Realizing Ultrahigh Energy Storage Density in (Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃-Based Ceramics via Manipulating the Domain Configuration and Grain Boundary Density

Dielectric capacitors with a high power density are widely used in various pulsed power electronic systems. However, their low comprehensive energy storage performance severely limits the development of these systems in terms of miniaturization and lightweight design. Herein, we achieved decent energy storage performance in a class of (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 (BNTBT)-based ceramics by synergistically manipulating domain configurations and grain boundary densities. High-resolution transmission electron microscopy and piezoresponse force microscopy confirm that composition-driven refined domain configurations with weak polarity effectively improve the polarization response of BNTBT-based ceramics. The results of experimental and phase-field simulation analysis indicate that the refined grain size contributes to its high breakdown electric strength ( E b ). Benefiting from the high polarization difference (Δ P ) of 32.62 μC/cm 2, delayed saturation polarization behavior, and an ultrahigh E b of 815.00 kV/cm, BNT-based ceramics simultaneously achieve a high energy storage density ( W rec ) of ∼12.25 J/cm 3 and an efficiency (η) of ∼86.90%. Because of these structure-induced advantages, the ceramics also exhibit good energy storage temperature stability in the range of 30–150 °C. We believe that the findings of this work may provide practical guidance for the development of high-performance energy storage ceramics.