Self-assembled HVxOy nanobelts/rGO nanocomposite with an ultrahigh specific capacitance: Synthesis and promising applications in supercapacitors

Abstract

Abstract Since the development of preparing vanadium oxide-graphene nanohybrids holds great promise recently, we report an HVxOy/rGO nanocomposite with novel microstructure assembling V3O7·H2O/V12O26 nanobelts and rGO nanosheets by a green facile one-step hydrothermal approach. The HVxOy nanobelts are self-assembled onto surfaces of rGO nanosheets intimately to develop a unique 3D microstructure through the in-situ and self-assembly growth mechanism. By taking full advantages of individual components, synergy has been created that HVxOy nanobelts offer abundant active sites whereas high conductive rGO nanosheets provide conductive bridges for charge transfer and act as conductive support skeletons to keep a robust structure. Evaluated as electrodes for SCs in a two-electrode system, the nanocomposite exhibits an ultrahigh specific capacitance of 813\u202fF·g−1 at 0.5\u202fA·g−1, a maximum power density of 3000\u202fW·kg−1, a maximum energy density of 40.7\u202fW·h·kg−1 as well as an ultralong lifespan up to 10,000\u202fcycles with only 7% capacitance decline. As far as we know, the specific capacitance that we have obtained is higher than any of vanadium oxide-related materials which have been used for SCs in previous reports.