Multiscale Modulation for Enhanced Breakdown Strength and Relaxation Performance in Bi0.5Na0.5TiO3-Based Ferroelectric Films

The development of effective material modification strategies to enhance the energy-storage performance in dielectric film capacitors remains a critical research focus. Typically, it is difficult to achieve a comprehensive improvement with one single strategy, constrained by complicated interrelationships in materials. Herein, a multiscale modulation strategy is designed in Bi0.5Na0.5TiO3(NBT)-based films. Incorporation of Bi3.25La0.75Ti3O12(BLT) synergistically optimizes the domain structure and microstructure evolution at the multiscale, contributing to the generation of highly dynamic polar nanoregions, reduced grain sizes, low remnant polarization, and enhanced breakdown strength. Consequently, the 0.8NBT–0.2BLT film exhibits a high energy-storage density of 52.2 J cm–3 and a high efficiency of 70.1% under a high breakdown field of 1836 kV cm–1, accompanied by exceptional fatigue endurance, thermal stability, and frequency stability. This multiscale modulation strategy offers a tremendous opportunity for customizing and optimizing the synthetic capability of dielectric materials for energy-storage applications.