Lead-free BaTiO3-Bi0.5Na0.5TiO3-Na0.73Bi0.09NbO3 relaxor ferroelectric ceramics for high energy storage

A series of (1-x)(0.65BaTiO3-0.35Bi0.5Na0.5TiO3)-xNa0.73Bi0.09NbO3 ((1-x)BBNT-xNBN) (x = 0-0.14) ceramics were designed and fabricated using the conventional solid-state sintering method. The microstructure, dielectric property, relaxor behavior and energy storage property were systematically investigated. X-ray diffraction results reveal a pure perovskite structure and dielectric measurements exhibit a relaxor behavior for the (1-x)BBNT-xNBN ceramics. The slim polarization electric field (P-E) loops were observed in the samples with x ≥ 0.02 and the addition of Na0.73Bi0.09NbO3 (NBN) could decrease the remnant polarization (Pr) of the (1-x)BBNT-xNBN ceramics obviously. The sample with x = 0.08 exhibits the highest energy storage density of 1.70 J/cm3 and the energy storage efficiency of 82% at 172 kV/cm owing to its submicron grain size and high relative density. These results show that the (1-x)BBNT-xNBN ceramics may be promising lead-free materials for high energy storage density capacitors.