Excellent Energy‐Storage Performance in Lead‐Free Capacitors with Highly Dynamic Polarization Heterogeneous Nanoregions

Abstract

Lead‐free dielectric ceramics with excellent energy‐storage performance are crucial to the development of the next‐generation advanced pulse power capacitors. However, low energy‐storage density limits the evolution of capacitors toward lightweight, miniaturization, and integration. Here, an effective strategy of constructing highly dynamic polarization heterogeneous nanoregions is proposed in lead‐free relaxors to realize an ultrahigh energy‐storage density of ≈8.0 J cm−3, making almost ten times the growth of energy‐storage density compared with pure Bi0.5Na0.5TiO3 ceramic, accompanied by a higher energy efficiency of ≈80% as well as an ultrafast discharge rate of ≈20 ns. Ultrasmall polarization heterogeneous nanoregions with different orientations and ultrahigh flexibility, and significantly decreased grain size to submicron lead to reduced heat loss, improved breakdown electric field and polarization, enhanced relaxation, and delayed polarization saturation behaviors, contributing to the remarkable energy‐storage performance. Moreover, the breakdown path distribution or electrical tree evolution behaviors are systematically studied to reveal the origin of ultrahigh breakdown electric field through phase field simulations. This work demonstrates that constructing highly dynamic polarization heterogeneous nanoregions is a powerful approach to develop new lead‐free dielectric materials with high energy‐storage performance.

Excellent Energy Storage Performance Achieved in Sr(Sc0.5Nb0.5)O3-Doped Bi0.5Na0.5TiO3-Based Lead-Free Relaxor Ferroelectric Ceramics

“…E b . 46,54,55 The improvement of E b is crucial for the optimization of ESP. We fit the E b of each sample using the Weibull distribution function to guarantee the stability of the experimental data.…”

“…Reduction in grain size increases the amount of grain boundaries that block the breakdown path, effectively increasing. E b . ,, The improvement of E b is crucial for the optimization of ESP. We fit the E b of each sample using the Weibull distribution function to guarantee the stability of the experimental data. , As shown in Figure f, compared to the other cold isostatic ceramics, the x = 0.20 (RRP) ceramic exhibits a higher slope β (20.22 > 10), indicating that its breakdown is well stable.…”

High-entropy superparaelectrics with locally diverse ferroic distortion for high-capacitive energy storage

“…The absence of the largescale ferroelectric domain in HR-TEM images points to the lack of both long-range polarization and BO 6 tilt order. The SAED patterns exhibit 1/2(ooe) type superlattice diffraction dots caused by the in-phase tilt of the oxygen octahedron and 1/2(ooo) type superlattice diffraction points caused by the anti-phase tilt of the oxygen octahedron, respectively 33,34 . These results demonstrate that different localized BO 6 tilt types are induced in SLTT-0.30 ceramic, which can impede the appearance of electric eld-induced texture domain states, thereby delaying polarization saturation 25 .…”