Enhanced Energy Storage Properties in Lead-Free (Na_0.5Bi_0.5)_0.7Sr_0.3TiO₃-Based Relaxor Ferroelectric Ceramics through a Cooperative Optimization Strategy

Abstract

Although relaxor ferroelectrics have been widely investigated owing to their various advantages, there are still impediments to boosting their energy-storage density (W rec) and energy-storage efficiency (η). In this paper, we propose a cooperative optimization strategy for achieving comprehensive outstanding energy-storage performance in (Na0.5Bi0.5)0.7Sr0.3TiO3 (NBST)-based ceramics by triggering a nonergodic-to-ergodic transformation and optimizing the forming process. The first step of substituting NaNbO3 (NN) for NBST generated an ergodic state and induced polar nanoregions under the guidance of a phase-field simulation. The second step was to apply a viscous polymer process (VPP) to the 0.85NBST-0.15NN ceramics, which reduced porosity and increased compactness, resulting in a significant polarization difference and high breakdown strength. Consequently, 0.85NBST-0.15NN-VPP ceramics optimized by this cooperative two-step strategy possessed improved energy-storage characteristics (W rec = 7.6 J/cm3, η = 90%) under 410 kV/cm as well as reliable temperature adaptability within a range of 20–120 °C, outperforming most reported (Na0.5Bi0.5) TiO3-based ceramics. The improved energy-storage performance validates the developed ceramics’ practical applicability as well as the advantages of implementing a cooperative optimization technique to fabricate similar high-performance dielectric ceramics.

Interfacial Polarization Restriction for Ultrahigh Energy‐Storage Density in Lead‐Free Ceramics

“…In addition to the intrinsic bandgap, E b of ceramics can be affected by many extrinsic factors, including defects, grain size, sample thickness, secondary phase, porosity, preparation technology, and space charge, [9,10] Therefore, many approaches have been proposed to boost E b , such as the viscous polymer process (VPP) used to synthesize ceramics can thin the thickness, reduce defects, and boost E b , [11][12][13] hot-pressing treatment (for refining grain size, increasing the density, and removing voids), [14] reducing sample thickness (for minimizing defects and improving homogeneity), [15] and interface polarization (for modifying field redistribution). [16] Among them, interfacial polarization is a significant factor that affects energy-storage performance.…”

Phase evolution and strong temperature‐dependent electrostrictive effect in (1−x)Pb(Mg1/3Nb2/3)O3‐xPbTiO3 solid solutions

“…Figure 2A1–E1 displays the dielectric permittivity ( ε r ) and loss tangent versus temperature curves measured at 1, 10, 100, and 1000 kHz. At 42.6°C, a broad dielectric peak with a significant dielectric dispersion characteristic on the low temperature side is observed in the x = 0.1 composition, demonstrating a typical feature of RFEs 27–29 . Dielectric dispersion decreases and dielectric peaks become sharper as PT concentration increases, demonstrating the enhancement of ferroelectricity 19,22 .…”

“…At 42.6 • C, a broad dielectric peak with a significant dielectric dispersion characteristic on the low temperature side is observed in the x = 0.1 composition, demonstrating a typical feature of RFEs. [27][28][29] Dielectric dispersion decreases and dielectric peaks become sharper as PT concentration increases, demonstrating the enhancement of ferroelectricity. 19,22 In Figure 2F1, the T m of the examined compositions increases monotonously with increasing…”

Enhanced electrostrains in PMN–xPZN solid solutions driven by a rather small electric field

“…The propensity for 1:1 locally ordered bonds is incompatible with the overall 1:2 stoichiometry, yielding a short‐range ordered state. In general, permittivity above T m can be characterized by the Curie–Weiss law (CWL), which is inapplicable to the dielectric behavior of FEs with DPT characteristics 37,38 . We employ a modified approach to further determine the breadth of the dielectric peaks in this scenario.…”

“…In general, permittivity above T m can be characterized by the Curie-Weiss law (CWL), which is inapplicable to the dielectric behavior of FEs with DPT characteristics. 37,38 We employ a modified approach to further determine the breadth of the dielectric peaks in this scenario. The relationship between ε r /ε m and T-T m is depicted in Figure 2F.…”