High energy storage performances of Bi1−xSmxFe0.95Sc0.05O3 lead-free ceramics synthesized by rapid hot press sintering

Abstract Lead-free Bi 1−x Sm x Fe 0.95 Sc 0.05 O 3 ( x  = 0.15–0.19) ceramics were fabricated by rapid hot press sintering, and their structure, ferroelectric and energy storage properties were comprehensively investigated. All the samples are in the mixed phases with R3c rhombohedral and Pbnm orthorhombic structures. With increasing x , the ferroelectric polarization decreases gradually, while the polarization loop becomes gradually slimed too. An high recoverable energy density (˜2.21 J/cm 3 ) and a large efficiency (˜76%) with good thermal stability (20 °C–120 °C) are obtained under electric field (230 kV/cm) for the optimized sample x = 0.17. Moreover, transmission electron microscopy and piezo-response force microscopy measurements reveal that the presence of two-phase coexistence favors the formation of polar nano-regions, leading to the linear-towards polarization behaviors and the enhanced dielectric breakdown field, which is responsible for the superior energy storage performance of Bi 1−x Sm x Fe 0.95 Sc 0.05 O 3 ceramics. These results indicate a significant step to tailor lead-free BiFeO 3 -based ceramics towards high dielectric energy storage applications.