Improved energy storage in antiferroelectric AgNbO3-modulated 0.925Bi0.5Na0.5TiO3 – 0.075BaTiO3 relaxor ferroelectric ceramics

Abstract

In this report, antiferroelectric AgNbO3-modified (1-x)(0.925Bi0.5Na0.5TiO3-0.075BaTiO3)-xAgNbO3 (x = 0–0.2) relaxor-ferroelectric ceramics were studied to optimize energy density and storage efficiency. Dielectric properties and microstructure were analyzed to explore the influence of antiferroelectric AgNbO3 (AN) in energy-storage performance of 0.925Bi0.5Na0.5TiO3-0.075BaTiO3 (BNBT) ceramics. By substituting proper AN concentrations (x ≤ 0.15), dielectric breakdown strength (BDS) can be effectively increased, while remanent polarization (Pr) and coercive field (Ec) were evidently reduced. The optimal recoverable energy density (Wrec) of 3.92 J/cm3 and storage efficiency (η) of 70% are respectively achieved for x = 0.1 (at E = 180 kV/cm) and x = 0.05 (at E = 110 kV/cm). Temperature-dependent dielectric permittivities show that 0.1∼0.15 AN-doped BNBT ceramics maintain low dielectric losses (tan δ < 0.1%) with a stable temperature coefficient of capacitance (TCC), which meets the X7R specification. This work demonstrates that antiferroelectric AN-doped BNBT relaxor-ferroelectric ceramics are suitable for using in high-density energy storage.