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

Abstract

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 (Eb). 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 ∼200 nm is prepared via pulsed laser deposition, which has a dense microstructure and a small average grain size of ∼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 M2 phase. Due to the small thickness and fine grain size, a high Eb of 1200 kV/cm is obtained, which boosts a recoverable energy storage density (Wrec) of 9.3 J/cm3 and an energy efficiency (η) of 63.7 % in the AgNbO3 film. In addition, Wrec exhibits good temperature stability at 30–120 °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.