Effect of TiO2 grain size on performance of Ba0.5Sr0.5TiO3 based capacitors for energy storage application

Abstract

Performance of energy storage devices, particularly metal-insulator-metal capacitors are evaluated mainly by leakage current and specific capacitance. The insulator material Ba 0.5 Sr 0.5 TiO 3 shows high specific capacitance owing to its high relative permittivity. In this work, Ba 0.5 Sr 0.5 TiO 3 nanopowder is synthesized using commercially available TiO 2 nanopowder (ACS reagent grade) as well as using synthesized TiO 2 nanopowder from Ti isopropoxide. The crystallinity and grain sizes of commercially available and synthesized TiO 2 nanopowder differ. The effects of crystallinity and grain size of TiO 2 nanopowder on specific capacitance and leakage current density of Ba 0.5 Sr 0.5 TiO 3 ceramic based metal-insulator-metal capacitors are investigated in this paper. An 88 % reduction in grain size is achieved in TiO 2 nanopowder synthesized from Ti isopropoxide compared to commercially available TiO 2 nanopowder. A 45 % enhancement in specific capacitance and 57 % enhancement in leakage current are achieved in Ba 0.5 Sr 0.5 TiO 3 ceramic based metal-insulator-metal capacitor synthesized using TiO 2 nanopowder with lower grain size. The lower leakage current of metal-insulator-metal capacitor with Ba 0.5 Sr 0.5 TiO 3 ceramic of low grain size is investigated with its structure using X-ray powder diffraction pattern analysis as well. The Ba 0.5 Sr 0.5 TiO 3 ceramics synthesized using TiO 2 nanopowder with lower grain size is a suitable candidate for insulator material in metal-insulator-metal capacitors for energy storage application.