Structural, Dielectric, and Energy Storage Properties of Citric Acid and Ethylene Glycol Assisted Hydrothermally Synthesized Y2FeCoO6

Citric acid and ethylene glycol assisted hydrothermal synthesis of pure-phase double perovskite oxide Y(2)FeCoO(6)is reported. The Rietveld refinement confirm the orthorhombic phase formation withPnmaspace group symmetry and lattice parameters as,a = 5.5039 angstrom,b = 7.4734 angstrom, andc = 5.2094 angstrom. The high-resolution transmission electron micrographs exhibit formation of flakes, composed of agglomerated crystallites, oriented in [121] direction. The oxidation states of Fe as Fe(3+)and Co as Co2+/Co(3+)are observed by X-ray photoelectron spectroscopy. The room temperature relative permittivity, 6.8 x 10(4), is found to increase to 1.3 x 10(7)at 473 K and frequency 500 Hz. The specific capacitance of approximate to 31.32 F g(-1)is obtained at the current density of 1 A g(-1). The effective charge storage involve the redox reactions of Fe2+/Fe3+, Co2+/Co3+, and Co3+/Co4+, and excellent capacitance retention of approximate to 99% is achieved after 5000 charging/discharging cycles at current density of 6 A g(-1).