Optimized electric-energy storage in BiFeO3–BaTiO3 ceramics via tailoring microstructure and nanocluster

Abstract

This study demonstrates the high energy-storage performance using 0.1 wt% MnO2–added 0.7(Bi1−xSmxFeO3)− 0.3(BaTiO3) (x = 0–0.3) ceramics through tailoring microstructures and polar order. Sequential structure transitions were identified from a co-occurrence of nonpolar pseudo-cubic Pm-3m and ferroelectric rhombohedral R3c symmetries to antipolar orthorhombic Pbam and nonpolar orthorhombic Pnma symmetries as Sm substitution increases. Recoverable energy densities (Wrec) of 4.5 J/cm3 and 4.1 J/cm3 with efficiencies (η) of 62.1% and 78.1% were achieved respectively for x = 0.15 and 0.2 at a field of 220 kV/cm. The improved energy storage is associated with microstructure modification and complex grain matrix, consisting of grain boundaries, nanocluster/nanomosaic structures, core-shell structures, and polar nanoregions. The nanocluster/nanomosaic structures may act as barriers to suppress polar order and enhance dielectric breakdown strength. This work provides an efficient route to utilize binary BiFeO3-BaTiO3 ceramics for electrical energy storage.