Influence of Bi nonstoichiometry on the energy storage properties of 0.93KNN–0.07BixMN relaxor ferroelectrics

Ceramic-based dielectric capacitors are becoming more and more important in electronic devices. The ceramics of 0.93K[Formula: see text]Na[Formula: see text]NbO3–0.07Bix(Mg[Formula: see text]Nb[Formula: see text])O3 (0.93KNN–0.07BixMN) ([Formula: see text], 2/3, 0.75 and 0.95) were successfully fabricated by virtue of the solid reaction process in this work. The results showed that the amount of Bi content has a significant impact on the ceramics of 0.93KNN–0.07BixMN. XRD indicates that all specimens exhibit a pure perovskite structure and existing oxygen vacancy in the specimens. The mean grain size for all specimens belong to submicron scale, and the sample of [Formula: see text] owns the smallest grain size is 0.11[Formula: see text][Formula: see text]m. The maximum dielectric constant increases but the phase transition temperature [Formula: see text] exhibits a contrary tendency at 1[Formula: see text]MHz with increasing Bi concentration. Besides, all ceramics are relaxor ferroelectric. The impedance analysis further revealed that the activation energy of the ceramics increases with Bi content. Eventually, the highest [Formula: see text] of 58.8% and [Formula: see text] of 1.30[Formula: see text]J/cm3 are simultaneously achieved in the sample with [Formula: see text]. Overall, we demonstrate in this work that stoichiometry control of Bi in 0.93KNN–0.07BixMN ceramics is a practical method to obtain the desired structural, dielectric and energy storage properties.