Graphene supported alpha-MnO2 nanocomposite cathodes for lithium ion batteries

Abstract

In this study, Graphene/alpha-MnO2 nanocomposite cathodes were produced using ultra-sonication and mechanical alloying facilities. Before production of Graphene/alpha-MnO2 composites, Graphene structure was fabricated by reduction of Graphene Oxide produced using Hummer's Method and alpha-MnO2 nanowires was synthesized using microwave hydrothermal synthesis method. The effect of Graphene support on the electrochemical performance of the Graphene/alpha-MnO2 nanocomposite cathodes were investigated by dispersing different amounts of Graphene (10 wt.%, 30 wt.% and 50 wt.%) in the composite cathodes. Structures of the Graphene/alpha-MnO2 nanocomposites were characterized using Xray diffraction (XRD) and Raman Spectroscopy techniques. Surface morphology of the electrodes was characterized using scanning electron microscopy (SEM). Electrochemical cycling tests of the Graphene/alpha-MnO2 nanocomposite cathodes were performed in the voltage range of 1.5 V-4.5 V at a constant current density of 50 mA/g (C/5). This study proved that Graphene enhance the electrochemical reaction of alpha-MnO2 and provide stable cathode materials. Eventually, Graphene/alpha-MnO2 cathode containing 50 wt.% Graphene showed 225 mAh/g discharge capacity even after 200 cycles. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.