Enhanced energy-storage performance in silver niobate-based dielectric ceramics sintered at low temperature

Abstract

Silver niobate (AgNbO3, AN) dielectric ceramics and their antiferroelectric behavior have attracted increasing attention for their potential applications in energy-storage capacitors. However, AN’s inferior dielectric breakdown strength, recoverable energy storage density, and efficiency have limited its application. In this work, a combination of chemical composition design and liquid-phase sintering was considered for the fabrication of highly insulated and desensitized AN-based ceramics for enhancing Eb, Wrec, and η of AN. We design and prepare (1 − x)AgNbO3-x(Sr0.7Bi0.2)HfO3 (AN-100xSBH, x = 0.00–0.06) ceramics with the addition of 1 mol% BaCu(B2O5) (BCB) as a sintering aid to realize this. It is found that highly desensitized ceramics can be formed at 1000–1030 °C over the course of 2 h. The electrical property characterization results indicate that the AFE state and Eb are significantly enhanced with increasing SBH concentration. High Wrec and η values of 6.1 J/cm3 and 73%, respectively, under an applied field of 330 kV/cm are achieved in the AN-5.5SBH ceramic. Meanwhile, the AN-5.5SBH ceramic shows excellent thermal stability over a wide temperature range (25–120 °C) under an externally applied field of 290 kV/cm, in which the fluctuations of Wrec and η are 3.8% and 1.5%, respectively. These results provide an effective method for obtaining AN-based ceramics with excellent electrical properties under a lower sintering temperature than that required for pure AN ceramics. This method could be further generalized to develop new lead-free energy-storage dielectric materials.