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

## TL;DR

A new material design using quasi-antipolar nanoclusters in high-entropy relaxor ferroelectrics achieves excellent energy storage performance in capacitors.

## Contribution

Engineering quasi-antipolar nanoclusters in high-entropy relaxors to optimize polarization behavior and energy storage.

## Key findings

- Quasi-antipolar nanoclusters reduce polar nanoregion coupling and enable ferroelectric transitions under high electric fields.
- The material achieves a recoverable energy density of 18.3 J·cm−3 with 91.5% efficiency and energy storage strength of 0.25 J/(kV·mm−5).
- The system exhibits excellent thermal and frequency stability for energy storage applications.

## Abstract

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 Na0.73Ba0.1Bi0.11Li0.06Nb0.73Ti0.22Fe0.05O3 (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 Wrec
of 18.3 J·cm−3 with a high efficiency η of 91.5% and an outstanding energy storage strength Wrec/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.

Quasi‐antipolar nanoclusters are engineered in lead‐free NaNbO3‐based high‐entropy relaxors that weaken polar nanoregion coupling and induce distinct ferroelectric transition under high fields to enable desirable polarization response. This breakthrough system achieves ultrahigh recoverable‐energy‐density  (≈18.3 J cm−3), efficiency (≈91.5%), and breakthrough energy‐storage‐strength (0.25 J/(kV·mm−5)), supporting superior energy‐storage in eco‐friendly multilayer ceramic capacitors.