Energy storage properties of NaNbO₃-CaZrO₃ ceramics with coexistence of ferroelectric and antiferroelectric phases

Anti-ferroelectric materials with large saturated polarization, small remnant polarization, and moderate breakdown strength are receiving increasing attention for modern high-power electrical systems. Here we demonstrated that by incorporating CaZrO₃ into NaNbO₃ ceramics, the antiferroelectricity in NaNbO₃-CaZrO₃ solid solutions could be stabilized at room temperature. The effects of phase constitution and microstructure on the dielectric properties, electrical breakdown strength, and energy storage properties of the NaNbO₃-CaZrO₃ ceramics were investigated. Ferroelectric and antiferroelectric phase coexistence in the NaNbO3-CaZrO₃ was confirmed by XRD and TEM analyses. With increasing CaZrO₃ content, the grain size was reduced, and the dielectric breakdown strength was improved. Therefore, a high energy density of 0.55 J/cm³ and efficiency of 63% was obtained in the NaNbO₃-0.04CaZrO₃ ceramics. These lead-free NaNbO₃-CaZrO₃ antiferroelectrics with good electrical energy storage can be exploited for high-power storage devices.