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

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).