Partitioning polar-slush strategy in relaxors leads to large energy-storage capability.

Relaxor ferroelectric (RFE) films are promising energy-storage candidates for miniaturizing high-power electronic systems, which is credited to their high energy density ( U e ) and efficiency. However, advancing their U e beyond 200 joules per cubic centimeter is challenging, limiting their potential for next-generation energy-storage devices. We implemented a partitioning polar-slush strategy in RFEs to push the boundary of U e . Guided by phase-field simulations, we designed and fabricated high-performance Bi(Mg 0.5 Ti 0.5 )O 3 -SrTiO 3 -based RFE films with isolated slush-like polar clusters, which were realized through suppression of the nonpolar cubic matrix and introduction of highly insulating networks. The simultaneous enhancement of the reversible polarization and breakdown strength leads to a U e of 202 joules per cubic centimeter with a high efficiency of ~79%. The proposed strategy provides a design freedom for next-generation high-performance dielectrics.