Enhanced Energy Storage Performance in Yb-Doped AgNbO₃ Antiferroelectric Ceramics

AgNbO3 lead-free ceramics have garnered significant attention in energy storage applications owing to their exceptional power density and environmental compatibility; however, they are limited by their low breakdown strength and large hysteresis. In this study, Ag(1–3x)YbxNbO3 powders are synthesized via a hydrothermal method, followed by conventional sintering in an ambient atmosphere. Raman spectroscopy analysis reveals that progressive Yb3+ doping induces attenuation and broadening of the V5 phonon mode, effectively suppressing the Nb5+ cation displacement, and this structural modification significantly enhanced the antiferroelectric phase. At x = 0.02, the optimal energy storage performance is achieved with an energy density of 4.05 J/cm3 and energy efficiency of 61%, which represents a 50% enhancement over the conventional solid-state synthesized counterparts. Remarkably, the ceramics display excellent temperature and frequency stability. The variation in Wrec and η is less than 5 and 14% between room temperature and 110 °C, and less than 8 and 9% over the 10–100 Hz frequency range. Furthermore, the material exhibits a superior power density (41 MW/cm3) and ultrafast discharge characteristics (t0.9 = 1.06 μs). These results provide insights into the design of AgNbO3 antiferroelectric ceramics.