High Energy Storage Density and Large Strain in Bi(Zn2/3Nb1/3)O3-Doped BiFeO3-BaTiO3 Ceramics

High recoverable energy density (W-rec similar to 2.1 J/cm(3)) was obtained in (0.7 x)BiFeO3-0.3BaTiO(3)-xBi(Zn2/3Nb1/3)O-3 + 0.1 wt % Mn2O3 (BF-BT-xBZN, x = 0.05) lead-free ceramics at <200 kV/cm. Fast discharge speeds (<0.5 mu s), low leakage (similar to 107 A/cm(2)), and small temperature variation in Wrec (similar to 25% from 23 to 150 degrees C) confirmed the potential for these BiFeO3-based compositions for use in high energy density capacitors. A core-shell microstructure composed of a BiFeO3-rich core and BaTiO3-rich shell was observed by scanning and transmission electron microscopy which may contribute to the high value of energy density. In addition, for x = 0.005, a large electromechanical strain was observed with S-pos = 0.463% and effective d(33)* similar to 424 pm/V, suggesting that this family of ceramics may also have potential for high strain actuators.