Preparation method of sodium bismuth titanate-based relaxor ferroelectric material

Abstract

The invention relates to the technical field of dielectric lead-free energy storage ceramic materials, in particular to a preparation method of a sodium bismuth titanate-based relaxor ferroelectric material, and the ceramic material prepared by the method is excellent in energy storage performance. When x is equal to 0.20, the ceramic has high energy storage density (13.60 J / cm < 3 >) and good energy storage efficiency (83.88%). Meanwhile, the change of the energy storage density is about 4.1% in the test temperature range of 30-140 DEG C, and very stable energy storage performance can be maintained, so that the problem that the practical application is limited by relatively high residual polarization and low breakdown electric field of the existing sodium bismuth titanate-based relaxor ferroelectric is solved.

Description

Technical Field

[0001] The invention relates to the technical field of dielectric lead-free energy storage ceramic materials, and in particular to a method for preparing a sodium bismuth titanate-based relaxor ferroelectric material. Background Art

[0002] In recent years, with the rapid development of science and technology and the national economy, the available energy forms have diversified. Under the concept of green and sustainable development in my country, how to use advanced technology to efficiently store and utilize energy has become a research hotspot. Dielectric energy storage capacitors are widely used in various pulse power and high-voltage systems due to their ultra-high power density and ultra-fast discharge rate.

[0003] However, its low energy storage density limits the development of miniaturization of such devices. Sodium bismuth titanate-based relaxor ferroelectrics have received extensive attention due to their high polarization strength, but their high remnant polarization and low breakdown electric field limit their practical applications. Therefore, how to improve the energy storage performance of sodium bismuth titanate-based relaxor ferroelectrics has become a current research hotspot. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a sodium bismuth titanate-based relaxor ferroelectric material, aiming to solve the problem that the existing sodium bismuth titanate-based relaxor ferroelectric has high residual polarization and low breakdown electric field which limit its practical application.

[0005] To achieve the above object, the present invention provides a method for preparing a sodium bismuth titanate-based relaxor ferroelectric material, comprising the following steps:

[0006] Using Bi2O3, Na2CO3, TiO2, BaCO3, Sm2O3, MgO and Sb2O5 with purity ≥99% as raw materials, weigh and mix the ingredients according to their chemical formula composition;

[0007] Using anhydrous ethanol and zirconium oxide balls as ball milling media, wet-milling the ingredients, drying, pre-calcining and heat preservation to obtain powder;

[0008] Using anhydrous ethanol as the ball milling medium, the powder is placed in a nylon jar for secondary ball milling, then taken out and placed in a dry blower for drying;

[0009] Pressing the dried powder to obtain a small cylinder;

[0010] The small cylinder is placed in a sealed bag under vacuum, pressed by cold pressing, and the pressed small cylinder is sintered to obtain the target ceramic material.

[0011] Among them, in “using anhydrous ethanol and zirconia balls as ball milling media, wet-milling the ingredients, drying, pre-burning and keeping warm to obtain powder”, the ball milling time is 8 hours, the pre-burning temperature is 900°C, and the insulation time is 4 hours.

[0012] Among them, in "weighing and mixing the powder according to the chemical composition, using anhydrous ethanol as the ball milling medium, putting the powder into a nylon jar for ball milling, taking it out, and putting it into a dry blower for drying", the ball milling time is 8 hours, and the drying temperature is 100°C-120°C.

[0013] Among them, in “pressing the dried powder to obtain a small cylinder”, the pressed diameter of the small cylinder is 8 mm and the thickness is 2 mm.

[0014] Among them, in "putting the small cylinder into a sealed bag in vacuum, pressing it by cold pressing, and sintering the pressed small cylinder to obtain the target ceramic material", the sintering temperature is 1160℃-1220℃, and the sintering time is 2.5h.

[0015] The preparation method of a sodium bismuth titanate-based relaxor ferroelectric material of the present invention comprises the following steps: using Bi2O3, Na2CO3, TiO2, BaCO3, Sm2O3, MgO and Sb2O5 with a purity of ≥99% as raw materials, weighing and proportioning the ingredients according to their chemical formula composition; using anhydrous ethanol and zirconium oxide balls as ball milling media, wet-milling the ingredients, drying, pre-burning and heat preservation to obtain powder; weighing and proportioning the powder according to the chemical composition, using anhydrous ethanol as the ball milling medium, putting the powder into a nylon can, ball milling, taking it out, and putting it into a dry blower for drying; pressing the dried powder to obtain a small cylinder; putting the small cylinder into a sealed bag vacuum, pressing it by cold pressing, and sintering the pressed small cylinder to obtain the target ceramic material. The ceramic material prepared by the present invention has excellent energy storage performance. When x=0.20, the ceramic has a high energy storage density (13.60J / cm 3 ) and good energy storage efficiency (83.88%). At the same time, the energy storage density changes by about 4.1% in the test temperature range of 30℃-140℃, which can maintain a very stable energy storage performance, thus solving the problem that the existing sodium bismuth titanate-based relaxor ferroelectrics have high residual polarization and low breakdown electric field that limit their practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The present invention provides a flow chart of a method for preparing a sodium bismuth titanate-based relaxor ferroelectric material.

[0018] Figure 2 It is the unipolar PE hysteresis loop of different components under the breakdown electric field.

[0019] Figure 3 It is the unipolar PE hysteresis loop of x=0.16 ceramic under different electric fields. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0021] See also Figures 1 to 3 The present invention provides a method for preparing a sodium bismuth titanate-based relaxor ferroelectric material, comprising the following steps:

[0022] S1 uses Bi2O3, Na2CO3, TiO2, BaCO3, Sm2O3, MgO and Sb2O5 with a purity of ≥99% as raw materials, and weighs and mixes the ingredients according to their chemical formula composition;

[0023] Specifically, Bi2O3, Na2CO3, TiO2, BaCO3, Sm2O3, MgO and Sb2O5 with a purity of ≥99% are used as raw materials, and the ingredients are weighed and prepared according to their chemical formula compositions.

[0024] S2 uses anhydrous ethanol and zirconium oxide balls as ball milling media to wet-mill the ingredients, pre-sinter and keep them warm after drying to obtain powder;

[0025] The ball milling time is 8 hours, the pre-burning temperature is 900° C., and the heat preservation time is 4 hours.

[0026] Specifically, anhydrous ethanol and zirconium oxide balls were used as ball milling media, wet milling was performed for 8 h, and after drying, the mixture was pre-calcined at 900 °C and kept warm for 4 h;

[0027] S3 uses anhydrous ethanol as the ball milling medium, puts the powder into a nylon jar for secondary ball milling, then takes it out and puts it into a dry blower for drying;

[0028] The ball milling time is 8 hours, and the drying temperature is 100°C-120°C.

[0029] Specifically, according to (1-x)[0.94Bi 0.5 Na 0.5 TiO3-0.06BaTiO3]-xSm(Mg 2 / 3 Sb 1 / 3 )O3(0.08≤x≤0.12) is weighed and mixed; anhydrous ethanol is used as the ball milling medium, the powder is put into a nylon jar and ball milled for 8 hours, then taken out and put into a dry blower box for drying at 100-120°C

[0030] S4 compresses the dried powder to obtain a small cylinder;

[0031] The pressed diameter of the small cylinder is 8 mm and the thickness is 2 mm.

[0032] Specifically, the dried powder is pressed into a small cylinder with a diameter of 8 mm and a thickness of 2 mm.

[0033] S5: placing the small cylinder into a sealed bag under vacuum, pressing it by cold pressing, and sintering the pressed small cylinder to obtain a target ceramic material.

[0034] The sintering temperature is 1160° C.-1220° C., and the sintering time is 2.5 hours.

[0035] Specifically, the small cylinder is placed in a sealed bag and evacuated, and then cold pressed to form. Finally, the pressed small cylinder is sintered at 1160-1220°C for 2.5 hours to obtain the desired target ceramic material. The chemical composition formula of the target ceramic is: (1-x)[0.94Bi 0.5 Na 0.5 TiO3-0.06BaTiO3]-xSm(Mg 2 / 3 Sb 1 / 3 )O3 lead-free relaxor ferroelectric ceramics, wherein x is a molar ratio, 0.08≤x≤0.20.

[0036] Embodiment 1:

[0037] The BNT-BT-SMS ultra-high performance lead-free relaxor ferroelectric energy storage ceramic prepared by this invention (the preparation method thereof is as described above), Figure 2-Figure 3The unipolar hysteresis loops of the energy storage characteristics of sodium bismuth titanate-based relaxor ferroelectric ceramics with different components (0.08≤x≤0.12) are shown in Table 1. The energy storage performance of the corresponding components is shown in Table 1. It can be seen that when x=0.16, the total energy storage density of the ceramic under an electric field of 760 kV / cm is as high as 16.22 J / cm 3 , and the recoverable energy storage density can reach 13.60J / cm 3 ; and the energy storage efficiency is stable at around 83.88%. These data are higher than most of the previously reported lead-free energy storage ceramic materials, indicating that the energy storage ceramic has great application prospects.

[0038] Table 1

[0039]

[0040] The above disclosure is only a preferred embodiment of the preparation method of a sodium bismuth titanate-based relaxor ferroelectric material of the present invention. Of course, it cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for preparing a sodium bismuth titanate-based relaxor ferroelectric material, characterized in that: The following steps are involved: Using Bi2O3, Na2CO3, TiO2, BaCO3, Sm2O3, MgO and Sb2O5 with purity ≥99% as raw materials, weigh and mix the ingredients according to their chemical formula composition; Using anhydrous ethanol and zirconium oxide balls as ball milling media, wet-milling the ingredients, drying, pre-calcining and heat preservation to obtain powder; Using anhydrous ethanol as the ball milling medium, the powder is put into a nylon jar for ball milling, then taken out and put into a dry blower box for drying; Pressing the dried powder to obtain a small cylinder; The small cylinder is placed in a sealed bag under vacuum, pressed by cold pressing, and the pressed small cylinder is sintered to obtain the target ceramic material.

2. The method for preparing the sodium bismuth titanate-based relaxor ferroelectric material according to claim 1, characterized in that: In "using anhydrous ethanol and zirconium oxide balls as ball milling media, wet-milling the ingredients, drying, pre-burning and keeping warm to obtain powder", the ball milling time is 8 hours, the pre-burning temperature is 900°C, and the keeping warm time is 4 hours.

3. The method for preparing the sodium bismuth titanate-based relaxor ferroelectric material according to claim 1, characterized in that: In "the powder is weighed and prepared according to the chemical composition, anhydrous ethanol is used as the ball milling medium, the powder is placed in a nylon jar for ball milling, and then taken out and placed in a dry blower for drying", the ball milling time is 8 hours, and the drying temperature is 100°C-120°C.

4. The method for preparing the sodium bismuth titanate-based relaxor ferroelectric material according to claim 1, characterized in that: In “pressing the dried powder to obtain a small cylinder”, the pressed diameter of the small cylinder is 8 mm and the thickness is 2 mm.

5. The method for preparing the sodium bismuth titanate-based relaxor ferroelectric material according to claim 1, characterized in that: In "placing the small cylinder into a sealed bag in vacuum, pressing it by cold pressing, and sintering the pressed small cylinder to obtain a target ceramic material", the sintering temperature is 1160°C-1220°C, and the sintering time is 2.5h.

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