Ultrahigh energy storage density and efficiency in AgNbO<sub>3</sub>-based ceramics by percolating interaction between antipolar regions and defect pairs.

He, Liqiang; Zhang, Le; Ran, Yating; Bo, Cunle; Chen, Kaiyun; Liu, Yao; Zhang, Chen; Zheng, Zihao et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

A critical challenge for the application of lead-free antiferroelectrics in energy storage systems is their poor thermal stability and low efficiency when the superior energy storage density is attained, primarily due to the inherent first-order nature and narrow temperature window of antiferroelectric-to-ferroelectric transitions. Here, we elucidate a unique percolating interaction between antipolar regions in antiferroelectrics and engineered defect pairs using density functional theory and phase field calculations. Strategic distribution of the strongly coupled Li-Ta pairs in AgNbO<sub>3</sub> fosters a percolating interaction that facilitates antipolar rotations, enabling a pronounced polarization change with minimal hysteresis. Guided by theoretical calculations, a large recoverable energy storage density of 12.8 J/cm<sup>3</sup>, with a high efficiency of 90%, is achieved at room temperature in Ag<sub>0.95</sub>Li<sub>0.05</sub>Nb<sub>0.35</sub>Ta<sub>0.65</sub>O<sub>3</sub> ceramics. Moreover, the superior energy storage performance can remain stable within a wide temperature range from -70 to 170 °C, which paves the way for application in advanced energy capacitors.