Improved energy storage performance of AgNbO3 ceramics via Yb3+/Bi3+ co-doping

Lead-free antiferroelectric AgNbO 3 (AN) ceramics hold significant potential for pulsed power systems; however, their inferior energy storage density and efficiency limit their practical deployment. Optimizing performance under moderate electric fields (300–500 kV cm −1 ) is particularly critical for industrial viability. Herein, a Bi 3+ /Yb 3+ A-site co-doping strategy is proposed to optimize the microstructural characteristics and improve the electrical properties of AN ceramics. The synergistic doping effect effectively enhances antiferroelectric stability and dielectric relaxation behavior, while concurrently suppressing the rapid decay of saturation polarization intensity. Furthermore, refined grain size and a widened band gap jointly improve the breakdown electric field strength. Benefiting from such multi-scale modulation, Ag 0.82 Bi 0.03 Yb 0.03 NbO 3 (ABYN3) ceramic demonstrates a high recoverable energy density of 6.8 J cm −3 and an energy efficiency of 77% under an applied field of 431 kV cm −1 . Moreover, ABYN3 demonstrates superior thermal stability, high frequency tolerance, and resistance to cyclic fatigue. Charge–discharge measurements reveal that ABYN3 exhibits a discharge energy density of 4.06 J cm −3 and an ultrahigh power density of 144 MW cm −3  at 300 kV cm −1 , along with an ultrafast discharge speed (t < 100 ns). This study presents a feasible and effective strategy for performance optimization of lead-free antiferroelectric ceramics, providing valuable guidance for their practical industrial applications in pulsed power systems.