Time-stable giant energy density and high efficiency in lead free (Ce,Mn)-modified (Na0.8K0.2)0.5Bi0.5TiO3 ceramic film capacitor

Abstract

The current urgent desire of the renewable energy has imposed much challenge and inspiration for the design and development of the lead-free dielectric capacitors. High recoverable energy storage density (Wrec) and efficiency (η) associated with long-time stability are highly demanded for the pulsed power systems. Here, we present a significantly enhanced energy storage performance in (Ce,Mn) hybrid doped (Na0.8K0.2)0.5Bi0.5TiO3–BiFeO3 [(Ce,Mn):NKBT-BFO] ceramic film capacitor deposited on indium tin oxide (ITO)/glass substrate. Meanwhile, the pure NKBT-BFO, Ce doped NKBT-BFO and Mn doped NKBT-BFO are studied for comparison. A large Wrec of 58.3 J/cm3 together with a high η of 58.1% is realized in (Ce,Mn):NKBT-BFO at 2200 kV/cm, which is proposed by the formation of a slim loop with a large difference between the remanent polarization (Pr) and maximum polarization (Pmax) at a high dielectric breakdown field strength. Moreover, the energy storage property is weakly dependent on time with small variations of Wrec (<23.4%) and η (<11.3%) over a long time range of 2 days–6 months. These results indicate that the (Ce,Mn)-codoped NKBT-BFO ceramic thin film has great potential for the applications in lead-free energy storage film capacitors.