Antiferroelectric-ferroelectric phase transition in lead-free AgNbO3ceramics for energy storage applications
The high-energy storage density reported in lead-free AgNbO3ceramics makes it a fascinating material for energy storage applications. The phase transition process of AgNbO3ceramics plays an important role in its properties and dominates the temperature and electric field dependent behavior. In this work, the phase transition behavior of AgNbO3ceramics was investigated by polarization hysteresis and dielectric tunability measurements. It is revealed that the ferrielectric (FIE) phase at room temperature possesses both ferroelectric (FE)-like and antiferroelectric (AFE)-like dielectric responses prior to the critical AFE-FE transition point. A recoverable energy storage density of 2 J/cm3was achieved at 150 kV/cm due to the AFE-FE transition. Based on a modified Laudau phenomenological theory, the stabilities among the AFE, FE and FIE phases are discussed, laying a foundation for further optimization of the dielectric properties of AgNbO3.