Optimized energy storage performance of SBT-based lead-free relaxor ferroelectric thin film

Relaxor ferroelectric thin films, that demonstrate high energy storage performances due to their slim polarization–electric field hysteresis loops, have attracted extensive attentions in the application of miniaturized advanced pulsed power electronic systems. However, the ubiquitous defects induced in the thin films, for example, due to the volatilization of cations, limit the energy storage performance to a great extent due to the reduced breakdown strength. Here, the shallow trap defects, but not the oxygen vacancy, in 0.9Sr_0.7Bi_0.2TiO₃-0.1BaTiO₃ (SBT-BT) relaxor ferroelectric thin films are effectively suppressed by the Mn doping. An improved high energy storage density of 55 J/cm³ and an optimized high energy storage efficiency of 80.9% are achieved in the Mn-doped SBT-BT relaxor ferroelectric thin films, and high fatigue resistance, frequency and temperature stability are also achieved simultaneously. These results indicate this SBT-BT-based relaxor ferroelectric thin films exhibit high energy storage performance and can be used as an important component in energy storage electrical and electronic systems. More importantly, this work provides an effective approach to achieve high energy storage performances by shallow trap defect quenching.