Superior energy storage capacity of a Bi0.5Na0.5TiO3-based dielectric capacitor under moderate electric field by constructing multiscale polymorphic domains

The challenge of electronic components failing in service when exposed to ultra-high electric fields necessitates the development of dielectric capacitors with a higher energy storage density per electric field. Therefore, the development of dielectric capacitors with high energy storage density under moderate electric fields is of great importance. To address this issue, a polymorphic multiscale domain construction strategy has been proposed in this work. Guided by the results of phase field simulations, lead-free Bi0.5Na0.5TiO3-Sr0.7Bi0.2TiO3-La(Mg0.5Ti0.5)O3 ceramics have been prepared, which enable the coexistence of rhombohedral (R) + tetragonal (T) nanodomains and polar nanoregions (PNRs). This has resulted in a total energy density of 7.3 J·cm−3 and efficiency of 93% at 390 kV·cm−1 in the current system. Additionally, the energy storage potential (Wrec/Eb) of this ceramic is the highest in Bi0.5Na0.5TiO3-based systems among the latest research. Furthermore, the ceramic displays excellent thermal stability from − 50 to 200 ℃. This work provides a new approach to enhance the energy storage properties (ESPs) of dielectric ceramics under moderate electric fields. [Display omitted] •The Wt of 7.3 J·cm−3 and η of 93%, with a Wrec/Eb of 17.41 J·cm−2·V−1 are achieved.•The specimen presented excellent temperature stability (−50–200 ℃).•Combining phase field simulations and experimental data is conducted in this work.•A polymorphic multiscale domain construction strategy is adopted.•The significance of ESPs under moderate electric field is emphasized.