Energy Storage Performance Enhanced and High Stability Achieved in BNT-Based Lead-Free Ceramics under Low Electric Field via Domain Engineering

The urgent energy crisis in modern society has driven the search for dielectric ceramic materials with high power density and rapid charging–discharging capabilities. However, their practical applications are hindered by challenges such as the inability to simultaneously achieve high energy density and energy storage efficiency, the requirement for extremely high electric fields to attain excellent energy storage performance (ESP), and poor stability. In this study, a series of relaxor ferroelectric ceramics with the composition (1 – x )(0.8 Bi 0.5 Na 0.5 TiO 3 -0.2 Bi 0.5 K 0.5 TiO 3 )-xSr 0.7 Sm 0.2 TiO 3 were prepared by combining a multicomponent strategy with A-site defect engineering. The results demonstrate that 0.48BNT-0.12BKT-0.4SST ceramics achieve a recoverable energy density of 3.52 J/cm 3 and an energy storage efficiency of 92.13% under a low electric field of 189 kV/cm. These properties surpass those of other lead-free energy storage ceramics under comparable electric field conditions, highlighting their significant potential for practical applications. Furthermore, the ceramics exhibit exceptional stability in terms of temperature, frequency, and cycling, along with a high power density of 157.19 MW/cm 3 and ultrafast discharging speeds of 73.8 ns, making them highly suitable for high-power energy storage devices.