Novel transparent Eu and Hf co-doped AgNbO3 antiferroelectric ceramic with high-quality energy-storage performance

Low energy-storage density hinders the miniaturization of energy-storage devices. Therefore, improving the dielectric constant and field strength of dielectric materials has become a research focus for energy storage. In this study, a novel type of transparent AgNbO3 antiferroelectric ceramic co-doped with Eu3+ and Hf4+ ions was prepared using the traditional solid-phase sintering method. The effects of Eu3+ and Hf4+ additions on the phase, microstructure, transmittance, and energy-storage performance of AgNbO3 transparent antiferroelectric ceramics were systematically studied. The results show that a few Hf4+ ions doped into the AgNbO3 matrix do not change the perovskite structure of AgNbO3. Meanwhile, Eu3+ doping can induce a phase red-shift. This reveals that the co-doping of Eu3+ and Hf4+ can reduce the phase transition temperatures of the monoclinic M1-M2 and M2-M3 phases. The (Ag0.91Eu0.03) (Nb0.96Hf0.05)O3 ceramic possesses high transparency, with an optical transmittance of 42% at 780 nm, and its energy-storage density and energy efficiency can reach 4.08 J/cm3 and 65.0%, respectively, at an electric field of 320 kV/cm. Furthermore, the as-prepared antiferroelectric sample exhibited satisfactory thermal stability at 20–120 °C. All the aforementioned merits make it a most promising original energy-storage material.