Enhanced energy storage performance of NaNbO3-based ceramics by constructing weakly coupled relaxor behavior

Dielectric capacitors are extensively utilized in various pulse power systems due to their ultra-high power density and rapid discharge rate. However, their relatively low energy storage density impedes the advancement towards miniaturization of these applications. Herein, we achieve a class of weakly coupled relaxor ferroelectrics that demonstrate both an exceptional energy storage capacity with an effective storage energy density (Wrec) of 6.49 J/cm3 and remarkable thermal stability ranging from 20 °C to 160 °C. The refined grain size and enhanced insulating properties contributed to the increased electric breakdown strength (Eb) of the system. The emergence of weakly coupled polar nanodomains leads to an enhanced polarization difference (∆P) in the system. These findings offer a viable paradigm for designing dielectric capacitors with decent energy storage performance.