In-situ hydrothermal synthesis of graphene woven VO2 nanoribbons with improved cycling performance

To overcome the problems of vanadium dissolution and the higher charge transfer resistance that results from it, VO2/graphene composite has been synthesized by an in-situ hydrothermal process directly from graphene oxide and V2O5, and characterized by X-ray diffraction, Raman spectroscopy, FT-IR spectroscopy, thermogravimetric analysis, atomic force microscope, and field emission scanning electron microscopy. Electrochemical tests show that the VO2/graphene composite features high discharge capacity (380 mAh g(-1)) and 99% capacity retention after 50 cycles. It has very low resistance, only 67% of that of pure VO2, indicating the enhancement of electronic conductivity. Carbon dispersed in the electrode material can provide a pathway for electron transport, resulting in improvement of the electronic conductivity. Graphene woven VO2 nanoribbons prevent the agglomeration of VO2 nanoribbons, meanwhile graphene and the VO2 nanoribbons together form a porous network in the random hybrid composite that can be filled with electrolyte, resulting in superior performance and enhanced reversible capacity in comparison with the pure VO2. Thus, this work provides a facile route to synthesize VO2/graphene composite which shows excellent electrochemical performance and is a potential material for lithium ion battery. (C) 2012 Elsevier B.V. All rights reserved.