Tunable polarization-drived high energy storage performances in flexible PbZrO₃ films by growing Al₂O₃ nanolayers

In recent years, PbZrO₃ (PZO) films have become favorable electric storage materials due to the unique electric field-induced phase transition behavior, but the severe hysteresis effect leads to low energy storage density and efficiency. In this work, inserting Al₂O₃ (AO) insulation nanolayers is proposed to tune the polarization behavior of flexible PZO films, anticipating optimization of energy storage performance. The results show that the thickness of the AO nanolayers has a deep influence on the polarization behavior of the PZO films, and PZO/AO/PZO (PAP) sandwiched films with 8 nm AO interlayer deliver relaxor ferroelectric-like polarization instead of antiferroelectric counterpart. To further utilize the AO nanolayers as top/bottom layers, the linear-like polarization and the highest breakdown strength are achieved in the AO/PZO/AO/PZO/AO (APAPA8) multilayer films, leading to both high discharged energy storage density of 35.2 J/cm³ and efficiency of 92.9%, as well as excellent fatigue and bending endurance, good temperatures, and frequency stability. The tunable polarization induced by growing the AO nanolayers makes antiferroelectric PZO films have great potential to be used as energy storage dielectrics.