An investigation of the dielectric energy storage performance of Bi(Mg_2/3Nb_1/3)O₃-modifed BaTiO₃ Pb-free bulk ceramics with improved temperature/frequency stability

In order to fabricate high performance dielectric capacitors for pulsed power applications, dense and homogenous Bi(Mg_2/3Nb_1/3)O₃-modifed BaTiO₃-based Pb-free relaxor ferroelectric ceramics were obtained through a isostatic pressing technique at room temperature. Obvious relaxor behavior with a high diffusion degree is confirmed by broad and frequency-dependent dielectric peaks in 0.875BaTiO₃-0.125Bi(Mg_2/3Nb_1/3)O₃ (BT-0.125BMN). Good energy storage properties including a high recoverable energy density of ∼1.89 J/cm³, an relatively high efficiency of ∼83%, good dielectric/temperature/frequency dependent stability and also fatigue resistance are achieved in this composition at a high electric field of 240 kV/cm, together with a fast discharging speed of <160 nm and high maximum current density of 503.46 A/cm² and a large power density of 25.12 MW/cm³. These properties indicate that BT-0.125BMN is a promising candidate of capacitors for the pulsed power applications.