CN117735974B - Leadless high-entropy ferroelectric ceramic material and preparation method and application thereof - Google Patents
Leadless high-entropy ferroelectric ceramic material and preparation method and application thereof Download PDFInfo
- Publication number
- CN117735974B CN117735974B CN202410186437.2A CN202410186437A CN117735974B CN 117735974 B CN117735974 B CN 117735974B CN 202410186437 A CN202410186437 A CN 202410186437A CN 117735974 B CN117735974 B CN 117735974B
- Authority
- CN
- China
- Prior art keywords
- entropy
- ceramic
- ceramic material
- ferroelectric
- energy storage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229910002112 ferroelectric ceramic material Inorganic materials 0.000 title claims abstract description 26
- 238000002360 preparation method Methods 0.000 title claims abstract description 15
- 239000000919 ceramic Substances 0.000 claims abstract description 145
- 238000004146 energy storage Methods 0.000 claims abstract description 97
- 229910010293 ceramic material Inorganic materials 0.000 claims abstract description 30
- 239000000126 substance Substances 0.000 claims abstract 2
- 239000000843 powder Substances 0.000 claims description 51
- 238000005245 sintering Methods 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 27
- 238000000498 ball milling Methods 0.000 claims description 25
- 238000004321 preservation Methods 0.000 claims description 25
- 238000010438 heat treatment Methods 0.000 claims description 22
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 21
- 239000003292 glue Substances 0.000 claims description 21
- 229910052709 silver Inorganic materials 0.000 claims description 21
- 239000004332 silver Substances 0.000 claims description 21
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 claims description 16
- WMWLMWRWZQELOS-UHFFFAOYSA-N bismuth(iii) oxide Chemical compound O=[Bi]O[Bi]=O WMWLMWRWZQELOS-UHFFFAOYSA-N 0.000 claims description 16
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Chemical compound O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 claims description 16
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 15
- 238000001035 drying Methods 0.000 claims description 15
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 15
- 239000011230 binding agent Substances 0.000 claims description 13
- 238000007599 discharging Methods 0.000 claims description 13
- 238000000465 moulding Methods 0.000 claims description 12
- 239000002002 slurry Substances 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 11
- 230000003179 granulation Effects 0.000 claims description 9
- 238000005469 granulation Methods 0.000 claims description 9
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 239000003153 chemical reaction reagent Substances 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 8
- 229910052593 corundum Inorganic materials 0.000 claims description 8
- 239000010431 corundum Substances 0.000 claims description 8
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 8
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 8
- LEDMRZGFZIAGGB-UHFFFAOYSA-L strontium carbonate Chemical compound [Sr+2].[O-]C([O-])=O LEDMRZGFZIAGGB-UHFFFAOYSA-L 0.000 claims description 8
- 229910000018 strontium carbonate Inorganic materials 0.000 claims description 8
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 claims description 8
- XLOMVQKBTHCTTD-UHFFFAOYSA-N zinc oxide Inorganic materials [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 8
- 238000007747 plating Methods 0.000 claims description 7
- 230000008569 process Effects 0.000 claims description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 6
- 239000002612 dispersion medium Substances 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 4
- 238000005498 polishing Methods 0.000 claims description 4
- 238000003756 stirring Methods 0.000 claims description 4
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 238000007873 sieving Methods 0.000 claims description 2
- 238000003786 synthesis reaction Methods 0.000 claims description 2
- 230000002194 synthesizing effect Effects 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- 238000005303 weighing Methods 0.000 claims description 2
- 239000013078 crystal Substances 0.000 abstract description 20
- 238000013461 design Methods 0.000 abstract description 8
- 230000007246 mechanism Effects 0.000 abstract description 8
- 238000005457 optimization Methods 0.000 abstract description 4
- 230000007547 defect Effects 0.000 abstract description 2
- 238000009827 uniform distribution Methods 0.000 abstract 1
- 238000012360 testing method Methods 0.000 description 29
- 239000012071 phase Substances 0.000 description 22
- 230000006399 behavior Effects 0.000 description 20
- 230000005684 electric field Effects 0.000 description 16
- 208000028659 discharge Diseases 0.000 description 14
- 239000000463 material Substances 0.000 description 14
- 239000006104 solid solution Substances 0.000 description 10
- 239000003990 capacitor Substances 0.000 description 8
- 238000012512 characterization method Methods 0.000 description 8
- 238000002367 polarised neutron reflectometry Methods 0.000 description 8
- 229920000636 poly(norbornene) polymer Polymers 0.000 description 8
- 238000003917 TEM image Methods 0.000 description 6
- 229910002113 barium titanate Inorganic materials 0.000 description 6
- 239000008187 granular material Substances 0.000 description 6
- 239000010410 layer Substances 0.000 description 6
- 229920003023 plastic Polymers 0.000 description 6
- 239000004033 plastic Substances 0.000 description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 5
- -1 polytetrafluoroethylene Polymers 0.000 description 5
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 5
- 239000004810 polytetrafluoroethylene Substances 0.000 description 5
- 238000003825 pressing Methods 0.000 description 5
- 238000002441 X-ray diffraction Methods 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 210000001161 mammalian embryo Anatomy 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 238000003746 solid phase reaction Methods 0.000 description 4
- 239000007858 starting material Substances 0.000 description 4
- 239000003985 ceramic capacitor Substances 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000002003 electron diffraction Methods 0.000 description 3
- 238000007373 indentation Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 230000008520 organization Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000033228 biological regulation Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 238000005381 potential energy Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000013112 stability test Methods 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
Landscapes
- Inorganic Insulating Materials (AREA)
Abstract
The invention discloses a lead-free high-entropy ferroelectric ceramic material, a preparation method and application thereof, and relates to the technical field of ceramic materials, wherein the chemical formula of the ceramic material is ：(0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/6Ta1/3Nb1/3)O3;, x=0.04 or 0.06 or 0.08 or 0.10, and x represents mole fraction. Introducing multiple principal components into BFBT-based lead-free relaxation ceramic through a high-entropy design strategy to make the ceramic body structure high in entropy, so that the random field and relaxation performance of the ceramic body can be improved, the defect of symmetry of a crystal structure is induced, a coexistence structure of a three-phase (R3 c) and a pseudo-cubic phase (Pm-3 m) is formed, meanwhile, crystal grains are refined, polar nanometer micro-regions (PNRs) with smaller dimensions and uniform distribution are formed, and the formed high-entropy ferroelectric ceramic material has better energy storage performance and ultrahigh mechanical property; the discovery of the microcosmic mechanism has great significance and value for the physical origin of the excellent performance of the high-entropy ferroelectric ceramic and the further optimization of the performance of the high-entropy ferroelectric ceramic in the future.
Description
Technical Field
The invention relates to the technical field of ceramic materials, in particular to a lead-free high-entropy ferroelectric ceramic material, a preparation method and application thereof.
Background
Currently, batteries, electrochemical capacitors, and dielectric capacitors are the primary elements and devices for energy storage and conversion systems. The dielectric capacitor has ultrahigh power density, excellent mechanical property and thermal stability and rapid charge and discharge rate, and is widely applied to high power/pulse power technology in the emerging industries such as electric automobiles, internet of things and the like. With the development of electronic information technology, higher requirements are put on the performance and service life of the capacitor and the materials used. However, the low energy storage density and low energy storage efficiency of dielectric capacitors have been the main factors limiting their rapid development and large-scale application. In view of this, in recent years, many different types of dielectric capacitor materials have been rapidly developed, such as relaxed ferroelectric (REF), ferroelectric (FE), and Antiferroelectric (AFE) materials. Antiferroelectric materials, such as Pb (Zr, hf) O 3、 AgNbO3 and NaNbO 3, possess a large ΔP (P max–Pr) and excellent energy storage density due to the ferroelectric-antiferroelectric phase transition occurring at a low electric field, whereas a higher hysteresis loop results in a smaller energy storage efficiency. From the application point of view, the low energy storage efficiency can lead to more heat generation, and the service stability and the service life of the capacitor are greatly influenced. In addition, for the relaxation ferroelectric material, the body contains the polar nanometer micro-region (PNRs), so that the material has extremely low hysteresis loop and has great application prospect in energy storage equipment.
Among the numerous ferroelectrics, biFeO 3 -based lead-free ferroelectric ceramics have gained much attention in recent years due to their higher Curie temperature (≡830 ℃), greater spontaneous polarization strength (100 [ mu ] C/cm 2) and lower sintering temperature. In particular, biFeO 3-BaTiO3 -based ferroelectric ceramic materials synthesized by solid-dissolving BaTiO 3 in BiFeO 3 -based ferroelectric ceramics are always hot spots for research by scientific researchers, and have been unprecedented in the field of energy storage application. For example, the introduction of CaTiO 3 into BiFeO 3-BaTiO3 -based lead-free ferroelectric ceramics can achieve higher energy storage properties at 380 kV/cm applied electric field, such as recoverable energy storage density W rec=5.03 J/cm3, energy storage efficiency η=89.7% and excellent thermal stability (the amount of change in the value of W rec is less than <4% at temperatures from 30 to 150 ℃). For another example, a ternary 0.85 (0.67 BiFeO 3-0.33BaTiO3)-0.15Sr(Nb0.5Al0.5)O3 -based ceramic material is synthesized by introducing a paraelectric phase Sr (Nb 0.5Al0.5)O3) into a BiFeO 3-BaTiO3 -based leadless ferroelectric ceramic material, the intervention of Sr (Nb 0.5Al0.5)O3) is beneficial to reducing dielectric loss and residual polarization intensity of a solid solution, so that a larger recoverable energy storage density W rec=3.95 J/cm3 and a higher energy storage efficiency eta=85.9% are obtained under an external electric field of 300 kV/cm, the Nd (Zn 0.5Zr0.5)O3 also can realize the induction of the enhanced recoverable energy storage density W rec=2.45 J/cm3 under a smaller external electric field (E=240 kV/cm) and a moderate energy storage efficiency eta=72%. The class of relaxation ferroelectric with better energy storage performance under a low electric field, and an alternative ceramic material with a very good prospect can be provided for advanced energy storage and conversion device (such as a ceramic capacitor) with a thickness of 10 mu m in practical engineering, the BiFeO 3-BaTiO3 -based leadless ferroelectric material has a better energy storage capacity and a brand-new energy storage mechanism of the potential energy conversion device is designed in the current industry, and the potential mechanism of the BiFeO is still clear from the research of the current industry, and the potential mechanism of the FeO is still realized under the research of the principle of the research of the advanced energy storage device is still more advanced, and the potential mechanism of the FeO is still a novel ceramic material is still clear in the field.
In recent years, scholars have tried to develop ceramic materials with high entropy of multi-principal organization by utilizing "entropy engineering", which is one of the popular and novel strategies developed so far for regulating the structure and performance of ceramic materials. The method realizes a single stable phase with enhanced structural entropy by equimolar occupation of a certain lattice position in the ceramic material by multiple elements. Variations in the configurational entropy, lattice distortion, and slow diffusion effects will significantly affect the structure and performance of such high entropy ferroelectric ceramic materials. In addition, the increase in entropy will induce the appearance of polar nano-regions PNRs in the ferroelectric ceramic material, rather than forming a long-range ordered domain structure like in ferroelectric solid solution. Under the condition, the ceramic material presents dispersion phase transition, so that the relaxation performance is enhanced, and meanwhile, a hysteresis loop with lower hysteresis characteristic is hopeful to be obtained, and the ceramic material has great application potential in the aspects of regulating and controlling the energy storage characteristic and mechanical property of ferroelectric ceramic. Based on this, this "high entropy design" strategy can be tried in BiFeO 3-BaTiO3 -based ferroelectric ceramic materials in order to achieve high energy storage and mechanical properties and reveal potential microscopic mechanisms under new design strategies.
Disclosure of Invention
Based on the background technology, the invention aims to provide a lead-free high-entropy ferroelectric ceramic material, a preparation method and application thereof, and a novel high-entropy ferroelectric ceramic with high recoverable energy storage density W rec=2.40 J/cm3, high energy storage efficiency eta=75%, enhanced thermal stability (25 to 110 ℃) and frequency stability (1 to 100 Hz) and ultra-high mechanical hardness H=7.2 GPa is obtained under a lower external electric field (E=190 kV/cm) by introducing a high-entropy principal component to realize comprehensive regulation and control of the structure and performance of a BiFeO 3-BaTiO3 -based ceramic system.
The invention is realized by the following technical scheme:
In a first aspect, the present application provides a lead-free high entropy ferroelectric ceramic material having the formula ：(0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/6Ta1/3Nb1/3)O3; wherein x=0.04 or 0.06 or 0.08 or 0.10 and x represents the mole fraction.
The invention synthesizes a multi-principal element tissue high-entropy lead-free ferroelectric ceramic material ：(0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/6Ta1/3Nb1/3)O3( which is BFBT-SMZTN-x for short, wherein x=0.04, 0.06, 0.08 and 0.10 by coexisting configuration entropy regulation and B-site multielement. The high entropy of organism tissue and the coexistence of three pseudo-cubic phases are realized through the intervention of a high entropy principal element, and meanwhile, a ferroelectric domain structure with long range order is destroyed so as to form a polar nanometer micro-region PNRs with excellent dynamic characteristics and obtain enhanced configuration entropy (delta S config), thereby achieving the aim of better energy storage and mechanical property. The detection result shows that the optimized high-entropy principal element SMZTN-0.08 is added into BF-BT ceramic, and the high recoverable energy storage density W rec=2.40 J/cm3, the high energy storage efficiency eta=75%, the enhanced thermal stability (25 to 110 ℃) and frequency stability (1 to 100 Hz) and the ultra-high mechanical hardness H=7.2 GPa are obtained under a lower external electric field (E=190 kV/cm), and the optimized performances show that the novel high-entropy ferroelectric ceramic material is expected to be applied to advanced energy storage and conversion devices at present or in future. Meanwhile, multiple characterization discovers that the introduction of the high-entropy principal component is beneficial to the grain refinement of the material system, increases random field and relaxation performance of the system, realizes coexistence of a three-phase R and a pseudo-cubic phase T, and generates a polar nanometer micro-region PNRs with uniform size, thereby realizing higher energy storage and mechanical performance. The invention provides a novel dielectric high-entropy ferroelectric ceramic material with low electric field, high energy storage and high mechanical property, and simultaneously discloses a micro-macro mechanism for generating high performance, which lays a foundation for the application and popularization of the energy storage device.
Further, the chemical reagents used to prepare the ceramic materials include Bi2O3、Fe2O3、MgO、ZnO、BaCO3、SrCO3、Ta2O5、Nb2O5 and TiO 2.
In a second aspect, the application provides a preparation method of a lead-free high-entropy ferroelectric ceramic material, which sequentially comprises the steps of powder synthesis, granulation molding, glue discharging sintering and electrode plating process treatment.
Further, the specific method for synthesizing the powder comprises the following steps:
S1: weighing chemical reagent Bi2O3(AR 99%),Fe2O3(AR 99%),MgO (AR 98%),ZnO(AR 99%),BaCO3(AR 99%),SrCO3(AR 99%),Ta2O5(99.5%),Nb2O5(99.9%) and TiO 2 (AR 99%) on a high-precision balance according to a formula (0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/6Ta1/3Nb1/3)O3 in a stoichiometric ratio, placing the mixture into a polytetrafluoroethylene ball milling tank, ball milling the mixture into 20-24 h by using an absolute ethyl alcohol as a dispersion medium and using a planetary ball mill at a rotating speed of 215 r/min;
S2: taking out the slurry with uniform height and mixing, drying, putting the dried powder into an alumina crucible, covering a crucible cover, and putting into a muffle furnace for presintering;
s3: after presintering, the powder is put into a ball milling tank for ball milling, ball milling is carried out for 10-20 h at the rotating speed of 215 r/min, and then the slurry is taken out for drying.
Further, the presintering temperature in the step S2 is set to be 820-880 ℃, and the presintering is carried out for 2-4 hours.
Further, the specific method for granulating and molding comprises the following steps:
S1: adding a binder into the obtained powder, stirring and granulating;
S2: and (3) respectively sieving the powder particles obtained by granulation with 80-mesh and 120-mesh screens, and tabletting and forming. The powder dry pressing forming machine is used for forming the wafer blank with the diameter of 12 mm and the thickness of 1.0-1.3 mm, the pressure is set to be 3-15 MPa, and 0.45-0.50 g of powder is weighed for each tabletting.
Further, the binder in step S1 includes 7% by mass of polyvinyl alcohol.
Further, the specific method for discharging glue and sintering comprises the following steps:
S1: and placing the formed wafer blank on a corundum plate, and then placing the corundum plate into a muffle furnace for glue discharging treatment. Wherein, set up the temperature of glue discharging: raising the temperature from room temperature to 120 ℃ at a heating rate of 1 ℃/min for heat preservation of 2 h, raising the temperature to 450 ℃ at a heating rate of 1 ℃/min for heat preservation of 4 h, raising the temperature to 600 ℃ at a heating rate of 1 ℃/min for heat preservation of 4 h, and naturally cooling to room temperature after heat preservation; ( The purpose of the glue discharging is as follows: for discharging PVA binder introduced by granulation out of ceramic green bodies )
S2: and (3) placing the wafer blank subjected to glue discharge in a muffle furnace for sintering treatment, and obtaining a ceramic wafer sample after sintering (the purpose of sintering is to increase the grain size, improve the density and enhance the mechanical strength). In order to prevent volatilization of elements in the sintering process, a buried sintering mode is generally adopted, and a wafer blank is required to be covered by corresponding powder; setting the sintering temperature to 940-1000 ℃, preserving heat for 2-4 h, and naturally cooling to room temperature to obtain the ceramic wafer sample.
Furthermore, the sintered ceramic sample has no conductivity, and in order to facilitate the subsequent electrical test and engineering application, a layer of conductive noble metal film with the thickness of hundreds of nanometers is uniformly coated on the upper and lower surfaces of the polished ceramic sample to form an electrode; conductive silver is used as an electrode. The silver plating electrode comprises the following steps:
S1: polishing the ceramic sheet on a polishing machine, washing the ceramic sheet in an ultrasonic cleaner for about 10min, and drying the ceramic sheet in a drying oven;
S2: and (3) coating a layer of uniform silver paste on the upper and lower surfaces of the ceramic sheet after drying, drying for 30min at 120 ℃ in an oven, finally placing the ceramic sample in the oven to burn silver, heating to 550 ℃ at a heating rate of 5 ℃/min, preserving heat for 30min, and naturally cooling.
In a third aspect, the present application provides an application of the ceramic material, for preparing an energy storage and conversion device, such as a dielectric capacitor, serving in advanced industries such as electric vehicles, internet of things, biomedical and the like, of high power/pulse power technology.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) Excellent energy storage performance is achieved under low electric field: the multi-principal-element tissue high-entropy lead-free high-entropy ferroelectric ceramic obtained by the high-entropy design strategy has an optimal component x=0.08, and the obtained recoverable energy storage density (W rec) is as high as 2.4J/cm 3 and the energy storage efficiency (eta) is as high as 75% under a lower electric field (190 kV/cm), so that the ceramic material can provide a very promising alternative ceramic material for advanced energy storage and conversion devices (such as ceramic capacitors) which have a single-layer thickness of 10 mu m and work under a low electric field in actual engineering.
(2) Excellent energy storage stability is obtained: the multi-principal element organization high-entropy lead-free high-entropy ferroelectric ceramic obtained by the high-entropy design strategy has the optimal component x=0.08, and the energy storage performance of the ceramic keeps good stability under the test frequency of 1-100 Hz, for example, the recoverable energy storage density is only reduced by delta W rec <15.29%, and the energy storage efficiency is only reduced by delta eta <15.76%. The energy storage performance of the energy storage device also maintains good stability at the test temperature of 25-110 ℃, for example, the recoverable energy storage density is only reduced by delta W rec <13.09%, and the energy storage efficiency is only reduced by delta eta <9.91%.
(3) The ultra-high mechanical properties are obtained: the lead-free high-entropy ferroelectric ceramic with high entropy of multi-principal element tissue, which is obtained by a high entropy design strategy, has an optimal component x=0.08, shows excellent plastic deformation resistance, and obtains an ultrahigh mechanical hardness value H=7.2 GPa; the ultrahigh mechanical behavior can lay a foundation for the reliability and stability of the ceramic material in the practical application, which is resistant to external force interference.
(4) According to the microscale characterization, a multi-principal component is introduced into BFBT-based lead-free ferroelectric ceramic through a high-entropy design strategy, so that the organization of the ceramic body is high in entropy, the random field and relaxation performance of the body can be improved, the defect of the spatial symmetry of a crystal structure is induced, a coexisting structure of a three-phase (R3 c) and a pseudo-cubic phase (Pm-3 m) is formed, meanwhile, crystal grains are refined, a polar nano micro-region (PNRs) with smaller scale and even distribution is formed, and the formed high-entropy ferroelectric ceramic material has better energy storage performance and ultrahigh mechanical property; the discovery of the microcosmic mechanism has great significance and value for the physical origin of the excellent performance of the high-entropy ferroelectric ceramic and the further optimization of the performance of the high-entropy ferroelectric ceramic in the future.
Drawings
In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings that are needed in the examples will be briefly described below, it being understood that the following drawings only illustrate some examples of the present invention and therefore should not be considered as limiting the scope, and that other related drawings may be obtained from these drawings without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a flow chart of the design and performance optimization of BFBT-SMZTN high-entropy ferroelectric ceramic in example 1 of the present invention;
FIG. 2 is a crystal structure diagram of BFBT-SMZTN high-entropy ferroelectric ceramics according to example 1 to example 4 of the present invention; plot (a) is the XRD pattern of BFBT-SMZTN-x ceramic, plots (b) and (c) are partial magnified plots of diffraction peaks (111) and (200) in the XRD pattern, plots (d) and (e) are selected electron diffraction (SAED) patterns under the [100] and [111] crystal axes obtained by TEM characterization;
FIG. 3 is a graph showing the characterization of polar nanodomains of BFBT-SMZTN high-entropy ferroelectric ceramic in example 1 of the present invention; fig. (a) is a low-power TEM image of a high-entropy ferroelectric ceramic with optimal composition x=0.08; fig. (b) is an enlarged TEM image; fig. (c) is a further enlarged TEM image;
FIG. 4 is a graph showing dielectric relaxation behavior of BFBT-SMZTN high-entropy ferroelectric ceramics according to examples 1 to 4 of the present invention; FIG. (a) is a map of the medium temperature of BFBT-SMZTN-x ceramic; the graph (b) is a fitted medium-temperature curve, and the fitting coefficient is 1.46-1.89;
FIG. 5 shows hysteresis curves and energy storage behaviors of BFBT-SMZTN high-entropy ferroelectric ceramics according to examples 1 to 4 of the present invention; FIG. (a) shows the hysteresis curves obtained for BFBT-SMZTN-x ceramics at low electric fields (less than 200 kV/cm); FIG. (b) is a plot of recoverable energy storage density and energy storage efficiency for BFBT-SMZTN-x ceramic;
FIG. 6 is a graph showing the energy storage stability test of BFBT-SMZTN high-entropy ferroelectric ceramic in example 1 of the present invention; fig. (a) is a P-E curve of the optimal component x=0.08 high entropy ferroelectric ceramic obtained at a test frequency of 1-100 Hz; graph (b) is the recoverable energy storage density and energy storage efficiency that it achieves at different test frequencies; graph (c) is a P-E curve obtained at a test temperature of 25 ℃ -110 ℃ for the high-entropy ferroelectric ceramic with optimal component x=0.08; graph (d) is the recoverable energy storage density and energy storage efficiency that it achieves at different test temperatures;
FIG. 7 is a graph showing the mechanical properties of BFBT-SMZTN high-entropy ferroelectric ceramic according to example 1 of the present invention; graph (a) is a force-displacement curve obtained by testing the high-entropy ferroelectric ceramic with optimal component x=0.08 under different loads; the inset is an indentation morphology graph obtained under AFM test and plastic deformation behavior; FIG. b is the true hardness value of the high entropy ferroelectric ceramic calculated by using the PSR model; h 01 and H 02 are two real hardness values related to elasticity and plastic deformation, and the final hardness value of the high-entropy ferroelectric ceramic is the intermediate value of the two, h=7.2 GPa.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
This example provides a method for preparing BFBT-SMZTN-0.08 lead-free high-entropy ferroelectric ceramics.
The preparation starting material was ：Bi2O3(AR 99%),Fe2O3(AR 99%),MgO (AR 98%),ZnO(AR 99%),BaCO3(AR 99%),SrCO3(AR 99%),Ta2O5(99.5%),Nb2O5(99.9%) and TiO 2 (AR 99%).
The preparation method comprises the following steps:
S1: the experimental materials are weighed and proportioned on a high-precision balance according to a stoichiometric formula (0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/ 6Ta1/3Nb1/3)O3（ which is BFBT-SMZTN-x, wherein x=0.08), then the mixture is placed in a polytetrafluoroethylene ball milling tank, absolute ethyl alcohol is used as a dispersion medium, and a planetary ball mill is used for ball milling for 20-24 h, and the rotating speed is 215 r/min, so that chemical reagents are fully mixed.
S2: taking out the BFBT-SMZTN-0.08 slurry with uniform height, drying in a high-temperature furnace, placing the dried powder in an alumina crucible, covering a crucible cover, and placing in a muffle furnace for presintering. The presintering temperature is set to be 820-880 ℃, the temperature is kept at 2-4 h ℃, and the solid solution compound with a certain structure and BFBT-SMZTN-0.08 ceramic main crystal are obtained through solid phase reaction. After presintering, the powder is put into a ball milling tank, ball milling is carried out for 10-20 h at the rotating speed of 215 r/min, and then the slurry is taken out and dried.
S3: in order to make BFBT-SMZTN-0.08 powder have small flowability granules and convenient for forming, firstly, 7% of polyvinyl alcohol (PVA) binder by mass fraction is added into the obtained powder for stirring and granulating, and the granulated powder granules are respectively passed through 80-mesh and 120-mesh screens and then are pressed into tablets for forming. The molding instrument uses a powder dry pressing molding machine, the pressure is set to be 3-15 MPa, 0.45-0.50 g of powder is weighed by tabletting each time, and the powder is molded into a BFBT-SMZTN-0.08 wafer embryo body with the diameter of 12mm and the thickness of 1.0-1.3 mm.
S4: in order to discharge BFBT-SMZTN-0.08 of PVA binder introduced by granulation, a formed BFBT-SMZTN-0.08 wafer blank is placed on a corundum plate and then placed in a muffle furnace for glue discharge treatment. The glue discharging setting temperature is that the temperature is raised to 120 ℃ from the room temperature at the heating rate of 1 ℃/min for heat preservation of 2 h, then raised to 450 ℃ at the heating rate of 1 ℃/min for heat preservation of 4 h, finally raised to 600 ℃ at the heating rate of 1 ℃/min for heat preservation of 4 h, and naturally cooled to the room temperature after heat preservation. Then, in order to increase the grain size, improve the density and enhance the mechanical strength, the BFBT-SMZTN-0.08 wafer blank after glue discharge is placed in a muffle furnace for sintering treatment. In order to prevent volatilization of elements in the sintering process, a buried sintering mode is generally adopted, and a BFBT-SMZTN-0.08 wafer blank is required to be covered with corresponding powder. Setting the sintering temperature to 940-1000 ℃, preserving heat for 2-4 h, and naturally cooling to room temperature to obtain the BFBT-SMZTN-0.08 ceramic wafer sample.
S5: the sintered BFBT-SMZTN-0.08 ceramic sample has no conductivity, and in order to facilitate the subsequent electrical test and engineering application, the upper and lower surfaces of the ceramic are polished, a layer of silver paste with the thickness of hundreds of nanometers is uniformly coated on the polished surfaces, the ceramic sample is placed in an oven for drying for 30min at 120 ℃, finally the ceramic sample is placed in the oven for silver burning, the temperature is raised to 550 ℃ at the heating rate of 5 ℃/min, and the ceramic sample is naturally cooled after heat preservation for 30min, so that a silver electrode is formed.
The properties of the ceramic materials prepared in this example were characterized.
1) The electrical properties and mechanical properties of BFBT-SMZTN high-entropy ferroelectric ceramic are characterized, and the results are shown in figure 1.
The characterization method comprises the following steps: and measuring the relation between the dielectric constant and the dielectric loss of the ceramic sample and the temperature by utilizing high-temperature dielectric Wen Puyi, wherein the test temperature is 35-450 ℃, and then fitting a dielectric temperature curve by utilizing a modified Curie-Extra law to obtain the relaxation behaviors of the ceramic sample under different components. The ferroelectric analyzer is used for testing the hysteresis (P-E) curve of the ceramic sample under different electric fields (30-190 kV/cm), and the test data are subjected to integral treatment, so that the recoverable energy storage density (W rec) and the energy storage efficiency (eta) of the sample can be obtained. Meanwhile, an hysteresis (P-E) curve of the ceramic sample is obtained at different test frequencies (1 Hz-100 Hz), and the frequency stability of the ceramic sample is analyzed. Finally, hysteresis (P-E) curves of the ceramic samples are obtained at different temperatures (25-110 ℃) to characterize the temperature stability of the ceramic samples. The mechanical behavior (e.g., hardness H and mechanical deformation) of the ceramic coupon was characterized using a nanoindenter. In the nanoindentation test, loads (10 mN,20 mN,30 mN,40 mN and 50 mN) with different magnitudes are applied to the test sample to obtain a loading displacement curve and hardness, and simultaneously, an Atomic Force Microscope (AFM) is used for analyzing indentation morphology and mechanical deformation, and then, the real hardness of the ceramic test sample is obtained by using a PSR model.
As can be seen from fig. 1, when the multi-principal element SMZTN is not introduced, the BFBT ferroelectric ceramic has a domain structure with a larger size and a more saturated hysteresis curve, after the multi-principal element SMZTN is introduced into BFBT, the ceramic body tissue is subjected to high entropy, the random field of a material system is improved, the symmetry of the crystal structure is subjected to space fracture, and a polar nano micro-region (PNRs) is induced, so that the energy storage performance is greatly improved and the mechanical performance is finally enhanced.
2) The structure of BFBT-SMZTN high-entropy ferroelectric ceramic was characterized and the results are shown in fig. 2.
The characterization method comprises the following steps: the ceramic samples were characterized for crystal structure using an X-ray diffractometer (XRD). Before the test, the surfaces of all ceramic samples are cleaned by an ultrasonic instrument, and Cu target K alpha rays are used, wherein the test angle range (2 theta) is 20-80 degrees, and the scanning speed is 2 degrees/min. The grain size, grain distribution, domain size, domain distribution, domain structure characteristics, selected electron diffraction (SAED), phase structure characteristics, and analysis of the crystal structure of the ceramic sample were observed using a Transmission Electron Microscope (TEM) at an acceleration voltage of 200 kV. The ceramic sample is required to be thinned by using an ion gun voltage of 5 kV on an ion thinning instrument, and after a small hole is formed, the ion gun voltage is reduced to 3.5 kV, and the thinning is continued for 30 min, so that the TEM sample is obtained.
The ceramic sample is tested by XRD and TEM, and the multi-principal element SMZTN-0.08 is successfully introduced into BFBT crystal lattice, so that a solid solution structure (shown in figure 2) with coexistence of a three-phase (R3 c) and a pseudo-cubic phase (Pm-3 m) is formed, and a foundation is laid for the occurrence of the polarized nanometer micro-region.
In FIG. 2, plot (a) is the XRD pattern of BFBT-SMZTN-x ceramic, and plots (b) and (c) are partial magnified views of the diffraction peaks of (111) and (200) in the XRD pattern. The peak cracking behavior appears in the graph, and the crystal structure is proved to be a coexisting structure of a three-phase (R3 c) and a pseudo-cubic phase (Pm-3 m). Graphs (d) and (e) are selected electron diffraction (SAED) patterns obtained by TEM characterization under the [100] and [111] crystal band axes. Further shows that the BFBT-SMZTN high-entropy ferroelectric ceramic is a crystal structure in which a trigonal phase (R3 c) and a pseudocubic phase (Pm-3 m) coexist.
3) Characterization of the polar nano-domains of BFBT-SMZTN high-entropy ferroelectric ceramic is performed, and the results are shown in fig. 3.
The surface morphology of BFBT-SMZTN-0.08 ceramic samples was observed by TEM, and it was found that grains of the ceramic materials were refined by tissue high entropy, and that a large number of uniformly distributed Polar Nanodomains (PNRs) were present inside the grains, ranging in size from several to tens of nanometers, the presence of these polar nanodomains being beneficial for providing energy storage properties and mechanical properties.
In fig. 3, the low-power TEM image of the high-entropy ferroelectric ceramic with the optimal component x=0.08 in the image (a), the morphology of the regularly arranged grains can be seen, and the size is about 1.42 um, which is much smaller than that of the BFBT ceramic sample without the multi-principal element, indicating that the grains of the ceramic are refined after the high-entropy principal element is introduced. Fig. b is an enlarged TEM image showing a number of polar nano-domains (PNRs) uniformly distributed on the grains. Fig. (c) is a further enlarged TEM image, and it can be seen that the size of these polar nanodomains is on the order of several or tens of nanometers. The occurrence of the polar nano regions directly influences the energy storage performance and the mechanical performance of the high-entropy ferroelectric ceramic, and is of great help to the optimization of the energy storage performance and the mechanical performance of the material system.
4) The dielectric behavior and relaxation behavior of the ceramic sample are measured by utilizing the high-temperature dielectric Wen Puyi, and the fact that the relaxation degree of the BFBT ceramic material is greatly enhanced (shown in fig. 4) after SMZTN-0.08 multi-main element is introduced is found to be beneficial to improving the energy storage performance.
In FIG. 4, FIG. (a) is a mesophilic map of BFBT-SMZTN-x ceramic. The dielectric constant and the dielectric loss change obviously along with the increase of the loading temperature, and the dielectric peak is widened obviously, so that the strong relaxation behavior is shown. And the graph (b) is a fitted mesophilic curve, the fitting coefficient is 1.46-1.89, and the BFBT-SMZTN-x high-entropy ferroelectric ceramic system is proved to have obvious relaxation behavior.
5) The hysteresis curve of the ceramic sample was tested by a ferroelectric analyzer to obtain the recoverable energy storage density (W rec) and the energy storage efficiency (eta) of BFBT-SMZTN-0.08 of the ceramic sample, wherein the recoverable energy storage density (W rec) is 2.4J/cm 3, and the energy storage efficiency (eta) is as high as 75% (as shown in figure 5). Can provide a promising alternative ceramic material for advanced energy storage and conversion devices (such as ceramic capacitors) with a monolayer thickness of 10 μm and operating at low electric fields in practical engineering.
In FIG. 5, plot (a) is the hysteresis curve obtained for BFBT-SMZTN-x ceramic at low electric fields (less than 200 kV/cm). Graph (b) is the recoverable energy storage density and energy storage efficiency of BFBT-SMZTN-x ceramic. It can be seen that for the high entropy ferroelectric ceramic of optimal composition x=0.08, at a lower electric field (190 kV/cm), the highest recoverable energy storage density (W rec=2.4 J/cm3) and highest energy storage efficiency (η=75%) are obtained.
6) The BFBT-SMZTN-0.08 ceramic sample has good stability in energy storage performance under the test frequency of 1-100 Hz, the recoverable energy storage density is only reduced by delta W rec <15.29%, and the energy storage efficiency is only reduced by delta eta <15.76%. The energy storage performance of the composite material also keeps good stability at the test temperature of 25-110 ℃, the recoverable energy storage density is only reduced by delta W rec <13.09%, and the energy storage efficiency is only reduced by delta eta <9.91% (as shown in figure 6).
In fig. 6, graph (a) is a P-E curve obtained for the high entropy ferroelectric ceramic with optimum composition x=0.08 at a test frequency of 1-100 Hz. Graph (b) is the recoverable energy storage density and energy storage efficiency that it achieves at different test frequencies. It can be seen that the optimized high-entropy ferroelectric ceramic has a recovery energy storage density reduced by DeltaW rec <15.29% and an energy storage efficiency reduced by Deltaeta <15.76% under different test frequencies, which indicates that the high-entropy ferroelectric ceramic has good frequency stability. Graph (c) is a P-E curve obtained at a test temperature of 25 ℃ -110 ℃ for the high entropy ferroelectric ceramic with optimal component x=0.08. Graph (d) is the recoverable energy storage density and energy storage efficiency that it achieves at different test temperatures. It can be seen that the optimized high-entropy ferroelectric ceramic has the advantages that the recoverable energy storage density is only reduced by delta W rec <13.09%, the energy storage efficiency is only reduced by delta eta <9.91% at different test temperatures, and the high-entropy ferroelectric ceramic has good temperature stability.
7) The mechanical properties of BFBT-SMZTN-0.08 ceramic samples were tested using a nanoindenter, and the ceramic samples exhibited different mechanical behaviors under different loads. The results show that BFBT-SMZTN-0.08 ceramics have very good resistance to plastic deformation, while obtaining an ultra high mechanical hardness h=7.2 GPa (as shown in fig. 7). The ultrahigh mechanical behavior can lay a foundation for the reliability and stability of the ceramic material in the practical application, which is resistant to external force interference.
In fig. 7, graph (a) is a force-displacement curve of a high entropy ferroelectric ceramic with an optimal composition x=0.08 tested under different loads. The inset is an indentation topography obtained under AFM testing and the plastic deformation behavior. And (b) the true hardness value of the high-entropy ferroelectric ceramic calculated by using a PSR model. H 01 and H 02 are two real hardness values related to elasticity and plastic deformation, and the final hardness value of the high-entropy ferroelectric ceramic is the intermediate value of the two, h=7.2 GPa.
Example 2
This example provides a method for preparing BFBT-SMZTN-0.04 lead-free relaxed high entropy ferroelectric ceramic.
The preparation starting material was ：Bi2O3(AR 99%),Fe2O3(AR 99%),MgO (AR 98%),ZnO(AR 99%),BaCO3(AR 99%),SrCO3(AR 99%),Ta2O5(99.5%),Nb2O5(99.9%) and TiO 2 (AR 99%).
The preparation method comprises the following steps:
S1: the experimental materials are weighed and proportioned on a high-precision balance according to a stoichiometric formula (0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/ 6Ta1/3Nb1/3)O3（ which is BFBT-SMZTN-x, wherein x=0.04), then the mixture is placed in a polytetrafluoroethylene ball milling tank, absolute ethyl alcohol is used as a dispersion medium, and a planetary ball mill is used for ball milling for 20-24 h, and the rotating speed is 215 r/min, so that chemical reagents are fully mixed.
S2: taking out the BFBT-SMZTN-0.04 slurry with uniform height, drying in a high-temperature furnace, placing the dried powder in an alumina crucible, covering a crucible cover, and placing in a muffle furnace for presintering. The presintering temperature is set to be 820 oC~880o C, and the temperature is kept at 2-4 h, and a solid solution compound with a certain structure and BFBT-SMZTN-0.04 ceramic main crystal are obtained through solid phase reaction. After presintering, the powder is put into a ball milling tank, ball milling is carried out for 10-20 h at the rotating speed of 215 r/min, and then the slurry is taken out and dried.
S3: in order to make BFBT-SMZTN-0.04 powder have small fluidity granules and be convenient to form, firstly, 7% of polyvinyl alcohol (PVA) binder by mass fraction is added into the obtained powder to be stirred and granulated, and the granulated powder particles are respectively passed through 80-mesh and 120-mesh screens and then are pressed into tablets for forming. The molding instrument uses a powder dry pressing molding machine, the pressure is set to be 3-15 MPa, 0.45-0.50 g of powder is weighed by tabletting each time, and the powder is molded into a BFBT-SMZTN-0.04 wafer embryo body with the diameter of 12mm and the thickness of 1.0-1.3 mm.
S4: in order to discharge BFBT-SMZTN-0.04 ceramic green bodies from PVA binder introduced by granulation, a formed BFBT-SMZTN-0.04 wafer green body is placed on a corundum plate and then placed in a muffle furnace for glue discharge treatment. The glue discharging setting temperature is that the temperature is raised to 120 ℃ from the room temperature at the heating rate of 1 ℃/min for heat preservation of 2 h, then raised to 450 ℃ at the heating rate of 1 ℃/min for heat preservation of 4 h, finally raised to 600 ℃ at the heating rate of 1 ℃/min for heat preservation of 4 h, and naturally cooled to the room temperature after heat preservation. Then, in order to increase the grain size, improve the density and enhance the mechanical strength, the BFBT-SMZTN-0.04 wafer blank after glue discharge is placed in a muffle furnace for sintering treatment. In order to prevent volatilization of elements in the sintering process, a buried sintering mode is generally adopted, and a BFBT-SMZTN-0.04 wafer blank is required to be covered with corresponding powder. Setting the sintering temperature to 940-1000 ℃, preserving heat for 2-4 h, and naturally cooling to room temperature to obtain the BFBT-SMZTN-0.04 ceramic wafer sample.
S5: the sintered BFBT-SMZTN-0.04 ceramic sample has no conductivity, the upper and lower surfaces of the ceramic are polished, a layer of silver paste with the thickness of hundreds of nanometers is uniformly coated on the polished surfaces, the ceramic sample is dried in an oven at 120 ℃ for 30min, finally the ceramic sample is placed in the oven for silver burning, the temperature is raised to 550 ℃ at the heating rate of 5 ℃/min, and the ceramic sample is naturally cooled after heat preservation for 30min, so that the silver electrode is formed.
The properties of the ceramic materials prepared in this example were characterized.
1) The ceramic sample is tested by XRD and TEM, and the multi-principal element SMZTN-0.04 is successfully introduced into BFBT crystal lattice, so that a solid solution structure (shown in figure 2) with coexistence of a three-phase (R3 c) and a pseudo-cubic phase (Pm-3 m) is formed, and a foundation is laid for the occurrence of the polarized nanometer micro-region.
2) The dielectric behavior and relaxation behavior of the ceramic samples were measured using high temperature dielectric Wen Puyi and it was found that the BFBT ceramic materials exhibited certain relaxation characteristics (as shown in fig. 4) after the introduction of SMZTN-0.04 multi-main elements.
3) The hysteresis curve of the ceramic sample was tested by ferroelectric analysis to obtain the recoverable energy storage density (W rec) and the energy storage efficiency (eta) of BFBT-SMZTN-0.04 ceramic sample, wherein the recoverable energy storage density (W rec) is 1.37J/cm 3, and the energy storage efficiency (eta) is as high as 61% (as shown in FIG. 5).
Example 3
This example provides a method for preparing BFBT-SMZTN-0.06 lead-free relaxed high entropy ferroelectric ceramics.
The preparation starting material was ：Bi2O3(AR 99%),Fe2O3(AR 99%),MgO (AR 98%),ZnO(AR 99%),BaCO3(AR 99%),SrCO3(AR 99%),Ta2O5(99.5%),Nb2O5(99.9%) and TiO 2 (AR 99%).
The preparation method comprises the following steps:
S1: the experimental materials are weighed and proportioned on a high-precision balance according to a stoichiometric formula (0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/ 6Ta1/3Nb1/3)O3（ which is BFBT-SMZTN-x, wherein x=0.06), then the mixture is placed in a polytetrafluoroethylene ball milling tank, absolute ethyl alcohol is used as a dispersion medium, and a planetary ball mill is used for ball milling for 20-24 h, and the rotating speed is 215 r/min, so that chemical reagents are fully mixed.
S2: taking out BFBT-SMZTN-0.06 slurry which is mixed evenly, drying in a high temperature furnace, putting the dried powder in an alumina crucible, covering a crucible cover, and then putting in a muffle furnace for presintering. The presintering temperature is set to be 820 oC~880o C, and the temperature is kept at 2-4 h, and the solid solution compound with a certain structure and BFBT-SMZTN-0.06 ceramic main crystal are obtained through solid phase reaction. After presintering, the powder is put into a ball milling tank, ball milling is carried out for 10-20 h at the rotating speed of 215 r/min, and then the slurry is taken out and dried.
S3: in order to make BFBT-SMZTN-0.06 powder have small fluidity granules and be convenient to form, firstly, 7% of polyvinyl alcohol (PVA) binder by mass fraction is added into the obtained powder to be stirred and granulated, and the granulated powder particles are respectively passed through 80-mesh and 120-mesh screens and then are pressed into tablets for forming. The molding instrument uses a powder dry pressing molding machine, the pressure is set to be 3-15 MPa, 0.45-0.50 g of powder is weighed by tabletting each time, and the powder is molded into a BFBT-SMZTN-0.06 wafer embryo body with the diameter of 12 mm and the thickness of 1.0-1.3 mm.
S4: in order to discharge BFBT-SMZTN-0.06 of PVA binder introduced by granulation, a formed BFBT-SMZTN-0.06 wafer blank is placed on a corundum plate and then placed in a muffle furnace for glue discharge treatment. The glue discharging setting temperature is that the temperature is raised to 120 ℃ from the room temperature at the heating rate of 1 ℃/min for heat preservation of 2 h, then raised to 450 ℃ at the heating rate of 1 ℃/min for heat preservation of 4 h, finally raised to 600 ℃ at the heating rate of 1 ℃/min for heat preservation of 4 h, and naturally cooled to the room temperature after heat preservation. Then, in order to increase the grain size, improve the density and enhance the mechanical strength, the BFBT-SMZTN-0.06 wafer blank after glue discharge is placed in a muffle furnace for sintering treatment. In order to prevent volatilization of elements in the sintering process, a buried sintering mode is generally adopted, and a BFBT-SMZTN-0.06 wafer blank is required to be covered with corresponding powder. Setting the sintering temperature to 940-1000 ℃, preserving heat for 2-4 h, and naturally cooling to room temperature to obtain the BFBT-SMZTN-0.06 ceramic wafer sample.
S5: the sintered BFBT-SMZTN-0.06 ceramic sample has no conductivity, in order to facilitate the subsequent electrical test and engineering application, the upper and lower surfaces of the ceramic are polished, a layer of silver paste with the thickness of hundreds of nanometers is uniformly coated on the polished surfaces, the ceramic sample is dried in an oven at 120 ℃ for 30 min, finally the ceramic sample is placed in the oven for silver burning, the temperature rising rate of 5 ℃/min is increased to 550 ℃, and the ceramic sample is naturally cooled after heat preservation for 30 min, so as to form the silver electrode.
The properties of the ceramic materials prepared in this example were characterized.
1) The ceramic sample is tested by XRD and TEM, and the multi-principal element SMZTN-0.06 is successfully introduced into BFBT crystal lattice, so that a solid solution structure (shown in figure 2) with coexistence of a three-phase (R3 c) and a pseudo-cubic phase (Pm-3 m) is formed, and a foundation is laid for the occurrence of the polarized nanometer micro-region.
2) The dielectric behavior and relaxation behavior of the ceramic samples were measured using high temperature dielectric Wen Puyi and it was found that the degree of relaxation of BFBT ceramic materials was enhanced by the introduction of SMZTN-0.06 multi-major elements (as shown in fig. 4).
3) The hysteresis curve of the ceramic sample was tested by ferroelectric analysis to obtain the recoverable energy storage density (W rec) and the energy storage efficiency (eta) of BFBT-SMZTN-0.06 of the ceramic sample, wherein the recoverable energy storage density (W rec) is 1.56J/cm 3, and the energy storage efficiency (eta) is as high as 73% (shown in figure 5).
Example 4
This example provides a method for preparing BFBT-SMZTN-0.10 lead-free relaxed high entropy ferroelectric ceramics.
The preparation starting material was ：Bi2O3(AR 99%),Fe2O3(AR 99%),MgO (AR 98%),ZnO(AR 99%),BaCO3(AR 99%),SrCO3(AR 99%),Ta2O5(99.5%),Nb2O5(99.9%) and TiO 2 (AR 99%).
The preparation method comprises the following steps:
S1: the experimental materials are weighed and proportioned on a high-precision balance according to a stoichiometric formula (0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/ 6Ta1/3Nb1/3)O3（ which is BFBT-SMZTN-x, wherein x=0.10), then the mixture is placed in a polytetrafluoroethylene ball milling tank, absolute ethyl alcohol is used as a dispersion medium, and a planetary ball mill is used for ball milling for 20-24 h, and the rotating speed is 215 r/min, so that chemical reagents are fully mixed.
S2: taking out BFBT-SMZTN-0.10 slurry which is mixed evenly, drying in a high-temperature furnace, putting the dried powder in an alumina crucible, covering a crucible cover, and then putting in a muffle furnace for presintering. The presintering temperature is set to be 820 oC~880o C, and the temperature is kept at 2-4 h, and a solid solution compound with a certain structure and BFBT-SMZTN-0.10 ceramic main crystal are obtained through solid phase reaction. After presintering, the powder is put into a ball milling tank, ball milling is carried out for 10-20 h at the rotating speed of 215 r/min, and then the slurry is taken out and dried.
S3: in order to make BFBT-SMZTN-0.10 powder have small flowability granules and convenient for forming, firstly, 7% of polyvinyl alcohol (PVA) binder by mass fraction is added into the obtained powder for stirring and granulating, and the granulated powder granules are respectively passed through 80-mesh and 120-mesh screens and then are pressed into tablets for forming. The molding instrument uses a powder dry pressing molding machine, the pressure is set to be 3-15 MPa, 0.45-0.50 g of powder is weighed by tabletting each time, and the powder is molded into a BFBT-SMZTN-0.10 wafer embryo body with the diameter of 12 mm and the thickness of 1.0-1.3 mm.
S4: in order to discharge BFBT-SMZTN-0.10 of PVA binder introduced by granulation, a formed BFBT-SMZTN-0.10 wafer blank is placed on a corundum plate and then placed in a muffle furnace for glue discharge treatment. The glue discharging setting temperature is that the temperature is raised to 120 ℃ from the room temperature at the heating rate of 1 ℃/min for heat preservation of 2 h, then raised to 450 ℃ at the heating rate of 1 ℃/min for heat preservation of 4 h, finally raised to 600 ℃ at the heating rate of 1 ℃/min for heat preservation of 4 h, and naturally cooled to the room temperature after heat preservation. Then, in order to increase the grain size, improve the density and enhance the mechanical strength, the BFBT-SMZTN-0.10 wafer blank after glue discharge is placed in a muffle furnace for sintering treatment. In order to prevent volatilization of elements in the sintering process, a buried sintering mode is generally adopted, and BFBT-SMZTN-0.10 wafer blanks are required to be covered with corresponding powder. Setting the sintering temperature to 940-1000 ℃, preserving heat for 2-4 h, and naturally cooling to room temperature to obtain the BFBT-SMZTN-0.10 ceramic wafer sample.
S5: the sintered BFBT-SMZTN-0.10 ceramic sample has no conductivity, the upper and lower surfaces of the ceramic are polished, a layer of silver paste with the thickness of hundreds of nanometers is uniformly coated on the polished surfaces, the ceramic sample is dried in an oven at 120 ℃ for 30min, finally the ceramic sample is placed in the oven for silver burning, the temperature is raised to 550 ℃ at the heating rate of 5 ℃/min, and the ceramic sample is naturally cooled after heat preservation for 30min, so that the silver electrode is formed.
The properties of the ceramic materials prepared in this example were characterized.
1) The ceramic sample is tested by XRD and TEM, and the result shows that the multi-principal element SMZTN-0.10 is successfully introduced into BFBT crystal lattice, and a solid solution structure (shown in figure 2) in which a three-phase (R3 c) and a pseudo-cubic phase (Pm-3 m) coexist is formed, so that a foundation is laid for the occurrence of the polarized nanometer micro-region.
2) The dielectric behavior and relaxation behavior of the ceramic samples were measured using high temperature dielectric Wen Puyi and it was found that the degree of relaxation of BFBT ceramic materials was enhanced by the introduction of SMZTN-0.10 multi-major elements (as shown in fig. 4).
3) The hysteresis curve of the ceramic sample was tested by ferroelectric analysis to obtain the recoverable energy storage density (W rec) and the energy storage efficiency (eta) of BFBT-SMZTN-0.10 ceramic sample, wherein the recoverable energy storage density (W rec) is 1.44J/cm 3, and the energy storage efficiency (eta) is as high as 85% (as shown in FIG. 5).
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A lead-free high entropy ferroelectric ceramic material, characterized by a chemical formula ：(0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/6Ta1/3Nb1/3)O3; wherein x = 0.04 or 0.06 or 0.08 or 0.10 and x represents a mole fraction.
2. The lead-free high entropy ferroelectric ceramic material according to claim 1, wherein the chemical reagents for preparing the ceramic material comprise Bi2O3、Fe2O3、MgO、ZnO、BaCO3、SrCO3、Ta2O5、Nb2O5 and TiO 2.
3. A method for preparing the leadless high-entropy ferroelectric ceramic material according to claim 1 or 2, which is characterized by sequentially performing powder synthesis, granulation molding, glue discharging sintering and electrode plating process treatment.
4. The method for preparing the lead-free high-entropy ferroelectric ceramic material according to claim 3, wherein the specific method for synthesizing the powder comprises the following steps:
S1: weighing a chemical reagent Bi2O3、Fe2O3、MgO、ZnO、BaCO3、SrCO3、Ta2O5、Nb2O5 and TiO 2 on a high-precision balance according to a formula (0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/6Ta1/3Nb1/3)O3 in a stoichiometric ratio, and then placing the mixture into a ball milling tank, and performing ball milling by taking absolute ethyl alcohol as a dispersion medium;
s2: taking out the slurry with uniform height and mixing, drying, putting the dried powder into a crucible, covering a crucible cover, and putting into a muffle furnace for presintering;
s3: after presintering, placing the powder into a ball milling tank for ball milling, and then taking out the slurry for drying.
5. The method for preparing a lead-free high-entropy ferroelectric ceramic material according to claim 4, wherein the presintering temperature in the step S2 is set to 820-880 ℃, and the presintering temperature is kept for 2-4 h hours.
6. A method for preparing a lead-free high-entropy ferroelectric ceramic material according to claim 3, wherein the specific method for granulating and molding comprises the following steps:
S1: adding a binder into the obtained powder, stirring and granulating;
S2: sieving the powder particles obtained by granulation, and tabletting and forming.
7. The method for preparing a lead-free high-entropy ferroelectric ceramic material as claimed in claim 6, wherein the binder in the step S1 comprises 7% by mass of polyvinyl alcohol.
8. The method for preparing the lead-free high-entropy ferroelectric ceramic material according to claim 3, wherein the specific method for discharging and sintering comprises the following steps:
s1: placing the formed wafer blank on a corundum plate, and then placing the corundum plate into a muffle furnace for glue discharging treatment;
S2: and placing the wafer blank subjected to glue discharge in a muffle furnace for sintering treatment, and obtaining a ceramic wafer sample after sintering.
9. The method for preparing the lead-free high-entropy ferroelectric ceramic material according to claim 3, wherein the plating electrode is a silver plating electrode, and the method for plating the silver plating electrode is as follows:
s1: polishing the ceramic wafer on a polishing machine, washing the ceramic wafer in an ultrasonic cleaner, and drying;
s2: uniformly coating a layer of silver paste on the surface of the polished and dried ceramic sheet, and drying the ceramic sheet in an oven at 120 ℃ for 30 min;
s3: and (3) placing the silver-plated and dried ceramic sheet in a furnace for silver burning, heating to 550 ℃ at a heating rate of 5 ℃/min, and naturally cooling after heat preservation for 30min to form a silver electrode.
10. Use of a ceramic material according to claim 1 or 2 or a ceramic material prepared by a method according to any one of claims 3 to 9 for the preparation of an energy storage and conversion device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410186437.2A CN117735974B (en) | 2024-02-20 | 2024-02-20 | Leadless high-entropy ferroelectric ceramic material and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410186437.2A CN117735974B (en) | 2024-02-20 | 2024-02-20 | Leadless high-entropy ferroelectric ceramic material and preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117735974A CN117735974A (en) | 2024-03-22 |
| CN117735974B true CN117735974B (en) | 2024-04-30 |
Family
ID=90281726
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410186437.2A Active CN117735974B (en) | 2024-02-20 | 2024-02-20 | Leadless high-entropy ferroelectric ceramic material and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117735974B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101308900A (en) * | 2007-05-14 | 2008-11-19 | 富士胶片株式会社 | Piezoelectric device, process for driving the piezoelectric device, and piezoelectric actuator |
| CN114956809A (en) * | 2022-05-23 | 2022-08-30 | 陕西科技大学 | High-entropy lead-free X7R type ceramic material with high energy storage capacity and preparation method thereof |
| CN115180944A (en) * | 2022-07-11 | 2022-10-14 | 中国科学院上海硅酸盐研究所 | Full-filled tungsten bronze structure high-entropy ferroelectric ceramic material and preparation method thereof |
| CN115385675A (en) * | 2022-08-12 | 2022-11-25 | 陕西师范大学 | Bismuth ferrite based lead-free ferroelectric ceramic material with high Curie temperature and energy storage characteristic and preparation method thereof |
| CN115991599A (en) * | 2021-10-20 | 2023-04-21 | 深圳先进电子材料国际创新研究院 | High-entropy perovskite oxide doped ceramic, preparation method and application thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109923245A (en) * | 2016-10-31 | 2019-06-21 | 奎斯特综合有限责任公司 | The monocrystalline perovskite solid solution with indifference point for epitaxial growth monocrystalline |
-
2024
- 2024-02-20 CN CN202410186437.2A patent/CN117735974B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101308900A (en) * | 2007-05-14 | 2008-11-19 | 富士胶片株式会社 | Piezoelectric device, process for driving the piezoelectric device, and piezoelectric actuator |
| CN115991599A (en) * | 2021-10-20 | 2023-04-21 | 深圳先进电子材料国际创新研究院 | High-entropy perovskite oxide doped ceramic, preparation method and application thereof |
| CN114956809A (en) * | 2022-05-23 | 2022-08-30 | 陕西科技大学 | High-entropy lead-free X7R type ceramic material with high energy storage capacity and preparation method thereof |
| CN115180944A (en) * | 2022-07-11 | 2022-10-14 | 中国科学院上海硅酸盐研究所 | Full-filled tungsten bronze structure high-entropy ferroelectric ceramic material and preparation method thereof |
| CN115385675A (en) * | 2022-08-12 | 2022-11-25 | 陕西师范大学 | Bismuth ferrite based lead-free ferroelectric ceramic material with high Curie temperature and energy storage characteristic and preparation method thereof |
Non-Patent Citations (16)
| Title |
|---|
| Achieving high energy storage density and efficiency simultaneously in Sr(Nb0.5Al0.5)O3 modified BiFeO3 based lead-free ceramics;Shuo Liu et al.;Chemical Engineering Journal;20220830;第451卷;全文 * |
| Achieving high energy storage properties in perovskite oxide via high-entropy design;Yating Ning et al.;Ceramics International;20221210;第49卷(第8期);全文 * |
| A位无序高熵钙钛矿氧化物的介电及铁电性能;倪波 等;硅酸盐学报;20220630;第50卷(第06期);全文 * |
| Ba(0.85)Ca(0.15)Zr(0.1)Ti(0.88)Sn(0.02)O3-水泥复合材料的电热行为（英文）;P.SURESH;P.MATHIYALAGAN;K.S.SRIKANTH;;Transactions of Nonferrous Metals Society of China;20190415(第04期);全文 * |
| Bismuth Ferrite-Based Lead-Free High-Entropy Piezoelectric Ceramics;Hongtian Li et al.;ACS Applied Materials & Interfaces;20240207;全文 * |
| Design and preparation of lead-free (Bi0.4Na0.2K0.2Ba0.2)TiO3-Sr(Mg1/3Nb2/3)O3 high-entropy relaxor ceramics for dielectric energy storage;Bo Yan et al.;Chemical Engineering Journal;20230201;第453卷;全文 * |
| Enhanced energy storage properties in La(Mg1/2Ti1/2)O3-modified BiFeO3-BaTiO3 lead-free relaxor ferroelectric ceramics within a wide temperature range;Donggeng Zheng et al.;Journal of the European Ceramic Society;20160821;第37卷;全文 * |
| Excellent energy storage properties in (Bi0.4Na0.2K0.2Ba0.2)(Ti0.95Zr0.05)O3-based high-entropy ceramics by introduction of Sr(Mg1/3Nb1/3Ta1/3)O3 medium-entropy endmember;Wenhui Ye et al.;Journal of Energy Storage;20240118;第82卷;全文 * |
| Giant energy-storage density with ultrahigh efficiency in lead-free relaxors via high-entropy design;Liang Chen et al.;Nature Communications;20220602;全文 * |
| High-entropy enhanced capacitive energy storage；Dielectric, ferroelectric, and energy storage properties of Ba(Zn1/3Nb2/3)O3-modfied BiFeO3–BaTiO3 Pb-Free relaxor ferroelectric ceramics;Bingbing Yang et al.;Nature Materials;20220606;第21卷;全文 * |
| High-Entropy Strategy for Improved Mechanical and Energy Storage Properties in BaTiO3–BiFeO3-Based Ceramics;Shuai Chen et al.;ACS Applied Materials & Interfaces;20240229;全文 * |
| Improved energy storage density and efficiency in BaTiO3-BiFeO3- based relaxor-ferroelectric ceramics;Ting Wang et al.;Journal of Alloys and Compounds;20220624;第920卷;全文 * |
| Lead-free bismuth ferrite-based (0.67-x)BiFeO3-0.33BaTiO3-xSr(Al0.5Ta0.5)O3 ceramics with good energy storage characteristics;Yan He et al.;Solid State Sciences;20221210;第135卷;全文 * |
| Ultrahigh Polarization Response along Large Energy Storage Properties in BiFeO3–BaTiO3-Based Relaxor Ferroelectric Ceramics under Low Electric Field;Zixiong Liu et al.;ACS Applied Materials & Interfaces;20221120;全文 * |
| 铁电材料与多铁性材料的熵变效应研究;陈加文;中国优秀硕士学位论文全文数据库 工程科技II辑;20120615(06);全文 * |
| 镓掺杂对0.7BiFeO3-0.3BaTiO3固溶体的结构和性能的影响;刘小辉;徐卓;屈绍波;魏晓勇;陈江丽;;科学通报;20070915(第17期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117735974A (en) | 2024-03-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Li et al. | Simultaneously enhanced energy storage density and efficiency in novel BiFeO3-based lead-free ceramic capacitors | |
| Guo et al. | Composition-induced antiferroelectric phase and giant strain in lead-free (Na y, Bi z) Ti 1− x O 3 (1− x)− x BaTiO 3 ceramics | |
| Wang et al. | High energy-storage performance of lead-free AgNbO3 antiferroelectric ceramics fabricated via a facile approach | |
| Cui et al. | Improvement of energy storage density with trace amounts of ZrO2 additives fabricated by wet-chemical method | |
| Lv et al. | Enhancing the dielectric and energy storage properties of lead-free Na0. 5Bi0. 5TiO3–BaTiO3 ceramics by adding K0. 5Na0. 5NbO3 ferroelectric | |
| CN111393149B (en) | Lanthanum lead zirconate stannate antiferroelectric ceramic and preparation method and application thereof | |
| Li et al. | BaTiO3-based ceramics with high energy storage density | |
| Huang et al. | Superior energy storage performances achieved in (Ba, Sr) TiO3-based bulk ceramics through composition design and Core-shell structure engineering | |
| CN113321506A (en) | Lead-free relaxor ferroelectric ceramic material and preparation method thereof | |
| CN109650875B (en) | Giant dielectric calcium copper titanate composite ceramic material and preparation method and application thereof | |
| Wang et al. | Fabrication of BaTiO3@ FeO core-shell nanoceramics for dielectric capacitor applications | |
| CN112209711A (en) | Zirconium-titanium-tin lead niobate thick film ceramic and preparation method and application thereof | |
| CN108409320A (en) | A kind of double textural composite magnetic dielectric ceramic materials and preparation method | |
| CN115504784A (en) | Lead-free relaxor ferroelectric high-energy-density ceramic material and preparation method thereof | |
| CN111018516A (en) | Barium titanate-based high-energy-density electronic ceramic and preparation method thereof | |
| Infantiya et al. | Calcium copper titanate a perovskite oxide structure: effect of fabrication techniques and doping on electrical properties—a review | |
| Zhang et al. | Excellent energy storage performance of paraelectric Ba0. 4Sr0. 6TiO3 based ceramics through induction of polar nano-regions | |
| CN117735974B (en) | Leadless high-entropy ferroelectric ceramic material and preparation method and application thereof | |
| CN108863349A (en) | A kind of barium titanate-based lead-free height Jie temperature-stable ceramic material and preparation method thereof | |
| Zhang et al. | Effect of La (Nb1/3Mg2/3) O3 addition on phase transition behavior and energy storage properties of NaNbO3 ceramics | |
| CN109320236B (en) | Composite material with high energy storage density and charge-discharge performance and preparation method thereof | |
| CN114716243B (en) | High-temperature stable sodium bismuth titanate-strontium titanate-based dielectric energy storage ceramic material and preparation and application thereof | |
| Chan et al. | Microstructural evolution and macroscopic property relationship in antiferroelectric lead lanthanum stannate zirconate titanate ceramics | |
| Kaushiga et al. | Influence of sintering temperature strategy on structural, dielectric, and resistive switching in bulk Ba0. 7Sr0. 3TiO3 ceramics | |
| CN110357629B (en) | Solid solution formed by tungsten bronze and perovskite structure oxide and preparation method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |