Superior Energy‐Storage Performance in Sandwich‐Structured AgNbO ₃ ‐Based Ceramics

Abstract Antiferroelectric (AFE) ceramics with typical double polarization‐electric field loops hold exceptional potential for high capacitance density capacitors. However, the inherent contradiction between polarization and breakdown strength limits the energy storage performance in AFE ceramics. Herein, the polarization and breakdown strength are improved simultaneously via optimizing the sandwich structure with alternate large polarization (Ag 0.82 Bi 0.06 )NbO 3 layer and high breakdown strength (Ag 0.70 Bi 0.10 )NbO 3 layer. A recoverable energy storage density W rec of 16.8 J cm −3 with energy efficiency η of 81.3% is realized in (Ag 0.70 Bi 0.10 )NbO 3 /(Ag 0.82 Bi 0.06 )NbO 3 /(Ag 0.70 Bi 0.10 )NbO 3 ceramic, attaining the peak value of AgNbO 3 ‐based AFE ceramics. Moreover, the sandwich‐structured ceramic shows good stabilities with variations of less than 7.0% over a temperature range of 30–150 °C, frequency range of 1–500 Hz, and 10 5 cycling in W rec , and a discharge energy density W d of 6.2 J cm −3 along with a fast discharge time t 0.9 of 120 ns. This research provides an effective strategy for enhancing the energy storage performance of lead‐free AFE ceramics, highlighting their potential for practical applications in pulse power systems.