Tunable polarization-drived high energy storage performances in flexible PbZrO <sub>3</sub> films by growing Al <sub>2</sub>O <sub>3</sub> nanolayers
Chao Yin, Tiandong Zhang, Zhuangzhuang Shi, Bowen Zhang, Changhai Zhang, Qingguo Chi
Abstract
In recent years, PbZrO<sub>3</sub> (PZO) films have become a favorable electric storage material due to the unique electric field-induced phase transition behavior, but the severe hysteresis effect leads to the low energy storage density and efficiency. In this work, inserting Al<sub>2</sub>O<sub>3 </sub>(AO) insulation nanolayers is proposed to tune the polarization behavior of flexible PZO films, anticipating the optimization of energy storage performances. The results show that the thickness of the AO nanolayers has a deep influence on the polarization behavior of PZO films, PZO/AO/PZO (PAP) sandwiched films with 8 nm-AO interlayer deliver relaxor ferroelectric-like polarization instead of antiferroelectric counterpart. To further utilize AO nanolayers as top/bottom layers, a linear-like polarization and 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/cm<sup>3</sup> and efficiency of 92.9%, as well as excellent fatigue and bending endurance, good temperature and frequency stability. The tunable polarization induced by growing AO nanolayers makes antiferroelectric PZO films have great potential to be used as the energy storage dielectrics.