Achieving improved dielectric energy storage properties and temperature stability in 0.91Na0.5Bi0.5TiO3-0.09K0.7La0.1NbO3 based ferroelectric ceramics by composition design and processing optimization

Abstract

In this study, a ternary solid solution was designed by incorporating varying concentrations of the B-site composite perovskite Ba(Mg1/3Ta2/3)O3 (BMT) into 0.91Na0.5Bi0.5TiO3-0.09K0.7La0.1NbO3 (NBT-KLN-based) ferroelectric ceramics to optimize their energy storage performance. The introduction of BMT disrupted the long-range ordered state of the A/B site in the original perovskite structure, resulting in increased structural disorder and enhanced relaxor characteristics. The viscous polymer processing (VPP) method was employed to attain a significantly denser structure. The 0.10BMT-vpp ceramic has ultimately achieved optimal energy storage performance, along with exceptional temperature and frequency stability. It boasts a high dielectric breakdown strength (BDS) of 440 kV/cm, an ultra-high effective energy storage density (Wrec) of 6.7 J/cm3, and an energy storage efficiency (η) of 82%. Moreover, the 0.10BMT-vpp ceramic exhibits robust pulse performance, characterized by an ultra-fast discharge time (t0.9) of only 77 ns. Furthermore, within the temperature range of −66 °C–354 °C, the temperature coefficient of capacitance (TCC) of the 0.25BMT ceramics undergoes a variation of no more than ±15%, in compliance with X9R specifications (−55 °C–200 °C). The introduction of BMT endows NBT-KLN-based ceramics with remarkable temperature stability and comprehensive energy storage performance, making it a ceramic material with practical potential for industrial applications.