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Layer-by-Layer Grown Electrodes Composed of Cationic Fe₃O₄ Nanoparticles and Graphene Oxide Nanosheets for Electrochemical Energy Storage Devices

Sarac Oztuna, F. Eylul, Unal, Ozlem, Erdem, Emre, Yagci Acar, Havva, Unal, Ugur
Journal of physical chemistry 2019 v.123 no.6 pp. 3393-3401
X-ray photoelectron spectroscopy, additives, atomic force microscopy, carbon nanotubes, coatings, dielectric spectroscopy, electrical conductivity, electrical equipment, electrochemistry, electrodes, electron paramagnetic resonance spectroscopy, energy, graphene, graphene oxide, hydrazine, nanoparticles, nanosheets, physical chemistry, quartz crystal microbalance, transmission electron microscopy, ultraviolet-visible spectroscopy, vapors
Ultrathin electrodes composed of layer-by-layer assembled (3-aminopropyl)trimethoxysilane functionalized iron oxide nanoparticles and graphene oxide nanosheets were prepared by a simple and low-cost dip coating method without using any binders or conductive additives. The thickness of the Fe₃O₄/GO films was simply altered with the number of dip coating cycles. Multilayered films were chemically reduced with hydrazine vapor in order to increase the electrical conductivity. Characterization of multilayer films was performed with scanning transmission electron microscopy, UV–vis spectroscopy, atomic force microscopy, quartz crystal microbalance, X-ray photoelectron spectroscopy, and electron paramagnetic resonance spectroscopy. We have performed cyclic voltammetry and electrochemical impedance spectroscopy for the evaluation of Fe₃O₄/GO multilayers as possible electrochemical capacitor electrodes. Reduced Fe₃O₄/GO films exhibit high specific capacitances (varying between 200 and 350 F g–¹ at 5 mV s–¹), outperforming the layer-by-layer assembled iron oxides/carbon derivatives (carbon nanotube, graphene).