Novel perovskite-type of (1-x)BaTiO 3 -xBiYbO 3 solid solutions with x = 0.00 ~ 0.20 were synthesized by conventional solid-state reaction methods. A systematic structural change from the ferroelectric tetragonal to pseudo-cubic phase was observed at about x = 0.050 ~ 0.051 at room temperature. Dielectric measurements revealed a gradual change from normal ferroelectric behavior to highly diffusive and dispersive relaxor-like characteristics, where the phase transition temperature shifted to higher temperature with increasing frequency. With the increase of BiYbO 3 content, the nonlinearity of the (1-x)BaTiO 3 -xBiYbO 3 ceramic was weakened obviously. The bulk ceramics were characterized by high polarization maxima and low remnant polarization, exhibiting slim P-E hysteresis loops. The results demonstrated that the (1-x)BaTiO 3 -xBiYbO 3 ceramics were promising lead-free relaxor materials for energy storage application.Recently, lead-free relaxor ferroelectrics have received dramatic attention because of toxicity of lead. Researchers find that Bi 3+ ion is a promising alternative to Pb 2+ ion due to their similar lone pair electronic 6s 2 configuration. 17 The Bi 2 O 3 -doped BaTiO 3 materials are characterized to exhibit both ferroelectric and relaxor properties depending on the composition.

Dielectric capacitors with high energy density and low energy loss are of great importance in high power electric and electronic systems. Traditional BaTiO 3 (BT) or its solid solutions have been widely explored as high energy density materials owing to their notably high dielectric constants. However, these materials often suffer from significant drawbacks of strong dielectric nonlinearity, low breakdown strength and high hysteresis loss, limiting the energy storage density and energy utilization efficiency. In this study, by using core-satellite structured nanocubic SrTiO 3 (ST) decorated BT assemblies, a composite capacitor with enhanced breakdown strength and weaker dielectric nonlinearity was successfully fabricated in contrast with the pure ferroelectric BT ceramic, resulting in elevated energy storage density and high energy efficiency as extracted from the polarization-electric field loops. The mechanism behind the improved electric and dielectric performances was discovered to be the remarkable suppression of grain size owing to the existence of the ST nanocubes and also the ferroelectric relaxor behaviors arising from the local compositionally graded structure due to the controlled sintering and modulated diffusion of Sr. This work provided a new approach for fabrication of dielectric materials with promising high energy density and low loss.

The (1−x)BaTiO3–xBi(Zn2/3Nb1/3)O3 (x = 0.01–0.30) ceramics were synthesized by solid‐state reactions. The solubility limit was determined to be x = 0.20. A systematic structural transition from a tetragonal phase (x ≤ 0.034), to a mixture of tetragonal and rhombohedral phases (0.038 ≤ x ≤ 0.20), and finally to a pseudocubic phase (x ≥ 0.22) at room temperature was identified. Dielectric measurement revealed a ferroelectric (x ≤ 0.04) to relaxor (x ≥ 0.06) transition with permittivity peak broadening and flattening, which was further verified by Raman spectroscopy and differential scanning calorimetry (DSC). Activation energies obtained from the Vogel–Fulcher model displayed an increasing trend from ~0.03 eV for x ~ 0.05, to unusually high values (>0.20 eV) for the compositions with x ≥ 0.15. With the increase in Bi(Zn2/3Nb1/3)O3 content, the polarization hysteresis demonstrated a tendency from high nonlinearity to sublinearity coupled with the reduction in remnant polarization and coervice field. The deconvolution of the irreversible/reversible polarization contribution was enabled by first‐order reversal curve distributions, which indicates that the decreasing polarization nonlinearity with the increase in Bi(Zn2/3Nb1/3)O3 concentration could be related with the change from the ferroelectric domain and domain wall contributions to the weakly coupled relaxor behaviors.

Excellent piezoelectric properties of d 33 * = 768 pm/V and strain = 0.07% at 1 kV/mm, were obtained by lead-free in (Na 0.52 K 0.4425 Li 0.0375 )(Nb 0.86 Ta 0.06 Sb 0.08 )O 3 ceramics. They displayed good temperature stability up to 200°C. Significantly enhanced piezoelectricity originated from nanodomains of width 20-30 nm, and the result was confirmed by transmission electron microscopy. The above-mentioned nanodomains emerged because of low domain wall energy near polymorphic phase transition regions and insignificant differences in cell parameters between orthorhombic and tetragonal phases. The nanodomain configuration easily responded to an external electric field, leading to high electric field-induced strain.

0.9BaTiO3–0.1Bi0.5Na0.5TiO3‐based (0.9BT–0.1BNT) ceramics with Tc = 180°C were prepared using a novel chemical coating method. The relationships among compositions, microstructures, and properties were investigated. TEM morphologies displayed the Nb‐coated powders, which were confirmed by energy dispersive spectroscopy (EDS). Temperature‐dependence of permittivity for Nb‐modified 0.9BT–0.1BNT ceramics measured at different frequencies showed no relaxor characteristic at high temperature, but frequency dispersion at low temperature. The microstructures were characterized by two types of grains: Nb‐rich grains and Nb‐free grains, which were responsible for temperature‐stable dielectric properties. The sample with 5 mol% Nb addition satisfied the X9R specification. The permittivity was 1934 and the dissipation factor was 1.53% at room temperature.