Enhanced nanoscale conduction capability of a MoO2/Graphene composite for high performance anodes in lithium ion batteries

A MoO2/Graphene composite as a high performance anode for Li ion batteries is synthesized by a one pot in-situ low temperature solution phase reduction method. Electron microscopy and Raman spectroscopy results confirm that 20 graphene layers entrap MoO2 nanoparticles homogeneously in the composite. X-ray photoelectron spectroscopy shows the presence of oxygen functionalities on graphene, which allows intimate contact between MoO2 nanoparticles and the graphene. Conductive atomic force microscopy reveals an extraordinarily high nanoscale electronic conductivity for MoO2/Graphene, greater by 8 orders of magnitude in comparison to bulk MoO2. The layered nanostructure and the conductive matrix provide uninhibited conducting pathways for fast charge transfer and transport between the oxide nanoparticles and graphene which are responsible for the high rate capability, a large lithium ion capacity of 770 mAh g(-1). and an excellent cycling stability (550 mAh g(-1) reversible capacity retained even after 1000 cycles!) at a current density of 540 mA g(-1), thereby rendering it to be superior to previously reported values for neat MoO2 or MoO2/Graphene composite. Impedance analyses demonstrate a lowered interfacial resistance for the composite in comparison to neat MoO2. Our results demonstrate the enormous promise that MoO2/Graphene holds for practical Li-ion batteries. (C) 2012 Elsevier B.V. All rights reserved.