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The ferroelectric, lead-free perovskite sodium bismuth titanate-barium titanate (BNT-BT) has excellent electrical performance and is now recognized as a possible alternative material for lead zirconate titanate (PZT). It can be doped with some active elements to form a solid solution with a morphotropic phase boundary (MPB), where the solid solution has high dielectric properties and high energy storage performance. In this paper, the research results of BNT-BLT, BNT-BLZT, BNT-BSLZT, BNT-BMNLT and BNT-BST-KNN ceramic materials are summarized, and the influence of their doping mode on the phase structure and electrical properties are analyzed. The study found a rhombohedral and tetragonal phase coexistence region, where the tolerance factor value of ceramics is between 0.7530 and 0.7803. Moreover, the energy storage density of antiferroelectric ceramics increases with the expansion of the MPB region and is affected by the dielectric constant. [ABSTRACT FROM AUTHOR]

[(Bi1/2Na1/2)0.92Ba0.05La0.02](Mg1/3Nb2/3)xTi(1-0.5x)O3(BNT-BLMNT, x = 0.01, 0.03,0.05,0.07) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state. The effects of B-doped Mg4Nb2O9 groups on phase structures, compositional distribution and electrical properties of BNT-BLMNT ceramics were systematically investigated to further understand the mechanism of phase transition.It was found that the grain size of ceramic materials tends to decrease and the distribution becomes more uniform, indicating that Mg4Nb2O9 is conducive to the synthesis of ceramic materials in this system and effectively improves the grain size and distribution of this material with the increase of B-doped Mg4Nb2O9 group content. According to SEM and XRD analysis, Mg4Nb2O9 was completely dissolved in the ceramic crystal, forming a solid solution, all of which were of a single perovskite crystal structure.With the increase of it's content, the remnant polarization (Pr) decreased significantly, from 38.9 µC/cm2(x = 0.01) to 10.4 µC/cm2(x = 0.05), and the difference between the maximum polarization(Pmax) and the remnant polarization(Pr) became larger and larger, indicating that the addition of Mg and Nb elements increased the transition trend of the anti-ferroelectric phase. [ABSTRACT FROM AUTHOR]

(1−x)Bi1/2Na1/2TiO3–xBa1/2Sr1/2TiO3–0.05KNaNbO3 (BNT–BST–KN, x = 0.01, 0.03, 0.05, 0.07) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state. The hysteresis loop of the ceramic at different temperature under 70 kV/cm electric field was analyzed. In this paper, the energy storage properties of BNT–BST–KNN ceramics are studied. It was found that the addition of Sr element helps to improve the electric field strength tolerance and the breakdown resistance performance the material, so as to improve its energy storage density. At room temperature, the P–E curves of the materials in the system basically show a double hysteresis loop, and with the increase of temperature, the characteristics of the double hysteresis curve are particularly obvious. The ceramics exist in the ferroelectric–antiferroelectric coexistence phase region near 303 K, namely the morphotropic phase boundary region. It shows that the ceramic has anti-ferroelectric characteristics at room temperature, and is a typical anti-ferroelectric material. [ABSTRACT FROM AUTHOR]

(1-x)Bi1/2Na1/2TiO3-xBa1/2Sr1/2TiO3-0.05KNaNbO3(BNT-BST-KNN, x = 0.01, 0.03,0.05,0.07) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state. The effects of co-doping of Sr element and KNN group on phase structures, compositional distribution and electrical properties of BNT-BST-KNN ceramics were systematically investigated to further understand the mechanism of phase transition. It was found that the grain size decreased obviously, indicating that the addition of Sr element inhibited the grain growth. According to SEM and XRD analysis, the components of the samples obtained were all perovskite phase structure, and the coke free green stone was equal to other heterophases, indicating that K1+, Na1+, Nb4+ and Sr2+ ions successfully diffused into the crystal lattice of BiNaTiO3-BaTiO3 and formed a uniform solid solution. It shows that the doping of Sr element and KNN effectively promotes the transformation of trigonal phase to tetragonal phase. From the analysis results, the doping of Sr element and KNN effectively reduces the dielectric loss of the materials, and the dielectric property stability is greatly improved. [ABSTRACT FROM AUTHOR]

[(Bi1/2Na1/2)0.94Ba0.06]0.97La0.02TiO3 (BNT-BLT) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state.By analyzing TGA and DSC curves, the material should be calcined at about 800 °C. The effects of different milling time on the microstructure of the materials were also studied. Microstructures analysis and the calculation from the X-ray diffraction results reveal that the milling time of BNT-BLT ceramic should be controlled within a reasonable range, around 15 h. [ABSTRACT FROM AUTHOR]

0.96Pb(Ni1/3Nb2/3)O3-0.04PbZrO3(PNN-PZ) ceramics prepared via columbite method exhibit high crystallinity and high density, typical relaxor behavior is demonstrated by the dielectric data. The high dielectric tunability (˜87%) and low dielectric loss (˜0.007) were obtained for PNN-PZ at room temperature around 30kV/cm and 1 kHz, at fields below 13kV/cm, a double-wells model work well between tunability and dc bias electric field, in contrast, at all fields, the thermodynamic model can do better in fitting the dielectric nonlinear tunability behavior of the PNN-PZ ceramics than the double-wells model. These properties indicate that PNN-PZ ceramics might be a promising candidate for tunable materials. [ABSTRACT FROM PUBLISHER]