Antiferroelectric-ferroelectric crossover induced by composition variation in AgNbO3-based lead-free ceramics

AgNbO 3 antiferroelectric (AFE) ceramics have attracted much attention because of their high-energy storage performance and environment-friendly characteristics. In this paper, Sb 2 O 5 -doped AgNbO 3 ceramics are prepared by the traditional solid-state reaction method, and the effects of phase structure, microstructure, dielectric, and ferroelectric properties are systematically investigated. Lattice shrinkage and obvious grain size change are caused by the introduction of Sb 5+ ions. The dielectric constant increases significantly with the introduction of Sb 5+ ( ε r from 210 to 550 at room temperature), and the phase transition temperatures of M 1 –M 2 and M 2 –M 3 shift to a lower temperature as the Sb-doping level increases. High relaxor degree γ = 1.97 of M 1 –M 2 peak is achieved in the AgNb 0.98 Sb 0.02 O 3 ceramics, showing typical relaxor antiferroelectric characteristics. Simultaneously, the relaxor characteristics lead to lower remanent polarization values, a finer P–E hysteresis loop, and an improved AFE phase in AgNb 0.98 Sb 0.02 O 3 ceramics. Compared to pure AgNbO 3 , AgNb 0.98 Sb 0.02 O 3 ceramics have a higher recoverable energy density ( J rec = 1.70 J/cm 3 ) and higher energy efficiency ( η  = 30.05%).