Enhanced energy storage density and efficiency in La(Mg2/3Ta1/3)O3-doped BiFeO3 based ceramics
Chen Wu, Xiaoming Qiu, Wenwei Ge, Luyao Chen, Changyi Liu, Hongwei Zhao, Liang Li
Abstract
High-performance dielectric capacitor materials are required for the miniaturization of electronic devices. To this end, (1- x )(0.65BiFeO 3 -0.35BaTiO 3 )- x La(Mg 2/3 Ta 1/3 )O 3 (BFBT- x LMT, x = 0, 0.06,0.10, 0.14 and 0.18) ceramics were fabricated by a solid-state method. The experimental results indicate that LMT doping can well improve the energy storage density (W rec ) and efficiency (η) of BFBT ceramics. Especially, the optimal energy storage performance (ESP) (W rec =4.92 J/cm 3 , η = 85%) was obtained in BFBT-0.14LMT ceramics under 390 kV/cm. The enhancement of ESP of BFBT-0.14LMT ceramics can be ascribed to the decreased hysteresis of polarization (P) - electric field (E) loops resulting from the aggravation of the composition and charge disorder in the system, and the improved breakdown strength (E b ) which is related to the reduced grain size, the widened band gap (E g ) and the decreased oxygen vacancy concentration. Additionally, the thermal stability of ESP of BFBT-0.14LMT ceramics is also enhanced compared with pure BFBT ceramics. Meanwhile, BFBT-0.14LMT ceramics exhibit a fast discharge rate (t 0.9 = 152 ns) under 180 kV/cm. These results indicate that BFBT-0.14LMT ceramics could be a promising dielectric capacitor material. In general, our study reveals that LMT is good dopant to enhance the E b and ESP of BF-based ceramics.