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NaNbO3‐based (NN) energy storage ceramics are known for exhibiting high maximum polarization (Pmax) and large recoverable energy density (Wrec). However, the huge energy loss density (Wloss) has been a limiting factor in improving energy storage performance. Therefore, a ternary system was designed to achieve both huge Wrec and efficiency (η). The combination of 0.35Bi(Zn0.5Ti0.5)O3–0.65BaTiO3 (BZTBT) was chosen to reduce grain size and disrupt the long‐range ordered domains, thereby inducing the polar‐nano‐regions to mitigate Wloss. The optimal performance was achieved with the 0.75NaNbO3–0.25(0.35Bi(Zn0.5Ti0.5)O3–0.65BaTiO3) (0.75NN–0.25BZTBT) ceramic, which exhibited a high Wrec = 2.68 J/cm3 and superior η = 82.7% under 310 kV/cm. Remarkably, the 0.75NN–0.25BZTBT ceramic displayed an exceptionally fast discharge time to 90%, t0.9 = 88 ns, coupled with a huge energy density Wd = 0.95 J/cm3. This study demonstrates the significant potential of 0.75NN–0.25BZTBT ceramic in the realm of energy storage and rapid charge–discharge applications. [ABSTRACT FROM AUTHOR]

In this study, the dielectric properties of SrTiO3 ceramics prepared by plasma‐activated sintering (PAS) were investigated. One of the striking findings is that the material exhibits giant room temperature permittivity (k∼3.5 × 104) and low dielectric loss (∼0.05) at 1 kHz, with the permittivity exceeding that of the conventionally prepared SrTiO3（ST） ceramics (k∼300) by two orders of magnitude. The enhancement of the polarizability was caused by the high concentration of defect dipoles. In this paper, two dielectric relaxation modes of the PAS ceramics below 0°C have been mainly discussed. One dielectric relaxation mode showed higher activation energy than that of the dielectric peak in the same temperature range for the conventional SrTiO3‐based ceramics. This mode was sensitive to humidity, and the strength of this mode was associated with the oxygen vacancies concentration in the ceramics. The other mode exhibited abnormal slowing down of relaxation rate with increasing temperature, which is contrary to the typical dielectric relaxation behavior, and the anomaly persisted over a narrow temperature range. Both modes were observed at the same interface between the grain and grain boundaries. [ABSTRACT FROM AUTHOR]

There is a great demand to develop ferroelectric ceramics with both high piezoelectric coefficient and broad temperature usage range for emerging electromechanical applications. Herein, a series of Sm3+‐doped 0.25Pb(Mg1/3Nb2/3)O3‐(0.75−x)PbZrO3‐xPbTiO3 ceramics were fabricated by solid‐state reaction method. The phase structure, dielectric and piezoelectric properties were investigated, where the optimum piezoelectric coefficient d33 = 745 pC/N and electromechanical coupling factor k33 = 0.79 were obtained at the morphotropic phase boundary composition x = 0.39, with good Curie temperature TC of 242°C. Of particular importance is that high‐temperature stability of the piezoelectric and field‐induced strain was obtained over the temperature range up to 230°C for the tetragonal compositions of x = 0.40. The underlying mechanism responsible for the high piezoelectricity and temperature stability is the synergistic contribution of the MPB and local structural heterogeneity, providing a good paradigm for the design of high‐performance piezoelectric materials to meet the challenge of piezoelectric applications at elevated temperature. [ABSTRACT FROM AUTHOR]

Defect chemistry of Sr site nonstoichiometry in SrxTi0.985(Nb2/3Zn1/3)0.015O3 ceramics and the resulting effects on the structure and dielectric behavior are systematically investigated by experiment and density functional theory (DFT) methods. The results indicate that, appropriate Sr deficiency benefits the dielectric properties and grain growth due to the creation of Sr vacancy. While Sr excess deteriorates the dielectric properties and inhibits the grain growth by forming a Ruddlesden‐Popper structure. In Sr‐deficient sample, more point defects arise and aggregate into defect clusters, resulting in great changes in local structures and the enhancement of dielectric properties. The Sr vacancy benefits the generation of oxygen vacancy, thus facilitating the localization of electrons and the decrease in dielectric loss. Besides, the electronic polarization and structural polarization are also improved by Sr vacancy and the resultant oxygen vacancy, leading to the further enhanced dielectric properties. These findings may facilitate the development of defect engineering towards novel multifunctional electronic materials. [ABSTRACT FROM AUTHOR]

Relaxor perovskite ferroelectric 0.1Bi(Zn1/2Zr1/2)O3‐0.9BaTiO3(0.1BZZ‐0.9BT) ceramics were successfully prepared, whose powders synthesized by the sol‐gel process, with average grain size about 1.29 μm. 1.75 J/cm3 discharge energy density and good dielectric stability were obtained over a wide temperature range from 25°C to 140°C. The pulse discharge capability of 0.1BZZ‐0.9BT ceramics was tested under different electric fields. The discharge time was 2.13 μs, which proved its ability to charge and discharge quickly. Complex impedance analysis and thermally stimulated depolarization current tests were applied to investigate the defect types and activation of 0.1BZZ‐0.9BT ceramics. The evolution process of composite defects and oxygen vacancies profoundly affects the dielectric temperature stability of 0.1BZZ‐0.9BT ceramics' energy storage property. [ABSTRACT FROM AUTHOR]

In this work, the influence of starting particle size and sintering conditions on the microstructures and dielectric properties of BaTiO3‐based ceramics coated with 0.3Bi(Zn1/2Ti1/2)O3‐0.7BaTiO3 were investigated to reveal the core‐shell structure by using high resolution transmission electron microscopy technique coupled with energy‐dispersive spectrometer analysis. The ion‐diffusion behavior plays a critical role in the formation and evolution of the core‐shell structure and, therefore, significantly influences the dielectric properties. When using starting powders containing BaTiO3 particles larger than 100 nm in size and sintering for shorter dwelling times (0.5‐2.0 hours), a core‐shell structure could be formed and retained owing to the limited diffusion behavior, enabling BaTiO3‐based ceramics to meet the X8R specification for multilayer ceramic capacitors applications at high temperatures. However, when using 80 nm BaTiO3 nanopowders and further extending the dwelling time to 6.0 hours, more driving energy was provided to prompt ion diffusion, which led to the compositional inhomogeneity becoming homogenized. [ABSTRACT FROM AUTHOR]

Rare earth (Eu3+)‐modified Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT) polycrystalline ferroelectric ceramics were fabricated by high‐temperature solid‐state sintering, the phase structure, dielectric and piezoelectric properties were investigated. Eu3+ addition was found to significantly improve dielectric and piezoelectric properties of PMN‐PT, where the optimized properties were achieved for the composition of 2.5 mol%Eu: 0.72PMN‐0.28PT, with the piezoelectric d33 = 1420 pC/N, dielectric εr = 12 200 and electromechanical k33 = 0.78, respectively. All these results indicate that the Eu3+‐doped PMN‐PT ceramics are promising candidates for high‐performance room‐temperature piezoelectric devices. [ABSTRACT FROM AUTHOR]

In this study, we reported a new BaTiO3-Na0.5Bi0.5TiO3-Nb2O5-Mn2O3/Fe2O3/Co3O4/In2O3 X8R system with high dielectric constant (>2100) at room temperature. The impacts of oxygen vacancy ( [ABSTRACT FROM AUTHOR]

Microstructural effects on the microwave dielectric properties of (Ba0.4Sr0.6)TiO3 ( BST) polycrystalline ceramics were investigated, focusing on the grain size. Sintering temperatures between 1350°C and 1500°C have a strong effect on the permittivity (880 < ε r < 990), quality factor (570 GHz < Q× f < 1150 GHz), and temperature coefficient of resonant frequency (3920 ppm/°C < τ f < 4560 ppm/°C) at microwave frequency (≈1.4 GHz). The tunable permittivity characteristics (measured at 10 kHz), were also found to be sensitive to the sintering process, demonstrating the possibility of tailoring material property by designed processing. In addition, the effect of the sintering process on grain structure was investigated by XRD calculation and Raman scattering characterization. Less confined phonons were believed to contribute to the enhanced microwave performance as an intrinsic effect (grain size effect), for samples with higher sintering temperature and longer dwell time. On the contrary, the macroscopic properties tend to saturate (or deteriorate), for samples at intensified sintering condition, being thought to be dominated by the extrinsic factors (such as the abundant defects in large grains), as confirmed by the SEM observations. [ABSTRACT FROM AUTHOR]

The microstructure, phase structure, ferroelectric, and dielectric properties of (1− x)Bi0.5Na0.5TiO3- xNaNbO3 [(1− x) BNT- xNN] ceramics conventionally sintered in the temperature range of 1080°C-1120°C were investigated as a candidate for capacitor dielectrics with wide temperature stability. Perovskite phase with no secondary impurity was observed by XRD measurement. With increasing NN content, (1− x) BNT- xNN was found to gradually transform from ferroelectric ( x = 0-0.05) to relaxor ( x = 0.10-0.20) and then to paraelectric state ( x = 0.25-0.35) at room temperature, indicated by P- I- E loops analysis, associated with greatly enhanced dielectric temperature stability. For the samples with x = 0.25-0.35, the temperature coefficient of capacitance ( TCC) was found <11% in an ultra-wide temperature range of −60°C-400°C with moderate dielectric constant and low dielectric loss, promising for temperature stable capacitor applications. [ABSTRACT FROM AUTHOR]

A novel BaTiO3-Na0.5Bi0.5TiO3-Nb2O5-NiO ( BT- NBT-Nb-Ni) system that meets the X8R specification (−55°C-150°C, Δ C/ C≤±15%) of multilayer ceramic capacitors ( MLCCs) was fabricated, with a maximum dielectric constant of 2350 at room temperature (25°C). Core-shell microstructure was observed by transmission electron microscopy ( TEM), accounting for the good dielectric temperature stability. The role of Ni on the formation of core-shell structure and phase structure, and the subsequent relationship between structure and dielectric/ionic conduction properties were investigated. It was observed that the addition of Ni could adjust the ratio of core/shell, and significantly reduces the dielectric loss over the studied temperature range. A new Ba11(Ni, Ti)28O66+ x phase with a 10-layer close-packed structure was identified by X-ray diffraction ( XRD), serving as a source of oxygen vacancies for ionic conduction in addition to Ba(Ni,Ti)O3. Furthermore, the impedance spectroscopy measurements demonstrated the remarkable impact of these Ni-induced oxygen vacancies on both the grain and grain-boundary conductivities. [ABSTRACT FROM AUTHOR]

The modified polymer-network gel route has been developed to prepare a multilayer core-shell structure of BaTiO3-based dielectric ceramics. The core of particle was BaTiO3, whereas 0.7BaTiO3-0.3Bi(Zn1/2Ti1/2)O3 (0.7BT-0.3BZT) and Nb oxides were coated as the multilayer shell compositions, which were confirmed by energy dispersive spectroscopy testing. The dielectric properties of BaTiO3-based samples with multilayer core-shell structure were found to meet the X9R specification. The dielectric constant was 1190 and the dielectric loss was 1.3% at room temperature. [ABSTRACT FROM AUTHOR]

SrTiZr x O3 ( x = 0, 0.002, 0.006, 0.01, and 0.014) ceramics with a weak temperature-dependent giant permittivity (>104) and a very low dielectric loss (<0.01) were fabricated using the conventional solid-state reaction method by sintering them in N2 at 1500°C. With increasing Zr content, the permittivity decreased from approximately 48 000 to 18 000 and the dielectric loss decreased from approximately 0.005 to 0.003. According to the XRD, XPS, and ac conductivity analysis, the dielectric properties of pure SrTiO3 ceramics sintered in N2 were due to the existence of the giant defect dipoles [ABSTRACT FROM AUTHOR]

(1− x) BaTiO3- x BiYO3 [(1− x) BT- x BY] polycrystalline ceramics were prepared by solid-state reaction method. The ceramics are in tetragonal phase when x ≤ 0.04, transform to pseudocubic at x ≥ 0.06, showing a classic ferroelectric to relaxor transition at x = 0.06, where the phase transition temperature was found to shift to higher temperature with increasing frequency. The dielectric permittivity peaks were analyzed by the modified Curie-Weiss law. Both parameters ΔTdiffuse and ΔTrelaxor were found to increase with increasing BY content, demonstrating a stronger relaxor characteristic. [ABSTRACT FROM AUTHOR]

(1− x)BaTiO3- xBi(Mg1/2Ti1/2)O3 [(1− x)BT- xBMT] polycrystalline ceramics were obtained via solid-state processing techniques. The solubility limit for (1− x)BT- xBMT was determined to be about x=0.07. A systematic structural change from the ferroelectric tetragonal phase to pseudocubic phase was observed at about x≥0.05 at room temperature. Dielectric measurements revealed a gradual change from normal ferroelectric of pure BaTiO3 to highly dispersive relaxor-like characteristics in the solid solution with 30-60 mol% Bi(Mg1/2Ti1/2)O3, showing low-temperature coefficients of capacitance over a wide temperature range. The properties of Nb2O5-doped 0.85BT-0.15BMT ceramics were investigated to better understand the formation mechanism of core-shell structure, for further improving the temperature stability of the dielectric behavior. [ABSTRACT FROM AUTHOR]

In this paper, the microwave-assisted molten salt method (MAMSS) and molten salt method (MSS) were used to synthesize SrBi4Ti4O15 (SBT). The phase constitution was determined by powder X-ray diffraction and the microstructure of powder was examined by scanning electron microscopy. In contrast to the conventional MSS method, MAMSS produces more distinct plate-like grains and synthesizes both SBT and Bi4Ti3O12 (BTO) at 600°C with a 30-min soaking time. The increase of temperature and soaking time can make the plate-like grains of BTO more distinct. [ABSTRACT FROM AUTHOR]