Search

Recently, NaNbO3-based ceramics with excellent energy storage performances (ESPs) and fast charge-discharge characteristics have attracted great attention. In this case, BaTiO3 modified 0.85NaNbO3-0.15Bi(Zn2/3Nb1/3)O3 (0.85NN-0.15BZN-yBT) ceramics were designed and successfully fabricated using solid state synthesis. The discharge storage density of the ceramics increases from 1.22 J/cm3 at y = 0–1.84 J/cm3 at y = 8%, which is 1.5 times higher than pure 0.85NN-0.15BZN ceramics. This ceramic reveals excellent temperature stability up to 150 °C, good discharge cycling after 105 cycles and high discharge speed of 2.0 μs, broadening the scope of NaNbO3-based ceramics for energy storage applications.

The preparation of low-cost multilayer piezoelectric devices requires using cheap internal electrodes between the dielectric layers. A general strategy is to reduce the sintering temperature Ts of the ceramic layer by sintering aids which can form a liquid phase. Here, 0.2 wt% Li2CO3 was added as a sintering aid to tailor the sinterability and piezoelectricity of the commercial PZT ceramics. As verified from experiments, the piezoelectric ceramics could be densified at a sintering temperature above 940 °C, suitable for co-firing with the cheap internal electrode. The optimized sintering temperature of 980 °C can be confirmed for the 0.2 wt% Li2CO3-modified PZT ceramics due to its high piezoelectric coefficient d33 ~ 701 pC/N, planar coupling factor kp ~ 66.7%, and a low mechanical quality factor Qm ~ 71 with a transition temperature of Tc ~ 226 °C, presenting the characteristics of typical soft piezoelectric ceramics. Moreover, both the potential piezoelectric strain ~0.13% under 20 kV/cm and the good cycling fatigue characteristic (>104 cycles) of the studied piezo compositions indicates strong competitiveness in the field of multilayer piezoelectric devices.

Improving energy storage density and efficiency is the ultimate goal of dielectric materials used in ceramic capacitors. Among different dielectric materials, dielectrics in thin film state own superior energy performances due to less defects compared with ceramic. Herein, we report an optimized lead-free Zr-modified BiMg0.5Zr0.04Tix-0.04O3 composition with enhanced energy storage behavior via microstructural engineering. Rapid annealing can result in poorly crystallization in the film matrix confirmed by grazing incident X-ray diffraction GIXRD. The excess Ti source can effectively increase polarization and dielectric breakdown till to 97.0 μC/cm2 and 3403 kV/cm at x = 0.775, respectively. The optimized energy properties can be achieved at x = 0.775 with a high recoverable energy storage density Wreco of 87.8 J/cm3 and an efficiency η of 50%, indicative of excellent stability of storing electricity for the applications of pulse power electronics.

In this study, the intermediate rare-earth oxide Gd2O3 (Gd) was substituted in different amounts (x = 0.2–2 mol%) for the formulation of BaTi1-xGdxO3-x/2 (BTGx) dielectric materials. The effect of B-site substitution was confirmed by the additional Raman active A1g octahedral peak at ~835cm-1 strengthened at x ≥ 0.4 mol%. Additionally, properties of 0.9BTG0.007-0.1BA dielectric ceramics were analysed based on the influence of various processing methods as a function of sintering temperature. The focal samples were labelled Method-A (direct-mix) and Method-B (indirect-mix). As the sintering temperature (1075–1200 °C) increased, the 1 kHz response of the e–T curves of Method-A samples transformed from a single peak to broad-narrow double peaks of high dielectric loss tangent (tan δ). Nonetheless, samples of Method-B possessed a clearly defined transmission electron microscopy (TEM) core-shell structure, flattened double-peak e-T curves, optimised dielectric properties (e = ~1563–1851 and tan δ

In this work, Mn modified 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 thin films (abbreviation for BNT-BT-Mnx) are prepared on Pt/Ti/SiO2/Si substrate via sol-gel and spin-coating. The influences of Mn dopant on the microstructural characteristics, dielectric and energy storage performances are studied systematically. It is found that by incorporating the Mn into BNT-BT, the breakdown strength and maximum polarization are enhanced dramatically, leading to the giant energy storage density of 54 J/cm3, with high permittivity 355 at 1 kHz. Moreover, the dominant leakage conduction mechanisms of the thin films are studied by linear fitting method, revealing that the leakage current mechanism of BNT-BT-Mnx films transforms from space-charge-limited conduction (SCLC) to Schottky emission as the increasing of electric field. The excellent energy storage density as well as dielectric properties suggest that BNT-BT-Mn6 thin film might be an attractive lead-free material for energy storage devices.

A core-shell structural nanoparticles preparative technique was applied to produce BaTiO3@NiO ceramics with excellent energy storage performance. Shell layers of NiO were coated onto BaTiO3 nanoparticles by sol-precipitation method. The structures, dielectric and energy storage properties of the BaTiO3@NiO ceramics were systematically investigated. Results show that, high-densification microstructures with fine-crystalline and uniform distribution are observed in all the ceramics, and excellent energy storage density of 2.72 J cm−3 with low remnant polarization is achieved at 230 kV cm-1 in BaTiO3@1 %NiO ceramics, which also possesses fast discharge features (τ0.9

Energy storage dielectric ceramics play a more and more important role in power or electronics systems as a pulse power material, and the development of new technologies has put forward higher requirements for energy storage properties. Here, the sol-gel method was used to synthetize the 0.9BaTiO3-0.1Bi(Mg1/2Zr1/2)O3 (0.9BT–0.1BMZ) precursor powder and 0.9BT-0.1BMZ ceramics with pseudocubic phase was obtained. The 0.9BT-0.1BMZ dielectric ceramics possessed a strong relaxation behavior with 1.64 relaxation degree (g) and 0.15 eV relaxation activation energy (Ea) fitted by modified Curie–Weiss law and Vogel-Fulcher formulas, respectively. The most important was that by controlling the grain size to be reduced, the discharge energy storage density had been improved to 2.0 J/cm3 with high breakdown strength (325 kV/cm). In addition, the comprehensive analysis of electric field distributions, breakdown paths, and impedance spectra was illustrated the enhanced grain boundary effect can improve the energy storage performance obviously.

Capacitor is an important part of many electronic devices, so the temperature stability as one key parameter of capacitor needs to be improved constantly for meeting the requirements of various application temperature. Here, combined with the X-ray diffraction (XRD), selected area electron diffraction (SAED) and Vienna Ab-initio Simulation Package (VASP) calculation, it was confirmed that Ca ion can substitute the Ti site in the BaTi1-xCaxO3-x [BTC100×] (0 ≤ x ≤ 0.05) ceramics synthesized by solid-phase method which greatly improved the low-temperature stability of dielectric constant. Moreover, introducing Bi3+ and Zn2+ into BTC4 to form (1-y)BaTi0·96Ca0·04O2.96-yBi(Zn0·5Ti0.5)O3 [(1-y)BTC4-yBZT] (0.1 ≤ y ≤ 0.2) ceramics can further improve the dielectric-temperature stability by means of diffused phase transition and core-shell structure. Most importantly, the 0.85BTC4-0.15BZT ceramics with a pseudocubic perovskite structure possessed a temperature coefficient of capacitance at 25 °C ( T C C 25 °C ) being less than ±15% over a wide temperature range of −55 °C–200 °C and a temperate dielectric constant (e = 1060) and low dielectric loss (tanδ = 1.5%), which measure up to the higher standard in the current capacitor industry such as X9R requirements.

[(0.12BiAlO3-0.88BaTiO3)+0.5 wt%Nb2O5]+x wt.% B–Al–Si glass ceramics (x = 0, 1, 2, and 4) were prepared by solid-state method. The effects of B–Al–Si glass additive on microstructural and electrical properties were investigated. After the adding of B–Al–Si glass, quartz appeared as a new impurity phase and the average grain size of the samples decreased (from 540 nm to 330 nm). All the samples satisfy the EIA X8R specification, meanwhile, the breakdown strength (BDS) increased (from 17 kV/mm to 29 kV/mm) with the rising glass content. The ratios of relaxation time of grain boundary to grain (τgb/τg) of the ceramics at 460 °C were calculated according to the complex impedance data. It is found that decreased value of τgb/τg suggests a weakened interfacial polarization effect after B–Al–Si glass addition, which is beneficial to the BDS performance of ceramics.

The solid-state sintering route was employed for the production of (1-x)Bi2(Li0.5Ta1.5)O7-xTiO2 (x = 0, 0.02, 0.04, 0.06, 0.08) ceramics. The phase, microstructure and microwave dielectric properties of each ceramic composition were determined via X-ray diffraction, scanning electron microscopy and Haki Colmon resonator technique, respectively. The dielectric constant, tan δ and AC conductivity were also determined for the composition of x = 0.04. The TiO2 addition developed new phases of Bi3Ti4O12 and Bi3TaTiO9 for x = 0.04 along with Bi2(Li0.5Ta1.5)O7 phase which disappeared for x = 0.08. The τf of Bi2(Li0.5Ta1.5)O7 was tuned through zero by TiO2 addition and good microwave dielectric properties er~67.2, Qufo13,767 GHz and τf ~ −1.45 ppm/°C can be obtained for the composition of x = 0.04 sintered at 1050 °C for 2 h. This ceramic composition is a suitable candidate for 5G cellular base station resonator application.

The epoxy resin (E-51) was used as polymer matrix, conductive carbon black (CB) as conductive filler, and PZT was used to prepare a composite by curing. The effects of PZT and CB content on the properties of PZT/ CB/ EP piezoelectric composite were studied. When the PZT content reaches 40 wt%, the optimized vibration attenuation properties of PZT/CB/EP materials could be achieved with a loss factor of 0.9 from room temperature to 60 °C. With the increase of PZT content, the bending strength of PZT/CB/EP piezoelectric composite vibration reduction material firstly increased from 45 MPa to 65 MPa and then decreased to 38 MPa. At room temperature, the dielectric constant increased from 7 to 50, and the dielectric loss increased from 0.1 to 0.5.

0.5wt%MnO2-doped (1 − x)BaTiO3–xBiCoO3 ceramics short as (1 − x)BT–xBC–M sintered in air and reducing atmosphere via solid-state process were investigated. The X-ray diffraction results showed that solid solubility in (1 − x)BT–xBC ceramics sintered in the air was higher than that in reducing atmosphere. (1 − x)BT–xBC–M ceramics sintered in air transformed from tetragonal to pseudo-cubic phase when x ≥ 0.1. The scanning electron microscopy results indicated that the average grain size increased with the BC component increasing; however, opposite phenomena occurred in samples sintered in the reducing atmosphere. The dielectric temperature curves of samples sintered in reducing atmosphere were flatted with excellent insulation resistivity of an order of magnitude of 1013 Ω·cm, while anomalous dielectric constant and dielectric loss of samples sintered in the air with deteriorated insulation resistivity of an order of magnitude of 107 Ω·cm. The anti-reduction mechanism of (1 − x)BT–xBC–M system was explained by the “electron–hole” trapping effect and formation of defect dipoles $$\left[ {{\text{Mn}}_{{{\text{Ti}}}} ^{{\prime \prime }} - V_{{\text{O}}}^{{ \cdot \cdot }} } \right]$$ and $$\left[ {2{\text{Co}}_{{{\text{Ti}}}} ^{\prime } - V_{{\text{O}}}^{{ \cdot \cdot }} } \right]$$ .

Effects of different sintering atmospheres (O2 and air) on the energy storage properties and dielectric characteristics were systematically investigated for 2MgO–2Al2O3–5SiO2 (MAS)-coated Er0.02Sr0.97TiO3 (EST) ceramics. The core–shell structure was formed by the sol-precipitation method. The ceramic sintered in O2 features fine grain, excellent frequency stability, low leakage current, high dielectric breakdown strength (BDS), and high energy storage density (Wreco). Compared with air-sintered ceramics, the dielectric DC breakdown strength of ceramic sintered in oxygen atmosphere has been enhanced significantly from 375 to 590 kV/cm. Besides, the maximum Wreco of 2.01 J/cm3 and efficiency of 86.2% were obtained at 460 kV/cm, which demonstrated that the core–shell structure and atmosphere sintering provide an instructive strategy for the design of high energy storage materials.

Discovering new materials with high breakdown strength is of great significance for scientific research and industrial applications. Here, we combine experiments and density functional theory (DFT) calculations to report a systematic study of two titanosilicates - A2TiSi2O8 (A = Br, Sr) as a family of functional materials with wide band gaps, ultrahigh breakdown strength, and high thermal stability. The A2TiSi2O8 materials possess ultrahigh electric breakdown (Eb >200 kVmm−1, at 200 ℃), and good temperature stability (the variation of capacitance 3 %, from −100 to 200 ℃). DFT results show that electrons are likely localized in the Si O and Ti O polyhedrons. The electron difference density map and density of states (DOS) results elucidate the wide band gaps in titanosilicate family due to the strong Si O and Ti O bonds, indicating that the semiconductive behaviors are similar. The temperature-dependent structural evolution (from −100 to 500 ℃) is investigated via in-situ Raman spectroscopy.

A comparison between poly(vinyl alcohol) (PVA)-formed (TYPE-I), Ba(OH)2/TiO2 [Ba/Ti] suspension-formed (TYPE-II), and cold isostatic pressed (CIP) pellets (TYPE-II+CIP) of 0.9BaTi1–xCaxO3-x–0.1BiAl...

Nb-containing antiferroelectric materials have recently attracted great research interest as energy storage materials for pulsed power capacitors due to their extraordinary energy storage performances. In this case, the optimization of the energy storage performance is obtained by a compositional modulation of NaNbO3-Bi(Zn2/3Nb1/3)O3 bulk ceramics. An optimal energy performance can be obtained with a composition of 0.85NaNbO3-0.15Bi(Zn2/3Nb1/3)O3, which is accompanied by a stable charge energy density in temperatures up to 150 °C owing to its relaxor characteristics and excellent cycling stability after 105 cycles. This work further broadens the scope of NaNbO3-based ceramic applications in the area of pulsed power sources.

BaTiO3@xMgO (BT@xMg, x = 0–7 mol%) ceramics were prepared by MgO-coated BT powders, which were synthesized by a chemical precipitation method. The effects of MgO coating on the phase structure, microstructure and dielectric properties of BT@xMg ceramics were explored. The solid solubility of Mg2+ at B-site in BT was about 0.8 mol%, which was confirmed by the c/a ratio variation. When x

Due to advances in electronic device integration, miniaturization, and performance requirements, dielectric materials with a high energy storage density are required. Here, new BiMg0.5Ti0.5O3 lead-free energy storage thin films with excess Mg (i.e., nominal BiMgyTi0.5O3, with y = 0.50-0.62) were deposited on Pt/Ti/SiO2/Si substrates by sol-gel and spin-coating methods. The introduction of excess Mg can obviously increase the dielectric breakdown strength of thin films due to the appearance of an amorphous phase. The maximum recoverable energy storage density increased from 26 J/cm3 at y = 0.50 to 44.1 J/cm3 at y = 0.56. Furthermore, the dielectric films exhibited excellent thermal stability of the energy storage density from 30 °C to 100 °C, indicating that bismuth-magnesium-titanium films are promising candidates for next-generation lead-free energy storage capacitor applications.

For dielectric energy storage materials, high polarization and high breakdown strengths are a long-standing challenge. A modulating crystalline/amorphous phase structure strategy is proposed by Mn-doping and annealing temperature to enhance the energy storage performance of pure BaTiO3 (BT) films. In this study, lead-free Mn-doped BT films were prepared on Pt/Ti/SiO2/Si substrates via the sol-gel method, and the effects of the crystalline/amorphous phase ratio on polarization and electric properties were analyzed. A small amount of Mn-doping in BT could reduce the annealing temperature and enhance polarization with an Mn content of 8%. In addition, the energy storage properties of BT-8%Mn films achieve the best energy storage performance in terms of energy density and efficiency of 72.4 J/cm3 and 88.5% by changing the annealing temperature to 640 °C. BT-8%Mn energy storage films also possess good stability over a wide temperature range of 20 °C–200 °C, which demonstrates that crystalline/amorphous engineering is a simple and effective way to enhance energy storage applications of dielectric films.

Relaxor-type ferroelectrics show important potential in energy storage fields due to their significantly enhanced energy performance and good temperature stability compared to normal ferroelectrics. Here, a novel, high-performance ternary composition, (0.4−x)BiFeO3-xBi(Mg1/2Ti1/2)O3–0.6BaTiO3 (x = 0.2, 0.25, 0.3, 0.35, 0.4), was designed by compositional modulation, which displays typical relaxor characteristics. The optimum energy storage properties can be attained at x = 0.35, accompanied by energy efficiency of 84.87%, a promising energy storage density of 2.3 J/cm3 and good temperature stability of less than 10% over 20–160 °C. Moreover, the samples provide stable cycling fatigue after 105 cycles and a fast discharge time of t0.9 < 0.1 μs, indicative of promising applications in energy units.

This letter replies to the comments by Tkach et al. on our previous publication about the issues of ZnO volatilization, Ti3+ content and lattice constant etc. In this reply, we present a detailed discussion and rebuttal on the issues concerned in the comments.

Relaxor-ferroelectric ceramics capacitors have been in the front lines of investigations aimed at optimizing energy density due to their high Pmax, suppressed Pr, and high BDS levels, attributed to their highly dynamic polar nano-regions. A set of (1 − x)SrTiO3–x[0.88BaTiO3–0.12Bi(Li0.5Ta0.5)O3] ceramics (x = 0, 20, 40, 60 and 80 mol%), abbreviated as (1 − x)ST–x(BT–BLT), was designed and fabricated via a solid-state reaction route. A striking energy-storage density of 2.24 J cm−3, coupled with a high efficiency of η = 81% at 300 kV cm−1, was measured for these (1 − x)ST–x(BT–BLT) ceramics. The incorporation of BT–BLT ceramics was found to dramatically transform the paraelectric state of strontium titanate into the relaxor-ferroelectric state, by introducing broad relaxor behavior. The energy storage properties of the ceramic with x = 60 mol% showed outstanding stability in frequency (10–100 Hz) and temperature (20–120 °C), with minimal variation of (±≤0.5%), over the course of 105 cycles. Moreover, under various electric fields, rapid charge and discharge (≤1.5 μs) was also observed for this x = 60 mol% ceramic. Most significantly, the outcomes of this study are expected to provide a standard for other emerging lead-free dielectric ceramics displaying very good energy-storage properties and excellent electric field endurance, which are of pragmatic importance for cutting-edge pulsed power technology.

Defect engineering is applied to induce controllable changes in structures and dielectric behaviors in oxides. SrTiO3 ceramics modified by complex ions (Nb, Zn)x+ (x = 2, 3, 4 and 5) with variable valence states are prepared by standard solid state method. Phase structures, microstructures, defect structures and dielectric properties of the (Nb, Zn) co-doped SrTiO3 ceramics have been systematically investigated. In acceptor co-doping, M2 ceramics (x = 2) exhibits extremely low dielectric loss (≤0.001). M3 ceramics (x = 3) shows low conductivity and excellent thermal stability. In equivalent co-doping, M4 ceramics (x = 4) possesses giant permittivity and low dielectric loss. In donor co-doping, M5 ceramics (x = 5) presents improved permittivity while deteriorated dielectric loss. Further investigations reveal that oxygen vacancy is beneficial to the localization of charge carriers and then the low tangent loss, while excess electrons not only contribute to the improved permittivity but also result in high dielectric loss. Appropriate concentrations of oxygen vacancy and electron are significantly important for the formation of multiple defect dipoles or defect clusters, and therefore the greatly modified dielectric properties. The findings may facilitate the ability to engineer the advanced electronic materials.

Dielectric capacitors with high energy storage properties are key enablers for potential applications. We report SrTi0.985(Zn1/3Nb2/3)0.015O3–x wt%ZnNb2O6 ceramics with high breakdown strength and energy storage performance by synergy manipulation. The structures, energy storage and dielectric properties of the ceramics are systematically investigated. Introduction of ZnNb2O6 mediates the contradiction between permittivity and breakdown strength. As a result, a high breakdown strength of 422 kV cm−1 and an excellent energy storage density of 2.35 J cm−3 are achieved in x = 4.5 ceramics, which also exhibit fast discharge features (τ0.9 < 1.5 μs), good thermal stability (25–150 °C) and outstanding cyclic characteristics (up to 5 × 105 times). Further results indicate that ZnNb2O6 additives partly dissolve into perovskite lattices to promote the formation of superlattice structures, improving the local polarization, and partly disperse around grain boundary regions to inhibit grain growth and relieve the direct damage from a strong electric field to grains, increasing the breakdown strength. This strategy should be generalizable for designing high performance dielectrics and other novel composite materials that benefit from synergistic effect manipulation.