Phase structure and energy storage properties of Ba(Mg_1/3Nb_2/3)O₃-modified NaNbO₃-Bi(Mg_2/3Nb_1/3)O₃-SrTiO₃ ceramics

Sodium niobate (NaNbO₃)-based lead-free ceramics have received great attention in the field of pulse power capacitors due to their relatively high energy density and environmental friendliness. Whereas, the mutual optimization of recoverable energy storage density (W_rec) and efficiency (η) remains a critical challenge that hinders their commercialization progress. In this study, the novel 0.95(0.90NaNbO₃-0.10((1-x)Bi(Mg_2/3Nb_1/3)O₃-xBa(Mg_1/3Nb_2/3)O₃))-0.05SrTiO₃ (NBiMNST-xBaMN) antiferroelectric energy storage ceramics were designed mainly through increasing the energy barrier between AFE and FE states by diminishing ionic displacements in B-site to optimize the energy storage performance (ESP), and synthesized by high-temperature solid-phase reaction. Promisingly, not only excellent W_rec with 3.895 J/cm³ but also outstanding η of 80.36% were obtained simultaneously in NBiMNST-0.35BaMN ceramics under an electric field of 380 kV/cm. Besides, a remarkable frequency stability (the fluctuation of W_rec < 2% within 1–300 Hz) was also performed. All the aforementioned results collectively validate the NBiMNST-0.35BaMN ceramics as an eminent candidate for high-performance pulsed power capacitors.