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 (eta = 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.