Enhanced Energy Storage Properties in Lead-Free (Na<sub>0.5</sub>Bi<sub>0.5</sub>)<sub>0.7</sub>Sr<sub>0.3</sub>TiO<sub>3</sub>-Based Relaxor Ferroelectric Ceramics through a Cooperative Optimization Strategy
Wen Wang, Leiyang Zhang, Wenjing Shi, Yule Yang, Denis Alikin, V. Ya. Shur, Zhihao Lou, Dong Wang, A‐Mei Zhang, Jinghui Gao, Xiaoyong Wei, Hongliang Du, Feng Gao, Li Jin
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 (Na 0.5 Bi 0.5 ) 0.7 Sr 0.3 TiO 3 (NBST)-based ceramics by triggering a nonergodic-to-ergodic transformation and optimizing the forming process. The first step of substituting NaNbO 3 (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/cm 3, η = 90%) under 410 kV/cm as well as reliable temperature adaptability within a range of 20–120 °C, outperforming most reported (Na 0.5 Bi 0.5 ) TiO 3 -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.