Electrochemical evaluation of the performance of cathodically grown ultra-fine magnetite nanoparticles as electrode material for supercapacitor applications

Abstract

Ultra-fine nanoparticles of magnetite iron oxide (Fe3O4) were prepared through a poly(vinyl alcohol) (PVA) assisted cathodic electrosynthesis. According to this method, Fe3O4 was deposited on a stainless steel cathode form an aqueous electrolyte containing 0.005 M Fe(NO3)3/FeCl2 and 0.1 g/L PVA. The structural characterization of the electro-synthesized deposit through X-ray diffraction (XRD), field emission and transmission electron microscopies (FE-SEM and TEM) confirmed that the product was composed of pure magnetite spherical particles with average size of 5 nm. The surface area of the resulting Fe3O4 nanoparticles was determined to be 171.5 m2/g through Brunauer–Emmett–Teller (BET) gas-sorption measurements. The electrochemical performance of the prepared ultra-fine nanoparticles was evaluated using cyclic voltammetry(CV), continuous charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. The obtained electrochemical data showed that the prepared Fe3O4 nanoparticles had suitable charge storage ability with a specific capacitance of as high as 195.8 F g−1, and they maintain about 94% of their initial capacity after 3000 cycles at a current load of 0.5 A g−1. These data proved the suitability of the prepared nanoparticles for use in supercapacitors. Furthermore, this work provides a facile electrochemical route for the synthesis of ultra-fine iron oxide nanoparticles for application in the next generations of energy storage materials.