Effect of Dy₂O₃ content on the dielectric, ferroelectric, and energy storage properties of lead-free 0.5Na_0.5Bi_0.5TiO₃–0.5SrTiO₃ bulk ceramics

In the past decades, lead-free ceramics with high polarization, low remnant polarization and high electric breakdown strength have drawn a lot of attention because of their potential applications in dielectric capacitors with excellent energy storage performance. In the current investigation, we develop a novel lead-free Dy doped 0.5Na_0.5Bi_0.5TiO₃–0.5SrTiO₃ ceramics, which were fabricated by the conventional electroceramic processing route. By doping Dy₂O₃ into 0.5Na_0.5Bi_0.5TiO₃–0.5SrTiO₃ with various contents from 0.1 at.% to 0.5 at.%, pure perovskite phases and relatively dense structures were obtained. The increase of Dy₂O₃ concentration not only shifts the T_m toward to lower temperature, but also reduces the permittivity and gain sizes, thus enhancing the temperature stability of dielectric properties. The enhanced dielectric energy storage properties were systematically investigated by testing the polarization–electric field hysteresis loops as a function of the applied electric field, temperature, and loading cycles. The dielectric energy storage density of in 0.1 at.% doped 0.5Na_0.5Bi_0.5TiO₃–0.5SrTiO₃ is 1.59 J/cm³, which is nearly twice higher than that of undoped NBT–ST. Hence, the Dy modified 0.5Na_0.5Bi_0.5TiO₃–0.5SrTiO₃ ceramics have exhibited potential application as dielectric capacitors with relatively good energy storage performance.