Improved energy storage density and efficiency in BaTiO3-BiFeO3- based relaxor-ferroelectric ceramics

Abstract

It remains a huge challenge to enhance the energy-storage density (ESD) and efficiency (ESE) of Pb-free dielectrics for ES applications. However, most of the developed lead-free dielectrics do not have these properties due to some factors. In this study, 0.33BaTiO3-(0.67-x)BiFeO3-xBi(Mg2/3Ta1/3)O3 bulk relaxor-ferroelectric ceramic materials were established using a conventional solid-state technique, where a typical B-site composite perovskite-structured Bi(Mg2/3Ta1/3)O3 was used as an additive. The breakdown strength, relaxation behavior and ES performance of BaTiO3-BiFeO3 ceramics were improved after adding Bi(Mg2/3Ta1/3)O3 because of the generation of polar nanoregions (PNRs). The composite ceramics, with x = 0.10, demonstrated an excellent ESE (η) of 80.2 % and a high recoverable ESD (Wrec) of 3.0 J/cm3 at 240 kV/cm. In addition, the composite ceramics had high stability and good thermal stability in the frequency and temperature ranges of 0.5–100 Hz and 25–130 °C. These properties suggest that novel Bi(Mg2/3Ta1/3)O3-doped 0.33BaTiO3-0.67BiFeO3 ceramic is attractive for ES applications.