Wang Fenglin,Mao Haijun,Chen Xingyu,Li Wei,Liu Zhuofeng,Zhang Weijun,Bai Shuxin
In this work, A -site Nd doped BaTiO 3 ceramics in the form of Ba 1− x Nd 2 x /3 TiO 3 with a wide substitution level range of x = 0–0.2 have been prepared via solid-state reaction method. Powder X-ray diffraction results reveal that Nd is completely incorporated into the BaTiO 3 lattice in all specimens. Further analyses based on Rietveld refinement suggest that tetragonal and pseudo-cubic phases coexist in Ba 1− x Nd 2 x /3 TiO 3 ceramics with x ≤ 0.06, and the amount of tetragonal phase is raised with the increase of x value. When x value is larger than 0.08, only pseudo-cubic is observed. The generated \(V^{\prime\prime}_{{{\text{Ba}}}}\) , \({\text{Nd}}_{{{\text{Ba}}}}^{\cdot }\) and \(V_{{\text{O}}}^{{\cdot \cdot }}\) defects, which are identified by X-ray photoelectron spectra, make the grain size displays a tendency of decrease first mainly due to the pining effect, and then increase ascribed to the accelerate of mass diffuse. By introducing such wide range of substitution level, Ba 1− x Nd 2 x /3 TiO 3 ceramics with colossal dielectric constant ( x = 0.08), temperature-stable dielectric properties ( x = 0.15), especially relaxor behavior ( x = 0.20) noticed for the first time, are, respectively, received, which is closely related to the variation of phases and defects induced by the addition of Nd. This study may provide a special idea to modify BaTiO 3 to satisfy diversified applications by single element with a wide doping range, and could lay the foundation of future works focusing on the various potential applications of Ba 1− x Nd 2 x /3 TiO 3 ceramics.
Dielectric capacitors have attracted growing attention because of their important applications in advanced high power and/or pulsed power electronic devices. Nevertheless, the synergistic enhancement of recoverable energy storage density (Wrec > 10 J/cm3) and efficiency (η > 80%) is still a great challenge for lead-free dielectric bulk ceramics. Herein, by introducing complex perovskite compound (Bi0.9Na0.1)(Fe0.8Ti0.2)O3 with a smaller tolerance factor into an NaNbO3 matrix (NN-BNFT), we have achieved and explored stable relaxor antiferroelectric ceramics with enhanced relaxor behavior. Of particular importance is the composition of 0.88NN-0.12BNFT, which exhibits a large electric breakdown strength Eb of 87.3 kV/mm, an ultrahigh Wrec of 12.7 J/cm3, and a high efficiency η of 82.5%, as well as excellent thermal reliability and an ultrafast discharge speed, resulting from the dense microstructure, the moderate dielectric constant, the reduced grain size, the dielectric loss, and the sample thickness. The outstanding energy storage properties of NN-BNFT display great promise in advanced dielectric capacitors for energy storage applications.
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