Core–Shell Grain Structure and High Energy Storage Performance of BNT-Based Relaxor Ferroelectric Ceramics

Bismuth sodium titanate (Bi 0.5 Na 0.5 TiO 3 , BNT) based ferroelectric ceramic is one of the important lead free dielectric materials for high energy storage applications due to its large polarization. Herein, we reported a modified BNT based relaxor ferroelectric ceramics composited with relaxor Sr 0.7 Bi 0.2 TiO 3 (SBT) and ferroelectric BaTiO 3 (BT), which exhibits a high recoverable energy density of 5.59 J/cm 3 and a high energy storage efficiency of 84.0% under large breakdown electric strength of 420 kV/cm. A core–shell grain structure is observed in the BNT-SBT-BT ceramics with high content BT additive, which plays crucial role on the enhancement of the energy storage performance. This ceramic also exhibits superior temperature stability with small energy density variation of less than 6.5% in wide temperature range from room temperature to 180 °C. The impedance spectroscopies show that the ceramics have good insulation properties at high temperature. These characteristics demonstrate that the BNT-SBT-BT ceramic is a promising candidate for high-power energy storage applications. Graphical Abstract