Relaxation behavior of BF-BT based ceramics and improved energy storage performance under low electric field

With the increasing demand for portable electronics, power electronics and other devices, energy storage materials with high power density and large energy storage density are becoming more and more important. BiFeO 3 -BaTiO 3 lead-free ferroelectric ceramics are deemed as a potential lead-free energy storage material due to their high spontaneous polarization and high Curie temperature. However, high remanent polarization has become a serious obstacle to its practical application. In this work, 0.67Bi (1- x ) Sm x FeO 3 -0.33BaTiO 3 (BS x F-BT, 0 ≤ x ≤ 0.10) was prepared by the conventional solid phase sintering method. The phase transforms from rhombohedral to pseudocubic, and the dielectric and electrical data reveal that relaxor ferroelectrics are favorable for achieving the small size polar nanoregions and enhanced relaxation behavior. Due to enhanced relaxation behavior by doping Sm 3+ , the recoverable energy storage density ( W rec ) reaches 1.99 J/cm 3 , and the energy storage efficiency ( η ) is 57% at a low electric field (190 kV/cm), which is higher than the undoped ceramic ( W rec = 0.272 J/cm 3 and η = 26%). This work also puts forward the concept of Ergodic relaxor ferroelectrics and Non-ergodic relaxor ferroelectrics to explain the improvement of energy storage performance.