Energy storage properties in a Bi(Mg1/2Ti1/2)O3 modified BiFeO3-Sr0.7Bi0.2TiO3 film

High-performance dielectric capacitor represents an emerging technological goal for energy storage in modern electrical and electronic systems. In this work, we report a lead-free film capacitor based on the Bi(Mg1/2Ti1/2)O3 modified BiFeO3-Sr0.7Bi0.2TiO3 relaxor. A large recoverable energy storage density of 77.5 J/cm3, together with an efficiency of 56.1% is achieved in the film with 15 mol. % Bi(Mg1/2Ti1/2)O3 in composition. The film also exhibits excellent fatigue endurance with a reduction less than 3% over 1 × 108 cycles in both recoverable energy storage density and efficiency. Such good properties are ascribed to the improved electrical insulation and breakdown strength and the enhanced relaxor behavior by introducing the bismuth-based perovskite-like compound.