An ultrahigh energy storage efficiency and recoverable density in Bi_0.5Na_0.5TiO₃ with the modification of Sr_0.85La_0.1TiO₃ via viscous polymer process

Currently, the development of dielectric ceramic capacitors is restricted by the contradiction between high efficiency and high recoverable density. Therefore, a novel strategy was designed to achieve a superior balance between them. Firstly, introducing Sr_0.85La_0.1TiO₃ can enhance the content of the weak polar phase (P4bm) to become the main component, which can optimize the relaxor behaviour and improve efficiency. Then, the electric breakdown strength was effectively enhanced by grain refinement and viscous polymer processing. Finally, a high recoverable energy density of ∼5.3 J/cm³ and an excellent efficiency of ∼92.2% were attained in 0.9Bi_0.5Na_0.5TiO₃-0.1Na_0.8Sr_0.1NbO₃ ceramic with the addition of 0.35Sr_0.85La_0.1TiO₃ after viscous polymer processing. The piezoelectric force microscope had been applied to prove the high activity of the polar nanoregions and finite element analysis was adopted to explain the reasons for the enhancing electric breakdown strength. In addition, this ceramic exhibits good temperature and frequency stability, and a fast discharging rate of 0.11 μs, making it a potential candidate for the actual application.