High temperature stable dielectric properties and enhanced energy-storage performance of (1− x)(0.85Na0.5Bi0.5TiO3 − 0.15Ba0.8Ca0.2Ti0.8Zr0.2O3)− xK0.5Na0.5NbO3 lead-free ceramics

Abstract Novel high temperature ceramic capacitors (1−  x )(Na 0.5 Bi 0.5 TiO 3 − 0.15Ba 0.8 Ca 0.2 Ti 0.8 Zr 0.2 O 3 )−  x K 0.5 Na 0.5 NbO 3 were synthesized in the solid-state reaction route. The influence of K 0.5 Na 0.5 NbO 3 modification on dielectric behavior, energy-storage properties, ac impedance and temperature stable dielectric performance were systematically investigated. The reduced grain size and enhanced relaxor properties are obtained with the addition of KNN. The content of x  = 0.1 exhibits a stable permittivity (~ 1630) and dielectric loss ( W rec ) of 0.52 J/cm 3 and efficiency (η) of 80.3% at 110 kV/cm. The possible contributions of the grain and the grain boundary to the ceramic capacitance are discussed by the ac impedance spectroscopy.