Preparation method of A-site doped PLZST-based anti-ferroelectric ceramic material

Abstract

The invention relates to the technical field of functional ceramic preparation, and particularly discloses a preparation method of an A-site doped PLZST-based anti-ferroelectric ceramic material, the chemical general formula of the anti-ferroelectric ceramic material is (Pb0.99-xLax) (Zr0. 6Sn0. 4) 0.9 Ta0. 02O3, the doping amount of A-site La is accurately limited in a range of 0.01 < = x < = 0.04, and multiple effects caused by La doping are effectively balanced. In the preferable range, the A-site vacancy generated by Laintroduction can be fully utilized to refine crystal grains and inhibit oxygen vacancy, so that the breakdown electric field intensity and insulativity of the material are remarkably improved, and the adverse effect of excessive doping on the saturation polarization intensity of the material is avoided. The coordination of high breakdown field strength, low hysteresis loss and high saturation polarization is realized, so that the obtained ceramic material has high energy storage density and high energy storage efficiency.

Description

Technical Field

[0001] This invention belongs to the field of functional ceramics preparation technology, specifically relating to a method for preparing A-site doped PLZST-based antiferroelectric ceramic materials. Background Technology

[0002] Antiferroelectric materials can undergo a reversible phase transition between antiferroelectric and ferroelectric states under the influence of an electric field. Their unique double hysteresis loop characteristic results in near-zero residual polarization after the removal of the external electric field, theoretically leading to extremely high releasable energy density and energy storage efficiency, making them ideal candidates for next-generation high-power pulse energy storage capacitors. Among numerous antiferroelectric material systems, PLZST ceramics have attracted significant attention due to their stable antiferroelectric phase near room temperature and tunable phase transition electric field.

[0003] One of the core methods for optimizing the properties of PLZST materials is A-site doping. Among various doping elements, replacing divalent Pb²⁺ with trivalent La³⁺ is a classic and effective modification method. Existing research shows that the introduction of La³⁺ triggers a series of complex microstructure effects: First, to maintain lattice neutrality, A-site lead vacancies are generated, which refines the grains and promotes sintering densification; second, the generation of lead vacancies inhibits the formation of oxygen vacancies, helping to reduce dielectric loss and improve insulation resistance; finally, La³⁺ doping disrupts long-range ferroelectric order, promoting the formation of ferroelectric nanoregions (PNRs) and causing the material to transition to relaxation characteristics.

[0004] However, there is an optimal range for La³⁺ doping. While excessive La doping can improve relaxation, it comes at the cost of sacrificing saturation polarization, which is detrimental to improving energy density. Therefore, in the more complex antiferroelectric system PLZST, accurately defining the amount of La³⁺ doping to balance its positive effects of grain refinement and loss reduction with the negative effect of potentially decreasing saturation polarization, thereby synergistically optimizing breakdown field strength and energy storage performance, is a key scientific problem and technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing A-site doped PLZST-based antiferroelectric ceramic materials, in order to solve the problem mentioned in the background art that the optimal doping range of the La-doped PLZST system is unclear, making it difficult to simultaneously obtain high breakdown field strength and high energy storage efficiency.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing A-site doped PLZST-based antiferroelectric ceramic materials:

[0008] The general chemical formula of the antiferroelectric ceramic material is:

[0009] (P b0.99-x La x (Zr) 0.6 Sn 0.4 ) 0.9 Ta 0.02 O3, where the value of x is in the range of 0.01≤x<0.05.

[0010] Preferably, x = 0.01, 0.02, 0.03 or 0.04.

[0011] A method for preparing an A-site doped PLZST-based antiferroelectric ceramic material includes the following steps:

[0012] S1. Weigh each raw material according to the general chemical formula, and perform a first ball milling using zirconia balls and anhydrous ethanol as the medium. After ball milling, dry the raw material and then perform a first calcination at 820-850℃ to obtain the initial powder. Perform a second ball milling on the initial powder, dry it, and then perform a second calcination at 820-850℃ to obtain the ceramic powder.

[0013] S2. The ceramic powder obtained in S1 is mixed with the organic binder polyvinyl alcohol solution, granulated, and then dry-pressed under a pressure of 10-20 MPa to obtain a ceramic green body.

[0014] S3. The ceramic green body obtained in S2 is subjected to debinding treatment, and then placed in a sealed crucible containing atmosphere powder of the same composition. The temperature is raised to 1260-1320℃ at a rate of 3-8℃ / min for sintering. The temperature is held for 2-3 hours, and then cooled with the furnace to obtain the PLZST-based antiferroelectric ceramic material.

[0015] Preferably, the first and second ball milling times in S1 are each 10-12 hours, and the ball-to-material ratio is 4:1.

[0016] Preferably, the holding time for both the first and second calcinations in S1 is 2-3 hours.

[0017] Preferably, the organic binder in S2 is an aqueous solution of polyvinyl alcohol with a concentration of 6-8 wt%.

[0018] Preferably, in step S3, the glue removal process involves heating the temperature to 450-550°C at a rate of 0.5-1.5°C / minute and holding it at that temperature for 10-12 hours.

[0019] Preferably, the energy storage density of the ceramic material is not less than 15.3 J / cm³, and the energy storage efficiency is not less than 78.3%.

[0020] The above preparation method also includes polishing the prepared antiferroelectric ceramic material with sandpaper of different grit sizes in sequence to obtain a thin ceramic sheet with a bright and smooth surface. Then, the thin ceramic sheet is silver-plated to obtain a silver electrode, and then heat-treated in a muffle furnace, that is, calcined at 800°C for 10 minutes. The resulting material can then be subjected to subsequent testing and characterization.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention effectively balances the multiple effects induced by La³⁺ doping by precisely limiting the doping amount at the A-site to the range of 0.01 ≤ x ≤ 0.04. Within this preferred range, the A-site vacancies introduced by La³⁺ can be fully utilized to refine the grains and suppress oxygen vacancies, thereby significantly improving the breakdown electric field strength and insulation of the material, while avoiding the adverse effects of excessive doping on the saturation polarization intensity of the material. This achieves a synergy of high breakdown field strength, low hysteresis loss, and high saturation polarization, resulting in a ceramic material with both high energy density and high energy storage efficiency.

[0023] Meanwhile, the process conditions of this invention help to obtain ceramic bodies with pure phase structure and good crystallinity. XRD and Raman spectroscopy analyses show that the material has a typical antiferroelectric phase structure, and SEM shows that its microstructure is dense and the grains are uniform. This stable structure is the basis for its clear antiferroelectric double hysteresis loops and excellent energy storage performance, ensuring the reliability of the material's performance under an electric field.

[0024] The preparation route adopted in this invention, which combines two calcinations with dry pressing, features simple process steps, clear parameter control, and requires no complex equipment. This method offers good repeatability and strong product consistency, effectively reducing production costs and possessing excellent potential for industrial scale-up. It is particularly suitable for manufacturing high-power pulse capacitors, advanced energy storage modules, and other electronic devices with stringent requirements for size, efficiency, and reliability, and has clear and broad application prospects in pulse power technology, new energy vehicles, and power electronics. Attached Figure Description

[0025] Figure 1 The XRD patterns of the antiferroelectric ceramic materials in Examples 1 to 4 are shown below.

[0026] Figure 2 The Raman spectra of the antiferroelectric ceramic materials in Examples 1 to 4 are shown.

[0027] Figure 3 This is a scanning electron microscope (SEM) image of the antiferroelectric ceramic material in Example 3;

[0028] Figure 4 The PE hysteresis loops of the antiferroelectric ceramic materials in Examples 1 to 4 are shown.

[0029] Figure 5 The graph shows the energy storage density statistics of the test samples in Examples 1 to 4.

[0030] Figure 6 The graph shows the energy storage efficiency statistics of the test samples in Examples 1 to 4. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figures 1 to 5 As shown

[0033] Example 1:

[0034] A chemical formula is (Pb 0.98 La 0.01 (Zr) 0.6 Sn 0.4 ) 0.9 Ta 0.02 The preparation method of O3 antiferroelectric ceramic material includes the following steps:

[0035] (1) Pb3O4, ZrO2, La2O3, SnO2 and Ta2O5 were selected as raw materials to prepare antiferroelectric ceramics. They were weighed according to their chemical composition, and anhydrous ethanol and zirconium balls were added to the ball mill for 24 hours to obtain a mixture. The mixture was then dried and the dried powder was calcined at 850°C for 3 hours to obtain calcined powder.

[0036] (2) After the calcined powder is subjected to secondary ball milling, discharge and drying, dry powder is obtained;

[0037] (3) The dry powder is mixed with 8wt% polyvinyl alcohol solution, and then granulated and pressed at 10MPa to obtain a ceramic body.

[0038] The ceramic preform was subjected to debinding treatment at 550℃ for 10 hours, and then heated to 1310℃ at a rate of 3℃ / min and sintered for 3 hours to obtain antiferroelectric ceramic material.

[0039] The antiferroelectric ceramic material in this embodiment of the invention has a tested energy storage density of 18.538 J / cm³.

[0040] Energy storage efficiency: 78.3%.

[0041] Example 2:

[0042] A chemical formula is (Pb 0.97 La 0.02 (Zr) 0.6 Sn 0.4 ) 0.9 Ta 0.02 The preparation method of O3 antiferroelectric ceramic material includes the following steps:

[0043] (1) Pb3O4, ZrO2, La2O3, SnO2 and Ta2O5 were selected as raw materials to prepare antiferroelectric ceramics. They were weighed according to their chemical composition, and anhydrous ethanol and zirconium balls were added to the mixture. The mixture was then ball-milled for 24 hours to obtain a mixture. The mixture was then dried and the dried powder was calcined at 850°C for 3 hours to obtain calcined powder.

[0044] (2) After the calcined powder is subjected to secondary ball milling, discharge and drying, dry powder is obtained;

[0045] (3) The dry powder is mixed with 8wt% polyvinyl alcohol solution, and then granulated and pressed at 10MPa to obtain a ceramic body.

[0046] The ceramic preform was subjected to debinding treatment at 550℃ for 10 hours, and then heated to 1310℃ at a rate of 3℃ / min and sintered for 3 hours to obtain antiferroelectric ceramic material.

[0047] The antiferroelectric ceramic material in this embodiment of the invention was tested and found to have an energy storage density of 16.568 J / cm³ and an energy storage efficiency of 82.4%.

[0048] Example 3:

[0049] A chemical formula is (Pb 0.96 La 0.03 (Zr) 0.6 Sn 0.4 ) 0.9 Ta 0.02 The preparation method of O3 antiferroelectric ceramic material includes the following steps:

[0050] (1) Pb3O4, ZrO2, La2O3, SnO2 and Ta2O5 were selected as raw materials to prepare antiferroelectric ceramics. They were weighed according to their chemical composition, and anhydrous ethanol and zirconium balls were added to the mixture. The mixture was then ball-milled for 24 hours to obtain a mixture. The mixture was then dried and the dried powder was calcined at 850°C for 3 hours to obtain calcined powder.

[0051] (2) After the calcined powder is subjected to secondary ball milling, discharge and drying, dry powder is obtained;

[0052] (3) The dry powder is mixed with 8wt% polyvinyl alcohol solution, and then granulated and pressed at 10MPa to obtain a ceramic body.

[0053] The ceramic preform was subjected to debinding treatment at 550℃ for 10 hours, and then heated to 1310℃ at a rate of 3℃ / min and sintered for 3 hours to obtain antiferroelectric ceramic material.

[0054] The antiferroelectric ceramic material in this embodiment of the invention has a tested energy storage density of 16.385 J / cm³.

[0055] Energy storage efficiency: 83.8%. The SEM (Scanning Electron Microscopy) of the antiferroelectric ceramic material is shown below. Figure 3 .

[0056] Example 4:

[0057] A chemical formula is (Pb 0.95 La 0.04 (Zr) 0.6 Sn 0.4 ) 0.9 Ta 0.02 The preparation method of O3 antiferroelectric ceramic material includes the following steps:

[0058] (1) Pb3O4, ZrO2, La2O3, SnO2 and Ta2O5 were selected as raw materials to prepare antiferroelectric ceramics. They were weighed according to their chemical composition, and anhydrous ethanol and zirconium balls were added to the mixture. The mixture was then ball-milled for 24 hours to obtain a mixture. The mixture was then dried and the dried powder was calcined at 850°C for 3 hours to obtain calcined powder.

[0059] (2) After the calcined powder is subjected to secondary ball milling, discharge and drying, dry powder is obtained;

[0060] (3) The dry powder is mixed with 8wt% polyvinyl alcohol solution, and then granulated and pressed at 10MPa to obtain a ceramic body.

[0061] The ceramic preform was subjected to debinding treatment at 550℃ for 10 hours, and then heated to 1310℃ at a rate of 3℃ / min and sintered for 3 hours to obtain antiferroelectric ceramic material.

[0062] The antiferroelectric ceramic material in this embodiment of the invention was tested and found to have an energy storage density of 15.320 J / cm³ and an energy storage efficiency of 86.7%.

[0063] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0064] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an A-site doped PLZST-based antiferroelectric ceramic material, characterized in that, The general chemical formula of the antiferroelectric ceramic material is: (P b0.99-x La x (Zr) 0.6 Sn 0.4 ) 0.9 Ta 0.02 O3, where the value of x is in the range of 0.01≤x<0.

05.

2. The method for preparing an A-site doped PLZST-based antiferroelectric ceramic material according to claim 1, characterized in that: x = 0.01, 0.02, 0.03 or 0.

04.

3. The method for preparing an A-site doped PLZST-based antiferroelectric ceramic material according to claim 1, characterized in that, Includes the following steps: S1. Weigh each raw material according to the general chemical formula, and perform a first ball milling using zirconia balls and anhydrous ethanol as the medium. After ball milling, dry the raw material and then perform a first calcination at 820-850℃ to obtain the initial powder. Perform a second ball milling on the initial powder, dry it, and then perform a second calcination at 820-850℃ to obtain the ceramic powder. S2. The ceramic powder obtained in S1 is mixed with the organic binder polyvinyl alcohol solution, granulated, and then dry-pressed under a pressure of 10-20 MPa to obtain a ceramic green body. S3. The ceramic green body obtained in S2 is subjected to debinding treatment, and then placed in a sealed crucible containing atmosphere powder of the same composition. The temperature is raised to 1260-1320℃ at a rate of 3-8℃ / min for sintering. The temperature is held for 2-3 hours, and then cooled with the furnace to obtain the PLZST-based antiferroelectric ceramic material.

4. The method for preparing an A-site doped PLZST-based antiferroelectric ceramic material according to claim 1, characterized in that: The first and second ball milling in S1 each take 10-12 hours independently, with a ball-to-material ratio of 4:

1.

5. The method for preparing an A-site doped PLZST-based antiferroelectric ceramic material according to claim 1, characterized in that: The holding time for both the first and second calcinations in S1 is 2-3 hours.

6. The method for preparing an A-site doped PLZST-based antiferroelectric ceramic material according to claim 1, characterized in that: The organic binder in S2 is an aqueous solution of polyvinyl alcohol with a concentration of 6-8 wt%.

7. The method for preparing an A-site doped PLZST-based antiferroelectric ceramic material according to claim 1, characterized in that: The adhesive removal process in S3 involves heating the material to 450-550℃ at a rate of 0.5-1.5℃ / minute and holding it at that temperature for 10-12 hours.

8. The antiferroelectric ceramic material prepared by the preparation method according to any one of claims 1-7, characterized in that, The energy storage density of the ceramic material is not less than 15.3 J / cm³, and the energy storage efficiency is not less than 78.3%.

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