ABSTRACT Achieving high recoverable energy density ( W rec ) with near‐unity efficiency ( η ) in lead‐free dielectrics remains a major challenge for advanced pulse power capacitors, given their central role in emerging pulsed power systems and high‐voltage electronics. Here, we show that targeted engineering of dynamic dipole behavior provides an effective route to remarkable energy storage performance. Guided by phase‐field simulations, we design (Bi 0.5 Na 0.5 )TiO 3 (BNT)‐based multilayer ceramic capacitors that transform a continuous network of strongly correlated dipoles into discrete nano‐domains. Within each nano‐domain, dipoles retain strong local cooperativity, which maintains high polarization while markedly suppressing hysteresis losses. As a result, the optimized multilayer ceramic capacitors (MLCCs) achieve a recoverable energy density of 16.2 J cm −3 , an η below 1.5%, and a record‐high figure of merit ( W F ) of 1080 at 650 kV cm −1 . This moderate operating field also produces an ultrahigh energy storage strength ( ξ ) of 249 J kV −1 m −2 , highlighting the efficiency of the dipole‐regulation strategy. These findings demonstrate that weakly correlated and dynamic dipoles can be harnessed to advance high‐performance, lead‐free energy storage devices and offer a viable design principle for next‐generation capacitive technologies.
Huang et al. (Tue,) studied this question.