High reversibility of Li intercalation and de-intercalation in MnO-attached graphene anodes for Li-ion batteries

A composite of graphene nanosheets (GNs) supported by MnO nanocrystals has been fabricated through a simple chemical-wet impregnation followed by the thermal reduction route. The hybrid contains MnO nanoparticles with an average size of 20 nm uniformly dispersed on GNs as observed by transmission electron microscopy and X-ray diffraction analysis. The MnO-attached GN anode delivers a reversible capacity of 635 mAh/g at 0.2 C in the voltage range between 0.01 and 3.5 V. The MnO doping in the GN network plays a positive role in improving the Coulombic efficiency (92.7%) at the 1st cycle and rate capability (capacity retention (5 C/0.2 C): >70%). The superior cell performance of the GN anodes is ascribed to its unique framework, which intimately combines the conductive GNs with well-dispersed MnO nanoparticles. This present work sheds some light on the feasibility of the MnO-attached GN anodes for high-performance Li-ion batteries. (C) 2011 Elsevier Ltd. All rights reserved.