A laser irradiation synthesis of strongly-coupled VOx-reduced graphene oxide composites as enhanced performance supercapacitor electrodes

A unique technique is present to synthesize three dimensional hierarchical vanadium oxides/reduced graphene oxide composites (denoted as 3D VOx/rGO composites) by laser irradiation over the mixture of V2O5 nanobelts and GO nanosheets. Electron microscopy and X-ray photoelectron spectroscopy (XPS) examinations reveal that polydisperse V2O5/VO2 heterostructured nanoparticles form strong coupling with rGO. As a result, a specific capacitance of 252 F g(-1) is achieved for 3D VOx/rGO composites when used as supercapacitor electrodes, and the capacitance can retain 92% of the initial specific capacitance even after 10000 cycles at a current density of 100 A g(-1). The improvement of supercapacitor performance is achieved by significantly increase on specific surface area of 3D VOx/rGO composites, which favors the easy access of the electrolyte and provides large electroactive surface, and strong V-O-C bond between VOx nanoparticles and rGO, which benefits the effective charge transfer. We believe that the facile laser irradiation approach represents a major step not only for the simple and efficient fabrication of high performance electrodes but also in the practical application of laser processing to synthesize other functional hierarchical nanocomposites. (C) 2017 Elsevier Ltd. All rights reserved.