High-performance (Na0.5Bi0.5)(Ti0.97Fe0.03)O3-based heterostructure thin films for energy storage capacitors

This work presents a simple process to fabricate Na0.5Bi0.5(Ti0.97Fe0.03)O3/Ba(1–x)SrxTiO3–based heterostructure thin films with a compositional graded sequence, and their energy storage properties are investigated systematically. A simulation technique is used to predict the experimental results. Interestingly, improved energy storage properties are obtained in the “up–graded” film, which is associated with the stress/strain. Furthermore, the “up–graded” film after aging with treating exhibits a higher breakdown strength (EBD = 3176.4 kV/cm), recoverable energy storage density (Wrec = 67.18 J/cm3) and efficiency (η = 75.65%). This can be attributed to the ordered defect dipoles induced by aging with treating driving domain switching, which is favorable for high (Pm–Pr) and large Wrec. These results provide an approach and guidance to design thin film-based devices with optimal energy storage performance.