Iron-based barium sodium niobate ceramic material with high energy storage performance and preparation method thereof

Abstract

The application discloses an iron-based barium sodium niobate ceramic material with high energy storage performance and a preparation method thereof. 4‑2x Sm 2x Na2Fe x Nb 10‑x O 30 , wherein 1<=x<=1.25. Barium carbonate, samarium oxide, sodium carbonate, ferrous oxide and niobium pentoxide are used as raw materials, and a standard solid-phase method is adopted to sinter the iron-based barium sodium niobate ceramic material. In the product formula, iron is used to replace niobium in the barium sodium niobate, which is lead-free, environment-friendly, rich in iron reserves and low in price, and is beneficial to control the cost of raw materials. In addition, the iron replacement is beneficial to enhance the relaxor ferroelectric performance of the material, can obtain a more slender hysteresis loop, and improves the energy storage efficiency of the material. The prepared ceramic material has few pores and cracks, high density, and the microstructure is obviously improved, the grain size is more fine and uniform, the ferroelectric polarization intensity and the breakdown field strength are significantly improved, the problem that the barium sodium niobate material is difficult to sinter is solved, and the ferroelectric performance and the energy storage performance are significantly improved.

Description

Technical Field

[0001] This invention relates to an iron-based sodium barium niobate ceramic material with high energy storage performance and its preparation method, belonging to the field of ceramic material technology. Background Technology

[0002] With the development of pulsed power technology, pulsed power energy storage devices capable of instantaneous charging and discharging have been widely used in modern industrial fields. Dielectric ceramic capacitors, due to their ultra-high power density, good thermal stability, mechanical stability, and excellent high-voltage resistance, have become one of the most widely used energy storage devices.

[0003] Sodium barium niobate ceramics possess high Curie temperatures, moderate dielectric constants and ferroelectric polarization values, and good temperature stability, making them highly promising for applications in dielectric energy storage devices. However, traditional sodium barium niobate ceramics suffer from poor sintering properties, are difficult to prepare, and are prone to cracking after sintering, exhibiting low breakdown strength and low energy storage density, making it difficult to meet the demands of modern industry. Therefore, modifying their sintering and energy storage properties is a major problem that urgently needs to be solved.

[0004] Ion substitution is an important approach to improving the properties of sodium barium niobate ceramics. Jindal et al. discovered that Cu... 2+ Ion substitution can effectively suppress abnormal grain growth in sodium barium niobate and reduce the remanent polarization (see S. Jindal, S. Devi, KMBatoo, G. Kumar, and A. Vasishth, Impact of copper substitution on the structural, ferroelectric and magnetic properties of tungsten bronzeceramics. Phys. B Condens. Matter, 2018, 537: 87-92); Run Li et al. found that Ca 2+ The substitution can reduce the pore size of the ceramic and increase the polarization intensity, resulting in a breakdown field strength of 120 kV / cm and 0.83 J / cm. 3 Storage density (see R. Li, YPPu, QW Zhang, W. Wang, JW Li, XY Du, M. Chen, X. Zhang, and ZX Sun, The relationship between enhanced dielectric property and structural distortion in Ca doped Ba2NaNb5O) 15(tungsten bronze ceramics. J.Eur.Ceram.Soc., 2020, 40:4509-4516). However, the sintering properties of most sodium barium niobate modified ceramics have not been significantly improved. The breakdown field strength of the materials is below 150 kV / cm, and the energy storage density and energy storage efficiency are low, which are far from meeting the requirements and limit their application in pulse power energy storage devices. Summary of the Invention

[0005] Objectives of the invention: The first objective of this invention is to provide an iron-based sodium barium niobate ceramic material with high energy storage performance. The second objective of this invention is to provide a method for preparing the iron-based sodium barium niobate ceramic material with high energy storage performance.

[0006] Technical solution: The present invention discloses an iron-based sodium barium niobate ceramic material with high energy storage performance, characterized in that the composition of the iron-based sodium barium niobate ceramic material is: Ba 4-2x Sm 2x Na2Fe x Nb 10-x O 30 , where 1≤x≤1.25, and x represents the amount of ion replacement.

[0007] Furthermore, the iron-based sodium barium niobate ceramic material with high energy storage performance is made by adding Nb at the B site in the sodium barium niobate crystal structure. 5+ Fe 3+ Replace, Ba at position A 2+ Use Sm 3+ replace.

[0008] Furthermore, the breakdown field strength of the iron-based sodium barium niobate ceramic material with high energy storage performance is 500–510 kV / cm, and the energy storage density is 4.20–5.02 J / cm³. 3 The energy storage efficiency is 68.9% to 74.5%.

[0009] The preparation method of the iron-based sodium barium niobate ceramic material with high energy storage performance according to the present invention includes the following steps:

[0010] (1) Using barium carbonate, samarium oxide, sodium carbonate, ferric oxide, and niobium pentoxide as raw materials, according to the chemical formula Ba 4-2x Sm 2x Na2Fe x Nb 10-x O 30 Weigh and mix the materials, then pre-fire them to obtain ceramic powder.

[0011] (2) The ceramic powder is mixed with the binder, and then granulated, sieved and pressed to obtain a ceramic green body;

[0012] (3) The ceramic green body is sintered to obtain the high-performance iron-based sodium barium niobate ceramic material.

[0013] Furthermore, in step (1), the purity of the raw material powders of barium carbonate, samarium oxide, sodium carbonate, ferric oxide, and niobium pentoxide is above 99%.

[0014] Further, in step (1), the mixing method is ball milling, anhydrous ethanol and zirconium oxide balls are used as the ball milling media, the ball milling speed is 100-130 rpm, and the mixing and ball milling time is 4-6 h.

[0015] Furthermore, in step (1), the pre-firing temperature is 1000-1200℃ and the pre-firing time is 2-4h.

[0016] Further, in step (2), the binder is a polyvinyl alcohol aqueous solution with a concentration of 4-6 wt%, the amount of binder added is 5-7% of the volume of ceramic powder, and the sieve used is 40 mesh.

[0017] Furthermore, in step (2), the pressure applied during pressing is 98 MPa, and the holding time after pressing is 3 to 5 minutes.

[0018] Furthermore, in step (3), the sintering temperature is 1175~1250℃, the heating rate is 5℃ / min, and the sintering time is 2~4h.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0020] (1) The product formula of the present invention selects iron to replace niobium in sodium barium niobate. Iron is abundant and inexpensive, which is conducive to controlling the cost of raw materials and is lead-free and environmentally friendly.

[0021] (2) The iron-based sodium barium niobate ceramic material prepared by the present invention has fewer pores and cracks and higher density.

[0022] Sodium barium niobate ceramics obtained by standard solid-state sintering are difficult to densify and have many pores and cracks. However, by replacing iron ions with iron ions and then using standard solid-state sintering, this invention can produce dense ceramic materials with few pores and cracks.

[0023] (3) The microstructure of the iron-based sodium barium niobate ceramic material prepared by this invention is significantly improved, with increased density, finer and more uniform grain size, and significantly improved ferroelectric polarization intensity and breakdown field strength (the highest breakdown field strength is 510 kV / cm, and the energy storage density is 5.02 J / cm). 3 (The energy storage efficiency is 74.5%). At the same time, iron replacement is beneficial to enhancing the relaxor ferroelectric properties of the material and to obtaining a more slender hysteresis loop, thereby improving the energy storage efficiency of the material.

[0024] (4) This invention solves the problem of the difficulty in sintering sodium barium niobate-based materials, and at the same time significantly improves the ferroelectric properties and energy storage properties of the material system. Attached Figure Description

[0025] Figure 1 XRD patterns of ceramic materials were obtained for Examples 1-2 and Comparative Examples 1-3;

[0026] Figure 2 Microscopic morphology images of ceramic materials obtained in Examples 1-2 and Comparative Examples 1-3;

[0027] Figure 3 The unipolar hysteresis loop diagram of the ceramic material obtained in Example 1;

[0028] Figure 4 The unipolar hysteresis loop diagram of the ceramic material obtained in Example 2.

[0029] Figure 5 The unipolar hysteresis loop diagrams of ceramic materials were obtained for comparative examples 1-3. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0031] Example 1 Ba 4-2x Sm 2x Na2Fe x Nb 10-x O 30 x = 1, i.e., Ba2Sm2Na2FeNb9O 30 Preparation

[0032] Based on the chemical reaction formula, the required amounts of raw materials for this experiment were precisely calculated according to the stoichiometric ratio. The raw materials are: barium carbonate (99.95% purity), samarium oxide (99.99% purity), sodium carbonate (99.99% purity), ferric oxide (99.9% purity), and niobium pentoxide (99.9% purity). A high-precision electronic balance was used for weighing, ensuring an accuracy of 0.001g. The prepared powders were placed in an alumina ball mill jar. Small-diameter zirconia balls and anhydrous ethanol solution were used as the milling media. The amount of anhydrous ethanol added did not exceed 1 / 2 of the jar's volume. The jar containing the sample was placed in a planetary ball mill for milling at 130 rpm for 6 hours to obtain a slurry. The mixed slurry was poured into a clean enamel tray and dried at room temperature. After drying, it was sieved through a 120-mesh sieve and pre-calcined in a muffle furnace at 1100℃ for 3 hours to obtain the desired powder. The pre-fired powder was placed in a ball mill for a second ball milling under the same conditions as the first milling. After ball milling, the powder was poured out and dried naturally at room temperature. After drying, it was sieved through a 120-mesh sieve. The sieved powder was then placed in a mortar and mixed thoroughly with a 6% (6 wt%) polyvinyl alcohol aqueous solution (by volume of the ceramic powder). After grinding, it was sieved through a 40-mesh sieve. An appropriate amount of powder was weighed and poured into a mold, and pressure was applied at 98 MPa. The pressure was maintained for 3-4 minutes after the pressure was applied. The pre-formed ceramic green cylindrical sheet was obtained with a diameter of 10 mm and a thickness of about 2-3 mm. The pre-formed ceramic green cylindrical sheet was placed in a muffle furnace and sintered under atmospheric conditions at a temperature of 1250℃, a heating rate of 5℃ / min, and a sintering time of 3 hours. After naturally cooling to room temperature, the ceramic sample was removed, yielding the iron-based barium sodium niobate ceramic material Ba2Sm2Na2FeNb9O. 30 .

[0033] The prepared iron-based sodium barium niobate ceramic material Ba2Sm2Na2FeNb9O 30 X-ray diffraction analysis was performed, and the results are as follows: Figure 1 As shown. (Attached) Figure 1 Example 1 demonstrates the yield of Ba2Sm2Na2FeNb9O 30 X-ray diffraction pattern.

[0034] Iron-based sodium barium niobate ceramic material Ba2Sm2Na2FeNb9O 30 After surface polishing, the sample was hot-etched at 1125℃ for 30 min. The hot-etched sample was then analyzed by scanning electron microscopy, and the results are as follows: Figure 2 As shown. (Attached) Figure 2 Example 1 demonstrates the yield of Ba2Sm2Na2FeNb9O 30 Surface morphology diagram.

[0035] Iron-based sodium barium niobate ceramic material Ba2Sm2Na2FeNb9O 30 Both sides were ground smooth and thinned to approximately 0.15 mm. Gold-plated electrodes were then applied, and the ferroelectric and energy storage properties were tested. The results are as follows: Figure 3 As shown. (Attached) Figure 3 Example 1 demonstrates the yield of Ba2Sm2Na2FeNb9O 30 The hysteresis loop.

[0036] Example 2Ba 4-2x Sm 2x Na2Fe x Nb 10-x O 30 , x=1.25, that is, Ba 1.5 Sm 2.5 Na2Fe 1.25 Nb 8.75 O 30 Preparation

[0037] The preparation process is the same as in Example 1, except that the value of x in the ingredient list is different from that in Example 1. The ingredients are barium carbonate (99.95% purity), samarium oxide (99.99% purity), sodium carbonate (99.99% purity), ferric oxide (99.9% purity), and niobium pentoxide (99.9% purity). The sintering temperature of the ceramic green cylindrical sheet is 1175℃. All other steps are the same as in Example 1, yielding the iron-based barium sodium niobate ceramic material Ba. 1.5 Sm 2.5 Na2Fe 1.25 Nb 8.75 O 30 .

[0038] The prepared iron-based sodium barium niobate ceramic material Ba 1.5 Sm 2.5 Na2Fe 1.25 Nb 8.75 O 30 X-ray diffraction analysis was performed, and the results are as follows: Figure 1 As shown, attached Figure 1 Example 2 shows the Ba obtained 1.5 Sm 2.5 Na2Fe 1.25 Nb 8.75 O 30 X-ray diffraction pattern.

[0039] Ba iron-based barium sodium niobate ceramic material 1.5 Sm 2.5 Na2Fe 1.25 Nb 8.75 O 30After surface polishing, the sample was hot-etched at 1090℃ for 30 min. Scanning electron microscopy analysis was then performed on the hot-etched sample, and the results are as follows: Figure 2 As shown, attached Figure 2 Example 2 shows the Ba obtained 1.5 Sm 2.5 Na2Fe 1.25 Nb 8.75 O 30 Surface morphology diagram.

[0040] Ba iron-based barium sodium niobate ceramic material 1.5 Sm 2.5 Na2Fe 1.25 Nb 8.75 O 300 Both sides were ground smooth and thinned to approximately 0.15 mm. Gold-plated electrodes were then applied, and the ferroelectric and energy storage properties were tested. The results are as follows: Figure 4 As shown, attached Figure 4 Example 2 shows the Ba obtained 1.5 Sm 2.5 Na2Fe 1.25 Nb 8.75 O 30 The hysteresis loop.

[0041] Comparative Example 1Ba 4-2x Sm 2x Na2Fe x Nb 10-x O 30 x = 0, i.e., Ba2NaNb5O 15 Preparation

[0042] The preparation process is the same as in Example 1, except that x = 0 during ingredient preparation. Apart from the different value of x during ingredient preparation and the different sintering temperature of the ceramic green cylindrical sheet (1300℃), all other steps are the same as in Example 1, yielding Ba2NaNb5O. 15 .

[0043] ceramic material Ba2NaNb5O 15 X-ray diffraction analysis was performed, and the results are as follows: Figure 1 As shown, attached Figure 1 This demonstrates the yield of Ba2NaNb5O in Comparative Example 1. 15 X-ray diffraction pattern.

[0044] ceramic material Ba2NaNb5O 15 After surface polishing, the sample was hot-etched at 1125℃ for 30 min. The hot-etched sample was then analyzed by scanning electron microscopy, and the results are as follows: Figure 2 As shown, attached Figure 2 This demonstrates the yield of Ba2NaNb5O in Comparative Example 1. 15 Surface morphology diagram.

[0045] ceramic material Ba2NaNb5O 15 Both sides were ground smooth and thinned to approximately 0.15 mm. Gold-plated electrodes were then applied, and the ferroelectric and energy storage properties were tested. The results are as follows: Figure 5 As shown, attached Figure 5 This demonstrates the yield of Ba2NaNb5O in Comparative Example 1. 15 The hysteresis loop.

[0046] Comparative Example 2Ba 4-2x Sm 2x Na2Fe x Nb 10-x O 30 , x=0.3, that is, Ba 3.4 Sm 0.6 Na2Fe 0.3 Nb 9.7 O 30 Preparation

[0047] The preparation process is the same as in Example 1, except that x = 0.3 when preparing the ingredients. Apart from the different value of x in the preparation process compared to Example 1, and the different sintering temperature of the ceramic cylindrical sheet green body at 1275℃, all other steps are the same as in Example 1, yielding the ceramic material Ba. 3.4 Sm 0.6 Na2Fe 0.3 Nb 9.7 O 30 .

[0048] Ba ceramic material 3.4 Sm 0.6 Na2Fe 0.3 Nb 9.7 O 30 X-ray diffraction analysis was performed, and the results are as follows: Figure 1 As shown, attached Figure 1 This demonstrates how Ba was obtained from Comparative Example 2. 3.4 Sm 0.6 Na2Fe 0.3 Nb 9.7 O 30 X-ray diffraction pattern.

[0049] Ba ceramic material 3.4 Sm 0.6 Na2Fe 0.3 Nb 9.7 O 30 After surface polishing, the sample was hot-etched at 1150℃ for 30 min. The hot-etched sample was then analyzed by scanning electron microscopy, and the results are as follows: Figure 2 As shown, attached Figure 2 Comparative example 2Ba is shown 3.4 Sm 0.6 Na2Fe0.3 Nb 9.7 O 30 Surface morphology diagram.

[0050] Ba ceramic material 3.4 Sm 0.6 Na2Fe 0.3 Nb 9.7 O 30 Both sides were ground smooth and thinned to approximately 0.15 mm. Gold-plated electrodes were then applied, and the ferroelectric and energy storage properties were tested. The results are as follows: Figure 5 As shown, attached Figure 5 This demonstrates how Ba was obtained from Comparative Example 2. 3.4 Sm 0.6 Na2Fe 0.3 Nb 9.7 O 30 The hysteresis loop.

[0051] Comparative Example 3Ba 4-2x Sm 2x Na2Fe x Nb 10-x O 30 x = 0.5, i.e., Ba3SmNa2Fe 0.5 Nb 9.5 O 30 Preparation

[0052] The preparation process is the same as in Example 1, except that x = 0.5 during ingredient mixing. Apart from the different value of x during ingredient mixing and the sintering temperature of the ceramic green cylindrical sheet being 1250℃, all other steps are the same as in Example 1, yielding the ceramic material Ba3SmNa2Fe. 0.5 Nb 9.5 O 30 .

[0053] ceramic material Ba3SmNa2Fe 0.5 Nb 9.5 O 30 X-ray diffraction analysis was performed, and the results are as follows: Figure 1 So, attached Figure 1 Comparative Example 3 shows the yield of Ba3SmNa2Fe 0.5 Nb 9.5 O 30 X-ray diffraction pattern.

[0054] ceramic material Ba3SmNa2Fe 0.5 Nb 9.5 O 30 After surface polishing, the sample was hot-etched at 1125℃ for 30 min. The hot-etched sample was then analyzed by scanning electron microscopy. The results are as follows: Figure 2 As shown, attached Figure 2Comparative Example 3 shows the yield of Ba3SmNa2Fe 0.5 Nb 9.5 O 30 Surface morphology diagram.

[0055] ceramic material Ba3SmNa2Fe 0.5 Nb 9.5 O 30 Both sides were ground smooth and thinned to approximately 0.15 mm. Gold-plated electrodes were then applied, and the ferroelectric and energy storage properties were tested. The results are as follows: Figure 5 As shown, attached Figure 5 Comparative Example 3 shows the yield of Ba3SmNa2Fe 0.5 Nb 9.5 O 30 The hysteresis loop.

[0056] Figure 1 The XRD patterns of the ceramic materials obtained in Examples 1-2 and Comparative Examples 1-3 are shown below. Figure 1 It can be seen that Comparative Examples 1, 2, and 3 are pure phases with a tetragonal tungsten bronze structure, while Examples 1 and 2 have a tetragonal tungsten bronze structure as the main phase, and also contain a small amount of ferric oxide second phase. The corresponding PDF cards for the comparative examples and examples are 40-1463 and 39-0265.

[0057] Figure 2 The images show the microstructures of the ceramic materials obtained in Examples 1-2 and Comparative Examples 1-3, where (a) is Comparative Example 1, (b) is Comparative Example 2, (c) is Comparative Example 3, (d) is Example 1, and (e) is Example 2. Figure 2 It can be seen that with the increase of iron content, cracks and pores are significantly reduced, density is significantly increased, and grain size is more uniform.

[0058] Compared with Comparative Examples 1, 2, and 3, Examples 1 and 2 have finer grain sizes.

[0059] Figure 3 The unipolar hysteresis loop diagram of the ceramic material obtained in Example 1 is shown below. Figure 4 The unipolar hysteresis loop diagram of the ceramic material obtained in Example 2 is shown below. Figure 5 To compare the unipolar hysteresis loops of ceramic materials obtained in Examples 1-3, the following comparisons were made. Figure 3-5 It can be seen that the maximum polarization values ​​in Examples 1 and 2 are larger, reaching 22.2 μC / cm. 2 and 19.5 μC / cm 2 The planned values ​​for ceramic materials obtained in Comparative Examples 1-3 were all 15 μC / cm. 2 the following.

[0060] according to Figure 3-5The unipolar hysteresis diagram shown can be used to obtain the breakdown field strength of each embodiment and comparative example, and to calculate their total energy storage density, effective energy storage density, and energy storage efficiency. The calculation formula is as follows:

[0061]

[0062] Among them, W total W rec η and E represent the total energy storage density, effective energy storage density, and energy storage efficiency, respectively. max and P r These are the applied electric field, polarization value, maximum polarization value, and residual polarization value, respectively.

[0063] The performance parameters of the ceramic materials obtained in Examples 1-2 and Comparative Examples 1-3 are shown in Table 1.

[0064] Table 1. Composition and energy storage performance parameters of ceramic materials

[0065]

[0066] As shown in Table 1, with the increase of iron content, the relaxor ferroelectricity of the material is enhanced, the hysteresis loop becomes more slender, and the energy storage efficiency is higher. The breakdown field strengths of Examples 1 and 2 are higher, at 510 kV / cm and 500 kV / cm, respectively, and the energy storage densities are higher, at 5.02 J / cm³. 3 4.20 J / cm 3 The energy storage efficiencies of Examples 1 and 2 were 74.5% and 68.9%, respectively. Therefore, the energy storage performance of the material improves with increasing iron content. The optimal energy storage performance is achieved when the iron content reaches x=1. Further increases in iron content lead to a decrease in energy storage performance. Compared to Comparative Example 1 (without iron) and Comparative Examples 2 and 3 (with less iron), the high energy storage performance of Example 1 with appropriate iron addition demonstrates that increasing iron enhances the energy storage performance of the material.

Claims

1. A sodium barium niobate iron-based ceramic material with high energy storage performance, characterized in that, The composition of the iron-based sodium barium niobate ceramic material is: Ba 4-2x Sm 2x Na2Fe x Nb 10-x O 30 , where 1≤x≤1.

25.

2. The iron-based sodium barium niobate ceramic material with high energy storage performance according to claim 1, characterized in that, The iron-based sodium barium niobate ceramic material with high energy storage performance is made by adding Nb at the B site in the sodium barium niobate crystal structure. 5+ Fe 3+ Replace, Ba at position A 2+ Use Sm 3+ replace.

3. The method for preparing the iron-based sodium barium niobate ceramic material with high energy storage performance as described in claim 1 or 2, characterized in that, Includes the following steps: (1) Using barium carbonate, samarium oxide, sodium carbonate, ferric oxide, and niobium pentoxide as raw materials, according to the chemical formula Ba 4- 2x Sm 2x Na2Fe x Nb 10-x O 30 Weigh and mix the materials, then pre-fire them to obtain ceramic powder. (2) The ceramic powder is mixed with the binder, and then granulated, sieved and pressed to obtain a ceramic green body; (3) The ceramic green body is sintered to obtain the high energy storage performance iron-based sodium barium niobate ceramic material.

4. The preparation method according to claim 3, characterized in that, In step (1), the purity of the raw material powders of barium carbonate, samarium oxide, sodium carbonate, ferric oxide, and niobium pentoxide is above 99%.

5. The preparation method according to claim 3, characterized in that, In step (1), the mixing method is ball milling, anhydrous ethanol and zirconium oxide balls are used as the ball milling media, the ball milling speed is 100-130 rpm, and the mixing and milling time is 4-6 hours.

6. The preparation method according to claim 3, characterized in that, In step (1), the preheating temperature is 1000-1200℃ and the preheating time is 2-4h.

7. The preparation method according to claim 3, characterized in that, In step (2), the binder is a polyvinyl alcohol aqueous solution with a concentration of 4-6 wt%, and the amount of binder added is 5-7% of the volume of ceramic powder. The sieve used is 40 mesh.

8. The preparation method according to claim 3, characterized in that, In step (2), the pressure applied during pressing is 98 MPa, and the holding time after pressing is 3 to 5 minutes.

9. The preparation method according to claim 3, characterized in that, In step (3), the sintering temperature is 1175-1250℃, the heating rate is 5℃ / min, and the sintering time is 2-4h.

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