Simultaneously achieving ultrahigh energy storage density and energy efficiency in barium titanate based ceramics

BaTiO3-BiMeO3 (Me represent trivalent or average trivalent metallic ions) lead-free relaxor ferroelectrics have been demonstrated to be excellent candidates for dielectrics in pulsed power capacitor applications. However, the recoverable energy density (U-rec) needs to be further improved to fulfil the demands of miniaturization and integration in electronic devices. In this work, an ultrahigh U-rec of 3.282 J/cm(3) was obtained in (1-x)BaTiO3-xBi (Mg2/3Ta1/3)O-3 (xBMT) (x = 0.12) lead-free ceramics. The significantly enhanced U-rec was first reported in BT-based bulk ceramics. Meanwhile, all components exhibit ultrahigh energy storage efficiency (eta) of 93% under a strong electric field (>= 300 kV/cm), which may be attributed to the low leakage current caused by the introduction of Ta ions. In addition, excellent temperature, frequency and fatigue stabilities (variation of U-rec < 9% over 25-140 degrees C, U-rec > 2 J/cm(3) in 1-100 Hz and U-rec < 2% after 10(4) cycles) can be observed. These results demonstrate that 0.12BMT relaxor ferroelectrics can be considered a promising lead-free material for application in pulsed power systems.