Evolution of the structure, dielectric and ferroelectric properties of Na0.5Bi0.5TiO3-added BaTiO3–Bi(Mg2/3Nb1/3)O3 ceramics

Via a traditional sintering process, (1-x) [0.85BaTiO3-0.15Bi(Mg2/3Nb1/3)O3] - x Na0.5Bi0.5TiO3 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1) (BT-BMN-NBT) ceramics were synthesized. The sintering temperature and density of the BT-BMN-NBT ceramics decreased with the increasing NBT content. All samples exhibited a pseudocubic phase and formed stable solid solutions with dense microstructures. The crystal structure of the BT-BMN-NBT ceramics gradually transformed from BT to NBT with increasing NBT content. The introduction of NBT with a high maximum polarization (Pmax) could not only enhance the relaxor ferroelectric (RFE) characteristics of the BT-based RFE, but also compensate for the reduction in Pmax of BT-based RFE that is due to the enhanced RFE characteristics. The temperature that corresponds to the maximum dielectric constant increases monotonously with the NBT content. Pmax of the BT-BMN-NBT ceramics increases significantly as the NBT content increases. The best energy storage (ES) performances (x = 0.3) of a releasable energy density (Wrec) of 2.91 J/cm3 and 85.55% efficiency were realized at 200 kV/cm. Compared with the unmodified BT-BMN ceramics (1.67 J/cm3), Wrec was improved by 1.48 times, which originated from the NBT modification induced increase in Pmax (39.5 μC/cm2) to 2.34 times the nominal BT-BMN value (16.9 μC/cm2). The results prove that the addition of NBT could improve the ES performances of BT-based relaxor ferroelectrics at low-field by increasing the polarization.