Synergistic enhancement of antiferroelectric energy storage in AgNbO₃ ceramics

Antiferroelectric AgNbO₃ has garnered considerable attention for high-power energy storage applications owing to its reversible phase transitions. However, its practical energy storage performance is severely limited by the large polarization-switching hysteresis. Although doping small-radius foreign cations at the Ag site can enhance antiferroelectricity, it typically results in a significant reduction in polarization. Herein, we propose a dual-regulation strategy that synergistically modulates the AFE polarization-switching behavior by combining “chemical pressure” and “the lone-pair electron effect”. To realize this strategy, we propose a co-doped AgNbO₃ system, (Ag_1–5xBi_xPb_x)NbO₃ (ABPN100x). The studied results reveal that a small concentration of co-doping (ABPN4) enhances AFE stability while reducing hysteresis and retaining high polarization. Consequently, energy-storage performance is doubled, achieving a W_rec of 3.5 J/cm³ and η of 74 %, compared to undoped AgNbO₃. At ABPN6, the Curie temperature shifts close to room temperature, where the AFE phase (Pbcm) coexists with the paraelectric phase(P4/mbm). This results in a relaxor-ferroelectric-like behavior, characterized by high polarization and minimized hysteresis, contributing to optimally balanced performance (W_rec = 3.2 J/cm³, η = 82 %). Discharge results for ABPN4 and ABPN8 ceramics show that, under E = 225 kV/cm, the W_dis values are 2.85 and 2.25 J/cm³, the P_D values are 86.7 and 105.5 MW/cm³, and the t_0.9 values are 70 and 80 ns, respectively. Our work demonstrates an effective approach to enhance the AFE energy-storage behavior of AgNbO₃.