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Structural, piezoelectric and high-density energy storage properties of lead-free BNKT-BCZT solid solution
摘要： A solid solution of lead-free piezoelectric ceramic (1-x)Bi0.50(Na0.80K0.20)0.50TiO3-xBa0.90Ca0.10Ti0.90Zr0.10O3 (with x=0.00, 0.02, 0.04, 0.06, 0.08) was synthesized by conventional solid-state reaction route. The effect of addition of BCZT on BNKT was investigated on structural, microstructural, dielectric, ferroelectric, piezoelectric and high-density energy storage properties experimentally. Modified Curie Weiss law and Vogel-Fulcher law were employed to study the diffusivity and activation energy. The dielectric dispersion with frequency reveals the relaxor behavior for all compositions. The value of Tv (calculated from Vogel-Fulcher relation) decreases while the corresponding value of Ea increases with the BCZT composition. The unipolar curve shows the increased strain of 0.15% and corresponding ? (Smax/Emax =311 pm/V) for x = 0.02 composition among all studied compositions. Furthermore, compositions x = 0.02 and x = 0.04 shows the improved energy storage efficiency ～50% with respect to pure BNKT.
关键词： Relaxor,Ferroelectric,Vogel-Fulcher,Piezoelectric
更新于2025-09-04 15:30:14
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Structure evolution and ferroelectric properties in stoichiometric Bi0.5+xNa0.5?xTi1?0.5xO3
摘要： The influence of B-site deficiency on the stability of electrically induced long-range ferroelectric order of Bi0.5+xNa0.5-xTi1-0.5xO3 (BNT-xVTi) (''h'' denotes vacancies) ceramics is studied. The depolarization and ferroelectric to relaxor transition are identified as separate and discrete processes in BNT-based materials. For BNT-0.02VTi, the resonance and anti-resonance peaks on dielectric permittivity-frequency curves indicate dominating ferroelectric phase at room temperature. The depolarization temperature, determined by thermally stimulated depolarization current, is * 65 °C. However, the ferroelectric to relaxor transition temperature is absent, as no distinct frequency-independent anomalies for the dielectric permittivity exist. This depolarization process can be ascribed to nanoscale ferroelectric domain at room temperature for BNT-0.02VTi, which is induced by chemical disorder and strong random field as VTi generated. Hence, the results imply that the B-site deficiency in BNT is a very effective route to tailor the stability of electrically induced long-range ferroelectric order.
关键词： depolarization,B-site deficiency,Bi0.5Na0.5TiO3,ferroelectric properties,relaxor transition
更新于2025-09-04 15:30:14
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Crystal structure and electrical properties of textured Ba2Bi4Ti5O18 ceramics
摘要： Highly textured Ba2Bi4Ti5O18 ceramic was prepared by spark plasma sintering (SPS). X-ray di?raction of the ceramics revealed the coexistence of a major ferroelectric phase (Space group, SG: B2cb) and a minor paraelectric phase (SG: I4/mmm) at room temperature. A di?used phase transition was observed at around 240 °C. The evolution of the switching current peaks in the electric current vs. electric ?eld (I-E) loops with increasing temperature was interpreted by the structural changes and temperature dependent polarisation reversal processes. The slim polarisation vs. electric ?eld (P-E) loops, the extra switching current peaks in the I-E loops and the non-zero piezoelectric d33 coe?cient indicate that Ba2Bi4Ti5O18 is a relaxor ferroelectric material. The recoverable energy density (0.41 ± 0.01 J/cm3) of Ba2Bi4Ti5O18 ceramics in the perpendicular direction to the SPS pressing direction is close to that of Pb(Mg1/3Nb2/3)O3-based ceramics. The obtained results suggest Ba2Bi4Ti5O18 ceramics might be promising for energy storage applications.
关键词： Ba2Bi4Ti5O18,Texture,Relaxor ferroelectrics,Energy storage,Bismuth layer-structured ferroelectrics
更新于2025-09-04 15:30:14