Ultrahigh Polarization Response along Large Energy Storage Properties in BiFeO3–BaTiO3-Based Relaxor Ferroelectric Ceramics under Low Electric Field

BiFeO₃-BaTiO₃ (BF-BT) dielectric ceramics are receiving more and more concern for advanced energy storage devices owing to their excellent ferroelectric properties and environmental sustainability. However, the energy density and efficiency are limited in spite of the large remanent polarization. Herein, we proposed a multiscale optimization strategy via a local compositional disorder with a Birich content and nanodomain engineering by introducing the Sr_0.7Bi_0.2Ca_0.1TiO₃ (SBCT) into BF-BT ceramics. Interestingly, an extraordinary energy storage property (ESP) with a high reversible energy storage density (W_rec) of ∼3.79 J/cm³ and an ultrahigh polarization discrepancy (ΔP) of ∼58.5 μC/cm² were obtained in the SBCT-modified BF-BT ceramics under 160 kV/cm. The boosted ESP should be attributed to the fact that the replacement of A/B-sites cations could transform the long-range ferroelectric order of the BF-BT system into polar nanoregions (PNRs) along with the refined grain size, decreased leakage current, and broadened energy band gap. Moreover, good frequency (1-10³ Hz) and temperature (25-125 °C) stabilities, high fatigue resistance (× 10⁵), large power density (∼31.1 MW/cm³), and fast discharge time (∼97 ns) were also observed for the optimized ceramics. These results illustrate a potentially effective method for creating high ESP lead-free ceramics at a low electric field.