# High‐Entropy Chemical Composition Design for Ultrahigh Capacitive Energy Storage

## TL;DR

This paper introduces a new lead-free ceramic material with excellent energy storage performance for advanced electronics and pulsed power systems.

## Contribution

A high-entropy lead-free ceramic system is designed using phase-field simulations and chemical composition strategies to achieve superior energy storage.

## Key findings

- The material achieves an ultrahigh energy density of ≈12.4 J cm⁻³ and efficiency of ≈82.6%.
- It maintains ≈6.2 J cm⁻³ energy density and ≈85.8% efficiency across a wide temperature range.
- The design stabilizes multiphase polar nanoregions, enhancing breakdown strength and performance.

## Abstract

Superior energy‐storage performance is imperative for next‐generation electronics and pulsed power systems. However, in lead‐free dielectric ceramics, achieving synergistic optimization of energy storage performance remains a critical challenge. The central obstacle lies in the simultaneous enhancement of both energy density (W
rec) and efficiency (η). Herein, a high‐entropy lead‐free Bi0.32Na0.32Ba0.32La0.04TiO3‐NaNbO3 ceramics system is designed, guided by phase‐field simulations and a strategic chemical composition approach. The synergistic effect of La‐donor doping and NaNbO3 addition induces local random fields and local random stresses, stabilizing multiphase ultrasmall polar nanoregions. Benefiting from these features, an ultrahigh energy storage performance of W
rec ≈ 12.4 J cm−
3 and η ≈ 82.6% is realized under the applied field 790 kV cm−1. Furthermore, a large W
rec of ≈6.2 J cm−3 and a high η ≈ 85.8% with less than 5% variation across a broad temperature (30–150 °C) range are highly promising results for lead‐free ceramics. This study marks a significant advancement in the energy storage performance and also provides a paradigm for the development of new lead‐free ceramics for the next generation of pulsed power applications.

La‐donor doping suppresses defect charges and reduces domain size via local random fields. Conversely, NaNbO3 addition in BNT‐based ceramics stabilizes the orthorhombic phase. This creates R‐O‐T multiphase polar nanoregions within a cubic matrix, which lowers the energy barrier, delays polarization saturation, and enables a high breakdown strength, leading to superior energy storage performance.