Polymorphic Polar Ordering Engineered Relaxor Antiferroelectric for High Energy Storage Performance

ABSTRACT Antiferroelectrics are promising for high‐energy‐density storage owing to their characteristic double hysteresis loops. However, their performance is severely limited by their antiferroelectricity instability, low breakdown strength, and high hysteretic loss. This study proposes a performance optimization strategy based on polymorphic polar order engineering. By the introduction of LaScO 3 nonpolar end‐member into antiferroelectric PbHfO 3 , the long‐range antipolar orders were disrupted and thus establish a polymorphic polar configuration, combining short‐range antipolar orders and disordered nonpolar regions. This structure, directly observed via atomic‐scale scanning transmission electron microscopy, simultaneously delays the antiferroelectric‐ferroelectric phase transition field, depresses the field‐induced hysteretic loss, and improves the breakdown field. Consequently, the optimized polymorphic PbHfO 3 −based relaxor antiferroelectric achieves a high energy density of 100.3 J cm − 3 and efficiency of 76.3%, rivaling the advanced antiferroelectrics. Moreover, the films demonstrate exceptional stability under a broad temperature (−100°C to 200°C) and frequency (1–100 kHz) ranges, as well as extended cycling (up to 10 8 cycles). This work not only elucidates the microscopic mechanism of polymorphic polar order in optimizing antiferroelectric energy storage performance but also provides a novel design strategy for antiferroelectrics that integrates high energy density, high efficiency, and superior reliability.