Design of SPE‐RFE state through Bi3+ substitution on CLT‐modified NBT‐6.5BT ceramics gaining enhanced energy density

Abstract The pursuit of environmentally sustainable, lead‐free ceramics with outstanding energy storage capabilities is crucial for the advancement of next‐generation high‐power capacitors. However, achieving this objective comes with significant hurdles. In this investigation, we have developed a highly effective method for inducing the relaxor ferroelectric phase (RFE) within super paraelectric (SPE) materials, specifically in Bi 3+ ‐substituted NBT‐BT‐CLT ceramics. This innovation has resulted in an exceptional energy storage density of approximately 5.83 J cm −3 under an electric field of 320 kV/cm, coupled with an impressive efficiency rating of around 79%. The outstanding performance in energy storage can be largely attributed to the intentional manipulation of ultrasmall polar nanoregions, as confirmed through HRTEM analysis. This engineering approach not only reduces grain size but also significantly enhances polarization and raises the thresholds for the breakdown of electric fields. The SPE‐RFE strategy demonstrated in this study holds broad applicability in optimizing dielectric properties and other essential functionalities, thereby facilitating the conceptualization of advanced energy storage devices.