Superior energy storage properties in (1−x)(0.65Bi_0.5Na_0.5TiO₃-0.35Bi_0.2Sr_0.7TiO₃)-xCaZrO₃ ceramics with excellent temperature stability

Novel (1−x)(0.65Bi_0.5Na_0.5TiO₃-0.35Bi_0.2Sr_0.7TiO₃)-xCaZrO₃ (BNT-BST-xCZ, x = 0–0.15) ceramics were manufactured through a solid phase sintering process and their structural and electrical performance have been systematically investigated. By doping CaZrO₃, a higher recoverable energy storage density of 2.9 J/cm³ and energy storage efficiency of 80% at 330 kV/cm can be simultaneously obtained in BNT-BST-0.1CZ ceramic. Further analysis with the aid of finite element simulation indicates that the improvement of energy storage performance lies in the refined grain size and reduced defects, which are both conductive to improve the dielectric breakdown strength. More importantly, incorporating CaZrO₃ gives slimmer hysteresis loops as well as excellent temperature (20–150 °C) and frequency (5–200 Hz) stability of energy storage properties. Moreover, a stable dielectric permittivity of in an ultra-wide range from 44 °C to 483 °C was achieved in BNT-BST-0.10CZ ceramic. Our findings suggest that the BNT-BST-0.1CZ ceramic has great potential applications in pulsed power systems and high-temperature capacitors.