Simultaneously achieved high energy storage density and efficiency in sol-gel-derived amorphous Mn-doped SrTiO3 thin films

Recently, dielectric energy storage capacitors obtain extensive attention and become a research hotspot owing to the high power density and ultrafast charge/discharge speed, while their applications are limited because of low energy storage density. Here, 1% Mn doped SrTiO3 (ST) thin films with different microstructure were prepared by modulating annealing temperature to optimize the energy storage performance. The X-ray diffraction analysis shows that the ST thin films annealed below 600 degrees C are amorphous structure while the thin film annealed at 700 degrees C is polycrystalline. The dielectric properties of amorphous ST thin films show outstanding frequency stability, electric field stability and temperature stability. The electric breakdown strength and discharge energy storage density of the thin films improve first, and then reduce with the annealing temperature. The optimal energy storage performance is obtained in ST thin film annealed at 550 degrees C: an ultrahigh discharge energy storage density of 53.9 J/cm(3) with high efficiency of 77.2% at 4.541 MV/cm. It reveals that amorphous ST thin film is promising as dielectric energy storage devices in pulse power fields. (C) 2020 Published by Elsevier B.V.