Dielectric and energy storage properties of SrTiO3 and SrZrO3 modified Bi0.5Na0.5TiO3-Sr0.8Bi0.1□0.1TiO3 based ceramics

A new lead-free system of (1−x−y)[0.9Bi0.5Na0.5TiO3- 0.1Sr0.8Bi0.1□0.1TiO3]-xSrTiO3-ySrZrO3 (x = 0.08, 0.12 and 0.16, y = 0.04, and x = 0.12, 0.18 and 0.24, y = 0.06; abbreviated as 100xST-100ySZ) was designed. The effects of SrTiO3 and SrZrO3 contents on the phase structure, microstructure, dielectric, ferroelectric and energy storage properties were investigated. The introduction of SrTiO3 and SrZrO3 leads to an expansion of cell volume and refinement of grain size. With the increasing of SrTiO3 and SrZrO3 contents, dielectric peaks shift to the lower temperature and become more diffused. A narrow P-E ferroelectric hysteresis loops are obtained due to the long-range broken ferroelectric order by the addition of SrTiO3 and SrZrO3. More importantly, when SrZrO3 content is fixed to y = 0.06, increasing SrTiO3 content leads to an enhancement of the breakdown strength (BDS) and simultaneously Pmax−Pr is remained nearly constant. The excellent energy storage properties are obtained at the composition of x = 0.24, y = 0.06, which has higher energy storage density (1.25 J/cm3) and comparable efficiency (79%) under the relatively lower electric field (108 kV/cm) compared with other lead-free systems.