Enhanced relaxor behavior and energy-storage properties in Na${}_{0.5}$Bi${}_{0.5}$TiO${}_3$-based ceramics by doping the complex ions (Al${}_{0.5}$Nb${}_{0.5}$)${}^{4+}$

Herein, (Na${}_{0.5}$Bi${}_{0.5}$)${}_{0.94}$Ba${}_{0.06}$Ti${}_{1-x}$(Al${}_{0.5}$Nb${}_{0.5}$)${}_x$O${}_3$ (NBBT-xAN) ceramics are fabricated through a solid reaction method. X-ray diffraction reveals the structure of NBBT-xAN ceramics transforms from coexistence of rhombohedral and tetragonal structures to a pseudocubic structure with increasing AN content. Raman spectroscopy indicates the long-range ferroelectric order of NBBT ceramics is broken by AN and the polar nanoregions (PNRs) with weak polarization are formed. The relaxor behavior of NBBT ceramics is enhanced by the enhanced random electric fields (REFs) through the heterovalent cations Al${}^{3+}$/Nb${}^{5+}$. Therefore, a slim and pinched P-E loop is obtained for NBBT ceramics by doping AN and the energy-storage properties (ESPs) can be improved dramatically under a low electric field. The maximum recoverable energy density (W${}_{rec}$) of 1.2 J cm${}^{-3}$ is obtained at x = 0.04 under a low electric field of 100 kV cm${}^{-1}$. However, a relatively high W${}_{rec}$ of 1.0 J cm${}^{-3}$ and efficiency ($\eta$) of 77% are simultaneously obtained at x = 0.05 under the same electric field strength. Moreover, NBBT-0.05AN ceramics also exhibit excellent temperature (30-180 °C), fatigue (10${}^4$) and frequency (1-40 Hz) stabilities. Most important, the study provides a strategy to design high energy-storage capacitors under a low electric field. (© 2022 Wiley‐VCH GmbH)