关键词: NaNbO$_{3}$, linear dielectric, energy storage performance, charge-discharge rate

Abstract: NaNbO$_{3}$-based lead-free dielectric ceramics possess significant application prospects in the field of dielectric capacitors. However, their development is hindered by low recoverable energy storage density ($W_{\rm rec}$) and energy storage efficiency ($\eta $). Herein, novel NaNbO$_{3}$-based ceramics, ($1-x$) [0.7Na$_{0.97}$Sm$_{0.01}$NbO$_{3}$-0.3(Sr$_{0.7}$Bi$_{0.2}$)(Ti$_{0.8}$Zr$_{0.2}$)O$_{3}$]-$x$CaTiO$_{3}$, were created by adding CaTiO$_{3}$ linear dielectric, aiming to improve their energy storage performance (ESP). The phase structure, microstructure, dielectric properties, energy storage and charge-discharge performances of the ceramics were methodically analyzed. All components of the ceramics exhibit a perovskite structure consisting of two phases: antiferroelectric $P$-phase (AFE $P$) and antiferroelectric $R$-phase (AFE $R)$, with the AFE $R$ phase increasing as $x$ rises. All ceramic surfaces exhibit clear grain morphology. The resultant ceramics have an appropriate dielectric constant and a small dielectric loss, which are beneficial for improving breakdown field strength ($E_{\rm b}$). Finally, at an $E_{\rm b}$ of 470 kV/cm, 0.85[0.7Na$_{0.97}$Sm$_{0.01}$NbO$_{3}$-0.3(Sr$_{0.7}$Bi$_{0.2}$)(Ti$_{0.8}$Zr$_{0.2}$)O$_{3}$]- 0.15CaTiO$_3$ ceramic achieves optimal ESP: $W_{\rm rec} = 3.9 $ J/cm$^{3}$, $\eta = 72.49$%. In addition, it has remarkable stability with temperature and frequency in energy storage and displays ultrafast speed in the charge-discharge process ($t_{0.9} = 27$ ns).

Key words: NaNbO$_{3}$, linear dielectric, energy storage performance, charge-discharge rate