(Na _0.5Bi _0.5) _0.7Sr _0.3TiO ₃ modified by Bi(Mg _2/3Nb _1/3)O ₃ ceramics with high energy-storage properties and an ultrafast discharge rate

Abstract

Novel (Na _0.5Bi _0.5) _0.7Sr _0.3TiO ₃-based lead-free ceramics with vastly improved energy-storage properties for high power system applications.

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 _0.3TiO ₃– xBi(Mg _2/3Nb _1/3)O ₃ systems based on refined grain size and the introduction of Bi ³⁺'s lone pair electron 6s ² 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.