B-site doping of ZrO2 to improve the dielectric and energy storge performances of a BNBS-(Ti1−x,Zrx) ceramic.

A group of (0.65Bi_0.5Na_0.5–0.35Bi_0.2Sr_0.7)(Ti_1−x,Zr_x)O₃ (BNBS-(Ti_1−x,Zr_x)) lead-free energy storage ceramic sheets are prepared by a conventional solid-state sintering method. We find that B-site doping of ZrO₂ may minimize the grain size while not change the perovskite structure of BNBS-(Ti_1−x,Zr_x). As such, BNBS-(Ti_1−x,Zr_x) possesses the uniform grains and clear grain boundaries, resulting in a high dielectric permittivity (ε_r) of about 2080 and a low dielectric loss (tanδ) of 0.05 at 100 Hz. Due to the lattice distortion caused by Zr⁴⁺ entering the TiO₆ octahedral lattice, T_m of BNBS-(Ti_1−x,Zr_x) decreases with the increase of ZrO₂ doping content. Attractively, BNBS-(Ti_1−x,Zr_x) exhibits relatively slender polarization-electric field (P-E) loops at a high electric field of 100 kV/cm, and BNBS-(Ti_0.97,Zr_0.03) achieves considerable recycle discharging energy density (W_rec) of 1.47 J/cm³ and high efficiency (η) of 86.94%. Thus, as a block ceramic synthesized by convenient process, this result is superior to most of similar BNT-based materials, and may provide a reference for pulse power capacitors. [ABSTRACT FROM AUTHOR]