Multi-element isovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material as well as preparation method and application thereof

Abstract

The invention discloses a multi-element isovalent ion co-doped AgNbO3 lead-free anti-ferroelectric energy storage ceramic material as well as a preparation method and application thereof, and the chemical formula of the energy storage ceramic material is Ag (0.7-3x) Bi (0.1) Tm (x) Nb (0.9) Ta (0.1) O3, 0lt, tm < 3 + > is introduced to the A site again on the basis of the Ag0. 7Bi0. 1Nb0. 9Ta0. 1O3 anti-ferroelectric energy storage ceramic material, so that the AgNbO3 lead-free anti-ferroelectric energy storage ceramic material co-doped with Bi < 3 + > and Tm < 3 + > at the A site and Ta < 5 + > at the B site is formed. According to the invention, under the synergistic effect of improving the stability of an antiferroelectric phase and improving the dielectric breakdown strength and relaxation, the prepared Ag0. 655Bi0. 1Tm0. 015Nb0. 9Ta0. 1O3 energy storage ceramic material obtains the energy storage density as high as 11.04 J / cm < 3 > and the conversion efficiency as high as 79.62% under the action of 428kV / cm, which are about four times of that of an AgNbO3 ceramic material.

Description

Technical Field

[0002] This invention belongs to the field of dielectric ceramic materials technology, specifically relating to a lead-free antiferroelectric energy storage ceramic material of AgNbO3 co-doped with multiple heterovalent ions, its preparation method and application. Background Technology

[0004] With the steady advancement of the national "dual carbon" strategy and the rapid development of high-end electronic equipment such as new energy power systems, electric vehicles, pulse power weapons, and industrial frequency converters, there is an unprecedented and urgent demand for high-performance, high-reliability, miniaturized, and lightweight energy storage capacitors.

[0005] As the core component of a capacitor, the performance of the dielectric material directly determines the size, efficiency, and lifespan of the capacitor device and equipment. Currently, dielectric materials can be divided into two main categories: linear dielectric materials and nonlinear dielectric materials. While linear dielectric materials possess a high breakdown electric field (E0), they are less efficient in achieving their full potential. b And lower dielectric loss, due to its smaller maximum polarization (P). max This limits its energy storage density (W). rec There is room for improvement in ferroelectrics. Ferroelectrics in nonlinear dielectrics have higher P values. max However, the remanent polarization intensity (P) r The energy density (W) is relatively high, resulting in higher energy loss and thus lower energy storage density. rec The small size and low conversion efficiency (ƞ) of high-power pulse devices cannot meet the requirements for integration, lightweighting, and miniaturization.

[0006] Compared to other dielectric materials, antiferroelectric (AFE) materials exhibit a larger P-value due to their unique double PE loop. max and P close to zero r Theoretically possessing a high W rec These properties, including η, demonstrate enormous application potential in the field of energy storage.

[0007] Currently, commercially used dielectric energy storage materials heavily rely on lead-based (PbZrO3) antiferroelectric materials. However, lead is highly volatile at high temperatures, polluting the environment and harming health, which contradicts the global consensus on environmental protection and sustainable development. Therefore, developing green, environmentally friendly, high-performance lead-free dielectric energy storage materials to adapt to future development is particularly urgent and a major national strategic need to support my country's high-end manufacturing industry and energy security.

[0008] AgNbO3 (AN), as a typical representative of lead-free AFE materials, possesses the unique double PE loop and large P of AFM materials. m (P) m~52μC / cm 2 ) and P close to zero r In addition to its characteristics, it also has a relatively wide band gap (E g =2.96eV) and has a high breakdown field strength (E b This indicates that this combination can achieve higher W. rec And thus, it has become one of the hot topics in energy storage material research.

[0009] However, AN exhibits abundant phase transition processes at room temperature, in which the M1 phase (Pbcm) contains Pmc21 exhibiting ferrielectricity (FIE), resulting in a large P r The energy loss during the phase transition from antiferroic phase (AFM) to ferroelectric phase (FM) under the action of an electric field is relatively large, resulting in low conversion efficiency and thus hindering its further commercial application.

[0010] In existing technologies, design strategies such as "ion doping or multi-component solid solution" are generally used to enhance the stability of the antiferroelectric phase of AN at room temperature and reduce P. r Improve E b To further optimize its energy storage characteristics.

[0011] In the prior art, patent document with application number CN201910305422.2 discloses the preparation of Ag by solid-state reaction method. 1-3x Tm x NbO3 (0.01≤x≤0.08) antiferroelectric ceramic materials have a storage density of 2.6~4.3 J / cm³. 3 The conversion efficiency is only 38% to 77%, and the energy storage density and conversion efficiency are relatively low.

[0012] In the prior art, patent document with application number CN202211559128.2 discloses the synthesis of AgNbO3 antiferroelectric energy storage ceramics using a hydrothermal reaction method, with an energy storage density reaching 3.8~4.5 J / cm³. 3 The efficiency is relatively low, with a conversion efficiency of only 38.5% to 45.1%, resulting in significant energy loss. Furthermore, the preparation process is relatively complex, leading to a small production volume and hindering mass production.

[0013] In the prior art, patent document with application number CN202111194580.9 discloses the (1-x)AgNbO3-x(Sr) antiferroelectric energy storage ceramic system. 0.7 Bi 0.2 Adding 0.01 BaCu(B₂O₇) as a co-solvent to HfO₃ lowers the sintering temperature and increases the density of the ceramic material. Although the storage density of the prepared ceramic material is 6.1 J / cm³. 3, the conversion efficiency reaches 73%, however, its preparation process is rather cumbersome, the chemical components are relatively complex, and it is not easy to popularize and apply the technology.

[0014] In the prior art, the patent document with the application number 202210689792.2 discloses the preparation of Ag 0.72 K 0.07 Sm 0.07 NbO3 ceramic material, which has an energy storage density of 3.9 6J / cm 3 under an applied electric field of 330 kV / cm and an energy storage efficiency of 73.56%. However, its energy storage density is less than 4J / cm 3 , which is not conducive to the popularization and application of technology.

[0015] In the prior art, the patent document with the application number CN2024102966068 discloses a preparation method of AgNbO3 lead-free antiferroelectric high energy storage density ceramic material co-doped with Bi 3+ and Y 3+ at the A / B site. Its chemical general formula is Ag 1-3x Bi x Nb 1-3x / 5Y x O3 (0 < x ≤ 0.01), where Ag 0.97 Bi 0.01 Nb 0.994 Y 0.01 O3 ceramic has an energy storage density of 5.4J / cm 3 under the breakdown field strength of 190 kV / cm, while the conversion efficiency is only 56%, and the energy loss is relatively large.

[0016] To sum up, in the existing technology of AgNbO3-based lead-free antiferroelectric materials, there are situations where the energy storage density is relatively large (5 - 8J / cm 3 ) while the energy conversion efficiency is relatively low (30% - 60%), or the energy storage density is relatively small (3 - 5J / cm 3 ) while the energy conversion efficiency is relatively high (50% - 70%). Often, one thing is sacrificed for another, and it is impossible to synergistically optimize the polarization non-linearity (directly affecting η) and breakdown field strength (directly affecting W rec ) of AgNbO3-based lead-free antiferroelectric materials, making it difficult to simultaneously achieve a high energy storage density (W rec > 10J / cm³) and a high conversion efficiency (η > 80%) for AgNbO3-based lead-free antiferroelectric materials. This is a key technical problem that urgently needs to be solved at present. Summary of the Invention

[0018] In view of the problems existing in the AgNbO3 antiferroelectric energy storage ceramics in the prior art, such as the instability of the antiferroelectric phase (AFM) at room temperature, large hysteresis loss, weak breakdown resistance, and the inability to balance the energy storage density and energy storage efficiency, the present invention provides a multi - element heterovalent ion co - doped AgNbO3 lead - free antiferroelectric energy storage ceramic material and its preparation method. By doping Bi 3+ and Tm 3+ at the A site and Ta 5+ at the B site in a co - doping component design scheme, using the mismatch of their ionic radii and the difference in chemical properties, controllable structural disorder and local strain fields are introduced into the AgNbO3 lattice, reducing the remanent polarization intensity (P r ), effectively broadening the band gap of the material, and enhancing the intrinsic breakdown field strength, thus solving the key technical problem of the restrictive development of the energy storage density and conversion efficiency of the current AgNbO3 - based lead - free antiferroelectric materials. The purpose of the present invention is to provide an AgNbO3 - based ceramic material that can simultaneously have high W rec (W rec ≥10 J / cm 3 ) and high η (η = 80%), and this AgNbO3 - based ceramic material can be used to prepare ceramic capacitors.

[0019] To solve the above - mentioned core technical problems, the present invention adopts the following technical solution. A multi - element heterovalent ion co - doped AgNbO3 lead - free antiferroelectric energy storage ceramic material, the chemical formula of the energy storage ceramic material is Ag 0.7-3x Bi 0.1 Tm x Nb 0.9 Ta 0.1 O3, where 0 < x ≤ 0.05. On the basis of the Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 O3 antiferroelectric energy storage ceramic material, Tm 3 + is introduced at the A site again, forming a Bi 3+ and Tm 3+ co - doped AgNbO3 lead - free antiferroelectric energy storage ceramic material at the A site and Ta 5+ at the B site.

[0020] Preferably, the energy storage ceramic material has a single perovskite structure with the Pbcm space group. The two diffraction peaks of (020) and (114) near 2θ = 32 o merge into one diffraction peak (114), indicating that the symmetry of the energy storage ceramic material is enhanced, stabilizing the antiferroelectric phase of the AgNbO3 material; the energy storage ceramic material presents a dense microstructure with extremely low porosity, uniform grain distribution, clear grain boundaries, and the grain size is 2 - 3 μm.

[0021] Preferably, the chemical formula of the energy storage ceramic material is Ag. 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 O3 (ABNT3) has a high energy storage density of 11.04 J / cm³. 3 The conversion efficiency is 79.62%, and the breakdown field strength is 428 kV / cm.

[0022] A method for preparing a lead-free antiferroelectric energy storage ceramic material co-doped with multi-component heterovalent ions AgNbO3, the specific preparation steps of which are as follows:

[0023] Step S1: Press Ag 0.7-3x Bi 0.1 Tm x Nb 0.9 Ta 0.1 The stoichiometric ratios of the chemical formulas of O3 were measured from the raw materials Ag2O, Bi2O3, Tm2O3, Nb2O5, and Ta2O5, respectively, where 0 <x≤0.05;

[0024] Step S2: Place the weighed raw materials into a star-shaped ball mill, add anhydrous ethanol as a medium for ball milling and drying to prepare a mixed powder;

[0025] Step S3: The mixed powder is heated to 850-900℃ for 4-8 hours under an oxygen atmosphere at a heating rate of 2-5℃ / min. The pre-sintered powder is then ball-milled and dried, and then sieved.

[0026] Step S4: Add binder to the sieved pre-calcined powder for granulation, and then press it into a cylindrical preform by isostatic pressing.

[0027] Step S5: The cylindrical preform is heated to 1050-1140℃ in an oxygen atmosphere at a heating rate of 2-5℃ / min and sintered for 4-8 hours. Then, it is cooled to 600℃ at a cooling rate of 2-5℃ / min and then cooled to room temperature in the furnace to obtain Ag. 0.7- 3x Bi 0.1 Tm x Nb 0.9 Ta 0.1 O3 energy storage ceramic materials.

[0028] Preferably, in step S1, the purity of the raw materials Ag2O is higher than 99.7%, the purity of Bi2O3 is higher than 99.9%, the purity of Tm2O3 is higher than 99.9%, the purity of Nb2O5 is higher than 99.99%, and the purity of Ta2O5 is higher than 99.99%.

[0029] Preferably, the ball milling process in step S2 is ball milling at a rotation speed of 300~600 r / min for 18~24 h.

[0030] Preferably, the sieving process in step S3 is to use a sieve with a mesh size of 100 to 200.

[0031] Preferably, the binder in step S4 is a 4wt.% to 6wt.% aqueous solution of polyvinyl alcohol (PVA), and the amount of the binder added is 3wt.% to 8wt.% of the mass of the pre-fired powder.

[0032] Preferably, in step S4, the pressing process involves pressing a cylindrical preform with a diameter of 8 mm and a thickness of 1 mm under an isostatic pressure of 200~250 MPa.

[0033] The application of the multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material described in this invention in the preparation of ceramic capacitors.

[0034] The application of the multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material described in this invention in the preparation of pulse power capacitors.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] (1) This invention utilizes Bi³ + (R) Bi ³ + =0.117nm, possessing lone pair electrons) and Tm³ + (R) Tm ³ + Co-doping with nanoparticles (0.087 nm) at the A-site of AgNbO3 energy storage ceramic material enhances structural disorder in the AgNbO3 lattice, induces relaxation behavior, breaks long-range antiferroelectric order, forms polar nanoferroelectric domains, refines the hysteresis loop (PE), reduces residual polarization intensity, and thus effectively improves the energy conversion efficiency of the energy storage ceramic material.

[0037] (2) Ta in the energy storage ceramic material of the present invention 5+ Replace Nb in the B position. 5+ By utilizing the stronger covalent nature of the Ta-O bond, the band gap of AgNbO3 material can be effectively widened, significantly improving the intrinsic breakdown field strength (BDS) and thus effectively increasing its energy storage density.

[0038] (3) The Bi³ in the energy storage ceramic material of the present invention + and Tm³ + In position A, Ta 5+When doping at the B site, the synergistic effect of both overcomes the limitations of single doping at the A site or the B site, and simultaneously solves two key problems: polarization response (which directly affects conversion efficiency) and breakdown field strength (which directly affects energy storage density).

[0039] (4) The present invention improves the stability of the antiferroelectric phase and enhances the dielectric breakdown strength and relaxation characteristics through a synergistic effect, thereby preparing Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 O3 energy storage ceramic material achieved 11.04 J / cm at 428 kV / cm. 3 Its energy storage density and conversion efficiency of 79.62% are approximately four times that of AgNbO3 ceramic materials. This aligns with the demand for miniaturized, integrated, and lightweight pulsed power devices.

[0040] (5) The energy storage ceramic material of the present invention achieves grain refinement (average grain size ≤3μm) and densification (relative density ≥95%) at the microscopic level through A / B site synergistic doping, induces relaxation antiferroelectric behavior at the mesoscopic level, and obtains excellent comprehensive energy storage performance at the macroscopic level.

[0041] (6) The preparation process of the energy storage ceramic material of the present invention is compatible with the traditional electronic ceramic preparation process and is easy to scale up production. Attached Figure Description

[0043] Figure 1 For AgNbO3 and Ag 0.7-3x Bi 0.1 Tm x Nb 0.9 Ta 0.1 X-ray diffraction pattern of O3 (0.01≤x≤0.02) energy storage ceramic material.

[0044] Figure 2 For AgNbO3 and Ag 0.7-3x Bi 0.1 Tm x Nb 0.9 Ta 0.1 SEM image of O3 (0.01≤x≤0.02) energy storage ceramic material.

[0045] Figure 3 For AgNbO3 and Ag 0.7-3x Tm x Bi 0.1 Nb 0.9 Ta 0.1 Hysteresis loops of O3 (0.01≤x≤0.02) energy storage ceramic materials under different electric fields.

[0046] Figure 4 For AgNbO3 and Ag 0.7-3x Tm x Bi 0.1 Nb 0.9 Ta 0.1 Energy storage parameters of O3 (0.01≤x≤0.02) energy storage ceramic material under different electric fields. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following embodiments are commercially available unless otherwise specified.

[0049] Example 1

[0050] Step S1: Press Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 The stoichiometric ratios of the chemical formulas for O3(ABNT1) were determined by weighing Ag2O (99.7% purity), Bi2O3 (99.9% purity), Nb2O5 (99.9% purity), and Ta2O5 (99.99% purity) separately to prepare Ag2O3(ABNT1). 0.9 Bi 0.1 Nb 0.9 Ta 0.1 The amount of O3 in the sample was 0.02 mol.

[0051] Step S2: Place the weighed raw material into a star-shaped ball mill, add 40 mL of anhydrous ethanol as the medium for ball milling, set the rotation speed of the star-shaped ball mill to 350 r / min, the ball milling time to 24 h, and then dry to prepare a mixed powder.

[0052] Step S3: The mixed powder is heated to 900℃ for 6 hours under an oxygen atmosphere at a heating rate of 3℃ / min. The pre-sintered powder is then ball-milled and dried. Finally, the pre-sintered powder is sieved through a 150-mesh sieve.

[0053] Step S4: Add 5 wt% of a polyvinyl alcohol aqueous solution (PVA) binder to the sieved pre-calcined powder for granulation. The amount of binder added is 6 wt.% of the mass of the pre-calcined powder. Then, press it into a cylindrical preform with a diameter of 8 mm and a thickness of 1 mm under an isostatic pressure of 200 MPa.

[0054] Step S5: The cylindrical preform is heated to 600℃ at a heating rate of 3℃ / min under an oxygen atmosphere and held at that temperature for 3 hours to remove the binder. Then, it is heated to 1140℃ at the same heating rate and sintered again for 6 hours. Finally, it is cooled to 600℃ at a cooling rate of 5℃ / min and then cooled to room temperature in the furnace to obtain Ag. 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials.

[0055] Figure 1 Example 1 is Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 X-ray diffraction pattern of O3(ABNT1) energy storage ceramic material, from Figure 1 As can be seen in Example 1, Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 The XRD pattern of the O3 energy storage ceramic material is consistent with the standard pattern (PDF: No. 52-0405), and no impurity phase peaks appear, indicating that the prepared Ag... 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials possess a single perovskite structure in the Pbcm space group. At 2θ=32 o The two diffraction peaks (020) and (114) nearby merge into a single diffraction peak (114), indicating that Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 The symmetry of O3 energy storage ceramic materials is enhanced.

[0056] Figure 2 Example 1 is Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 SEM morphology images of O3(ABNT1) energy storage ceramic materials, from Figure 2 As can be seen in Example 1, Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1O3 energy storage ceramic material exhibits a dense microstructure with extremely low porosity, uniform grain distribution, clear grain boundaries, and a grain size of approximately 2.69 μm.

[0057] Figure 3 Example 1 is Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 The unipolar electrode hysteresis loop diagram of O3(ABNT1) energy storage ceramic material, from Figure 3 As can be seen in Example 1, Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 The maximum polarization intensity P of O3 energy storage ceramic material under a maximum polarization electric field of 358 kV / cm max =53.1μC / cm 2 Residual polarization intensity P r =6.82μC / cm 2 .

[0058] Figure 4 Example 1 is Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 The graph shows the relationship between the energy storage density and conversion efficiency of O3(ABNT1) energy storage ceramic materials and the electric field (E). Figure 4 As can be seen in Example 1, Ag 0.67 Bi 0.1 Tm 0.01 Nb 0.9 Ta 0.1 The energy storage density W of O3 energy storage ceramic material under the maximum polarization electric field of 358 kV / cm rec =7.54J / cm 3 The energy storage efficiency η = 76.81%.

[0059] Example 2

[0060] Step S1: Press Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 The stoichiometric ratios of the chemical formulas for O3(ABNT2) were determined by weighing Ag2O (99.7% purity), Bi2O3 (99.9% purity), Nb2O5 (99.9% purity), and Ta2O5 (99.99% purity) separately to prepare Ag2O3(ABNT2). 0.655 Bi 0.1Tm 0.015 Nb 0.9 Ta 0.1 The amount of O3(ABNT2) sample was 0.02 mol.

[0061] Steps S2, S3 and S4 are the same as in Example 1.

[0062] Step S5: The cylindrical preform is heated to 600℃ at a heating rate of 3℃ / min under an oxygen atmosphere and held at that temperature for 3 hours to remove the binder. Then, it is heated to 1140℃ at the same heating rate and sintered again for 6 hours. Finally, it is cooled to 600℃ at a cooling rate of 5℃ / min and then cooled to room temperature in the furnace to obtain Ag. 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials.

[0063] Figure 1 Example 2 in the text is Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 X-ray diffraction pattern of O3(ABNT2) energy storage ceramic material, from Figure 1 As can be seen in Example 2, Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 The XRD pattern of the O3 energy storage ceramic material is consistent with the standard pattern (PDF: No. 52-0405), and no impurity phase peaks appear, indicating that the prepared Ag... 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials possess a single perovskite structure in the Pbcm space group. At 2θ=32 o The two diffraction peaks (020) and (114) nearby merge into a single diffraction peak (114), indicating that Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 The enhanced symmetry of O3 energy storage ceramic materials stabilizes the antiferroelectric phase of AN.

[0064] Figure 2 Example 2 in the text is Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1SEM morphology images of O3(ABNT2) energy storage ceramic materials, from Figure 2 As can be seen in Example 2, Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 O3 energy storage ceramic material exhibits a dense microstructure with extremely low porosity, uniform grain distribution, clear grain boundaries, and a grain size of approximately 2.41 μm.

[0065] Figure 3 Example 2 in the text is Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 The unipolar electrode hysteresis loop diagram of O3(ABNT2) energy storage ceramic material, from Figure 3 As can be seen in Example 2, Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 The maximum polarization intensity P of O3 energy storage ceramic material under a maximum polarization electric field of 428 kV / cm max =64.17μC / cm 2 Residual polarization intensity P r =7.11μC / cm 2 .

[0066] Figure 4 Example 2 in the text is Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 The graph shows the relationship between the energy storage density and conversion efficiency of O3(ABNT2) energy storage ceramic materials and the electric field (E). Figure 4 As can be seen in Example 2, Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 The energy storage density W of O3 energy storage ceramic material under the maximum polarization electric field of 428 kV / cm rec =11.04J / cm 3 The energy storage efficiency η = 79.62%.

[0067] Example 3

[0068] Step S1: Press Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta0.1 The stoichiometric ratios of the chemical formula for O3(ABNT3) were determined by weighing Ag2O (99.7% purity), Bi2O3 (99.9% purity), Nb2O5 (99.9% purity), and Ta2O5 (99.99% purity) separately to prepare Ag2O3(ABNT3). 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 The amount of O3 in the sample was 0.02 mol.

[0069] Steps S2, S3 and S4 are the same as in Example 1.

[0070] Step S5: The cylindrical preform is heated to 600℃ at a heating rate of 3℃ / min under an oxygen atmosphere and held at that temperature for 3 hours to remove the binder. Then, it is heated to 1140℃ at the same heating rate and sintered again for 6 hours. Finally, it is cooled to 600℃ at a cooling rate of 5℃ / min and then cooled to room temperature in the furnace to obtain Ag. 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials.

[0071] Figure 1 Example 3 is Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 X-ray diffraction pattern of O3(ABNT3) energy storage ceramic material, from Figure 1 As can be seen in Example 3, Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 The XRD pattern of the O3 energy storage ceramic material is consistent with the standard pattern (PDF: No. 52-0405), and no impurity phase peaks appear, indicating that the prepared Ag... 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials possess a single perovskite structure in the Pbcm space group. At 2θ=32 o The two diffraction peaks (020) and (114) nearby merge into a single diffraction peak (114), indicating that Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 The enhanced symmetry of O3 energy storage ceramic materials stabilizes the antiferroelectric phase of AgNbO3.

[0072] Figure 2 Example 3 is Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 SEM morphology images of O3(ABNT3) energy storage ceramic materials, from Figure 2 As can be seen in Example 3, Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 O3 energy storage ceramic material exhibits a dense microstructure with extremely low porosity, uniform grain distribution, clear grain boundaries, and a grain size of approximately 2.62 μm.

[0073] Figure 3 Example 3 is Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 The unipolar electrode hysteresis loop diagram of O3(ABNT3) energy storage ceramic material, from Figure 3 As can be seen in Example 3, Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 The maximum polarization intensity P of O3 energy storage ceramic material under a maximum polarization electric field of 428 kV / cm max =57.47μC / cm 2 Residual polarization intensity P r =6.96μC / cm 2 .

[0074] Figure 4 Example 3 is Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 The graph shows the relationship between the energy storage density and conversion efficiency of O3(ABNT3) energy storage ceramic materials and the electric field (E). Figure 4 As can be seen in Example 3, Ag 0.64 Bi 0.1 Tm 0.02 Nb 0.9 Ta 0.1 The energy storage density W of O3 energy storage ceramic material under the maximum polarization electric field of 343kV / cm rec = 7.78J / cm 3 The energy storage efficiency η = 77.36%.

[0075] Comparative Example 1

[0076] Step S1: Weigh Ag2O with a purity of 99.7% and Nb2O5 with a purity of 99.99% according to the stoichiometric ratio of AgNbO3 to prepare an AgNbO3 sample with a mass of 0.02 mol.

[0077] Steps S2, S3 and S4 are the same as in Example 1.

[0078] Step S5: The cylindrical preform is heated to 600°C at a heating rate of 3°C / min under an oxygen atmosphere and held at that temperature for 3 hours to remove the binder. Then, it is heated to 1070°C at the same heating rate and sintered again for 6 hours. Then, it is cooled to 600°C at a cooling rate of 5°C / min and then cooled to room temperature in the furnace to obtain AgNbO3 energy storage ceramic material.

[0079] Figure 1 Comparative Example 1 shows the X-ray diffraction pattern of AgNbO3(AN) energy storage ceramic material. Figure 1 Comparative Example 1 shows that at 2θ = 32.1 o Two diffraction peaks (020) and (110) are present nearby, consistent with the standard spectrum (PDF: No. 52-0405). No impurity peaks are present, indicating that the prepared AgNbO3 energy storage ceramic material has a single perovskite structure of the Pbcm space group.

[0080] Figure 2 Comparative Example 1 shows the SEM morphology of AgNbO3(AN) energy storage ceramic material. Figure 2 Comparative Example 1 shows that the AgNbO3 energy storage ceramic material exhibits a dense microstructure with extremely low porosity, uniform grain distribution, clear grain boundaries, and a grain size of approximately 3.29 μm.

[0081] Figure 3 Comparative Example 1 is the electrode hysteresis loop diagram of AgNbO3(AN) energy storage ceramic material. Figure 3 Comparative Example 1 shows that the maximum polarization intensity P of the AgNbO3 energy storage ceramic material under the maximum polarization electric field of 240 kV / cm max =47.12μC / cm 2 Residual polarization intensity P r =5.52μC / cm 2 .

[0082] Figure 4 Comparative Example 1 shows the relationship between the energy storage density and conversion efficiency of AgNbO3(AN) energy storage ceramic material and the electric field (E). Figure 4Comparative Example 1 shows that the energy storage density W of AgNbO3 energy storage ceramic material under the maximum polarization electric field of 240 kV / cm rec =2.65J / cm 3 The energy storage efficiency is 41.39%.

[0083] Comparative Example 2

[0084] Step S1: Press Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 The stoichiometric ratios of the chemical formulas for O3(ABNT) were determined by weighing Ag2O (99.7% purity), Bi2O3 (99.9% purity), Nb2O5 (99.9% purity), and Ta2O5 (99.99% purity) separately to prepare Ag2O3 (ABNT). 0.9 Bi 0.1 Nb 0.9 Ta 0.1 The amount of O3 in the sample was 0.02 mol.

[0085] Steps S2, S3 and S4 are the same as in Example 1.

[0086] Step S5: The cylindrical preform is heated to 600℃ at a heating rate of 3℃ / min under an oxygen atmosphere and held at that temperature for 3 hours to remove the binder. Then, it is heated to 1100℃ at the same heating rate and sintered again for 6 hours. Finally, it is cooled to 600℃ at a cooling rate of 5℃ / min and then cooled to room temperature in the furnace to obtain Ag. 0.7 Bi 0.1 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials.

[0087] Figure 1 Comparative Example 2 is Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 X-ray diffraction pattern of O3(ABNT) energy storage ceramic material, from Figure 1 Comparative Example 2 shows that Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 The XRD pattern of the O3 energy storage ceramic material is consistent with the standard pattern (PDF: No. 52-0405), and no impurity phase peaks appear, indicating that the prepared Ag... 0.7 Bi 0.1 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials possess a single perovskite structure in the Pbcm space group. At 2θ=32 oThe two diffraction peaks (020) and (114) nearby merge into a single diffraction peak (114), indicating that Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 The symmetry of O3 energy storage ceramic materials is enhanced.

[0088] Figure 2 Comparative Example 2 is Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 SEM morphology images of O3(ABNT) energy storage ceramic materials, from Figure 2 Comparative Example 2 shows that Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 O3 energy storage ceramic material exhibits a dense microstructure with extremely low porosity, uniform grain distribution, clear grain boundaries, and a grain size of approximately 3.16 μm.

[0089] Figure 3 Comparative Example 2 is Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 The unipolar electrode hysteresis loop diagram of O3(ABNT) energy storage ceramic material, from Figure 3 Comparative Example 2 shows that Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 The maximum polarization intensity P of O3 energy storage ceramic material under a maximum polarization electric field of 324 kV / cm max =26.65μC / cm 2 Residual polarization intensity P r = 2.63μC / cm 2 .

[0090] Figure 4 Comparative Example 2 is Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 The graph showing the relationship between the energy storage density and conversion efficiency of O3 energy storage ceramic materials and the electric field (E) is shown below. Figure 4 Comparative Example 2 shows that Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 The energy storage density W of O3(ABNT) energy storage ceramic material under a maximum polarization electric field of 324kV / cm rec =3.52J / cm 3, the energy storage efficiency η = 79.07%.

[0091] In summary, the present invention uses Bi 3+ and Tm 3+ at the A-site, and Ta 5+ at the B-site to design the composition of AgNbO3, and uses the solid-state reaction method to prepare high-performance Ag 0.7-3x Bi 0.1 Tm x Nb 0.9 Ta 0.1 O3 (0 < x ≤ 0.05) energy storage ceramic materials. Through the synergistic effect of the two, the antiferroelectric phase of the AgNbO3-based ceramics is stabilized, the breakdown field strength, energy storage density and energy storage efficiency are improved, and two key problems of polarization response (directly affecting the conversion efficiency) and breakdown field strength (directly affecting the energy storage density) are solved, realizing that Ag 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 O3 energy storage ceramic materials obtain an energy storage density W rec = 11.04 J / cm 3 , and the energy storage efficiency η = 79.62%.

[0092] The above shows and describes the basic principles, main features and advantages of the present invention. Without departing from the spirit and scope of the present invention, the present invention has various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A lead-free antiferroelectric energy storage ceramic material co-doped with AgNbO3 by multiple heterovalent ions, characterized in that: The chemical formula of the energy storage ceramic material is Ag 5+ Bi 0.1 Tm x Nb 0.9 Ta 0.1 O3, where 0 < x ≤ 0.

05. Based on the anti-ferroelectric energy storage ceramic material of Ag 0.7 Bi 0.1 Nb 0.9 Ta 0.1 O3, Tm is introduced again at the A-site to form a lead-free anti-ferroelectric energy storage ceramic material of AgNbO3 co-doped with Bi 3+ and Tm 3+ at the A-site and Ta 3+ at the B-site. 5+ ​ 2. The multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material according to claim 1, characterized in that: The energy storage ceramic material has a single perovskite structure in the Pbcm space group, at 2θ=32 o The two diffraction peaks (020) and (114) nearby merge into one diffraction peak (114), indicating that the symmetry of the energy storage ceramic material is enhanced and the antiferroelectric phase of the AgNbO3 material is stabilized. The energy storage ceramic material exhibits a dense microstructure with extremely low porosity, uniform grain distribution, clear grain boundaries, and a grain size of 2~4μm.

3. The multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material according to claim 1, characterized in that: The chemical formula of the energy storage ceramic material is Ag. 0.655 Bi 0.1 Tm 0.015 Nb 0.9 Ta 0.1 O3 has a high energy storage density of 11.04 J / cm³. 3 The conversion efficiency is 79.62%, and the breakdown field strength is 428 kV / cm.

4. A method for preparing a lead-free antiferroelectric energy storage ceramic material co-doped with AgNbO3 by any one of claims 1 to 3, characterized in that... The specific preparation steps are as follows: Step S1: Press Ag 0.7-3x Bi 0.1 Tm x Nb 0.9 Ta 0.1 The stoichiometric ratios of the chemical formulas of O3 were measured for the raw materials Ag2O, Bi2O3, Tm2O3, Nb2O5, and Ta2O5, respectively, where 0 <x≤0.05; Step S2: Place the weighed raw materials into a star-shaped ball mill, add anhydrous ethanol as a medium for ball milling and drying to prepare a mixed powder; Step S3: The mixed powder is heated to 850-900℃ for 4-8 hours under an oxygen atmosphere at a heating rate of 2-5℃ / min. The pre-sintered powder is then ball-milled and dried, and then sieved. Step S4: Add binder to the sieved pre-calcined powder for granulation, and then press it into a cylindrical preform by isostatic pressing. Step S5: The cylindrical preform is heated to 1050-1140℃ in an oxygen atmosphere at a heating rate of 2-5℃ / min and sintered for 4-8 hours. Then, it is cooled to 600℃ at a cooling rate of 2-5℃ / min and then cooled to room temperature in the furnace to obtain Ag. 0.7- 3x Bi 0.1 Tm x Nb 0.9 Ta 0.1 O3 energy storage ceramic materials.

5. The preparation method of the multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material according to claim 4, characterized in that: In step S1, the purity of raw materials Ag2O is higher than 99.7%, Bi2O3 is higher than 99.9%, Tm2O3 is higher than 99.9%, Nb2O5 is higher than 99.99%, and Ta2O5 is higher than 99.99%.

6. The preparation method of the multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material according to claim 4, characterized in that: In step S2, the ball milling process involves milling at a speed of 300-600 r / min for 18-24 hours; in step S3, the sieving process involves sieving using a 100-200 mesh sieve.

7. The method for preparing the multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material according to claim 4, characterized in that: In step S4, the binder is a 4wt.% to 6wt.% aqueous solution of polyvinyl alcohol, and the amount of the binder added is 3wt.% to 8wt.% of the mass of the pre-fired powder.

8. The preparation method of the multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material according to claim 4, characterized in that: In step S4, the pressing process involves pressing a cylindrical preform with a diameter of 8 mm and a thickness of 1 mm under an isostatic pressure of 200~250 MPa.

9. The application of the multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material according to any one of claims 1 to 3 in the preparation of ceramic capacitors.

10. The application of the multi-component heterovalent ion co-doped AgNbO3 lead-free antiferroelectric energy storage ceramic material according to any one of claims 1 to 3 in the preparation of pulse power capacitors.

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