Enhanced energy storage properties in lead-free NaNbO₃–Sr_0.7Bi_0.2TiO₃–BaSnO₃ ternary ceramic

The urgent requirement of environment-friendly materials with excellent energy storage performance for pulse power systems has sparked considerable research on lead-free ceramics. In this work, a new lead-free 0.90(0.80NaNbO₃–0.20Sr_0.7Bi_0.2TiO₃)–0.10BaSnO₃ ceramic with high recoverable energy storage density (W_r = 3.51 J/cm³) and decent energy storage efficiency (η = 70.85%) has been obtained. In particular, these ceramics exhibit an ultrahigh breakdown strength of 402 kV/cm due to the dense microstructure and small grain size. The impedance analysis also reveals that the incorporation of BaSnO₃ is conducive to the enhancement of insulation ability and breakdown strength. Additionally, great thermal stability (ΔW_r < 10% over 20–120 °C at 200 kV/cm) and fatigue resistance (ΔW_r < 1% after 120,000 electrical cycles at 200 kV/cm) are observed, indicating that the 0.90(0.80NaNbO₃–0.20Sr_0.7Bi_0.2TiO₃)–0.10BaSnO₃ ceramics have promising application prospect for high-temperature energy storage devices in pulse power applications.