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

Abstract

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 η 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.