Dynamic Dipole Engineering Enables Ultrahigh Energy Storage With Minimal Losses

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_0.5Na_0.5)TiO₃ (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.