Enhanced energy storage in high-entropy superparaelectrics via local ferroelectric polarization.

Dielectric ceramic capacitors with ultrahigh power density have become essential in modern power electronics. Guided by phase-field simulations and experiments, we propose a "local ferroelectric-global superparaelectric" strategy. This approach enhances Pm by introducing local ferroelectric polarization within a superparaelectric matrix, enabling superior energy storage performance. Introducing strong ferroelectric PbTiO₃ into a (Bi0.2Na0.2K0.2La0.2Sr0.2)Ti0.9Zr0.1O3 high-entropy superparaelectric achieves an ultrahigh energy storage density of ~21 J/cm³ with an efficiency of ~87% at 110 kV/mm. Multiscale structural characterization and theoretical calculations reveal the atomic-scale mechanism for this performance enhancement. At ≤ 30% PbTiO3, the Pb2+ lone pair effect is locally confined, boosting local ferroelectric distortion while maintaining a superparaelectric average structure for superior energy storage. At 40-50%, this effect extends throughout the matrix, inducing submicro-scale domains and macroscopic piezoelectricity. This work presents a design and material system for high-performance energy storage ceramics, laying the theoretical foundation for advanced high-entropy ferroelectric applications.