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 ℃). 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 ℃ to 200 ℃. 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.
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Environmentally friendly lead-free ceramics capacitors, with outstanding power density, rapid charging/discharging rate, and superior stability, have been receiving increasing attention of late for their ability to meet the critical requirements of pulsed power devices in low-consumption systems. However, the relatively low energy storage capability must be urgently overcome. Herein, this work reports on lead-free SrTi0.875Nb0.1O3 (STN) replacement of (Bi0.47La0.03Na0.5)0.94Ba0.06TiO3 (BLNBT) ferroelectric ceramics with excellent energy storage performance. Improving relaxor behaviour and breakdown strength (Eb), decreasing grain size, and mitigating large polarization difference are conductive to the enhancement of comprehensive energy storage performances. The phase-field simulation methods are further analysized evolution process of electrical tree in the experimental breakdown. In particular, the 0.70BLNBT-0.30STN ceramic exhibit a large discharged energy density of 4.2 J/cm3 with an efficiency of 89.3% at room temperature under electric field of 380 kV/cm. Additionally, for practical applications, the BLNBT-based ceramics achieve a high power density (~62.3 MW/cm3) and fast discharged time (~148.8 ns) over broad temperature range (20–200 ℃). Therefore, this work can provide a simple and effective guideline paradigm for acquiring high-performance dielectric materials in low-consumption systems operating in a wide range of temperatures and long-term operations.