Advancing energy storage properties in barium titanate-based relaxor ferroelectric ceramics through a stagewise optimization strategy

To propel advanced energy storage devices for high pulse power systems, overcoming the pivotal challenges of concurrently augmenting energy storage density (W_rec) and efficiency (η) in relaxor ferroelectric (RFE) ceramics is imperative. This study delineates a stagewise collaborative optimization strategy aimed at enhancing the energy storage property (ESP) of BaTiO₃ (BT)-based (Ba_0.8Sr_0.2)TiO₃ (BST) ceramics, namely, integrating (Na_0.73Bi_0.09)NbO₃ (NBN) with secondary processing technology. Capitalizing on the inherent strong polarity from A-site Bi³⁺ ions, the high valence, and wide-bandgap of B-sites introduce local random electric fields and impede the transition of electrons, generating polar nanoregions and expanding breakdown thresholds. Furthermore, the application of the viscous polymer process (VPP) in BST-NBN ceramics seeks to diminish porosity and enhance compactness, thereby sequentially improving polarization difference (ΔP) and breakdown strength (E_b). Guided by a stepwise optimization strategy, the anticipated energy storage characteristics (W_rec = 8.5 J/cm³, η = 93.4 %) under 640 kV/cm are realized in 0.91BST-0.09NBN-VPP ceramics, ensuring thermal reliability (20–120 °C) superior to most BT-based ceramics. This research marks a substantial advancement in the pursuit of more efficient and reliable ceramic dielectric capacitors, cruscial for powering modern high-power electronic devices.