Coupled Reconstruction of Local Polarization and Octahedral Tilting Enables Ultrahigh Dielectric Energy Storage

Dielectric capacitors are an indispensable component in modern electronic power systems. However, achieving high recoverable energy density ( W rec ), high efficiency ( η ), and excellent temperature stability simultaneously remains a significant challenge, limiting the practical application of advanced technologies. Here, guided by phase‐field simulations, we propose a dipole glass state strategy in NaNbO 3 ‐based ceramics, characterized by randomly distributed dipole‐glass nanodomains embedded within a nonpolar matrix, together with highly disordered and weakly antipolar BO 6 octahedral tilting. The approach can effectively reduce hysteresis losses and enhance breakdown electric field by decreasing domain size and refining grain, yielding an ultra‐high W rec of 15.1 J·cm −3 and a high η of 90.5%, which represents a breakthrough in NaNbO 3 ‐based ceramics with η greater than 90%. This work establishes a mechanism‐driven design principle for advancing next‐generation high‐performance dielectric energy‐storage materials.