Dielectric capacitors have been widely used in pulsed power devices owing to their ultrahigh power density, fast charge/discharge speed, and excellent stability. However, developing lead-free dielectric materials with a combination of high recoverable energy storage density and efficiency remains a challenge. Herein, a high energy storage density of 7.04 J/cm³ as well as a high efficiency of 80.5% is realized in the antiferroelectric Ag(Nb_0.85Ta_0.15)O₃-modified BiFeO₃-BaTiO₃ ferroelectric ceramic. This achievement is mainly attributed to the combined effect of a high saturation polarization (P_max), increased breakdown field (E_b), and reduction of the remnant polarization (P_r). The modification of pseudotetragonal BiFeO₃ by Ag(Nb_0.85Ta_0.15)O₃ leads to a high P_max, and the enhanced relaxor behavior gives rise to a small P_r. The promoted microstructure (such as a dense structure, fine grains, and compact grain boundaries) after modification results in a high breakdown strength. Furthermore, both the recoverable energy density and efficiency exhibit high stability over a broad range of operating frequencies (1–50 Hz) and working temperatures (25–120 °C). These results suggest that the (0.67–x)BiFeO₃-0.33BaTiO₃-xAg(Nb_0.85Ta_0.15)O₃ ceramics can be highly competitive as a lead-free relaxor for energy storage applications.

介质电容器因其超高的功率密度、快速的充放电速度和优异的稳定性而被广泛应用于脉冲功率器件。然而，开发兼具高可恢复能量存储密度和效率的无铅介电材料仍然是一个挑战。在此，反铁电Ag(Nb _0.85 Ta _0.15 -改性 BiFeO ₃ -BaTiO ₃ 铁电陶瓷。这一成就主要归功于高饱和极化 (P _max )、增加的击穿场 (E _b ) 和减少剩余极化 (P _r ）。 Ag(Nb _0.85 Ta _0.15 )O ₃ 修饰准四方 BiFeO ₃ 得到高 P _max 。改性后促进的微观结构（如致密结构、细晶粒和致密晶界）导致高击穿强度。此外，可恢复的能量密度和效率在较宽的工作频率（1-50 Hz）和工作温度（25-120 °C）范围内表现出高稳定性。这些结果表明 (0.67–x)BiFeO ₃ -0.33BaTiO ₃ -xAg(Nb _0.85 Ta _0.15 )O < b19>陶瓷作为储能应用的无铅弛豫剂具有很强的竞争力。