Enhanced energy storage properties of lead-free (1-x)Bi^sub 0.5^Na^sub 0.5^TiO3-xSrTiO3 antiferroelectric ceramics by two-step sintering method

The lead-free (1-x)Bi0.5Na0.5TiO3-xSrTiO3 antiferroelectric ceramics were synthesized by two-step sintering method. The influences of SrTiO3 contents, second sintering temperatures and soaking times on phase structure and energy-storage density were investigated in detail. As the content of SrTiO3 increases, the ceramics transform from rhombohedral ferroelectric phase into the tetragonal antiferroelectric phase (or pseudocubic phase). The appropriate soaking time and second sintering temperature are beneficial to obtain dense ceramics with fine homogeneous grains, whose the external breakdown electric field and maximum polarization have a large improvement. The optimum electrical performances with low remanent polarization (3.21 [mu]C/cm2), a large maximum polarization (31.05 [mu]C/cm2), and a large energy density (0.95 J/cm3) at 10 Hz were obtained at 1160 °C for BNT-35ST ceramics.