High capacitive energy storage performance in Bi0.5Na0.5TiO3–SrTiO3 relaxor ferroelectrics via nanodomain engineering

Dielectric capacitors are essential components in modern electronic devices, but their limited energy storage performance has become one of the core obstacles to their cutting-edge applications. Herein, by constructing nanodomains and improving electric field endurance, Bi0.5Na0.5TiO3–SrTiO3–Sr(Sc0.5Ta0.5)O3 relaxor ferroelectric ceramics achieve an ultrahigh recoverable energy density (Wrec) of 9.1 J/cm3 and a high efficiency (η) of 86.7% under 630 kV/cm. On the one hand, the introduction of perovskite-type end-member Sr(Sc0.5Ta0.5)O3 facilitates the phase transition between nonergodic and ergodic relaxor states, yielding the formation of local polymorphic nanodomains, which further promotes polarization switching responding to the external electric field. On the other hand, the reduced grain size and improved insulating property jointly contribute to a greatly enhanced electric breakdown. Moreover, the optimal composition also presents superior thermal stability (30–150 °C, ΔWrec < 0.56 J/cm3) and charge/discharge behavior (PD = 541.7 MW/cm3, t0.9 = 48 ns). This work offers a highly promising candidate material for advanced pulsed-/high-power applications.