Superior Temperature Stability Research Articles

Preparation, characterization and stability of cross linked nitrilase aggregates (nitrilase-CLEAs) for hydroxylation of 2-chloroisonicotinonitrile to 2-chloroisonicotinic acid.

Nitrilases capable of performing hydroxylation of 2-chloroisonicotinonitrile to 2-chloroisonicotinic acid were screened, and ES-NIT-102 was the best nitrilase for said biotransformation. Nitrilase was immobilized as cross linked enzyme aggregates (nitrilase-CLEAs) by fractional precipitation with iso-propanol, and cross linked with glutaraldehyde. The nitrilase-CLEAs prepared with optimized 35mM glutaraldehyde for 120min cross linking time had 82.36 ± 4.45% residual activity, and displayed type-II structural CLEAs formation as confirmed by particle size, SEM, FTIR, and SDS-PAGE analysis. Nitrilase-CLEAs had superior pH and temperature stability, showed a shift in optimal temperature by 5°C, and retained nearly 1.5 to 1.7 folds activity over free nitrilase at 50°C and 55°C after more than 9h incubation. Nitrilase-CLEAs showed reduced affinity and decreased conversion of substrate as indicated by slightly higher Km values by 5.19% and reduced Vmax by 17%. Furthermore, these nitrilase-CLEAs showed 98% conversion, 94.72g/L product formation, and 83.30% recovery after 24h when used for hydroxylation of 2-chloroisonicotinonitrile to 2-chloroisonicotinic acid. Nitrilase-CLEAs were catalytically active for 3 cycles showcasing 81% conversion, 75.53g/L product formation and 66.42% yield. The recovered product was confirmed by HPLC, FTIR, LC-MS, and 1H NMR, and displayed > 99% purity.

Excellent temperature stability of energy storage performance by weak dipolar interaction strategy

High-performance dielectric materials are widely used in energy storage applications, and temperature stability at extreme conditions is rarely considered yet. In this work, the Bi0.5Na0.5TiO3–Sr0.7Bi0.2□0.1TiO3–xNaNbO3 (x = 0, 0.05, and 0.15) system is designed with a room-temperature ergodic relaxor character to explore energy storage evolution with temperature. The addition of NaNbO3 increases tetragonal (P4bm) phase content and relaxor disorders and leads to a downshift of transition temperature, as verified by Rietveld refinement, dielectric analysis, and in situ Raman spectra. Superior temperature stability of recoverable energy storage density (WRec, change rate: δ ≤ 14%) and efficiency (η = 0.79–0.98) is found in x = 0.15 composition in a wide temperature range of 243–373 K, in contrast to a significant variation for x = 0 (δ ≤ 85%, η = 0.08–0.88) and 0.05 (δ ≤ 36%, η = 0.60–0.96) compositions. The dielectric relaxation speed is faster in x = 0.15, as characterized by on–off-electric field dielectric curves. This work demonstrates that the weak-dipolar-interaction system retards dipolar coalescence under cryogenic temperature and, thus, maintains high energy storage efficiency, which predicts their suitability in energy storage applications at an extreme condition.

Enhanced energy storage performance of BaTi0.97Ca0.03O2.97-based ceramics by doping high-entropy perovskite oxide

To improve the comprehensive energy storage performance of the BaTi0.97Ca0.03O2.97-based ceramics for pulse power capacitors, a typical bismuth-based high entropy compound, Bi(Li0.2Y0.2Mg0.2Ti0.2Ta0.2)O3 (BLYMTT) was introduced into 0.9Ba(Ti0.97Ca0.03)O3-0.1Bi0.55Na0.45TiO3 (0.9BTC-0.1BNT) matrix. The results indicate that the phase structure transforms from tetragonal phase to pseudo-cubic phase with increasing BLYMTT, and the relaxor ferroelectric behavior are also enhanced. The 0.91(0.9BTC-0.1BNT)-0.09BLYMTT ceramic simultaneously achieves a high energy storage density of 4.89 J/cm3 and efficiency of 91.2% at electric field of 240 kV/cm. Moreover, the 0.91(0.9BTC-0.1BNT)-0.09BLYMTT ceramic also exhibits superior temperature (30–100 ℃) and frequency (1–100 Hz) stability, as well as the ultrahigh power density of PD~66.01 MW/cm3 and rapid discharge rate of t0.9~97 ns at 140 kV/cm, which is of great potential for energy storage application.

High-performance and high-thermally stable PSN-PZT piezoelectric ceramics achieved by high-temperature poling

• A universal and practical method of high-temperature poling is put up forward. • Great comprehensive properties are obtained: d 33 = 562 pC/N and T C = 350 °C. • The mechanism of high-temperature poling is clarified. • High-temperature poling remarkably promote temperature stability of properties. High piezoelectric properties and superior thermal stability are both important indicators of piezoelectric ceramics serving at high temperature. However, since these properties are usually mutually exclusive, high performance and superior thermal stability are hard to achieve simultaneously. Here we report that a high piezoelectricity ( d 33 ∼ 562 pC/N) and superior thermal stability (the variation is within 7% from 20 to 330 °C) were both achieved in 0.4 mol% ZnO-doped 0.02Pb(Sb 1/2 Nb 1/2 )-0.51PbZrO 3 –0.47PbTiO 3 by high-temperature poling. Compared with traditional poling method, high-temperature poling method forms a small-sized and highly oriented domain structure, which can effectively improve the piezoelectric and dielectric properties of piezoelectric ceramics. At the same time, the enhanced pinning effect of defect ions and stabilized domain structure due to high-temperature poling also contribute to the superior temperature stability of the piezoelectric and dielectric properties. This work provides an effective method for designing piezoelectric materials with high performance and good temperature stability for high temperature sensor applications.

Achieving Good Temperature Stability of Dielectric Constant by Constructing Composition Gradient in (Pb1-x,Lax)(Zr0.65,Ti0.35)O3 Multilayer Thin Films.

Ferroelectrics with a high dielectric constant are ideal materials for the fabrication of miniaturized and integrated electronic devices. However, the dielectric constant of ferroelectrics varies significantly with the change of temperature, which is detrimental to the working stability of electronic devices. This work demonstrates a new strategy to design a ferroelectric dielectric with a high temperature stability, that is, the design of a multilayer relaxor ferroelectric thin film with a composition gradient. As a result, the fabricated up-graded (Pb,La)(Zr0.65,Ti0.35)O3 multilayer thin film showed a superior temperature stability of the dielectric constant, with variation less than 7% in the temperature range from 30 °C to 200 °C, and more importantly, the variation was less than 2.5% in the temperature range from 75 °C to 200 °C. This work not only develops a dielectric material with superior temperature stability, but also demonstrates a promising method to enhance the temperature stability of ferroelectrics.

Ultra-slim electrostrains with superior temperature-stability in lead-free sodium niobate-based ferroelectric perovskite

Large electrostrains with high temperature stability and low hysteresis are essential for applications in high-precision actuator devices. However, achieving simultaneously all three of the aforementioned features in ferroelectric ceramics remains a considerable challenge. In this work, we firstly report a high unipolar electrostrain (0.12% at 60 kV/cm) in (1–x)NaNbO3-x[(Ba0.85Ca0.15)(Zr0.1Ti0.9)O3] (NN-xBCZT) ferroelectric polycrystalline ceramics with excellent thermal stability (variation less than 10% in the temperature range of 30–160 °C) and ultra-low hysteresis (<6%). Secondly, the high-field electrostrain response is dominated by the intrinsic electrostrictive effect, which may account for more than 80% of the electrostrain. Furthermore, due to the thermal stability of the polarization in the pure tetragonal phase, the large electrostrain demonstrates extraordinarily high stability from room temperature to 140 °C. Finally, in-situ piezoelectric force microscopy reveals ultra-highly stable domain structures, which also guarantee the thermal stability of the electrostrain in (NN-xBCZT ferroelectrics ceramics. This study not only clarifies the origin of thermally stable electrostrain in NN-xBCZT ferroelectric perovskite in terms of electrostrictive effect, but also provides ideas for developing applicable ferroelectric ceramic materials used in actuator devices with excellent thermal stability.

Phase composition and property evolution of (Yb1−xHox)2Si2O7 solid solution as environmental/thermal barrier coating candidates

RE disilicates are good candidates as environmental/thermal barrier coating for SiCf/SiC composite in harsh gas turbine engines. We designed (Yb1−xHox)2Si2O7 solid solutions and studied mechanical properties, thermal properties, and water vapor resistance. Powders with different compositions were synthesized by pressureless sintering, and bulk samples were prepared by Spark Plasma Sintering (SPS). Polymorphic changes with temperature and composition of the solid solutions were examined. Through doping Ho into Yb2Si2O7, water vapor corrosion resistance is significantly promoted, and thermal expansion coefficient is maintained close to that of Si-based ceramics. Compared with host disilicates, thermal conductivity of solid solutions are decreased, and mechanical properties, including Vickers hardness and fracture toughness, are increased. A two-phase domain is found at (Yb1/2Ho1/2)2Si2O7, and the γ to δ phase transition of Ho2Si2O7 is observed during SPS. Among all samples, γ-(Yb1/3Ho2/3)2Si2O7 possesses superior high temperature stability, and excellent water vapor resistance, indicating its performance as environmental/thermal barrier coating.

Interface and defect modulation via a core–shell design in (Na0.5Bi0.5TiO3@La2O3)-(SrSn0.2Ti0.8O3@La2O3)-Bi2O3-B2O3-SiO2 composite ceramics for wide-temperature energy storage capacitors

Dielectric capacitors with high energy storage performance have attracted much attention in power electronics systems. However, the limited energy storage and unsatisfactory temperature stability are the main obstacles in practical applications. Herein, the joint control of interface and internal defects in core–shell structure is proposed to achieve capacitors with superior wide-temperature energy storage properties. Firstly, relaxor ceramics were prepared, in which multiphase ceramic phases including ferroelectric Na0.5Bi0.5TiO3 (NBT) and paraelectric SrSn0.2Ti0.8O3 (SST) were used to ensure relaxation, and Bi2O3-B2O3-SiO2 (BBS) glass was added to accelerate the ceramic densification. Secondly, notably, a buffer layer of La2O3 with wide band gap was introduced in a core–shell way at the interface between ceramic powders and glass to form composite ceramics. The experimental results show that the La2O3 coating can induce uniform and dense ceramic microstructure with a composition gradient, alleviating the local electric field distortion at the interface of ceramic/glass. Therefore, the capacitive wide-temperature energy storage properties are ultimately improved. Confirmed by XPS and EPR, partial La2O3 as a donor in grains generates LaA·-VTi‴ defect complex and optimizes the η and BDS of the ceramics. NBT@La2O3-SST@La2O3-BBS composites with 1.0 mol% La2O3 exhibit high η ∼ 82.1%, high BDS ∼ 275 kV/cm, medium Wrec ∼ 2.25 J/cm3, superior dielectric temperature stability (Δε/ε150 °C≤±15%) at 20–500 °C and thermal stability of energy storage. This work is expected to pave a new way to optimize the wide-temperature energy storage of composite ceramics via the core–shell design process.

Enhanced Curie temperature and superior temperature stability by site selected doping in BCZT based lead-free ceramics

In this work, Bi3+ doped Ba0.98-3x/2BixCa0.02Zr0.02Ti0.976Cu0.008O3 [0 ≤ x ≤ 0.03] lead free ceramics, to be employed for structural, dielectric and ferroelectric studies, have been synthesized via conventional solid state reaction method. Rietveld refinement of the X-ray diffraction (XRD) data evidences the existence of a pure perovskite phase with tetragonal symmetry for all ceramics. The Scanning Electron Microscopy (SEM) reveals that the grain size, which is 16.14 μm for x = 0 reduced to 2.11 μm for x = 0.03. Dielectric studies demonstrate excellent dielectric behavior with high Curie temperature (TC ∼159 °C), high dielectric constant (εr ∼834, εmax ∼ 3146), and a low dielectric loss (tanδ ∼ 0.019), for an optimum value of x = 0.02. The analysis of temperature coefficient of the dielectric permittivity indicates the applicability of these materials in multilayer ceramic capacitors. Impedance studies, conducted to understand the underlying physical mechanisms, are found to be in good agreement with the results of structural and dielectric studies. Furthermore, the ferroelectric measurement confirms the ferroelectric nature for all samples with an energy storage efficiency (η) of ∼42% for x = 0.02 composition.

Comparison of sputtering and atomic layer deposition based ultra-thin alumina protective layers for high temperature surface acoustic wave devices

Surface acoustic wave (SAW) can be used as passive wireless sensors in high temperature environments. For such applications, protective layers are crucial and important for the SAW sensors. In this paper, ultra-thin Al2O3 layers prepared by atomic layer deposition (ALD) and RF magnetron sputtering were used to protect SAW devices with platinum (Pt) electrodes and their temperature stability was studied systematically. The devices were thermally treated up to 1150 °C in air, the real-time resistance of Pt resistive tracks with a sputtering Al2O3 protective layer showed much better and improved thermal stability than those without or with an ALD Al2O3 protective layer. Microstructure characterizations showed that the superior temperature stability is attributed to its mixture of amorphous and nano-crystalline nature of the Al2O3 layer deposited by sputtering and full recrystallization at high temperatures. SAW devices with a sputtering Al2O3 protective layer after 1150 °C treatment maintained almost unchanged properties, while those with an ALD Al2O3 protective layer failed to work. Investigation also indicated there exists an optimal thickness for the sputtering Al2O3 layer to achieve best performance and thermal-stability for the SAW devices. Besides, the deposition rate of Al2O3 layer by sputtering is 10 times faster than that by ALD. All the results demonstrate that the sputtering Al2O3 protective layer is more suitable for high temperature SAW device applications owing to its lower cost, higher deposition rate and temperature stability.

Tailoring ferroelectric polarization and relaxation of BNT-based lead-free relaxors for superior energy storage properties

Dielectric energy storage materials have attracted much attention because of their wide applications in the electronics industry. However, low energy storage density and poor thermostability limit their application. In this work, a strategy was proposed to prepare lead-free relaxor ferroelectric ceramics with ultra-high energy storage properties and superior temperature stability by precisely adjusting the relaxation and ferroelectricity states and increasing the electric field intensity. An ultra-high recoverable energy storage density (Wr) of 4.97 J/cm3 and an efficiency (η) of 84.4% are simultaneously obtained for the 0.95(0.9Bi0.5Na0.5TiO3-0.1Ba0.85Ca0.15Zr0.1Ti0.9O3)-0.05BaSnO3 ceramic. Moreover, a high Wr of 2.73 J/cm3 with brilliant η of 80.6% are obtained in the ceramic at 140 ℃ and there is almost no thermal degradation of energy storage properties from 25 ℃ to 140 ℃. The Wr and η have decreased by 2.2% and 1.9% after 105 cycles under 200 kV/cm, respectively, which demonstrates the good cycle stability of the sample. A discharge power density of up to 99.0 MW/cm3 is obtained in the 0.95(0.9Bi0.5Na0.5TiO3-0.1Ba0.85Ca0.15Zr0.1Ti0.9O3)-0.05BaSnO3 ceramic and the good charge and discharge performance of this sample is important for practical applications.

Tetragonal (Ba, Ca) (Zr, Ti)O3 textured ceramics with enhanced piezoelectric response and superior temperature stability

Lead-free ceramics with both high piezoelectric response and good temperature stability are urgently demanded for electromechanical conversion devices. Unfortunately, owing to coexistence of polymorphic phases near room temperature (RT), enhanced piezoelectric properties were usually achieved with occurrence of strong temperature dependence in modified BaTiO3 (BT)-based ceramics. In this work, we demonstrate that tailoring grain orientations of tetragonal BT-based ceramics can effectively produce substantially enhanced and thermally stabilized piezoelectric response. Both <001>c- and <111>c-oriented tetragonal (Ba0.85Ca0.15) (Zr0.05Ti0.95)O3 (BCZT) ceramics with texture degrees F>90% were synthesized via templated grain growth. Interestingly, the ceramics textured along the <001>c polar axis show much higher microscopic and macroscopic piezoelectric properties than those with nonpolar <111>c texture, indicating an “extender” ferroelectricity nature. Compared with randomly oriented samples, the <001>c-oriented ceramics exhibit simultaneously ∼1.6 times higher piezoelectric strain d33∗ (∼760 pm/V), 4.4 times higher piezoelectric figure of merit d33×g33 (8.8 × 10−12 m2/N), and better temperature stability (strain variation ≤5% between RT and 110 °C). Such thermally stabilized strain response can be mainly attributed to wide temperature range of tetragonal phase and stable domain structure. This work provides a promising route for further developing lead-free piezoceramics with high and temperature-insensitive performance, which can greatly broaden their application areas.

High energy density, temperature stable lead-free ceramics by introducing high entropy perovskite oxide

Dielectric capacitors with fast charge–discharge rate and high power density are drawing more attention in pulse power equipment field. In this work, bismuth-based high entropy compound (HEC), Bi(Zn0.2Mg0.2Al0.2Sn0.2Zr0.2)O3 (BZMASZ), was introduced into BaTiO3-Na0.5Bi0.5TiO3 (BT-NBT) matrix, in order to improve the comprehensive energy storage performance. The addition of BZMASZ induced phase transition from tetragonal phase to cubic phase, along with the enhancement of relaxor behavior and local nanodomains. The 0.1 BZMASZ modified 0.75BT-0.25NBT ceramics exhibited excellent recoverable energy density of Wrec ~ 3.74 J/cm3, high conversion efficiency of η ~ 82.2 % and superior temperature stability of ± 4.5 % from −30 to 200 °C. Combined with the high power density of PD ~ 34.76 MW/cm3 and rapid discharge rate of t0.9 ~ 67 ns, the x = 0.1 ceramics are considered to be the promising candidate for future wide-temperature pulse power applications.

Multi-Component Nanofiber Composite Membrane Enabled High PM0.3 Removal Efficiency and Oil/Water Separation Performance in Complex Environment

Currently, industrial waste gas and oily wastewater are usually at high temperature and contain corrosive components (e.g., acid, alkali, oxidant, or high salt, etc.), presenting great challenges on filtration/separation materials. Here, a multi-purpose Poly(m-phenylene isophthalamide)/polyacrylonitrile/silica (PMIA/PAN/SiO2) nanofiber composite membrane with a high yield was prepared simply via electrospinning to satisfy the demands of air filtration and oil/water separation in complex environments. Under the synergy of PMIA, PAN and SiO2, the composite membrane possesses high PM0.3 removal capacity of 99.69%, robust purification ability against real smoke PM2.5, effective oil/water separation performance of > 99.6%, superior high temperature stability (about 250 °C) and excellent chemical resistance, showing the potential application in filtration/separation process under complex conditions. Moreover, the influence mechanism of SiO2 NPs on mechanical properties and filtration performance was systematically investigated through experiments and simulations, paving the way for future intensive research. This study provides an option for the facile and effective preparation of high-performance filtration/separation membranes applied in the field of dust filtration and oily wastewater separation, even in harsh environments.

Optimized piezoelectric properties and temperature stability in PSN‐PMN‐PT by adjusting the phase structure and grain size

AbstractFor relaxor ferroelectric materials, improving the piezoelectric properties and temperature stability simultaneously is still a great challenge up to now. In this work, the structure, electric properties, and thermal stability of xPSN‐(1 − x)PMN‐0.4PT (x = 0.15, 0.29, 0.43, and 0.5) ceramics were studied systematically by experiment and phase field simulation. A high Curie temperature Tc of 255℃ and good longitudinal electricmechanical coupling factor k33 of 0.75 and piezoelectric constant d33 of 650 pC/N are achieved in x = 0.43 ceramics with monoclinic C and tetragonal phases coexistence at room temperature. At 30℃, this composition ceramics sintered at 1260℃ shows the remnant polarization Pr and coercive field Ec are about 36.8 µC/cm2 and 8.2 kV/cm respectively. Moreover, as the temperature increases to 150℃, these values remain as high as 22.6 µC/cm2 and 5.7 kV/cm. In the temperature range of 30–230℃, the variation of k33 and d33 is about 24% and 25%. These high piezoelectric performance and superior temperature stability are related to the more complex domain structures caused by phase coexistence and larger grains with more stable domain structure due to internal stress. The former is beneficial in improving the piezoelectric properties, and the latter dominates the enhanced temperature stability.

Low hysteresis and temperature stable electrostrain in 0.97(0.94Na0.5Bi0.5TiO3-0.06BaTiO3)-0.03AgNbO3/xZnO composite ceramics

Na0.5Bi0.5TiO3-based solid solutions are one of the most promising lead-free piezoelectric candidates since they can be easily tailored to exhibit large electrostrain. However, the large hysteresis and temperature-dependence of the electrostrain response are longstanding obstacles for their practical applications. In the present study, 0–3 type composites were developed with 0.97(0.94Na0.5Bi0.5TiO3-0.06BaTiO3)-0.03AgNbO3 (NBT-6BT-3AN) matrix phase and ZnO inclusions. The optimum addition of 5 wt.% ZnO in the composites leads to reduction in hysteresis of electrostrain by 35% in comparison with pure NBT-6BT-3AN at room temperature. Meanwhile, electrostrain of the composites maintains superior temperature stability, with a variance of less than ±10% in the temperature range between 25 and 125 °C. The reason for the improvement of electrostrain is proposed to be attributed to the ergodic/nonergodic mixture phases induced by residual stress between the inclusion and matrix, as well as the phase evolution caused by the incorporation of Zn2+ into the matrix. Therefore, this work provides a new strategy to improve the electromechanical properties of Na0.5Bi0.5TiO3-based ceramics.

Decreasing polar-structure size: Achieving superior energy storage properties and temperature stability in Na0.5Bi0.5TiO3-based ceramics for low electric field and high-temperature applications

It is a grand challenge to achieve high energy density (W) and efficiency (η) simultaneously under a low electric field (LE) to obtain new high energy storage capacitors. Similar to anti-ferroelectrics, the (1-x)NBT-xBaMg1/3Nb2/3O3 relaxor material exhibits a non-linear dependence on electric field, which is caused by a reversible field-induced phase transition. This leads to high W (2.37 J/cm3) and η (81.5 %) under a LE of 155 kV/cm, which makes it superior to other bulk ceramics. Combining large polarizability of Ba2+ in A-site and local structural heterogeneity on the B-site by Mg1/3Nb2/34+, enhanced relaxor behavior and decreased polar-structure size were induced in (1-x)NBT-xBaMg1/3Nb2/3O3 ceramics. The permittivity, nevertheless, stays high at ∼2273±15 %. Furthermore, the electrical properties become stable in a wide temperature range from 44−396 °C for the sample with x=0.15. In addition, high current density/CD (450 A/cm2), power density/PD (23 MW/cm3) and discharge density/WD (0.57 J/cm3) were realized tested with pulse discharge testing. Our work will provide a development guidance for dielectric energy storage ceramics at low field and high fields with excellent temperature stability.

Significantly enhanced energy storage properties of Nd3+ doped AgNbO3 lead-free antiferroelectric ceramics

Lead-free dielectric capacitors for energy storage device have attracted increasing attention recently because of their high-power density and superior temperature stability. In this work, Nd-doped silver niobate (AgNbO3, abbreviated as AN) lead-free antiferroelectric ceramics were prepared by utilizing traditional solid state reaction method. A large energy storage density of 4.6 J/cm3 and an efficiency of 62.5% were simultaneously obtained in the 1% Nd-doped AN sample with an outstanding power density of 54.0 MW/cm3 and an ultrafast discharge speed (t0.9) of 59.2 ns. Additionally, the 1% Nd-doped AN ceramic demonstrates a good temperature stability from 25 ℃ to 130 ℃. The excellent energy storage properties of the 1% Nd-doped ceramic is ascribed to the enhanced breakdown electric field induced by grain size engineering and the construction of phase structure via heterovalent substitution at the A-site of the lattice structure at room temperature. Our present work suggests that the 1% Nd-doped AN ceramic show promise for energy storage application in miniaturized mobile electronic devices and high-power equipment.

Realizing room temperature double hysteresis loops in antiferroelectric NaNbO3 based ceramics

Lead-free antiferroelectric (AFE) materials have seen a surge of research activity in environmentally friendly energy storage technologies. Recently, considerable work has been done to improve the stability of AFE in NaNbO3 (NN) ceramics, but it remains a grand challenge to obtain typical AFE characteristic double P-E loops in NN ceramics at ambient conditions. In a preliminary estimate of tolerance factor versus average electronegativity difference, we reported the stable AFE phase in 0.95NaNbO3-0.05BiMg2/3Ta1/3O3 sample. The orthorhombic Q to P phase transition was verified by XRD and TEM. Then, the remarkable double P-E loops were obtained in 0.95NaNbO3-0.05BiMg2/3Ta1/3O3 ceramics. Furthermore, a phenomenological model was proposed to explain the P-E relationships and our results. Compared with other reported compounds, the TP-R decreased more obviously from 350 °C to 200 °C. Superior temperature stability (variations of maximum current, current density, and power density within 15% over 30–140 °C) and field induced phase transition were also confirmed by the pulse charge testing. Our work develops a new road for achieving room-temperature double P-E loops in NN ceramics by BiM1M2O3 (M1 might be Mg, Zn, etc; M2 might be Nb, Ta, etc) additives.

Temperature-insensitive PMN-PZ-PT ferroelectric ceramics for actuator applications

Piezoelectric actuators are essential for numerous electromechanical applications, because of their advantages of high resolution, large generated forces, no friction, low heat dissipation and fast response. The design of the next-generation piezoelectric actuators is desired to meet the complex needs of advanced machines and instruments, where the high-performance and stable output under the combined thermal and mechanical loads are expected. However, simultaneously achieving high-performance and good temperature stability of piezoelectric actuators is a challenge, which hinders the use temperature range in practical applications. Here, in the studied Sm-doped Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 system, the high piezoelectric strain coefficient d33* = 870 pm/V with superior temperature stability (below 7% variation over the temperature of 20°C to 280°C), together with negligible property degradation up to 106 cycles was successfully achieved. The outstanding blocking stress of 37.2 MPa and mechanical work of 6.4 kJ/m3 were obtained under the driving electric field of 15 kV/cm. This work provides a paradigm to achieve high piezoelectric strain properties with good temperature stability, where the studied materials are expected to greatly benefit the development of high temperature piezoelectric actuator applications.