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 NaNbO₃–based energy storage ceramics, low polarization limits the enhancement of energy storage performance. This study utilized defect engineering design to prepare (1–x)NaNbO₃-xSr(Fe_1/3Sb_2/3)O₃ ceramics with core–shell structure through a Fe/Sb dual oxidation state variable element synergistic regulation strategy. The goal is to enhance ΔP 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/cm³ and η of 80% at 645 kV/cm were achieved in NaNbO₃–based ceramic. Additionally, based on this study, we performed a detailed analysis of the origin of high ΔP 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.