Improved energy storage properties of La_(0.33)NbO_3 modified 0.94Bi_(0.5)Na_(0.5)TiO_3-0.06BaTiO_3 ceramic system

摘要

(1-x)[0.94Bi_(0.5)Na_(0.5)TiO_3-0.06BaTiO_3]-xLa_(0.33)NbO_3 (x=0,0.02,0.04,0.06,0.08,0.10) (BNBT-LN) bulk lead-free relaxor ferroelectric ceramics were synthesized via solid-state sintering method. Phase, microstructure and energy storage properties were determined. The X-ray diffraction (XRD) revealed a single perovskite phase for compositions of x≤0.02, while the second phase of Bi_2Ti_2O_7 along with the parent phase for x≥0.04. Dense microstructure with a decrease in grain size has been achieved via LN doping. The addition of LN decreased the remnant polarization (P_r), and coercive field (E_c), while increased the difference between the maximum polarization (P_(max)) and remnant polarization (P_r). The high energy-storage density of 2.96 J/cm~3 and high recoverable energy density of 1.66 J/cm~3 at a breakdown electric field of 214 kV/cm were achieved for the composition of x = 0.02 with good temperature stability satisfying the condition of △ε_r /ε_(r200°C)≤± 15% in a working temperature range of 70°C to 400°C. Similarly, a less discharge time of ＜ 4 μs achieved in this study for x = 0.02. These results demonstrate that this material may be a good candidate material for power pulsed applications.