Enhanced energy storage performance of NaNbO3-based ceramics by modifying phase structures and electrical insulation

The remarkable polarization and stability of ceramic capacitors make them promising candidates for pulse-power devices in energy-storage systems. However, the energy-storage density of ceramic capacitors is severely limited by the negative correlation between the maximum polarization ( P m ) and the breakdown strength (BDS), leading to the impediment of broader applications. Herein, we reconcile the contradiction by synthesizing high-performance NaNbO 3 -based ceramics via chemical doping with Bi(Ni 0.5 Ti 0.25 Zr 0.25 )O 3 (BNTZ). An antiferroelectric-paraelectric phase transition with a decline in polarization hysteresis is induced by the dopant. Further studies have shown that the existence of a tiny quantity of the polar phase in the nonpolar matrix contributes to a higher P m , and the enhancement of both electrical resistivity and activation energy of the conductance also improved their BDS. The thinning process is also identified to be important in the improvement of its BDS and W rec , resulting in the maximum energy-storage density of 3.53 J/cm 3 with an energy efficiency of 74.2 % in thinned 10 mol% BNTZ-doped NaNbO 3 samples. Our findings provide a feasible approach to simultaneously improving energy-storage density and efficiency in NaNbO 3 -based ceramic capacitors.