Excellent thermal stability and high energy storage performances of BNT-based ceramics via phase-structure engineering

Herein, a novel strategy for regulating the phase structure was used to significantly enhance the recoverable energy storage density (Wrec) and the thermal stability via designing the (1-x)[(Bi0.5Na0.5)0.7Sr0.3TiO3]-xBiScO3 ((1-x)BNST-xBS) relaxor ferroelectric ceramics. The incorporation of BS into BNST ceramics markedly increases the local micro-structure disorder, causing a high polarization and inhibiting polarization hysteresis for 0.95BNST-0.05BS ceramics, leading to a large Wrec of 5.41 J/cm3 with an ideal efficiency (η) of 78.5%. Meanwhile, transmission electron microscope (TEM) results further proved that the nano-domain structure and the tetragonal (P4bm) phase superlattice structure of 0.95BNST-0.05BS ceramics possess an excellent thermal stability (20–200 °C). An outstanding Wrec value of 3.18 × (1.00 ± 0.03) J/cm3 and an η value of 74.500 ± 0.025 are achieved under a temperature range from 20 °C to 200 °C. This work provides a promising method for phase-structure design that can make it possible to apply temperature-insensitive ceramic dielectrics with a high energy storage density in harsh environments.