Enhanced energy storage performance of Na0.5Bi0.5TiO3 lead–free ceramics under low electric field

The rapid progress of science and technology miniaturizes and integrates pulse power capacitors. High electric fields constrain miniaturized size applications and electric device integration; hence, ceramics with substantial recovered energy density (Wrec) at comparatively low electric fields are sought for high energy storage capacitors. Herein, (1-x)Na0.5Bi0.5TiO3-x(Sr0.7Bi0.2)(Ti0.8Zr0.2)O3 ((1-x)NBT-xSBTZ) lead–free ceramics with good energy storage properties were fabricated by solid-state reaction. The phase structures, dielectric properties, relaxation behavior, breakdown behavior, and energy storage properties were systematically investigated by the experiments and simulation method. Phase structure of NBT-based shifts from rhombohedral to pseudo-cubic phase and the relaxor behavior increases with SBTZ content. In addition, the 0.70NBT-0.30SBTZ ceramic demonstrates commendable temperature (25–150 °C) and frequency (1–200 Hz) stability at 120 kV·cm–1. A substantial power density of 40.48 MW·cm–3 and a fast discharge speed of 90.4 ns were attained. This research broadens the potential uses for ceramic capacitors operating in low electric field.