O3 Ceramics Research Articles

Improved energy-storage and charge–discharge properties achieved in NaNbO3-Bi(Mg0.5Zr0.5)O3 ceramics

Improved energy-storage and charge–discharge properties achieved in NaNbO3-Bi(Mg0.5Zr0.5)O3 ceramics

Study on curie temperature mechanism and electrical properties of BiFeO3-doped (Ba,Ca) (Ti,Sn)O3 ceramics

In this study, we investigated the phase structure, Curie temperature, dielectric properties, piezoelectricity, and energy-storage properties of BiFeO3 (BFO)-modified (Ba0.95Ca0.05) (Ti0.89Sn0.11)O3 (BCTSO) ceramics using both experimental and theoretical methods. The results indicated that the lattice distortion and chaotic distribution of the local charge increased with the BFO content, resulting in a phase transition and transformation from a ferroelectric to a relaxing ferroelectric. First-principles calculations revealed that the Curie temperature decreased with increasing BFO content, primarily because of an increase in the ground state energy. The variation in the permittivity of the BCTSO-xBFO ceramics with temperature and frequency is affected by the phase structure and Maxwell-Wagner interface polarisation, respectively. The electrical modulus measurements indicated that BCTSO-xBFO exhibited non-Debye-type dielectric relaxation for x = 0.0, 0.1, and 0.5 %, whereas BCTSO-xBFO showed Debye-type dielectric relaxation for x = 0.9%.

Strong pinning effect on domains in piezoelectrics

In high-power applications, since mechanical losses in piezoelectric devices always result in considerable heat generation, the temperature stability of the mechanical quality factor (Qm) is particularly crucial and should be considered in real piezoelectric applications. Here, we propose a poling-aging-repoling strategy to make the defect dipoles aligned with the poling direction as much as possible, thereby resulting in the strong pinning of ferroelectric domains. A giant internal bias field Ei (11.6 kV cm−1 @ 1 Hz) and a high Qm (2074), accompanied by almost unchanged d33, are obtained in the composition of CuO-doped (K0.48Na0.52)0.94Li0.06Nb0.94Ta0.06O3 (KNNLT-Cu) ceramics with a diffused polymorphic phase transition. Furthermore, and this is more encouraging, the high electromechanical performance exhibits good temperature stability in the range from room temperature to 100 °C, suggesting that the thermal stability of Qm can be effectively improved by combining the strong pinning of defect dipoles with composition design and providing a way for the development and design of future high-power piezoelectric devices.

Technology and Dielectric Properties of BLT4 Ceramics Modified with Special Glass

Lead-boron special glass was doped into Ba0.996La0.004Ti0.999O3 (BLT4) ceramics in order to control the sintering process and grain growth, consequently obtaining materials with a well-developed microstructure. Changes in the microstructure resulted in a significant decrease in electrical permittivity along with a substantial increase in its frequency dispersion. Glass-doped ceramics, similar to pure BLT4, are characterized by a first-order phase transition from the ferroelectric phase to the paraelectric phase. The temperature of this transition shifts slightly towards higher values with the increase in glass dopant concentration.

The structural evolution and electric field-induced strain performance of Bi0.5(Na0.41K0.09)TiO3–Ba(Fe0.5Sb0.5)O3 lead-free piezoelectric ceramics

In recent years, lead-free Bi0.5Na0.5TiO3 (BNT) based piezoelectric ceramics with excellent strain properties have gained widespread recognition for their application in high-precision displacement actuators. The (1-x)(0.82Bi0.5Na0.5TiO3-0.18K0.5Bi0.5TiO3)-xBa(Fe0.5Sb0.5)O3 ceramics were fabricated through the die-pressing method in this work. The effect of BFS introduction on the dielectric, ferroelectric and microstructure characteristics of BNKT ceramics was systematically investigated. Among these compositions, the BNKT-0.015BFS ceramics exhibited a piezoelectric strain coefficient (d33*) of 658 pm/V at an electric field of 55 kV/cm, while achieving a strain response of 0.51 % at 85 kV/cm. The observed improvement in strain performance can be attributed to the evolution from non-ergodic relaxor state to ergodic relaxor state caused by BFS substitution. Furthermore, transmission electron microscopy (TEM) explicitly confirmed coexistence of rhombohedral and tetragonal phase and revealed the morphology of nanosized domains. This study adds to a deeper comprehension of the characteristics of strain response enhancement in BNT-based ceramics, opening up avenues for designing novel lead-free piezoelectric ceramics with outstanding electromechanical performance.

Morphotropic phase boundary evolution with synergistic effect of sintering temperature to improve electrocaloric and energy storage performances of lead-free Ba0.95Ca0.05Sn0.09Ti0.91O3 (BCST) ceramic

The designing of lead-free ferroelectric ceramics for application in environment-friendly efficient electrocaloric cooling and energy storage devices is still challenging and need to be considered. A major challenge, however, is how to simultaneously achieve higher polarization and low hysteresis loss at low applied electric field. In this perspective, we comprehensively investigated sol-gel derived Ba0.95Ca0.05Sn0.09Ti0.91O3 (BCST) ceramics by varying the sintering temperature to explore its electrocaloric and energy storage capabilities. The excellent ∆T ∼ 1.03 K, ∆S ∼ 1.32 J/kg.K and high electrocaloric responsivity ΔT/ΔE ∼ 0.34 K.mm/kV at very low applied electric field of 30 kV/cm are obtained for pristine BCST sample sintered at 1400 °C. Additionally, we observed Wrec ∼ 136.18 mJ/cm3 and giant energy conversion efficiency η ∼ 94.29 % under very low applied electric field of 30 kV/cm for the same BCST sample. Our results reveal that control of sintering temperature contributes to a favorable and stable microstructure, including R-O-T phase coexistence and substitutional heterogeneity-induced nano-polar regions (PNRs) which strengthens the Polarization and supports the thin hysteresis loop. Thus all these factors simultaneously contributing to make BCST ceramic as a potential material for applications in advanced electrocaloric cooling and energy storage capacitors.

Highly enhanced electrothermal properties of 001-textured Pb-free ferroelectric (Ba, Ca) (Ti, Zr, Sn)O3 for energy harvesting and solid-state cooling

Ferroelectric ceramics hold great promise for applications in solid-state cooling and energy harvesting from waste heat due to their electrothermal energy conversion capabilities. Here, we synthesized crystallographically textured (Ba0.95Ca0.05) (Ti0.87Zr0.12Sn0.01)O3 (BCZTSn) ceramics using tape casting and SrTiO3 (ST) single-crystal templates, which resulted in preferred grain orientation with a Lotgering factor as high as ∼90.8 %. The grain morphology, pyroelectric properties and the thermal-to-electrical energy conversion of BCZTSn-ST were characterized in detail. The textured BCZTSn-ST ceramics exhibit a remarkably high thermal-to-electrical energy conversion density of 0.787 J cm−3 in the temperature range of 303–373 K and large electrocaloric (EC) temperature change of ∼2.3 K at 373 K. This works demonstrates that preferred grain orientation is a promising way to improve EC and energy harvesting properties in the Pb-free BaTiO3-based ferroelectric ceramics.

In situ construction of ether-based composite electrolyte with stable electrode interphase for high-performance solid state lithium metal battery

Ether-based polymer electrolyte shows promising potential for application in solid-state lithium batteries owing to its cost-effectiveness, excellent flexibility, and above all, remarkable stability to lithium metal anode. However, it still suffers from challenges related to low ionic conductivity and inferior oxidation resistance. Herein, an ether-based gel composite electrolyte containing Li6.5La3Zr1.5Ta0.5O12 (LLZTO) ceramics (LL-GCE) is fabricated via an in-situ polymerization method which can guarantee good interface contact with electrodes. The ceramics not only activate the interaction between polymers and lithium salts, resulting in significantly enhanced ionic conductivity (7.9 × 10−4 S cm−1), but also collaborate with poly(1,3-dioxolane) (PDOL) to construct favorable anion-rich solvation configurations, which effectively restrict the anion migration with Li+ transference number significantly increased to 0.83. Furthermore, the regulated solvation structures can passivate the electrode surface with a high content of robust LiF components formed on the electrolyte/electrode interphase. Consequently, the composite electrolyte demonstrates excellent abilities to inhibit Li dendrite growth and match with high-voltage cathodes. For instance, the LiFePO4||Li cell using such electrolyte conveys a capacity of 135.4mAh/g and the capacity retention is 99.3 % after 250 cycles at 1C. The LiCoO2||Li full cell also shows excellent cycling performance. This work provides an effective strategy to modify ether-based polymer electrolytes and can boost their development in high-performance solid state lithium metal batteries.

Investigation of Piezoelectric Properties in Ca-Doped PbBa(Zr,Ti)O3 (PBZT) Ceramics.

The perovskite-structured materials Pb0.75Ba0.251-xCax(Zr0.7Ti0.3)O3 for x = 1 and 2 at.% were synthesized using the conventional mixed-oxide method and carbonates. Microstructural analysis, performed using a scanning electron microscope, revealed rounded grains with relatively inhomogeneous sizes and distinct grain boundaries. X-ray diffraction confirmed that the materials exhibit a rhombohedral structure with an R3c space group at room temperature. Piezoelectric resonance measurements were conducted to determine the piezoelectric and elastic properties of the samples. The results indicated that a small amount of calcium doping significantly enhanced the piezoelectric coefficient d31. The calcium-doped ceramics exhibited higher electrical permittivity across the entire temperature range compared to the pure material, as well as a significant value of remanent polarization. These findings indicate that the performance parameters of the base material have been significantly improved, making these ceramics promising candidates for various applications.

High piezoelectric coefficient and thermal stability of BKT-BFPT ceramics with ex situ high depoling temperature at 520 °C

The in situ and ex situ temperature dependence of dielectric and piezoelectric properties of 0.1(Bi0.5K0.5)TiO3-0.6BiFeO3-0.3PbTiO3 (BKT-BFPT) ceramics were characterized, and related mechanisms were studied. The tetragonal distortion, Curie temperature Tc, depoling temperature Td, and piezoelectric coefficient d33 of BKT-BFPT are 0.06, 545 °C, 520 °C, and 205 pC/N, respectively. The in situ piezoelectric coefficient variation of BKT-BFPT ceramics from room temperature to 280 °C is only 10%, being 1/5 and 1/10 those of 0.36BiScO3-0.34PbTiO3 and Pb(Zr0.52Ti0.48)O3 ceramics. The better dielectric and piezoelectric thermal stabilities are owing to the temperature insensitive domain texture of BFPT-BKT ceramics due to their large lattice distortion. Resistivity results reflected that the higher depoling temperature derived from the ex situ measurement than that from the in situ test results from the high-temperature conductivity.

Lithium doping's effects on the microstructural, dielectric, energy storage, optical and electrical properties of BaTi0.89Sn0.11O3 ceramics

The present study discusses the synthesis of lithium-doped barium stannate titanate BaTi0.89Sn0.11O3 (BTS11) using sol–gel synthesis route and explores the influence of the lithium content on their structural, morphological, ferroelectric, optical, and electrical properties. The phase of the sol–gel prepared samples with different atomic composition BaLixTi0.89Sn0.11O3(BLxTS11), with x = 0 %, 2 %, 4 %, 6 %, 8 and 10 %, was investigated using X-ray diffraction (XRD) revealing the formation of pure perovskite exhibiting lattice strain. Structural characterization was additionally conducted using Raman spectroscopy to detect structural and the chemical environment modifications caused Li incorporation. The doping induced variation also in the morphology and grain size of BLxTS11 pellets studied using SEM micrographs, which revealed evident grain size changes inversely proportional to the BLxTS11 lattice strain. The samples were then inspected for their ferroelectric properties. The maximum dielectric constant of all samples was observed at a temperature of around 45–50 °C. In addition, correlations between the chemical, structural, and morphological properties of the BLxTS11 ceramics and their energy storage capabilities were established. According to the P-E hysteresis behavior, BL6TS11 ceramic (x = 6 %) ferroelectric demonstrated the highest energy-storage capabilities, with a recoverable energy-storage density of 225 mJ/cm3 and an energy-storage efficiency of 60 %. The optical and electrical properties of the material were also investigated revealing a decrease in the band gap values and a significant increase of resistivity by Li doping.

Effects of B- and A/B-sites Codoping on lattice distortion and defect concentration for high electromechanical response of lead-free piezoelectrics

Effects of different thermal conditions on lead-free (Bi0.65Ba0.35)(Fe0.65Ti0.35)O3 ceramics were studied to reduce secondary phase formation, regulate bismuth vacancies and resulting oxygen vacancies, and Fe ions valence transition during the heat treatment process. The optimal thermal conditions led to a higher d33 = 200 pC/N and a d33* = 420 pm/V. A/B-sites ions replacement in BF35BT, BF35BT-Zr, and BF35BTSZ ceramics were prepared to reveal the effects of different Zr or Sr-Zr-contents. A maximum tetragonality (cT/aT) was estimated for the single doping (Zr) and co-doping (Sr and Zr) cases. For Zr = 0.02, the electric field-induced strain reached its maximum value of d33* = 562 pm/V. Similarly, a strain of d33* = 701 pm/V was observed for Sr-Zr = 0.02. Additionally, the d33* improved to 870 pm/V (90 °C) in Zr = 0.02 and 1130 pm/V (120 °C) in Sr-Zr=0.02. The presence of local structural heterogeneity causes the domain size to decrease as it moves from the micro to the nanoscale. The results demonstrate that improved performance can be associated with reduced concentration of oxygen vacancies, nanodomains by local structural heterogeneity, high lattice anisotropy, higher relative density, and appropriate grain size.

Investigation of Ga–Nb co-doped barium strontium titanate ceramics for DC-bias free dielectrics

The Ba0.8Sr0.2Ti1−2x Ga x Nb x O3 (0 ≤ x ≤ 0.10) ceramics were fabricated and the electrical properties were evaluated regarding DC-bias and temperature characteristics of the dielectric properties. The ceramics with x = 0.10 exhibited a stable dielectric constant with a change of–40% within 25 °C–150 °C. The dielectric loss of all the co-doped ceramics was below 2% within 25 °C–200 °C. The Ba0.8Sr0.2Ti1−2x Ga x Nb x O3 ceramics showed a higher dielectric constant with a lower DC-bias dependence as compared to previous study on co-doped BaTiO3 ceramics. The Ba0.8Sr0.2Ti0.20Ga0.10Nb0.10O3 ceramics exhibited the best results of DC-bias dependence ≈−24%, dielectric constant at 100 kV cm−1 ≈ 560, and the dielectric constant at 0 kV cm−1 ≈ 735. The better results for the Ga–Nb co-doped BST ceramics might be due to the higher contribution of the ionic polarization in the BST base matrix resulting in a shallower potential energy curve.

Effect of (Mg1/2W1/2)4+ substitution on the structure and electrical properties of Bi4Ti3O12-based high-temperature piezoceramics

Bi4Ti3-x(Mg1/2W1/2)xO12 (BTMW100x) ceramics were synthesized using a direct reaction method combined with a two-step sintering technique. The study systematically investigated the effects of B-site equivalent substitution of (Mg1/2W1/2)4+ on BTMW100x ceramics. The experimental results indicate that an appropriate amount of (Mg1/2W1/2)4+ doping effectively reduces grain thickness, enhances grain distribution uniformity, and decreases the concentration of oxygen vacancies. Consequently, these modifications lead to improved piezoelectric performance while maintaining a high Curie temperature. Notably, Bi4Ti2.95(Mg1/2W1/2)0.05O12 (BTMW5) ceramics exhibit excellent piezoelectric properties and thermal stability, with a piezoelectric coefficient of 23 pC/N and a Curie temperature of 683 °C. These findings suggest that BTMW5 ceramics are promising candidates for high-temperature piezoelectric applications.

Temperature stability and low dielectric loss of (1-x)Ba0.4Sr0.6TiO3-xBi(Mg2/3Nb1/3)O3 ceramics for X9R capacitor applications

Temperature stability and low dielectric loss of (1-x)Ba0.4Sr0.6TiO3-xBi(Mg2/3Nb1/3)O3 ceramics for X9R capacitor applications

Enhanced ultra-high efficiency in high-energy–density PbHfO3-based antiferroelectric ceramics through synergistic effect design

PbHfO3-based antiferroelectric materials with the giant power density and ultrafast charge–discharge performance have exhibited the potential application in advanced pulsed power microelectronic devices. Nevertheless, the huge challenge of the large driving field of the AFE-FE phase transition (EAFE-FE) accompanied by the poor breakdown electric strength (Eb) still exists up to now and further becomes a key bottleneck restricting the simultaneous realization of high energy storage density and efficiency. Hence, we report the synergistic effect to combine the tailor ABO3 perovskite structure for minimizing the electric hysteresis and increasing bandgap width to obtain the ultrahigh Eb. Rietveld refinements of the XRD patterns and Raman spectra experiments that demonstrate the average electronegativity and a redshift with the elevated Sr content attributable to enhancing bonding energy of cation-O bonds and antipolar ordering in crystalline structure, effectively resulting in stability of the PbHfO3-based antiferroelectric structure. Meanwhile, a ultrahigh Eb of 450 kV/cm is achieved owing to optimizing the average grain size and widening bandgap width. A remarkable energy storage density of 7.29 J/cm3 and record-high energy storage efficiency of 96.40 % are achieved via synergistic effect in (Pb0.93La0.02Sr0.04)(Hf0.475Sn0.475Ti0.05)O3 (PLS4HST) ceramics under respective maximum applied field. In addition, large power density of 173.40 MW/cm3 and excellent discharge energy density of 4.90 J/cm3 as well as fast discharge rate of 166.90 ns and superior frequency stability (1 ∼ 140 Hz), along with outstanding thermal stability (25 ∼ 150°C), have been simultaneously presented in PLS4HST ceramic. These results provide a good paradigm by synergistic effect designing for exploring high-performance dielectrics to meet the demanding requirements of advanced pulsed power electronic devices.

The synthesis and characterization of alkaline niobate-based ceramic composites containing L-lysine Hydrochloride

Some lead-free piezoelectric ceramics are known to have high dielectric and piezoelectric properties but are limited by their brittle nature. A few amino acids have recently been reported to exhibit rather low dielectric and piezoelectric properties but have the advantage of being biocompatible and flexible. It would therefore be interesting to form a composite that will combine the inherent advantage of high dielectric properties from the ceramics and flexibility from the biomolecule. In this research, the properties of lead-free (K0.45Na0.51Li0.04)(Nb0.85Ta0.1Sb0.05)O3 (KNNLST) ceramics and L-lysine hydrochloride (L-LHCl) have been combined to produce dielectric composites. The samples were produced by mixing the constituents from 0 wt.% to 100 wt.%, pelletising and heat-treating them. Bulk density, X-ray diffraction, scanning electron microscopy, and dielectric characterisation were techniques used to determine the density, phases, morphology, and dielectric properties of the produced composites. The results show an increasing bulk density value from 1.2 g/cm3 for L-LHCl to 4.67 g/cm3 for the KNNLST ceramics. The morphology of the composite shows very tiny grains when small amounts of the ceramics were introduced. The L-LHCl transforms from an amorphous phase to a crystalline phase having the orthorhombic-tetragonal structure with the introduction of the KNNLST ceramics. The dielectric constant values increased with increasing KNNLST ceramics content from 10 @1 kHz to 200 for the composite with 80 wt%. KNNLST content. The dielectric loss values decreased for L-LHCl from 0.9 @1 kHz to 0.2 @1kHz. The electrical conductivity values increased with increasing KNNLST ceramics content. The results show that the composites produced from these constituents may be suitable for dielectric applications.

Microwave Dielectric Properties of Ge-substituted Nd(Ti0.5Mo0.5)O4 Ceramics for Application in Slot Antenna Liquid Sensor

Microwave Dielectric Properties of Ge-substituted Nd(Ti0.5Mo0.5)O4 Ceramics for Application in Slot Antenna Liquid Sensor

Hybrid improper ferroelectricity in La2Sr (Sc1−xFex)2O7 ceramics with double-layered Ruddlesden–Popper structures

Numerous hybrid improper ferroelectrics have been discovered in bulk oxides with layered perovskite structures. In contrast, the competition between the interlayer rumpling and oxygen octahedral rotation suppresses the ferroelectricity in layered perovskite material with trivalent cation at the B-site. In the present work, single-phase dense La2Sr(Sc1−xFex)2O7 ceramics with double-layered Ruddlesden–Popper structures have been prepared, and room-temperature ferroelectricity is discovered in the ceramics with x ≤ 0.10. The ferroelectric polarization and coercive field decrease with increasing content of Fe3+ cations, consistent with the decline of oxygen octahedral rotation and tilting angles. Although the linear relationship between the Curie temperature and the tolerance factor for La2Sr(Sc1−xFex)2O7 ceramics is established, the line is far away from that for A2+3B4+2O7 ceramics due to the large interlayer rumpling in the present ceramics. Although no single-phase multiferroic has been discovered in this work, an effective way to introduce magnetism into hybrid improper ferroelectric is provided.

Realization of ultra-high temperature stability and excellent electrical properties in LTO-based ceramics via A/B-site co-doing

La2Ti2O7 (LTO) ceramics, ideal for ultra-high temperature applications with a Curie temperature near 1460 °C, were previously limited by a low piezoelectric coefficient (d33) of 1.5 pC/N. In this work, the incorporation of Bi3+ and V5+ dopants have been employed to augment the piezoelectric properties of LTO. An enhanced d33 ∼ 4.0 pC/N is achieved in La1.91Bi0.09Ti1.97V0.03O7 (LBTV9) ceramics, while maintaining an ultra-high Curie temperature of 1437 °C. This improvement is attributed to local heterogeneity in the lattice structure induced by the doping. LBTV9 ceramics also exhibit excellent high-temperature stability and insulation properties, maintaining a d33 at 4.0 pC/N after annealing at 1000 °C for 48 h and stabilizing at 4.2 pC/N across temperatures from 200 °C to 1600 °C, with a DC resistivity of 1.7 × 106 Ω·cm at 1000 °C. These enhancements make LBTV9 ceramics suitable for extreme condition applications, thus unlocking new possibilities for their use in ultra-high temperature piezoelectric devices.