The microstructure and energy storage properties of Ba0.3Sr0.7TiO3 crystallite thin films

Abstract

Energy storage capacitors have gained much attention for their potential energy storage applications in pulse power system. In this paper, Ba0.3Sr0.7TiO3 (BST) crystallite thin films were prepared on Pt/Ti/SiO2/Si(100) substrates using a sol-gel method at different annealing temperatures from 650 to 850 °C. The films have a crystallite structure, in which amorphous phase forms a three-dimensional network structure and BST tiny grains are wrapped in it. The effects of annealing temperature on the phase structure, morphology, energy storage and dielectric properties of BST microcrystalline films were investigated. The grain size and the crystallinity increased with the increase of annealing temperature, and both pores and defects were produced on the surface when temperature reaches up to 750 °C. When annealing temperature increases, the breakdown strength and energy storage density increased initially, followed by an decrease. The optimal energy storage performance was achieved in the sample with the energy storage density of 31.6 J/cm3 at 3.0 M V/cm, while annealing at 700 °C. Moreover, the sample also exhibited a moderate dielectric constant (60) and a low dielectric loss (0.001).