Ultrahigh energy storage density in lead-free antiferroelectric rare-earth-substituted bismuth ferrite

Abstract

Rare-earth (Re) substitution in BiFeO${}_{3}$ can result in a tuning of the crystal structure from ferroelectric R3c to antiferroelectric Pnma, making (Bi,Re)FeO${}_{3}$ among the best dielectric materials for energy storage. Using a first-principle-based atomistic approach, the authors predict that playing with the Re elements and varying the composition can systematically alter the polarization-versus-electric field (P-E) hysteresis loop of (Bi,Re)FeO${}_{3}$, leading to promising storage performance. For instance, energy density as high as 239 J/cm${}^{3}$ in (Bi,Tm)FeO${}_{3}$ solid solutions and efficiencies being generally beyond 80% are predicted. The influential factors on these energy-storage properties, including transition fields, polarization of the ferroelectric state and dielectric constant, are further discussed based on a simple model.