(Na0.5Bi0.5)0.7Sr0.3TiO3 modified by Bi(Mg2/3Nb1/3)O3 ceramics with high energy-storage properties and an ultrafast discharge rate

Abstract

The design of ceramic dielectrics with high energy-storage properties and outstanding temperature stability is an important but challenging topic in advanced electronic and electrical power systems. Here, we utilized a strategy to achieve synergistic enhancement of energy density and energy efficiency in the (1 − x)(Na_0.5Bi_0.5)_0.7Sr_0.3TiO₃–xBi(Mg_2/3Nb_1/3)O₃ systems based on refined grain size and the introduction of Bi³⁺'s lone pair electron 6s² configuration, respectively. As a result, a giant discharge energy density of 3.45 J cm⁻³ and a high energy efficiency of 88.01% were simultaneously achieved in the 0.85NBST–0.15BMN ceramic, which precede those of recently reported lead-free dielectric ceramic materials. Meanwhile, excellent temperature (30–150 °C) and frequency (1–100 Hz) stability were also observed at 200 kV cm⁻¹. Moreover, an outstanding power density (P_D) of 38.47 MW cm⁻³ and an ultrafast discharge rate (t_0.9) of 52.8 ns were also achieved in the 0.85NBST–0.15BMN ceramic at 120 kV cm⁻¹. These results may provide a feasible approach to develop more NBST-based lead-free ceramics with vastly improved energy-storage properties.