High energy-storage performance in X9R-type Na0.5Bi0.5TiO3-based lead-free ceramics

KaTaO(3) (KT) modified Na0.5Bi0.5TiO3-BaTiO3 lead-free ceramics (1-x)(0.94Na(0.5)Bi(0.5)TiO(3)-0.06BaTiO(3))-xKTaO(3) (NBT-BT-xKT, x = 0.20, 0.25, 0.30, and 0.35) were fabricated via the solid-state reaction method. The effect of KT modification on the structural, dielectric, and energy-storage properties of the ceramics were systematically investigated. Our results show that the NBT-BT-xKT sample shows excellent thermal stability of dielectric constant (Delta epsilon ' /epsilon '(25 degrees C) <= +/- 15%) over the temperature range of -60-215 degrees C with very low loss (<= 0.02). Meanwhile, a large energy storage density (W-rec = 4.89 J/cm(3)), excellent efficiency (eta = 84%), and an ultrafast discharge rate of 29 ns were also achieved in the NBT-BT-0.3 KT ceramic. This work indicates that the NBT-BT-0.30 KT sample would be a promising material for pulsed electrical applications working in extreme environments.