Dielectric Temperature Stability Research Articles

Preparation and thermal/dielectric properties of medium/high entropy perovskite titanate ceramics

High-entropy ceramics have garnered significant attention in recent years owing to their exceptional properties and structural diversity. In this work, single-phase medium/high entropy ceramics, namely (Ca0.2Sr0.4Ba0.4)(Zr0.5Ti0.5)O3 and (Ca0.2Sr0.4Ba0.4)(Zr0.1Ti0.9)O3, were successfully designed and prepared utilizing Spark Plasma Sintering (SPS). A comprehensive investigation was conducted into the phase structure, microscopic morphology, dielectric properties, and thermal behavior of these ceramics. It was observed that all ceramics maintained a cubic perovskite structure (space group: Pm3‾m), and the introduction of multi-element doping rendered them more stable across a wide frequency and temperature range. Notably, (Ca0.2Sr0.4Ba0.4)(Zr0.5Ti0.5)O3 exhibited remarkably low dielectric loss (0.0001 at 1 kHz) at room temperature, along with excellent dielectric temperature stability (25–400 °C). By reducing the zirconium concentration in (Ca0.2Sr0.4Ba0.4)(Zr0.1Ti0.9)O3, a slight decrease in dielectric temperature stability was observed (25–350 °C); however, it demonstrated lower thermal conductivity (0.41 W/(m·K), 1200 °C) and maintained good high-temperature stability. The discovery highlights the promising practicality of both ceramics for high-temperature dielectric applications.

High‐entropy strategies boosting dielectric temperature stability in (Na0.4K0.1Bi0.5)TiO3 ceramics

AbstractUtilizing a high‐entropy strategy, we propose a novel approach for synthesizing (Na0.4K0.1Bi0.5)TiO3 (NKBT)‐based ceramics endowed with exceptional dielectric stability at elevated temperatures. The high‐entropy effect induces a random tilt in the oxygen octahedra of NKBT ceramics, leading to a broad dielectric response characterized by diffuse phase transitions. By weakening the dielectric abnormal peak at Ts of BNT, the dielectric stability of high‐entropy NKBT ceramics is significantly enhanced. Notably, at 100 kHz, the temperature stability range of (Na0.4K0.1Bi0.5)(Ti0.65Zr0.1Sn0.15Hf0.1)O3, synthesized through the traditional solid reaction method, reaches an impressive 311°C, surpassing undoped NKBT by 257%. This significant enhancement underscores the feasibility of our high‐entropy strategy in improving dielectric performance. Our work demonstrates a straightforward and cost‐effective method for significantly improving the dielectric temperature stability of NKBT ceramics.

Achieving improved dielectric energy storage properties and temperature stability in 0.91Na0.5Bi0.5TiO3-0.09K0.7La0.1NbO3 based ferroelectric ceramics by composition design and processing optimization

In this study, a ternary solid solution was designed by incorporating varying concentrations of the B-site composite perovskite Ba(Mg1/3Ta2/3)O3 (BMT) into 0.91Na0.5Bi0.5TiO3-0.09K0.7La0.1NbO3 (NBT-KLN-based) ferroelectric ceramics to optimize their energy storage performance. The introduction of BMT disrupted the long-range ordered state of the A/B site in the original perovskite structure, resulting in increased structural disorder and enhanced relaxor characteristics. The viscous polymer processing (VPP) method was employed to attain a significantly denser structure. The 0.10BMT-vpp ceramic has ultimately achieved optimal energy storage performance, along with exceptional temperature and frequency stability. It boasts a high dielectric breakdown strength (BDS) of 440 kV/cm, an ultra-high effective energy storage density (Wrec) of 6.7 J/cm3, and an energy storage efficiency (η) of 82%. Moreover, the 0.10BMT-vpp ceramic exhibits robust pulse performance, characterized by an ultra-fast discharge time (t0.9) of only 77 ns. Furthermore, within the temperature range of −66 °C–354 °C, the temperature coefficient of capacitance (TCC) of the 0.25BMT ceramics undergoes a variation of no more than ±15%, in compliance with X9R specifications (−55 °C–200 °C). The introduction of BMT endows NBT-KLN-based ceramics with remarkable temperature stability and comprehensive energy storage performance, making it a ceramic material with practical potential for industrial applications.

Giant dielectric properties and temperature stability of triple–doped AlxIn0.05−xTa0.05Ti0.9O2 ceramics

AlxIn0.05−xTa0.05Ti0.9O2 ceramics with x ranging from 0 to 0.05 were synthesized using a conventional solid–state reaction method. All samples achieved a pure rutile–TiO2 phase. Additionally, the lattice parameters of the samples increased with higher Al doping concentrations. The ceramics exhibited a dense microstructure and uniform dispersion of dopants. Raman spectroscopy revealed a decrease in oxygen vacancies in the structure with increasing Al3+ concentration. The presence of Ti3+ in the structure was confirmed by X–ray photoelectron spectroscopy. The dielectric properties of all samples were investigated as functions of frequency and temperature. The triple–doped AITTO ceramics demonstrated a high dielectric constant (ε′) of ∼2×104 and low dielectric loss (tanδ) ranging from 0.029 to 0.04, along with excellent temperature stability of ε′ at 1 kHz, showing a Δε′/ε′30 of less than ±15% over a temperature range of −60 to 210 °C. Notably, the tanδ of the triple–doped AITTO ceramics remained below 0.04 even at 200 °C. Impedance spectroscopy was utilized to analyze the electrical properties of the grains and grain boundaries. The observed dielectric properties are attributed to the formation of electron–pinned defect–dipoles, along with the impacts of both internal and surface barrier layer capacitors.

Flash sintering BaTiO3-0.01MgO-0.01Nb2O5-xBi2O3 ceramics with superior dielectric temperature stability via defect engineering

In this paper, Bi2O3 doped BaTiO3-0.01MgO-0.01Nb2O5 ceramics are designed to increase dielectric constant, reduce dielectric loss and improve temperature dielectric stability through inducing defects, and are prepared by flash sintering method to inhibit the volatilization of Bi element and ensure the element ratio. The microstructure, polarization mechanisms, dielectric properties and conduction mechanism of the ceramics are studied. The doping of Bi2O3 can enhance the relaxation behavior and dielectric properties. The defects evolution in BaTiO3-0.01MgO-0.01Nb2O-0.01Bi2O3 ceramics are studied. The results show that the BaTiO3 ceramics doped with different amounts of Bi2O3 can form defect dipoles {[BiBa∙‐MgTi″‐BiBa∙]×, [NbTi∙‐VBa″‐NbTi∙]×, [MgTi″‐VO∙∙]×} and oxygen vacancy, which enhance the short-range transition within the grain and inhibit the movement of free electrons at the grain boundary. The ceramics have excellent room temperature properties, high dielectric constant (εr = 2894) and low dielectric loss (tanδ < 0.03). The ceramics have superior temperature stability and satisfying the EIA X8R (Δεr/ε25 ≤ ±15 %, over the temperature range from −55 °C to 150 °C). It is found that flash sintering can effectively guarantee the stoichiometric concentration of bismuth element and obtain good properties of ceramics. This study demonstrates the potential of Bi2O3 doped BaTiO3-based ceramics synthetized by flash sintering as high-performance electronic device materials.

Excellent high-temperature dielectric stability of BNT-based ceramics modified by NaNbO3

In this work, (1-x)(K0.5La0.5)0.1Ba0.054(Bi0.5Na0.5)0.846Ti0.95(Cr0.5Ta0.5)0.05O3- xNaNbO3 (replaced by (1-x)KLBBNT-xNN) (x = 0.02, 0.04, 0.06, 0.08, 0.1) ceramics were fabricated by conventional solid-state reaction route. As the content of NaNbO3 increasing, an excellent dielectric temperature stability with a permittivity ∼2583 is obtained in the ceramic samples with x = 0.06. The temperature coefficient of capacitance (TCC) for x = 0.06 sample is less than ± 15% in the range of 58 °C to 338 °C. The XRD and temperature dependent permittivity results indicated that the large permittivity with excellent dielectric temperature stability maybe caused by NaNbO3 doping, which reduces the relaxation phase transition temperature of BNT-based ceramics and expands the temperature range of dielectric temperature stability. This work provides a new method to obtain BNT-based ceramic capacitors with large and stable dielectric constant in a wide temperature range.

Dielectric temperature stability and energy storage performance of BST-based lead-free ceramics for X8R capacitors

Dielectric temperature stability and energy storage performance of BST-based lead-free ceramics for X8R capacitors

High dielectric temperature stability in the relaxor ferroelectric thin films via using a multilayer heterostructure

The temperature stability of the relaxor ferroelectrics (RFEs) mainly originates from the diffuse phase transition (DPT). Higher atomic disorder degrees, more inhomogeneous lattice distortion and polymorphic phases could increase the compositional inhomogeneity for a stronger DPT. This work aims to enhance this compositional inhomogeneity for a high dielectric temperature stability by preparing the multicomponent RFE-based multilayer heterostructure polycrystalline thin films. The as-prepared RFE thin films show a relatively high dielectric constant (∼165.14), and a very high dielectric temperature stability with a very low relative variation ratio of dielectric constant (∼1.7 %) from -55 °C to 150 °C which can be comparable to most linear dielectric thin films. Meanwhile, the dielectric loss and leakage current densities were also optimized. This work brings the potential application of the RFE thin films in the thin-film capacitor with high temperature stability requirements.

Improved dielectric temperature stability and energy storage properties of BNT-BKT-based lead-free ceramics

The lead-free ceramics (1-x)(0.84Bi0.5Na0.5TiO3-0.16Bi0.5K0.5TiO3)-xBiMg2/3Nb1/3O3 (denoted as (1-x)BNKT-xBMN) and (1-y)(0.85BNKT-0.15BMN)-ySr0.7La0.2TiO3 with y = 0.3 (denoted as BNKMN-0.3SLT) were prepared by means of a conventional solid state sintering method. Effects of introduction of BiMg2/3Ni1/3O3 and Sr0.7La0.2TiO3 on phase structure, microstructure, and dielectric, ferroelectric and energy storage properties of the ceramics were studied in detail. The ceramics (1-x)BNKT-xBMN show pure perovskite structure, while BNKMN-0.3SLT appears a secondary phase. All ceramics exhibit dense microstructures with mean grain sizes between 0.56 μm and 1.36 μm. The introduction of SLT into BNKMN causes obvious decrease in dielectric constant around Curie temperature, inducing the widest temperature window of 263 °C from 29 °C to 292 °C for TCC≤±15 %. The ceramic BNKMN-0.3SLT shows high electric breakdown strength (Eb ∼ 300 kV/cm), large maximum polarization (Pm ∼ 36.48 μC/cm2), and low remanent polarization (Pr ∼ 1.70 μC/cm2), inducing high energy storage density of 4.03 J/cm3 as well as high energy storage efficiency of 85.2 %.

X9R-type SrTiO3 based ceramics with colossal dielectric permittivity and low loss derived from defect engineering and high-energy ball milling

The miniaturization of electronic components has become a megatrend in the future, making colossal dielectric permittivity materials receive unprecedented attention. In this work, we proposed a universal route to achieve colossal dielectric permittivity, low loss factor and excellent dielectric temperature stability in rare earth doped perovskite oxide SrTiO3. Sm doped SrTiO3 ceramics prepared by high-energy ball milling exhibit ultrahigh dielectric permittivity 441,543, low loss factor 0.02, good dielectric temperature stability (<15 %) in the temperature range of −55–200 °C, and very high resistance 109Ω, which meets the EIA X9R standard, XPS and impedance spectra indicate that the electron-pinned defect-dipoles effect is the origin of colossal dielectric permittivity and low loss factor. This work shows that Sm-doped SrTiO3 activated by high-energy ball milling has broad prospects in the applications of thermally-stable miniaturized capacitors.

Effect of the Firing Temperatures on the Phase Evolution and Electrical Properties of 0.85[0.94Bi0.5Na0.5TiO3-0.06BaTiO3]-0.15[Na0.73Bi0.09NbO3] Ceramics Synthesized via the Solid-State Combustion Method

In this research paper, we describe 0.85[0.94Bi0.5Na0.5TiO3-0.06BaTiO3]-0.15[Na0.73Bi0.09NbO3] (BNT-BT-NBN) ceramics fabricated by the solid-state combustion technique. The phase evolution, microstructure, dielectric, ferroelectric and energy storage properties were examined. The BNT-BT-NBN powders and ceramics were calcined and sintered between 650–900 °C and 1100–1175 °C, respectively, for 2 h. All samples showed a typical perovskite structure, as revealed by X-ray diffraction. The Rietveld refinement analysis of the ceramics suggested the samples sintered between 1100 and 1150 °C had coexisting R + T phases, while the R + T+C phases were observed in the ceramics sintered at 1175 °C. The average grain size of the samples increased from 0.52 to 1.39 μm with increased sintering temperature. The density of the ceramics increased from 5.12 to 5.45 g/cm3 when the sintering temperature increased from 1100 to 1150 °C, and then decreased. Increasing the sintering temperature from 1100 to 1150 °C caused the dielectric constant at T s (ε s) and the dielectric constant at T m (ε m) to increase from 1727 to 1945 and 1564 to 1750, respectively, and then ε s and ε m declined. All BNT-BT-NBN ceramics had good dielectric temperature stability with only a±10% change when the temperature ranged from room temperature to ∼300 °C. The optimum energy-storage properties (W rec = 0.62 J/cm3 and η = 83.2%) were obtained from the BNT-BT-NBN ceramics sintered at 1150 °C for 2 h. This data indicates that BNT-BT-NBN ceramics can be useful as lead-free materials for high density energy-storage capacitors.

Mg/Ti co‐substituted CaSmAlO4‐based microwave dielectric ceramics with temperature stability in a wide temperature range

AbstractTo obtain microwave dielectric ceramics with excellent dielectric properties and temperature stability over a wide temperature range, we co‐substituted CaSmAlO4 ceramics with Mg/Ti and prepared CaSmAl1−x(Mg0.5Ti0.5)xO4 (0.1 ≤ x ≤ 0.4) ceramics using traditional solid‐state methods. It was found that some Al3+ was replaced by composite ions (Mg0.5Ti0.5)3+, which optimized the dielectric properties of the ceramics. As the substitution amount increases, the dielectric constant of the sample increases synchronously, whereas the quality factor gradually decreases. The temperature coefficient of the resonant frequency first increases and then falls. Finally, the CaSmAl1−x(Mg0.5Ti0.5)xO4 (0.1 ≤ x ≤ 0.4) ceramics obtained excellent dielectric properties after sintering at 1450°C for 4 h at a substitution x of 0.2: εr = 19.9, Q × f = 64 920 GHz, τf = 3.17 ppm/°C (−40 to 25°C), and 0.17 ppm/°C (25–125°C).

Boosting ultra-wide temperature dielectric stability of multilayer ceramic capacitor through tailoring the combination types of polar nanoregions

With the rapid development of space exploration and new energy vehicles, it is urgent to build ultra-wide temperature multilayer ceramic capacitors (UWT MLCCs) to match electronic circuits that can withstand harsh environmental conditions. Relaxor ferroelectrics with diffuse phase transition feature are potential dielectrics for the construction of UWT MLCCs. However, how to ensure high dielectric constant together with low dielectric loss in the wide temperature region is still a big challenge. Here, the above difficulties are addressed by tailoring the combination types of polar nanoregions (PNRs) in the (1-x) (0.8Na0.5Bi0.5TiO3-0.2K0.5Bi0.5TiO3)-xNaTaO3 (NBT-KBT-xNT) system. Compared with PNRs types of P4bm + R3c and P4bm + Pbnm, the combination type of P4bm + Pbnm + R3c PNRs in NBT-KBT-0.31NT is the most beneficial to obtain comprehensive excellent dielectric performance because it can balance the relationship between high dielectric constant and temperature stability over a wide temperature region. Further, by optimizing the laminating pressure and co-firing temperature to realize a tight interfacial structure between the dielectric layer and the Pt inner electrode, a record-high dielectric constant (εr = (907% ± 15%)) together with low dielectric loss (tanδ ≤ 0.025) is achieved over an ultra-wide range from −61 °C to 306 °C for NBT-KBT-0.31NT MLCC, demonstrating that tailoring the combination types of PNRs is a powerful strategy in designing UWT MLCC dielectrics.

Interface Structure, Dielectric Behavior and Temperature Stability of Ba(Mg1/3Ta2/3)O3/PbZr0.52Ti0.48O3 Thin Films.

Multilayer films can achieve advanced properties and a wide range of applications. The heterogeneous interface plays an important role in the performances of multilayer films. In this paper, the effects of the interface of Ba(Mg1/3Ta2/3)O3/PbZr0.52Ti0.48O3 (BMT/PZT) thin films on dielectric behavior and temperature stability are investigated. The heterogeneous interface structures are characterized by Auger electron spectroscopy (AES). The PZT-BMT interface is different from the BMT-PZT interface in thickness. For the PZT-BMT interface, the PZT thin films are diffused to the whole BMT layers, and the interface thickness is about 90 nm, while the BMT-PZT interface's thickness is only about 8.6 nm. The presence of heterogeneous interfaces can improve the performances of BMT/PZT thin films and expand their applications. The dielectric constant of BBPP thin films is significantly lower than BPBP thin films, while the dielectric loss is exactly the opposite. The more interfaces there are, the greater the dielectric constant. The relationship between the electric-field-dependent dielectric constant curve and the P-E curve is established. The equivalent interface barrier of the diode is used to show that the dielectric peaks under the positive and negative voltage are different. Similarly, heterogeneous interfaces show a certain improvement in dielectric tunability and temperature stability.

KNN+Nb2O5 co-modified BNBST-based relaxor ferroelectric ceramics for X8R energy storage capacitors

Environmentally friendly ceramics with high dielectric temperature stability and excellent energy storage properties are desired for next generation low-voltage driven pulsed power supply systems. Herein, (Bi0.5Na0.5)0.65(Ba0.3Sr0.7)0.35(Ti0.98Ce0.02)O3+x wt% K0.5Na0.5NbO3 (KNN) + y wt% Nb2O5 (abbreviated as BNBSTC + KxNy) lead-free relaxor ferroelectric ceramics are prepared to investigate the effect of KNN + Nb2O5 co-modification on the structure and dielectric energy storage properties. In optimized BNBSTC + K8N8 ceramics, a medium high εr = 1310 with low tanδ = 5 × 10−3 (@25 °C & 1 kHz) meeting the EIA X8R standard can be achieved in addition to a recoverable energy storage density Wrec = 0.92 J/cm3 with high efficiency η = 93% only at a low electric field of 100 kV/cm. Moreover, the BNBSTC + K8N8 ceramics exhibits excellent energy storage stability under different frequency, fatigue cycle and temperature testing environments, showing an attractive prospect in low-voltage driven X8R dielectric energy storage capacitors.

Effective Dielectric Loss Reduction and Enhanced Dielectric Temperature Stability of (1−x)BaFe0.5Nb0.5O3-xBiCu0.75W0.25O3 Ceramics

Effective Dielectric Loss Reduction and Enhanced Dielectric Temperature Stability of (1−x)BaFe0.5Nb0.5O3-xBiCu0.75W0.25O3 Ceramics

Novel BCZT-based ceramics with ultrahigh energy storage efficiency and outstanding high temperature fatigue endurance and stability for practical application

Dielectric ceramic capacitors with superior energy storage efficiency and ability to operate in high temperature environments (T∼200 °C) are urgently needed for practical application. In this study, a relaxor component of Bi(Zn2/3Nb1/3)O3 (BZN) was massively doped into Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramic to improve energy storage properties and ability to operate in high temperature. The massive introduction of Bi(Zn2/3Nb1/3)O3 optimizes dielectric relaxor behavior, enhances bandgap width, refines grain size and improves electrical homogeneity, which can significantly increase breakdown strength (Eb), decrease remanent polarization (Pr) and broaden dielectric constant peak. Here, the 0.75BCZT-0.25BZN ceramic possesses an ultrahigh energy storage efficiency (∼96.8%) with a large recoverable energy density (∼2.39 J/cm3) under a medium applied field (260 kV/cm). In addition, the optimum sample exhibits prominent thermal stability within 20∼200°C and dielectric temperature stability (ΔC/C25°C ≤ ± 15%, −63∼234°C) in accordance with X9R. More critically, the same composition was firstly measured fatigue endurance at 200°C and possesses excellent fatigue stability. The above results demonstrate that the optimum sample has potential for practical application in high temperature environments.

Ultrahigh thermal stability of dielectric permittivity in 0.6Bi(Mg1/2Ti1/2)O3–0.4Ba0.8Ca0.2(Ti0.875Nb0.125)O3

0.6Bi(Mg1/2Ti1/2)O3–0.4Ba0.8Ca0.2(Nb0.125Ti0.875)O3 ceramics with a pseudo-cubic structure and re-entrant dipole glass behavior have been investigated via x-ray diffraction and dielectric permittivity–temperature spectra. It shows excellent dielectric–temperature stability with small variations of dielectric permittivity (±5%, 420–802 K) and dielectric loss tangent (tanδ &amp;lt; 2.5%, 441–647 K) in a wide temperature range. Three dielectric anomalies are observed from 290 to 1050 K. The low-temperature, weakly coupled re-entrant relaxor behavior was described using the Vogel–Fulcher law and the new glass model. The mid- and high-temperature dielectric anomalies are characterized by isothermal impedance and electrical modulus. The activation energy of both dielectric relaxation and conductivity follows the Arrhenius law in the temperature ranges of 633–753 and 833–973 K, respectively. The ultrahigh thermal stability of dielectric permittivity is attributed to the weak coupling of polar clusters, the formation of diffuse phase transition, and the local phase transition of calcium-containing perovskite. The results provide new insights into the defects behavior and the modification way of re-entrant relaxor behavior.

Structure and enhanced dielectric temperature stability of Ba[(Zr0.2Ti0.8)1−xCex]O3 ceramics prepared by liquid phase coating method

Structure and enhanced dielectric temperature stability of Ba[(Zr0.2Ti0.8)1−xCex]O3 ceramics prepared by liquid phase coating method

Single‐Crystalline BaZr0.2Ti0.8O3 Membranes Enabled High Energy Density in PEI‐Based Composites for High‐Temperature Electrostatic Capacitors (Adv. Mater. 22/2023)

Energy Storage In article number 2300962, Bin Peng, Houbing Huang, Ming Liu, and co-workers introduce a freestanding single-crystalline ferroelectric membrane to fabricate sandwich-structured inorganic/organic composites, which exhibit good dielectric-temperature stability and superior energy-storage performance. This effective strategy can underlie promoting the energy-storage performance of dielectric capacitors at high temperatures, thereby accelerating their application in advanced industrial fields.