O3 Ceramics Research Articles

Enhanced energy storage performance in Bi(Mg1/3Zn1/3Ta1/3)O3-doped (K1/2Na1/2)NbO3 high-entropy ceramics

Environmentally friendly high-performance dielectric capacitors are urgently required for clean energy and advanced pulse equipment. In this study, a high-entropy strategy was adopted to design (1−x)(K1/2Na1/2)NbO3-xBi(Mg1/3Zn1/3Ta1/3)O3 (KNN-BMZT) ceramics for energy storage applications. The phase compositions, dielectric properties, and energy storage performances of the KNN-BMZT ceramics were explored. The results demonstrated that all the ceramic samples exhibited a single perovskite phase with a pseudo-cubic structure and compact microstructure. More importantly, the addition of BMZT increased the disorder and configurational entropy, resulting in the formation of KNN-based high-entropy relaxor ferroelectrics. Moreover, 0.84KNN–0.16BMZT ceramic demonstrated the optimal energy storage performance, exhibiting a recoverable energy density (Wrec) of 2.72 J/cm3 and an energy storage efficiency (η) of 81.77% when an electric field of 335 kV/cm was applied. Furthermore, this ceramic exhibited an excellent temperature stability (30–135 °C) and frequency insensitivity (10–500 Hz). These results demonstrate that the 0.84 KNN–0.16 BMZT ceramic is a promising candidate for dielectric energy storage applications.

Enhanced piezoelectricity in Pb(Zr0.48Ti0.52)O3-Pb(Mn1/3Sb2/3)O3-Pb(Mg1/3Ta2/3)O3 ceramics through the synergistic effect of defect engineering and lattice distortion

With the increasing demand for industrial applications, it has become crucial to develop special high-power devices that can achieve both high piezoelectric performance and large mechanical quality factor. In this work, we prepared quaternary piezoelectric ceramics, namely (0.95-x)Pb(Zr0.48Ti0.52)O3-xPb(Mg1/3Ta2/3)O3-0.05Pb(Mn1/3Sb2/3)O3 (PZT-PMT-PMS), using a traditional solid-state route. These ceramics exhibit an excellent mechanical quality factor and low loss. By adding an appropriate amount of PMT (x = 0.09), the Mg2+ ions were homogeneously incorporated into the crystal lattice, resulting in a reduction in the content of the tetragonal phase. The formation of (MgZr,Ti′′−VO..) defect dipoles has been studied through Rietveld refinement, which indicates that defect dipoles can hinder domain-wall motion, strengthen the pinning effect, and result in a “harder” performance. Moreover, the high asymmetry caused by large lattice distortion, regulates the piezoelectric properties. The sample shows the optimal performance when the PMT content is 0.09, with d33 = 430 pC/N, Qm = 1740, TC = 258 °C, εr = 1740, tanδ = 0.16 %, Pr = 44.5μC/cm2, and kp = 0.569.

Perovskite Relaxor‐Dependent Contributions to Piezoelectric Power Generation of Multiple PZT Tape‐Based Cantilever Structures at Nonresonant Frequency

AbstractPiezoelectric energy harvesters based on Pb(Zr0.5Ti0.5)O3 (PZT) ceramics have been extensively studied for various low‐power applications. Herein, unprecedented multiple‐harvester structures with record‐breaking performance are proposed for targeting nonresonant‐frequency or extremely low‐frequency applications. Exceptional combinations of PZT with three different relaxor materials, namely, Pb(Co1/3Nb2/3)O3 (PCN), Pb(Ni1/3Nb2/3)O3 (PNN), and Pb(Zn1/3Nb2/3)O3 (PZN), are systematically investigated in terms of their structural changes and piezoelectricity. Following the optimization of the PCN–PZT, PNN–PZT, and PZN–PZT systems in terms of piezoelectricity and power generation, a few device structures are designed using the advantages of each system. For example, the highest g31 composition of 0.2PCN–0.8PZT is combined with the highest d31 of 0.4PZN–0.6PZT to maximize the power generation in the two‐parallel‐tape structure. Multilayer harvester structures with up to four layers are also evaluated to correlate the enhanced voltage and current with the layer thickness and effective area for surface‐charge polarization. The four‐layer 0.4PZN‐0.6PZT unimorph cantilever demonstrates exceptional energy‐harvesting performance of ≈535.9 µW, corresponding to the record power density of ≈10 mW cm−2 g−2 Hz−1 at 2 Hz. The outstanding outcome is believed to be a benchmark for various nonresonant‐frequency applications.

Fine-grained high-performance Ba0.85Ca0.15 Zr0.1Ti0.9O3 piezoceramics obtained by current-controlled flash sintering of nanopowders

Due to environmental concerns, extensive research has been carried out to develop high-performance lead-free piezoceramics capable of replacing commercial lead-based materials. The lead-free (Ba0.7Ca0.3)TiO3 −Ba(Zr0.2Ti0.8)O3 system has emerged as a candidate for room temperature transducer applications because a high piezoelectric charge coefficient is achieved in this system for compositions at the morphotropic phase boundary. However, conventional ceramic processing of these eco-friendly piezoceramics demands high energy consumption because long-lasting, high-temperature heat treatments are needed, which often lead to microstructural degradation that compromises the material reliability. Field-assisted flash sintering has started to be explored since the application of an adequate electric field was shown to significantly reduce the sintering time and temperature, thereby controlling grain growth. In this work, Ba0.85Ca0.15Zr0.1Ti0.9O3 ceramics are obtained by current-controlled flash sintering of mechanosynthesized nanopowders. Exhaustive control of the sintering parameters allows tailoring of the microstructure, which allows dense fine-grained flash-sintered ceramics exhibiting a high electric field-induced strain response to be obtained.

Pulse energy-storage performance and temperature stability of Bi2O3-added BaTiO3 based ceramics

The temperature stability and temperature stability range of barium titanate-based pulse energy-storage ceramics were modified by Bi2O3 tailoring in (Ba0.98-xLi0.02Bix) (Mg0·04Ti0.96)O3 (x = 0, 0.025, 0.05, 0.075, 0.1) and (Ba1.03-1.5xLi0.02Bix) (Mg0·04Ti0.96)O3 (x = 0.125, 0.15, 0.2, 0.25) ceramics. Excellent pulse energy-storage performances of ceramic films are achieved via the new dual priority strategy of establishing cationic vacancies and forming a liquid phase. The dielectric constant plateau appears due to the cubic phase and space charges. Outstanding temperature stability, frequency stability and antifatigue performance are obtained in the ceramics, and their variations are all less than 15%. The comprehensive energy-storage properties with dual priority parameters of energy-storage density and efficiency of 3.13 J/cm3 and 91.71%, accompanied by an excellent pulse discharge energy density of 2.48 J/cm3, current density of 1313.23 A/cm2 and power density of 195.26 MW/cm3 are gained at x = 0.1. The perfect pulse energy-storage performances as well as ultrahigh stability are correlated with synergistic effects of multiphase coexistence, cubic phase, liquid-phase sintering, grain size, ceramic resistance, space charges and polar nanoregions. The comprehensive parameters indicate that the (Ba0·88Li0·02Bi0.1) (Mg0·04Ti0.96)O3 ceramics have potential application in high precision fields.

Excellent temperature stability of strain in PZ-PT-BNT ternary ceramics

Lead-based Pb(Zr, Ti)O3 ceramics have been widely applied in piezoelectric actuators, and yet high temperature stability and large strain have been pursued for further application. In this work, a novel PbZrO3–PbTiO3-(Bi0.5Na0.5)TiO3 (PZ-PT-BNT) piezoelectric ceramic is designed and prepared by solid-state route. It is found that the introduction of BNT constituent enhances the relaxation behavior of PZ-PT ceramic, inhibits the abrupt change in dielectric properties near Curie temperature, and increases the proportion of tetragonal phase with high temperature stability. Meanwhile, the patterns of electric domains are intentionally modified by adjusting composition of PZ-PT-BNT. Short and broad electric domains in PZ-PT-0.03BNT ceramic are observed by piezoresponse force microscopy, which are insensitive to temperature and have faster response under electric field, contributing to strain characteristics. As a result, through integrating phase structure and electric domain configuration, a strain of 0.21% and excellent temperature stability where the variation of strain is less than 8% in the temperature range of 25–250 °C are achieved in PZ-PT-0.03BNT ceramic. The findings provide an effective strategy for improving the strain stability of PZ-PT-based piezoelectric ceramics, and demonstrate that PZ-PT-BNT ceramics have potential application prospects in high-temperature piezoelectric actuators.

Effect of rare earth substitution on pyroelectric, ferroelectric, and piezoelectric properties lead-free Ba0.85Ca0.12RE0.03Ti0.90Zr0.04Nb0.042O3 (RE = Ce or Pr) ceramics

Effect of rare earth substitution on pyroelectric, ferroelectric, and piezoelectric properties lead-free Ba0.85Ca0.12RE0.03Ti0.90Zr0.04Nb0.042O3 (RE = Ce or Pr) ceramics

Lead-Free Textured Ceramics with Ultrahigh Piezoelectric Properties by Synergistic Design.

Lead-free ceramics with superior piezoelectric performance are highly desirable in various electromechanical applications. Unfortunately, it is still challenging to achieve significantly enhanced piezoelectricity without sacrificing the Curie temperature (Tc) in current BaTiO3-based ceramics. To address this issue, a synergistic design strategy of integrating crystallographic texture, multiphase coexistence, and doping engineering is proposed here. Highly [001]c-textured (Ba0.95Ca0.05)(Ti0.92Zr0.06Sn0.02)O3 ceramics are synthesized through Li-related liquid-phase-assisted templated grain growth, with improved grain orientation quality (f of ∼96% and r of ∼0.16) achieved at substantially reduced texture temperatures. Encouragingly, ultrahigh comprehensive piezoelectric properties, i.e., piezoelectric coefficient d33 of ∼820 pC N-1, electrostrain Smax/Emax of ∼2040 pm V-1, and figure of merit d33 × g33 of ∼23.5 × 10-12 m2 N-1, are simultaneously obtained without sacrificing Tc, which are also about 2.3, 2.4, and 4.3 times as high as those of non-textured counterpart, respectively. On the basis of the experiments and theoretical modeling, the outstanding piezoelectric performance is attributed to more effective exploration of property anisotropy and easier polarization rotation/extension, owing to improved grain orientation quality, dissolution of templates into oriented grains, coexisting R + O + T phases, and domain miniaturization. This work provides important guidelines for developing novel ceramics with outstanding piezoelectric properties and can largely expand application fields of textured BaTiO3-based ceramics into high-performance and multilayer electronic devices.

Novel non-equimolar SrLa(Al0.25Zn0.125Mg0.125Ga0.25Ti0.25)O4 high-entropy ceramics with excellent mechanical and microwave dielectric properties

Novel non-equimolar high-entropy SrLa(Al0.25Zn0.125Mg0.125Ti0.25Ga0.25)O4 (SLAZMTG) ceramics with a layered perovskite structure have been prepared via the standard solid-state reaction method. The high-entropy composition belongs to the tetrahedral structure with a space group of I4/mmm, which is confirmed by the XRD and TEM analyses. Excellent microwave dielectric properties with a suitable dielectric constant (εr = 22.5), high quality factor (Qf = 83,003 GHz), and near-zero τf value of −1.7 ppm/°C are obtained in SLAZMTG ceramics sintered at 1400 °C. Meanwhile, a significant enhancement in compressive strength was achieved due to the improvement of configuration entropy, 912 MPa for SLAZMTG compared to 578 MPa in the pure SrLaAlO4 composition. Additionally, the high-entropy engineering in the present work suggests great potential in achieving low thermal conductivities. SLAZMTG ceramics exhibit low thermal conductivities ranging from 2.86 W/m•K at 323 K to 1.99 W/m•K at 673 K, much lower than those of SrLaAlO4 and other perovskite ceramics.

Effects of A, B-site multiple ion co-doping on the structure, magnetic, magnetocaloric effect, and critical behavior of La0.7-xNd0.1Sr0.2KxMn0.95Ni0.05O3 ceramics

The effects of K+ doping on structure, magnetic characteristics, magnetocaloric properties, and critical behavior of La0.7-xNd0.1Sr0.2KxMn0.95Ni0.05O3 (LNSKMNO) ceramics (x = 0.00, 0.05, and 0.10) were investigated. The X-ray diffraction and refinement findings revealed that LNSKMNO exhibited a distinctive rhombohedral structure of the R-3c space group (No. 167). To validate the chemical composition of LNSKMNO ceramics, EDS spectroscopy and X-ray photoelectron spectroscopy (XPS) were utilized. The magnetization of LNSKMNO exhibited a temperature-dependent behavior, revealing a phase transition from the ferromagnetic (FM) phase to the paramagnetic (PM) phase at approximately the Curie temperature (Tc). By utilizing normalization and Banerjee's criterion, the magnetic phase transition of LNSKMNO was determined to be a second order magnetic phase transition. The maximal magnetic entropy (−ΔSMmax) of LNSKMNO around Tc was 4.24, 4.53, and 4.07 J/(kg K) at the 5 T external magnetic field (H). The Kouvel-Fisher approach and modified Arrott plot were used for determining the values of the critical exponents of β, γ, and δ. The critical exponents for LNSKMNO ceramics generally conformed to those obtained based on the Mean-field model.

Crystal structures, chemical bond, and microwave dielectric properties of Ba1-xKx(Zn1/3Nb2/3)O3-x/2 ceramics

Ba1-xKx(Zn1/3Nb2/3)O3-x/2 (BKZN, x = 0–0.2) ceramics were prepared by the high-temperature solid-state reaction method. Based on P–V–L theory, Raman vibration spectroscopy and X-ray photoelectron spectroscopy (XPS), this paper investigates the relationship between the internal and external factors of K+ substitution in the Ba(Zn1/3Nb2/3)O3 (BZN) ceramics and the microwave dielectric properties of the ceramics. X-ray diffraction (XRD) characterisation revealed that all samples were single phase with no impure phases. Replacing Ba2+ with K+ greatly reduced the sintering temperature and optimised the microwave dielectric properties of the ceramics. The dielectric constant (εr) was closely related to the ion polarizability and density, and inversely proportional to Raman shift of the A1g(O) peak. The quality factor (Q × f) depended largely on the lattice energy (Ub) and the full width at half-maximum (FWHM) of A1g(O) near 790 cm−1. The temperature coefficient of the resonance frequency (τf) could be inferred from the bond energy (Eb) and oxygen octahedral distortion. Finally, outstanding microwave dielectric properties (εr = 40.83, Q × f = 71,658 GHz and τf = 2.52 ppm/°C) were acquired for Ba0.95K0.05(Zn1/3Nb2/3)O2.975 ceramics sintered at the optimum sintering temperature (1325 °C) for 4 h.

Structural, magnetic and ferroelectric properties of magnetoelectrically coupled xBa0.95Sr0.05TiO3-(1–x)BiFe0.90Sm0.10O3 ceramics

ABSTRACT The standard solid state reaction method was followed to synthesize the polycrystalline xBa0.95Sr0.05TiO3-(1–x)BiFe0.9Sm0.1O3 [xBST-(1–x)BFSmO, x = 0–0.35] ceramics. The XRD pattern revealed a structural transition of the prepared ceramics from rhombohedral to cubic symmetry. The mean grain size was estimated in the micrometer range, with values ranging from 0.40 to 1.95 μm. The maximum real part of the complex initial permeability of 28.26 was noticed for x = 0.30 multiferroic ceramics. The highest remanent magnetization determined for the x = 0.30 sample was 3.4 10−2 emu/g. For the sample with x = 0.35 the maximum recorded dielectric constant was found to be 677 at 103 Hz. A small value of dielectric loss (<5%) was observed. The compound exhibited significant remanent polarization and a reduction in the leakage current. In addition, the investigated materials comprise large magnetoelectric coefficients and the optimum magnetoelectric coefficient of 0.662 mV.cm−1.Oe−1was obtained for the x = 0.30 composition.

Structural evolution and energy storage properties of Bi(Zn0.5Zr0.5)O3 modified BaTiO3-based relaxation ferroelectric ceramics

A series of (1−x)BaTiO3−xBi(Zn0.5Zr0.5)O3 (x = 0–0.15) ceramics were synthesized using the conventional solid-state method. An ultrahigh recoverable energy storage density of 3.58 J/cm3 and a high energy efficiency of 90% are obtained for 0.85BaTiO3–0.15Bi(Zn0.5Zr0.5)O3 lead-free bulk ceramics under an electric field of 430 kV/cm; the energy storage density is thus enhanced by a factor of a ∼ 895% compared with that of the pure BT ceramics. Furthermore, an excellent temperature stability is obtained, with changes in the energy storage density and efficiency <5% and <0.1%, respectively, over the temperature range of 30 °C – 120 °C. These ergodic relaxor ferroelectric characteristics are attributed to the reduced grain size, the transition from the tetragonal phase to the pseudo-cubic phase, and the transformation of the domain structure from macro domains to polar nanoregions. This work provides a lead-free material for realizing high-temperature capacitors for use in energy storage devices.

Highly efficient lasing and thermal properties of Tm:Y2O3 and Tm:(Y,Sc)2O3 ceramics.

We report on thermal, spectroscopic, and laser properties of transparent 5 at.% Tm3+-doped yttria and "mixed" yttria-scandia ceramics fabricated by vacuum sintering at 1750°C using nanoparticles produced by laser ablation. The solid-solution (Tm0.05Y0.698Sc0.252)2O3 ceramic features a broadband emission extending up to 2.3 µm (gain bandwidth, 167 nm) and high thermal conductivity of 4.48 W m-1 K-1. A Tm:Y2O3 ceramic laser generated 812 mW at 2.05 µm with a slope efficiency η of 70.2%. For the Tm:(Y,Sc)2O3 ceramic, the output power was 523 mW at 2.09 µm with η = 44.7%. These results represent record-high slope efficiencies for any parent or "mixed" Tm3+-doped sesquioxide ceramics.

Revealing the influence of Nb-doping on the crystal structure and electromechanical properties of (K, Bi)(Mg, Ti, Nb)O3 ceramics

Revealing the influence of Nb-doping on the crystal structure and electromechanical properties of (K, Bi)(Mg, Ti, Nb)O3 ceramics

Fabrication of 〈100〉-oriented Bi(Mg0.5Ti0.5)O3-modified BiFeO3-BaTiO3 ceramics and their piezoelectric properties

Rhombohedral Bi(Mg0.5Ti0.5)O3-modified BiFeO3-BaTiO3 ceramics were successfully textured along the nonpolar 〈100〉 direction using the templated grain growth process for the first time. The textured 0.90(0.33BaTiO30.67BiFeO3)0.10Bi(Mg0.5Ti0.5)O3 (33BTBF-10BMT) ceramics were fabricated by a 33BTBF-10BMT matrix with BT templates. The degree of orientation was investigated by various sintering temperatures, and the 80% oriented 33BTBF-10BMT along the 〈100〉 direction was achieved at a relatively high sintering temperature. However, the degree of orientation abruptly decreased at the highest sintering temperature of 1100 °C due to the large pores and low relative density. Based on the analysis of the unipolar strain measurements, the highest strain and d 33 * values were observed in the textured ceramics with 80% orientation. These textured ceramics exhibited approximately 0.3% strain and a d 33 * exceeding 400 pm V−1, representing approximately 1.5 times higher values compared to the nontextured ceramics.

Electrocaloric effect of (Ba1-xSrx)(HfxTi1-x)O3 lead-free ferroelectric ceramics with phase structure regulation

Electrocaloric (EC) refrigeration is a new type of solid-state refrigeration technology based on the electrocaloric effect (ECE), which has the advantages of environmental protection, high efficiency, easy integration and miniaturization. In this paper, Sr2+ and Hf4+ are doped into the A and B sites of BaTiO3 (BT), respectively. By adjusting the proportional composition, the multicritical point is constructed to improve the adiabatic temperature change (ΔT), and the relaxor ferroelectrics are formed to broaden the working temperature span (Tspan). The effect of doping content on the crystal structure, surface morphology, dielectric, ferroelectric and electrocaloric properties of ceramics is studied systematically. The phase diagram of (Ba1-xSrx)(HfxTi1-x)O3 (BSHT) ceramics is established, and (Ba0.9Sr0.1)(Hf0.1Ti0.9)O3 (BSHT10) is at the multicritical point. It has the most excellent comprehensive electrocaloric performance, with ΔTmax obtained 1.2 K and Tspan (ΔT ≥ 0.9 ΔTmax) reached 45 °C under 50 kV/cm, indicating its potential as a lead-free bulk ceramic material for EC refrigeration applications.

Effect of sintering temperature on phase transformation and energy storage properties of 0.95NaNbO3-0.05Bi(Zn0.5Zr0.5)O3 ceramics

Dielectric materials with excellent energy storage performance are crucial to the development of renewable energy. In this work, we prepared 0.95NaNbO3–0.05Bi(Zn[Formula: see text]Zr[Formula: see text])O3 (0.95NN–0.05BZZ) ceramics using solid state sintering and investigated the effect of sintering temperature on phase structure. We find that the phase transformation of ceramics occurs with the change of sintering temperature. The cubic phase (Pm-3[Formula: see text]) and the antiferroelectric phase (Pbma) coexist at 1150[Formula: see text]C, the ferroelectric phase ([Formula: see text]21ma) appears at 1200[Formula: see text]C and its phase proportion decreases with the sintering temperature increasing from 1200[Formula: see text]C to 1280[Formula: see text]C. Finally, we achieve the high recoverable energy storage density ([Formula: see text][Formula: see text]) 0.74 J/cm3and efficiency ([Formula: see text]) 71% (at 140 kV/cm) at 1150[Formula: see text]C.

Optimizing energy storage properties under moderate electric fields in Na0.5Bi0.5TiO3-based ceramics via configuration entropy modulation

Lead-free ceramic capacitors with large energy storage density and efficiency synchronously under moderate electric fields is a challenging. In this work, a pathway of configuration entropy modulation (ΔSconfig) overcomes this challenge. The (1-x)(Na0.5Bi0.47La0.03)0.94Ba0.06TiO3-xSr(Sn0.2Ti0.2Al0.2Ta0.2Hf0.2)O3 ceramics were successfully synthesized. With the system ΔSconfig increases from 0.98 R to 1.79 R. The 0.85 NBLBT-0.15 SSTATH ceramic obtains a large recoverable energy density (Wrec = 4.28J/cm3) and ultra-high efficiency (η = 92.6%) under 260 kV/cm. The implementation of prominent energy storage performance can be attributed to the refinement of grain and domain size, and the increase of band gap and activation energy, which caused by the increase in ΔSconfig. More critically, the same composition also possesses great frequency (1–100 Hz) and thermal (20–140 °C) stability of energy storage performance as well as the high power density of PD ∼ 36.19 MW/cm3 and transient discharge rate of t0.9–44 ns at 120 kV/cm. This work shows that the regulation of ΔSconfig is an effective strategy to achieve outstanding energy storage properties under moderate electric fields.

Direct photoluminescence manipulation in Er-doped AgNbO3 lead-free antiferroelectrics via reversible electric-field-induced symmetry modulations

The electric field-modulated photoluminescent (E-PL) effect has received much attention because of its potential applications in optical data storage and communication. Based on the E-induced antiferroelectric-ferroelectric (AFE-FE) phase transition, a large and reversible modulation of the PL intensity was previously realized in lanthanum-doped Pb(Zr0.9Ti0.1)O3 (PLZT) ceramics. However, such systems contain abundant leads and are thus toxic to humans and the environment. In this work, Er-doped AgNbO3 (ANO) lead-free ceramics were prepared, and their E-PL effect was investigated. From the perspective of the crystallographic symmetry, the reversibly E-induced orthorhombic Pbcm to orthorhombic Pmc21 transition results in a negative PL intensity change of 25%, which is different from the positive 30% PL modulation in the PLZT system triggered by the AFE-FE orthorhombic-rhombohedral phase transition. This symmetry-dependent negative PL modulation in ANO ceramics enriches the understanding of the E-PL effect in AFEs and provides an environmentally friendly alternative for multifunctional optoelectronics.