X9R-type Ag1-3Bi NbO3 based lead-free dielectric ceramic capacitors with excellent energy-storage properties

Nowadays, environmental-friendly ceramics simultaneously possessing good dielectric temperature stability and energy-storage characteristics are receiving unparalleled attention. In this work, Bi2O3 modified AgNbO3 lead-free ceramics were successfully prepared by a traditional solid-state reaction method. The results showed that Bi2O3 plays an important role in adjusting the phase transition temperature. As a result, all dielectric anomalies shift to low temperatures with increasing Bi element doping level. Among all the compositions, the Ag0.88Bi0.04NbO3 ceramic has the best dielectric thermal stability of dielectric constant within ±15% over a temperature range of -55-200 °C, and a low loss simultaneously, satisfying the requirements for X9R capacitors. Moreover, excellent energy-storage characteristics of Wrec = 4.51 J/cm3 and ƞ = 85%, as well as good temperature (25–100°C) and frequency (5–200 Hz) stabilities were simultaneously achieved in the Ag0.88Bi0.04NbO3 sample, which suggests that the Bi2O3-doped AgNbO3 ceramic would be a potential dielectric for the applications of thermally-stable energy-storage pulse-power capacitors.