Outstanding Energy Storage Performance of NBT-Based Ceramics under Moderate Electric Field Achieved via Antiferroelectric Engineering

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.