Energy storage performance and piezoelectric response of silver niobate antiferroelectric thin film

AgNbO3-based antiferroelectric materials have attracted extensive attention in energy storage due to their double polarization-electric field hysteresis loops, but they always suffer from low breakdown strength (E-b). Films with few defects and small thickness exhibit high breakdown strength, which helps to improve energy storage performance. In the present work, an AgNbO3 film with a small thickness of similar to 200 nm is prepared via pulsed laser deposition, which has a dense microstructure and a small average grain size of similar to 34.5 nm. The AgNbO3 film displays an antiferroelectric nature, as confirmed by the double polarization-electric field hysteresis loops at room temperature. The room temperature phase structure of the AgNbO3 film determined by the dielectric behaviour is the antiferroelectric M-2 phase. Due to the small thickness and fine grain size, a high E-b of 1200 kV/cm is obtained, which boosts a recoverable energy storage density (W-rec) of 9.3 J/cm(3) and an energy efficiency (eta) of 63.7 % in the AgNbO3 film. In addition, W-rec exhibits good temperature stability at 30-120 degrees C. The AgNbO3 film shows an obvious piezoelectric response after the electric field-induced antiferroelectric-ferroelectric phase transition as confirmed by piezoresponse force microscopy. These results provide guidance for the development of AgNbO3 antiferroelectric films and devices with good energy storage performance.