Dielectric behavior and impedance spectroscopy in lead-free BNT-BT-NBN perovskite ceramics for energy storage

The dielectric behavior, impedance spectroscopy and energy-storage properties of 0.85[(1-x)Bi0.5Na0.5TiO3-xBaTiO(3)]-0.15Na(0.73)Bi(0.09)NbO(3) [(BNT-xBT)-NBN] ternary ceramics were investigated. Temperature dependent permittivity curves displayed two depressed anomalies, resulting in significantly improved dielectric temperature stability. (BNT-9BT)-NBN showed a permittivity of 1680 at 150 degrees C with Delta epsilon/epsilon(150 degrees C) varying no more than +/- 10% up to 340 degrees C. From the complex impedance analysis, grain and grain boundary shared the same time constant. The high temperature resistivity followed the Arrhenius law with E-a = 1.7-2.0 eV, suggesting intrinsic band-type electronic conduction. The maximum energy storage density of all the samples reached 1.1-1.4 J/cm(3), accompanied with good temperature stability in the range of 25-140 degrees C. These results indicate that (BNT-xBT)-NBN system should be a promising lead-free material for energy-storage capacitor applications. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.