Phase Transitions in Bi/Ca Modified AgNbO 3 Ceramics with Excellent Energy Storage Density and Storage Intensity

作者：Zhongna Yan, Jia He, Haiyan Chen, Dou Zhang, Yuan Liu, Hang Luo, Chuanchang Li, Isaac Abrahams, Haixue Yan · 发表于：Small · 年份：2025 · DOI：10.1002/smll.202500810 · 被引用次数：14 · 研究领域：Ferroelectric and Piezoelectric Materials、Acoustic Wave Resonator Technologies、Multiferroics and related materials

Abstract Lead‐free antiferroelectric (AFE) ceramics based on AgNbO 3 represent attractive materials for energy storage applications but are limited by their recoverable energy density ( W rec ). Here Bi 3+ /Ca 2+ A‐site modification of AgNbO 3 ceramics has yielded a particularly high W rec of 4.4 J cm −3 and a superhigh recoverable energy storage intensity ( ρ ) of 21.46 × 10 −3 J kV −1 cm −2 at 205 kV cm −1 , the latter being the highest known value obtained at such a relatively low field for a lead‐free ceramic. The modification shifts the dipole freezing temperature, T f , to below room temperature, enhancing the room temperature stability of the AFE structure. The high W rec is attributed to the enhancement of the maximum field‐induced dielectric displacement and improved forward ( E F ) and backward ( E B ) fields. The work has also allowed for an examination of the poorly understood ± E U current peaks evident in current–electric field loops of AgNbO 3 ‐based ceramics, which is proposed to be related to a field‐induced AFE to ferroelectric (FE) phase transition in the M 1 or M 2a phases and is absent in the M 2b phase due to increased stability of the AFE phase. The exceptional performance of Bi 3+ /Ca 2+ modified AgNbO 3 ceramics is promising for potential use in ceramic capacitors for high pulsed power applications.