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As a new member of lead-free Na 0.5 Bi 0.5 TiO 3 (NBT) ceramics based on bismuth layer-structured ferroelectrics (BLSFs), Bi x Ti 3 O 6+1.5 x ( x = 3.96, 3.98, 4.0, 4.02, 4.04) ceramics was prepared by a conventional mixed oxide route. In order to explore the ferroelectric and dielectric properties, we changed the content of Bi in the ceramics. XRD patterns of Bi x Ti 3 O 6+1.5 x demonstrated that the new material was a single phase of Bi-layered perovskite structure. Through impedance spectra analysis, we found that the Bi 4.02 Ti 3 O 12.03 ceramics sintered at 1100 °C showed excellent dielectric properties with a highest dielectric constant of 8967.49 and a lowest dielectric loss of 0.00298 measured under 10 kHz, which were enhanced much compared with Bi 4 Ti 3 O 12 prepared by the same means. Meantime, the Curie temperature of the whole samples was about 670 °C. In addition, the ferroelectric hysteresis loops of all the samples indicated that they were ferroelectric materials, and Bi 4 Ti 3 O 12 ceramics sintered at 1100 °C processed a remanent polarization (2 P r ) of 12.206 µC/cm 2 and a coercive field of 29.542 kV/cm. SEM can roughly describe the results of the dielectric spectrum and ferroelectricity with different Bi concentration through grain size mechanics. Because of the high dielectric constant, wide operating temperature and low dielectric loss, the Bi 4 Ti 3 O 12 ceramics have a broad application prospect in components, such as sensors, high-temperature capacitors and so on. [ABSTRACT FROM AUTHOR]