Self‐Generated Glass‐Ceramics‐Like Structure Boosts Energy Storage Performance of AgNbO ₃ ‐Based MLCC

Abstract Dielectric capacitors are strikingly attractive for use in advanced high‐power pulsed‐discharge devices for electronic systems. However, their poor energy‐storage density ( U _rec ) and efficiency ( η ) resulting from the large remanent polarization ( P _r ) and low breakdown strength (BDS), have been the major challenge for practical applications. Inspired by the glass ceramics in which the core‐shell microstructure is considered an effective method to improve the BDS, maintain large P _max , and reduce P _r values, the strategy of “self‐generated glass‐ceramics‐like structure” is proposed in this work, and the (Eu _x Ag _{1−3 x} )NbO ₃ (Eu _x AN) at 0.00 ≤ x ≤ 0.09 capacitors are designed. Similar to glass ceramics, the ceramics‐like AFE regions in the “self‐generated glass‐ceramics‐like structure” help to improve P _max value, while glass‐like PE regions are responsible for increasing the BDS of the capacitor, so as to achieve ultrahigh U _rec and η values. Because of the glass‐ceramics‐like structure, high recoverable energy storage U _rec ≈ 16.6 J cm ⁻³ along with an excellent η ≈ 93.1% are achieved in the Eu _x AN ( x = 0.07) multilayer capacitors. This work offers a good paradigm for improving the energy storage properties of AFE systems to meet the demanding requirements of advanced energy storage applications.