Enhanced energy storage performance in Na_0.5Bi_0.5(Ti,Mn)O₃-SrTiO₃ ferroelectric thin films via aging process

Optimizing energy storage performance often involves increasing the discrepancy between maximum polarization and remanent polarization (P_max-P_r) and breakdown strength (E_b). Here, aging treatment in acceptor doped NBT-based film is taken for increasing both E_b and P_max-P_r by constructing ordered defect dipoles. Enhanced P_max-P_r value of 80.6 μC/cm² and high E_b of 2630 kV/cm are obtained in the aged (Na_0.5Bi_0.5)_0.55Sr_0.45Ti_0.99Mn_0.01O₃ thin film, which can be attributed to the reversible domain switching caused by ordered defect dipoles and low oxygen vacancies concentration. Accordingly, an energy density of 72.4 J/cm³ with an efficiency of 76.8 % was achieved simultaneously in the aged film, which are approximately raised by 80.6 % and 45.2 %, respectively, compared with the unaged state. The stable energy storage performances are achieved within the scope of operating temperatures (20–200 ^◦C) and frequencies (0.2–10 kHz). These results provide a new route to take usages of aging process for optimizing the energy performance of NBT-based thin films.