Enhanced energy storage performance of (Bi0.5Na0.5)TiO3-SrTiO3 ceramics doped with ZrO2

This study presents a novel lead-free ceramics system (Bi0.25Na0.25Sr0.5)(Ti1-xZrx)O3 by introducing ZrO2 to 0.5 (Bi0.5Na0.5)TiO3-0.5SrTiO3 ceramics. The effects of Zr4+ addition on the crystalline structure, dielectric and ferroelectric properties have been investigated. The average grain size decreases during the introduction of Zr4+, improving the breakdown strength. With the increase of doping amount, the dielectric constant and dielectric loss decrease significantly, and the dependence on temperature and frequency becomes weaker obviously. Furthermore, the hysteresis loops of the optimized ceramics become thinner and the polarization saturation trend weakened obviously. The recoverable energy density of 1.89 J/cm3 and the energy storage efficiency of 70.3 % was obtained in the (Bi0.5Na0.5Sr0.5)(Ti0.88Zr0.12)O3 ceramics, which also showed good temperature and frequency stability over a wide range. The novel lead-free relaxor ceramics investigated in this study have significant advantages and promising for the frequency-stable and thermal-stable energy storage capacitor applications.