Energy storage in epitaxial multilayered BiFeO3/Na0.5Bi0.5TiO3/La0.7Sr0.3MnO3 thin films

Lead-free dielectric film capacitors with fast charge-discharge rates are ideal for pulsed power capacitors, but their energy storage density lags behind. Lead-free epitaxial multilayered BiFeO3 (BFO)/Na0.5Bi0.5TiO3 (NBT)/La0.7Sr0.3MnO3 (LSMO) films were designed and fabricated by solution processing and the effects of bottom electrodes as well as BFO thickness on microstructures, electrical properties and energy storage performances were investigated. Compared with the NBT film on Pt/Ti/SiO2/Si substrate, the leakage current densities are significantly suppressed and polarizations are obviously improved for the multilayered BFO/NBT/LSMO films. The BFO/NBT/LSMO film with BFO thickness of about 60 nm exhibits a recoverable energy storage density of 37.0 J/cm3 under 2680 kV/cm and excellent performance stability. These results demonstrate that the epitaxial multilayered BFO/NBT/LSMO films are promising candidates for high-power energy storage applications.