Outstanding Energy Storage Performance of NBT-Based Ceramics under Moderate Electric Field Achieved via Antiferroelectric Engineering
Wenjun Cao, Li Li, Hanyu Zhao, Changyuan Wang, Changyuan Wang, Cen Liang, Feng Li, Xuechen Huang, Chunchang Wang, Chunchang Wang
Abstract
Ultrahigh energy-storage performance of dielectric ceramic capacitors is generally achieved under high electric fields (HEFs). However, the HEFs strongly limit the miniaturization, integration, and lifetime of the dielectric energy-storage capacitors. Thus, it is necessary to develop new energy-storage materials with excellent energy-storage densities under moderate electric fields (MEFs). Herein, the antiferroelectric material Ag 0.9 Ca 0.05 NbO 3 (ACN) was used to modify the relaxor ferroelectric material 0.6Na 0.5 Bi 0.5 TiO 3 –0.4Sr 0.7 Bi 0.2 TiO 3 (NBT-SBT). The introduction of ACN results in high polarization strength, regulated composition of rhombohedral ( R 3 c ) and tetragonal ( P 4 bm ), nanodomains, and refined grain size. An outstanding recoverable energy density ( W rec = 4.6 J/cm 3 ) and high efficiency (η = 82%) were realized under an MEF of 260 kV/cm in 4 mol % ACN-modified NBT-SBT ceramic. The first-principles calculation reveals that the interaction between Bi and O is the intrinsic mechanism of the increased polarization. A new parameter Δ P / E b was proposed to be used as the figure of merit to measure the energy-storage performance under MEFs (∼200–300 kV/cm). This work paves a new way to explore energy-storage materials with excellent-performance MEFs.