Outstanding comprehensive energy storage performances in multiscale synergistic regulation-engineered (Bi_0.5Na_0.5)TiO₃-based multilayer ceramics

Environmentally friendly dielectric ceramics with superior energy storage performances (ESP) are strongly demanded in pulsed power capacitor applications. Unfortunately, it is challenging to achieve simultaneously large recoverable energy density (W_rec), high W_rec/E (E as electric field) and broad operating temperature range in those ceramics. Herein we propose a multiscale synergistic regulation strategy to enhance comprehensive ESP of (Bi_0.5Na_0.5)TiO₃ (BNT)-based ceramics. We introduce Ca(Zr_0.8Ti_0.2)O₃ (CZT) into the BNT to increase atomic chaos and lattice distortion, which enhances relaxor behavior and lowers domain-switching barriers, thus effectively reducing remanent polarization. Besides, both suppressed oxygen vacancy and refined submicron grains improve extrinsic resistivity, which works synergistically with the enlarged intrinsic bandgap and multilayer structure design, producing substantially enhanced breakdown strength. Encouragingly, a very large W_rec of 13.4 J/cm³, an ultrahigh W_rec/E of 160 J/(kV∙m²), and a high efficiency η of 90.2 % are simultaneously achieved in the novel (Bi_0.5Na_0.5)TiO₃-Ca(Zr_0.8Ti_0.2)O₃ (BNT-CZT) multilayer ceramics, together with outstanding energy storage stability over a broad working temperature range (20–180 °C). The comprehensive ESP of our multilayer ceramics are superior to most of previously reported lead-free ones. This work provides a feasible pathway for substantially improving comprehensive ESP of lead-free ceramics, and also highlights advanced energy storage potential of the BNT-CZT for high-performance pulsed power applications.