Improved energy storage performance of NaNbO3‐based antiferroelectrics by tuning polarizability and defect engineering

NaNbO3‐based antiferroelectric ceramics are promising candidates for high‐performance energy storage capacitors due to their environmental friendliness and low cost despite their current energy storage properties being inferior to those of their lead‐based and AgNbO3‐based counterparts. Typically, the antiferroelectric phase in NaNbO3 ceramics is not stable and the characteristic double hysteresis loops are seldom observed. In this work, the antiferroelectricity was improved by reducing the polarizability, resulting in well‐developed double hysteresis loops in 0.94NaNbO3–0.06(K0.5Bi0.5)SnO3 ceramics. To further improve the energy storage properties, defect engineering was performed for 0.94NaNbO3–0.06(K0.5Bi0.5)SnO3 by substituting Na+ with La3+ and introducing Nb vacancies. As a result, the stability of the field‐induced ferroelectric phase was reduced, and the energy storage properties were enhanced. The strategy of combining polarizability design and defect engineering can be a promising approach for optimizing NaNbO3‐based antiferroelectric ceramics.