Realizing high energy storage performance in Tb3+ and Ta5+ co-doped AgNbO ₃ -based ceramics under high breakdown electric field

Due to the unique double polarization hysteresis loops and large maximum polarization, lead-free AgNbO 3 -based antiferroelectric (AFE) ceramics have been regarded as one of the most promising materials for dielectric capacitor applications. However, its ferroelectric behavior and poor breakdown strength limited the improvement of energy storage properties. In this study, aiming to enhance AFE stability and improve breakdown strength, the Tb[Formula: see text] with smaller ionic radius and Ta[Formula: see text] with lower polarizability were co-doped in AgNbO 3 to form (Ag[Formula: see text]Tb[Formula: see text](Nb[Formula: see text]Ta[Formula: see text]O 3 (100xTa) solid solution. The 100xTa ceramics exhibited reduced grain size and increased breakdown electric field. A room temperature M2–M3 phase boundary was engineered by tuning the composition near 40Ta, which significantly enhances the AFE stability and relaxor feature. Of particular importance is that a high recoverable energy density of 7.5[Formula: see text]J/cm 3 and a good efficiency of 78% were simultaneously achieved in 40Ta ceramics under 570[Formula: see text]kV/cm, as well as excellent frequency stability, high discharged energy density and ultrafast discharge rate, demonstrating its great potential for practical applications.