Enhanced temperature stable dielectric property and energy-storage performance of (1-x)(0.66Bi_0.5Na_0.5TiO₃–0.34Sr_0.7Bi_0.2TiO₃)– xK_0.5Nd_0.5TiO₃ lead-free relaxor electroceramics

In this study, (1-x)(0.66Bi_0.5Na_0.5TiO₃–0.34Bi_0.2Sr_0.7TiO₃)–xK_0.5Nd_0.5TiO₃ (BNBST–xKNT) ceramics were designed and synthesized, and they present significantly enhanced dielectric temperature stability and energy storage properties. The BNBST–0.06KNT composition exhibits a remarkable dielectric stability, as reflected in its stable dielectric constant (△ԑ/ԑ_{150 °C} < ±15%) over a broad temperature range (25–401 °C). BNBST–0.02KNT achieves a high energy storage density W_rec = 1.2 J/cm³ under 110 kV/cm with an energy storage efficiency η of 76.9%, and the improved energy storage property originates from the improved breakdown field strength and decreased hysteresis behavior. The electrical conductivity and relaxation behaviors of BNBST–xKNT were also analyzed via impedance spectroscopy.