Superior temperature stability and outstanding fatigue resistance in Na0.5Bi0.5TiO3-BaTiO3 based Pb-free dielectric energy storage ceramics via a composite approach involving linear dielectric modification

Dielectric ceramic capacitors are candidates for a new generation of pulsed power supplies, owing to their superior power density. Nevertheless, low energy storage density and poor working reliability (such as temperature stability and fatigue resistance) have hindered the wide application of dielectric ceramic capacitors. To this end, a new composition-based optimization and process improvement strategy is proposed to build relaxor ferroelectric ceramic systems with weak pinning effect domain structure, which not only ensure the performance of ceramic energy storage, but also take into account the reliability of actual work. In this study, lead-free ceramics with formula 0.75(0.94Na 0.5 Bi 0.5 TiO 3 -0.06BaTiO 3 )-0.25CaTiO 3 , prepared by viscous polymer processing, exhibit an extremely high energy storage density, reaching up to 6.62 J/cm 3 under a field strength of 520 kV/cm. In addition, after 10 6 cycles at 200 kV/cm, the efficiency remains at 85.9 %, with the sample's energy storage density exhibits a change rate of only 4 %. Additionally, under 300 kV/cm and across a temperature range of 30–150 °C, the change rate is a mere 1.7 %, which indicates that it has exhibited great fatigue resistance and excellent temperature stability. Therefore, this developed ceramic possesses great potential for practical industrial application as dielectric capacitors.