Defect-engineered core-shell structured NaNbO3-based energy storage ceramics

As research on lead−free energy storage materials advances, high−performance substrates and their modification methods have been continuously explored. In NaNbO 3 –based energy storage ceramics, low polarization limits the enhancement of energy storage performance. This study utilized defect engineering design to prepare (1– x )NaNbO 3 - x Sr(Fe 1/3 Sb 2/3 )O 3 ceramics with core–shell structure through a Fe/Sb dual oxidation state variable element synergistic regulation strategy. The goal is to enhance Δ P and optimize E b of ceramics by adjusting the content of vacancy defects and phase structure, so that ceramics can achieving high energy storage characteristics. A W rec of 6.4 J/cm 3 and η of 80% at 645 kV/cm were achieved in NaNbO 3 –based ceramic. Additionally, based on this study, we performed a detailed analysis of the origin of high Δ P and the influence of defect structures on E b , with the aim of providing a new reference for development and research of high–performance lead–free energy storage ceramics. • Fe and Sb synergistically regulate the concentration of oxygen vacancies in the ceramics and induce the formation of core-shell structure. • The proportion of weakly coupled polar phases in ceramics is increased by phase structure regulation, thereby enhancing the relaxor behavior. • The generation mechanism of high intrinsic breakdown electric field and the origin of high polarization difference are expounded. • A high energy storage density of 6.4 J/cm 3 and an energy storage efficiency of 80 % were achieved at 645 kV/cm for 0.13SFS ceramic.