Superior energy storage performance realized in antiferroelectric 0.10 wt% MnO₂-AgNbO₃ ceramics via Bi-doping induced phase engineering

Dielectric capacitors based on antiferroelectric ceramics are promising for applications in advanced high-power electric and electronic devices, for which more efforts should be devoted to enhancing the recoverable energy storage density and energy efficiency. In this work, a record-high recoverable energy storage density W-rec up to 9.0 J cm(-3) and energy efficiency eta of 90% are achieved in lead-free AgNbO3-based ceramics composed of antiferroelectric and paraelectric phases, which were realized by phase engineering via Bi-doping. Compared with pristine AgNbO3, the enhancement in recoverable energy storage density and energy efficiency reaches 621% and 241%, respectively. In addition, the breakdown strength E-b exceeds 650 kV cm(-1) in 12 mol% Bi-doped 0.10 wt% MnO2-AgNbO3 ceramics, which greatly contributes to the exceptionally enhanced energy storage performance. The excellent performance could be retained at elevated temperatures, and various frequencies and cycles. Moreover, the discharge energy density W-d in direct-current charge-discharge performance reaches 8.0 J cm(-3), which is also superior to those reported in other lead-free dielectric energy storage ceramics. The strategy can provide an applicable method to optimize energy storage performance and other functionalities of dielectric materials.