Designing silver niobate-based relaxor antiferroelectrics for ultrahigh energy storage performance

AgNbO₃ and its modifications are extensively investigated as promising lead-free antiferroelectric (AFE) energy storage materials. Previous studies mainly focused on ion dopant at A/B-site to obtain stabilized AFE phase, through which, however, a simultaneous improvement of energy storage density (Wrec) and efficiency (η) is still difficult to realize. Herein, we innovatively construct an AgNbO₃-NaNbO₃-(Sr0.7Bi0.2)TiO₃ ternary solid solution in order to achieve relaxor AFE in AgNbO₃-based materials. The coexistence of antiferroelectric (M₃) and paraelectric (O) phases in 0.8(0.7AgNbO₃-0.3NaNbO₃)-0.2(Sr0.7Bi0.2)TiO₃ confirms the successful realization of relaxor AFE, attributed to the multiple ion occupation at A/B sites. Consequently, a high Wrecof 7.53 J×cm⁻³ and η of 74.0% are acquired, together with superior stability against varying temperatures, frequencies, and cycling numbers. Furthermore, a giant power density (298.7 MW×cm⁻³) and fast discharge speed (41.4 ns) are also demonstrated in the AgNbO₃-based relaxor AFE. This work presents a promising energy storage AgNbO₃-based ternary solid solution and also proposes a novel strategy for AgNbO₃-based energy storage application via designing relaxor AFE material.