Structural evolution and energy storage properties of Bi(Zn0.5Zr0.5)O3 modified BaTiO3-based relaxation ferroelectric ceramics

A series of (1−x)BaTiO3−xBi(Zn0.5Zr0.5)O3 (x = 0–0.15) ceramics were synthesized using the conventional solid-state method. An ultrahigh recoverable energy storage density of 3.58 J/cm3 and a high energy efficiency of 90% are obtained for 0.85BaTiO3–0.15Bi(Zn0.5Zr0.5)O3 lead-free bulk ceramics under an electric field of 430 kV/cm; the energy storage density is thus enhanced by a factor of a ∼ 895% compared with that of the pure BT ceramics. Furthermore, an excellent temperature stability is obtained, with changes in the energy storage density and efficiency <5% and <0.1%, respectively, over the temperature range of 30 °C – 120 °C. These ergodic relaxor ferroelectric characteristics are attributed to the reduced grain size, the transition from the tetragonal phase to the pseudo-cubic phase, and the transformation of the domain structure from macro domains to polar nanoregions. This work provides a lead-free material for realizing high-temperature capacitors for use in energy storage devices.