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

## TL;DR

Researchers directly observed how electric fields trigger phase changes in antiferroelectric materials, which could lead to better energy storage devices.

## Contribution

The study reveals a detailed atomic-scale pathway of phase transitions in PbZrO3 under electric fields, linking microscopic changes to energy storage performance.

## Key findings

- An intermediate orthorhombic ferrielectric phase and a monoclinic ferroelectric phase were identified during the AFE-to-FE transition.
- The polarization modulation period decreased continuously, suggesting stronger dipole–dipole interactions.
- Machine learning simulations confirmed the experimental observations and provided insights into structural evolution.

## Abstract

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 (FiEO) and a monoclinic ferroelectric phase (FEM), ultimately stabilizing into a rhombohedral ferroelectric structure (FER). 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.

The electric‐field‐driven antiferroelectric‐to‐ferroelectric phase transition in epitaxial PbZrO3 films is directly visualized by in situ aberration‐corrected scanning transmission electron microscopy. A sequential transition pathway involving an orthorhombic ferrielectric phase and a monoclinic ferroelectric phase, ultimately stabilizing into a rhombohedral ferroelectric structure is revealed, which is accompanied by a reduction in polarization modulation period, indicating enhanced dipole–dipole interaction.