Graphene supported α-MnO2 nanocomposite cathodes for lithium ion batteries

• Graphene/α-MnO2 composite cathodes were produced by mechanical alloying method.
• Decoration of α-MnO2 nanowires on graphene sheets increase the specific capacity and cycling performance.
• Graphene/α-MnO2 composite cathode containing 50 wt.% graphene showed 225 mAh/g discharge capacity after 200 cycles.

In this study, Graphene/α-MnO2 nanocomposite cathodes were produced using ultrasonication and mechanical alloying facilities. Before production of Graphene/α-MnO2 composites, Graphene structure was fabricated by reduction of Graphene Oxide produced using Hummer's Method and α-MnO2 nanowires was synthesized using microwave hydrothermal synthesis method. The effect of Graphene support on the electrochemical performance of the Graphene/α-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/α-MnO2 nanocomposites were characterized using X-ray diffraction (XRD) and Raman Spectroscopy techniques. Surface morphology of the electrodes was characterized using scanning electron microscopy (SEM). Electrochemical cycling tests of the Graphene/α-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 α-MnO2 and provide stable cathode materials. Eventually, Graphene/α-MnO2 cathode containing 50 wt.% Graphene showed 225 mAh/g discharge capacity even after 200 cycles.