Direct Observation of Electric‐Field‐Driven Phase Transitions Associated with Energy Storage in Antiferroelectric Films

Antiferroelectric materials are promising candidates for high-energy-density capacitors due to their reversible electric-field-induced phase transitions. However, the atomic-scale mechanism underlying the electric-field-driven antiferroelectric-to-ferroelectric (AFE-to-FE) transition, particularly in relation to high-performance energy storage, remains elusive. Here, we employ in situ aberration-corrected scanning transmission electron microscopy (STEM) to directly visualize the electric-field-driven AFE-to-FE transition in epitaxial PbZrO₃ (PZO) thin films. We reveal a sequential electric-field-driven transition pathway involving an intermediate orthorhombic ferrielectric phase (FiE_O) and a monoclinic ferroelectric phase (FE_M), ultimately stabilizing into a rhombohedral ferroelectric structure (FE_R). This transformation is accompanied by a continuous reduction in the polarization modulation period, indicating enhanced dipole-dipole interaction coupling, which may improve their energy storage performance. Our experimental findings are corroborated by machine learning molecular dynamics simulations, providing quantitative insights into the structural evolution. This work illustrated the relationship between microscopic phase evolution dynamics and macroscopic energy storage behavior, offering a powerful strategy for the design and optimization of next-generation antiferroelectric energy storage materials.