Realizing\nUltrahigh Energy Storage Density in (Bi<sub>0.5</sub>Na<sub>0.5</sub>)<sub>0.94</sub>Ba<sub>0.06</sub>TiO<sub>3</sub>‑Based Ceramics\nvia Manipulating the Domain Configuration\nan

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