Study on structure and electrical properties of BNBT-La2/3ZrO3 ceramic

Abstract

BNT-based energy storage dielectric material is a new type of multifunctional material with environmental friendliness, high energy storage density, and excellent temperature stability. It is a research hotspot where different components are introduced into BNT-based ceramics to obtain ceramic materials with high energy storage density. In this study, 0.94Bi_0.5Na_0.5TiO₃-0.06BaTiO₃ (BNBT) was selected as the substrate and doped with La_2/3ZrO₃ (LZ). Through the modification of La³⁺/Zr⁴⁺ at A/B sites, wider optical bandgap and finer grains with exceptionally large electrical breakdown strength and relatively strong relaxation behaviors in the appropriate range were obtained. Ultimately, an ultra-high energy storage density of 6.48 J/cm³ was attained at 480 kV/cm with a La_2/3ZrO₃ concentration of 0.07 mol%. In addition, the BNBT-LZ ceramics exhibited a good frequency-stabilized dynamic range (W_rec = 3.29 ± 6.7 % J/cm³, 10–200 Hz) and temperature stability (W_rec = 3.63 ± 9.9 % J/cm³, 20–160 °C), together with excellent charge-discharge performance(t_0.9 = 3.36 μs). All these characteristics demonstrate that the modification of BNT-based ceramics by La³⁺/Zr⁴⁺ has a significant effect on the energy storage density. The results show that the BNBT-LZ system can be used as a promising dielectric material for high energy storage density capacitors.