Silver deficiency effect on dielectric properties and energy storage performance of AgNbO₃ ceramics

As a lead-free material, AgNbO₃ has received a lot of attention for its potential application in the field of energy storage. Herein, Ag_xNbO_2.5+x/2 ceramics were successfully synthesized via solid state reaction with the x ranged from 1 to 0.92. The effect of silver deficiency on structure, dielectric properties and energy storage performance was investigated. As x value decreased from 1 to 0.94, the unit volume of Ag_xNbO_2.5+x/2 ceramics contracted. Meanwhile, all the compositions displayed double hysteresis loops with reduced P_max, P_r and enhanced transformation fields (E_F and E_B) as functions of silver deficiency. Silver deficiency stabilized the antiferroelectric state in the FIE (-like) phase and improved the energy storage performance of AgNbO₃ ceramics. Hence, an enhanced energy storage performance (W_rec = 3.1 J/cm³, η = 49%) were achieved in Ag_0.94NbO_2.97 ceramic.