Unfolding dielectric breakdown effects on energy storage performances of modified (Sr0.98Ca0.02)(Ti1-xZrx)O3 ceramics

Dielectric materials with large maximum polarization but small lossy hysteresis, high electrical breakdown, and postponed maximum polarization can store a large amount of electrical energy and are thus promising candidates for energy storage applications. In this work, a dielectric capacitor based on (Sr0.98Ca0.02)(Ti,Zr)O-3 system achieved the elevated energy storage performances calculated from the polarization-electric field hysteresis loops due to enhanced breakdown strength by Zr substitution. Dielectric relaxation could be ascribed to the appearance of the doubly ionized oxygen vacancies verified by activation energy. For the studied system, dielectric breakdown dominated for the enhancement of energy storage performances because of the difference of ferroelectric activity and cation stability between Zr and Ti ions. The optimal Zr-modified composition exhibited better energy storage performances in contrast with pure (Sr0.98Ca0.02)TiO3, suggesting that they might be an emerging candidate for next-generation high-energy devices.