Ultrahigh Energy Storage in Relaxor Ferroelectric Ceramics with Core–Shell Grains
Qizhen Chai, Peng Tan, Leiyang Zhang, Zhaobo Liu, Santan Dang, Zhanhui Peng, Di Wu, Xiaodong Xu, Bohan Xing, Xiaolian Chao, Houbing Huang, Shujun Zhang, Zupei Yang
Abstract
Abstract The achievement of record‐high energy storage performance in relaxor‐ferroelectric bulk ceramics represents a major advancement in the field of dielectric capacitors. Nonetheless, a trade‐off between breakdown strength and polarization has typically limited the optimization of overall performance. Here, guided by a rational composition design, K 0.5 Na 0.5 NbO 3 ‐based bulk ceramics are fabricated with grain core–shell structures and polymorphic nanodomains, leading to a synergistic enhancement of breakdown strength and polarization. This results in an unprecedented recoverable energy density of ≈20.4 J·cm −3 and an energy efficiency of ≈90% at an electric field of ≈1020 kV·cm −1 . Additionally, the ceramics exhibits excellent charge–discharge performance, including a high discharge energy density of ≈6.0 J·cm −3 and an ultrashort discharge time of ≈42 ns at 500 kV·cm −1 , along with superior reliability and stability. These advancements are expected to provide valuable insights for the exploration and utilization of advanced dielectric materials.