Simultaneously achieving high energy storage density and efficiency under low electric field in BiFeO3-based lead-free relaxor ferroelectric ceramics

BiFeO3-BaTiO3-based relaxor ferroelectric ceramic has attracted increasing attention for energy storage applications. However, simultaneously achieving high recoverable energy storage density (W-rec) and efficiency (eta) under low electric field has been a longstanding drawback for their practical applications. Herein, a novel relaxor ferroelectric material was designed by introducing (Sr0.7Bi0.2)TiO3 (SBT) into the composition 0.67BiFeO(3)-0.33BaTiO(3) (BF-BT-xSBT). A large W-rec of similar to 2.40 J/cm3 and a high eta of similar to 90.4 % were simultaneously realized under a low electric field of 180 kV/cm, which is superior to that of most previously reported lead-free ceramics. Moreover, moderate temperature endurance and excellent frequency stability were also obtained. More importantly, this ceramic has a large discharge current density (similar to 289.18 A/cm(2)), a discharge power density (similar to 14.46 MW/cm(3)) and short discharge time (< 0.25 mu s). These results not only demonstrate superior potential in BF-BT-SBT ceramics, but also offer a new design to tune the energy storage performance of lead-free relaxor ferroelectric ceramics.