sintering treatment at a temperature of 870 °C for 3.5 hours, cooled to room temperature with the furnace, and ground to obtain pre-sintered powder;

[0024] (3) The above-mentioned pre-fired powder is subjected to secondary ball milling treatment at a ball milling speed of 500 revolutions per minute and a ball milling time of 24 hours; the powder obtained after drying the resulting slurry in an oven at 80 °C for 12 hours is ground until it is uniform and does not agglomerate; then PVA with a concentration of 6% is added for granulation, and after passing through a 80-mesh sieve and aging for 24 hours, powder particles are obtained; the powder particles are uniformly placed in a mold and pressed into a ceramic green body under a pressure of 120 MPa.

[0025] (4) The above-mentioned ceramic green body is subjected to a debinding treatment by holding at a temperature of 700 °C for 30 minutes to fully discharge the PVA in the ceramic green body; then, using alumina as the buried firing powder, it is subjected to a buried firing treatment at a temperature of 1240 °C for a holding time of 2 hours, and after natural cooling, a zirconium tin composite ion-modified sodium bismuth titanate-based dielectric energy storage ceramic material is obtained.

[0026] The chemical general formulas of the embodiments of the present invention are shown in Table 1.

[0027] Using Bi2O3 (purity 99.0%), Na2CO3 (purity 99.8%), TiO2 (purity 98.0%), BaCO3 (purity 99.0%), SrCO3 (purity 99.0%) as raw materials, according to the chemical stoichiometry of the chemical formula (Bi 0.5 Na 0.5 ) 0.65 (Ba 0.3 Sr 0.7 ) 0.35 TiO3 for batching as a comparative example, and other process conditions are the same as those of the embodiments of the present invention.

[0028] As Figure 1 shown, the dielectric energy storage ceramic materials prepared in the embodiments of the present invention all exhibit a typical perovskite phase structure and no second phase is generated, indicating that Zr 4+ and Sn 4+ ions have uniformly entered the (Bi 0.5 Na 0.5 ) 0.65 (Ba 0.3 Sr 0.7 ) 0.35 TiO3 lattice to form a solid solution.

[0029] The effective energy storage density and energy storage efficiency of the dielectric energy storage ceramic materials prepared in the embodiments of the present invention and the comparative examples under a low electric field of 210 kV / cm are shown in Table 1.

[0030] Table 1 Chemical general formulas of the embodiments of the present invention and the comparative examples and performance indicators of their dielectric energy storage ceramic materials

[0031]

Claims

1. A sodium bismuth titanate-based dielectric energy storage ceramic material modified by zirconium-tin composite ions, characterized in that: With composite equivalent ions (Zr 0.8 Sn 0.2 ) 4+ Replacement (Bi 0.5 Na 0.5 ) 0.65 (Ba 0.3 Sr 0.7 ) 0.35 Ti at B site in TiO3 4+ ions, the chemical formula is (Bi 0.5 Na 0.5 ) 0.65 (Ba 0.3 Sr 0.7 ) 0.35 Ti (1-x) (Zr 0.8 Sn 0.2 ) x O3, where 0.01≤x≤0.

10.

2. The sodium bismuth titanate-based dielectric energy storage ceramic material modified by zirconium tin composite ions according to claim 1, wherein: The effective energy storage density of the dielectric energy storage ceramic material under a low electric field of 210 kV / cm is ≥ 2.95 J / cm 3 , the energy storage efficiency is ≥ 83.3%, and the dielectric constant in the temperature range of 20 - 249 °C is 2967 ± 15%.

3. The preparation method of the sodium bismuth titanate-based dielectric energy storage ceramic material modified by zirconium-tin composite ions as claimed in claim 1 or 2, characterized in that It includes the following steps: (1) Using Bi2O3, Na2CO3, TiO2, BaCO3, SrCO3, SnO2, ZrO2 as raw materials, after proportioning according to the chemical general formula, using anhydrous ethanol as the ball-milling medium for primary ball-milling and mixing to obtain a slurry; (2) After sieving and drying the slurry, it is press-molded and subjected to pre-sintering treatment at 750-900 °C for 3-6 h, cooled to room temperature with the furnace, and ground to obtain pre-sintered powder. (3) After the pre-sintered powder is subjected to secondary ball-milling treatment, it is dried, ground, granulated, aged, and press-molded to obtain a ceramic green body; (4) After the ceramic green body is subjected to debinding treatment, using alumina as the buried firing powder, it is subjected to buried firing treatment at a temperature of 1160-1280 °C for a holding time of 2-6 h, and after natural cooling, the sodium bismuth titanate-based dielectric energy storage ceramic material modified by zirconium tin composite ions is obtained.

4. The preparation method of the zirconium-tin composite ion modified sodium bismuth titanate-based dielectric energy storage ceramic material according to claim 3, characterized in that: In the step (1), the rotation speed of the primary ball-milling is 300-500 revolutions / min, and the ball-milling time is 10-24 h.

5. The preparation method of the zirconium-tin composite ion-modified sodium bismuth titanate-based dielectric energy storage ceramic material according to claim 3, characterized in that: In the step (2), it is press-molded under a pressure of 4-6 MPa.

6. The preparation method of the zirconium-tin composite ion-modified sodium bismuth titanate-based dielectric energy storage ceramic material according to claim 3, characterized in that: In the step (3), the rotation speed of the secondary ball-milling is 300-500 revolutions / min, and the ball-milling time is 12-36 h; it is press-molded under a pressure of 100-200 MPa.

7. The preparation method of the bismuth sodium titanate-based dielectric energy storage ceramic material modified by zirconium tin composite ions according to claim 3, characterized in that: In the step (4), the debinding treatment is carried out at a temperature of 600-800 °C.

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