Energy storage properties and nonstoichiometric ferroelectric properties of flexible Ba_0.5Sr_0.5Nb₂O₆ thin films influenced by oxygen partial pressure

Flexible Ba_0.5Sr_0.5Nb₂O₆ (BSN) thin films with excellent crystallinity were prepared on Pt/mica substrates where the Pt bottom electrodes with excellent crystallinity were formed on the mica substrates via. a reduced deposition rate. The BSN thin films with preferentially c-oriented excellent crystallinity showed a rapid change of nonstoichiometric ferroelectricity according to the change in oxygen partial pressure. The BSN thin films deposited under low oxygen partial pressures of 10 and 20 mTorr had relatively high remanent polarizations due to nonstoichiometric ferroelectricity. On the other hand, the BSN thin film deposited under a high oxygen partial pressure of 30 mTorr showed significantly reduced remanent polarization by reducing nonstoichiometric ferroelectricity, resulting in increased energy storage efficiency. The flexible BSN thin films with a bending radius of 2 mm demonstrated a consistent energy density, exhibiting a high recoverable energy density of approximately 81.5 J/cm³ and a significantly high energy storage efficiency of about 95.3 %. Moreover, it shows consistent recoverable energy density even after 10¹² cycles, making it suitable for potential use in energy storage applications.