Enhanced energy storage performance in (1-x)Bi0.85Sm0.15FeO3-xCa0.5Sr0.5Ti0.9Zr0.1O3 relaxor ceramics

Abstract

Producing dielectric ceramics with favorable energy storage density, efficiency, and thermal stability has become an urgent task for developing energy storage devices. In this work, the innovative Pb-free (1-x)Bi0.85Sm0.15FeO3-xCa0.5Sr0.5Ti0.9Zr0.1O3 [(1-x)BSF-xCSTZ, x = 0.0, 0.1, 0.2, 0.3 and 0.4] ceramics were fabricated via traditional solid phase sintering approach. Their structures, electrical characteristics, and energy storage properties were researched comprehensively. The results verified that all the samples form solid solutions with pseudo-cubic perovskites structure. The density of ceramic samples is improved accompanied by gradually refined grain size upon increasing the CSTZ doping content. Interestingly, an excellent recoverable density of ∼3.3 J/cm3 with high efficiency of ∼78% is received at x = 0.3 under the average breakdown electric field of 350 kV/cm. The energy storage performances remained stable in a broad temperature range of 20 – 110 ℃, a large frequency range of 1 Hz – 1 kHz, and beyond 105 repeated charging-discharging cycles. The enhanced energy storage performances of BSF ceramics by introducing CSTZ result from the improved relaxor behavior and the increased electric breakdown strength. Our strategy for relaxor modulation with a sealed sintering method to achieve high energy storage performance can be valuable in BiFeO3-based ceramic capacitors.