Quasi‐Antipolar Nanoclusters Driven Superior Energy Storage in High‐Entropy Relaxor Ferroelectrics

Relaxor ferroelectrics featuring highly dynamic polar nanoregions hold significant potential for pulse-power dielectric capacitor applications. Nevertheless, achieving an optimal polarization-field response that combines low hysteresis, delayed polarization saturation, and high maximum polarization remains a critical challenge toward superior comprehensive energy storage performance. Herein, we propose an effective strategy of engineering quasi-antipolar nanoclusters in relaxor ferroelectrics via a high-entropy composition design to optimize polarization behavior. By intentionally incorporating aliovalent ions with different ferroelectric activities into antiferroelectric NaNbO₃, local antiparallel-like polarization configurations were constructed within a high-entropy relaxor matrix of Na_0.73Ba_0.1Bi_0.11Li_0.06Nb_0.73Ti_0.22Fe_0.05O₃ (NBBLNTF). These quasi-antipolar nanoclusters not only weaken the coupling among polar nanoregions but also exhibit distinct transition behaviors under high electric fields toward a ferroelectric state. Consequently, a polarization-field loop with low hysteresis, high linearity, and large maximum polarization is achieved, yielding an ultrahigh recoverable energy density W_rec of 18.3 J·cm^-3 with a high efficiency η of 91.5% and an outstanding energy storage strength W_rec/E of 0.25 J/(kV·mm^-5) in NBBLNTF multilayer ceramic capacitors, together with excellent thermal and frequency stability. These results offer a feasible strategy for developing next-generation high-performance dielectrics with exceptional energy storage properties.