Enhanced energy storage performance of (Bi0·4Ba0·2K0·2Na0.2)TiO3–NaNbO3 high-entropy ceramics under moderate electric fields

Abstract

High-entropy perovskite oxides (HEPOs) have attracted considerable attention as dielectric ceramics. However, the energy-storage performance of these HEPOs still requires improvement. In this study, a series of (1-x)(Bi0.4Ba0.2K0.2Na0.2)TiO3-xNaNbO3 high-entropy ceramics were designed and prepared using a high-entropy strategy. The introduction of antiferroelectric NaNbO3 into the (Bi0.4Ba0.2K0.2Na0.2)TiO3 medium-entropy matrix increased the configurational entropy and cationic disorder, resulting in improved energy storage performance. The ceramic with an optimal composition of 0.775(Bi0.4Ba0.2K0.2Na0.2)TiO3-0.225NaNbO3 achieved a high recoverable energy density (Wrec) of 2.523 J/cm3 and a high efficiency (η) of 83.7% at an electric field of 220 kV/cm. Furthermore, the material demonstrated good temperature and frequency stability, as well as good anti-fatigue properties. This paper presents a dielectric ceramic suitable for energy storage under low to moderate electric fields.