VO2 nanoparticles on edge oriented graphene foam for high rate lithium ion batteries and supercapacitors

Abstract

With the fully exposed graphene edges, high conductivity and large surface area, edge oriented graphene foam (EOGF), prepared by deposition of perpendicular graphene network encircling the struts of Ni foam, is a superior scaffold to support active materials for electrochemical applications. With VO2 as an example, EOGF loaded VO2 nanoparticle (VO2/EOGF) electrode has high rate performance as cathode in lithium ion batteries (LIBs). In addition to the Li+ intercalation into the lattice, contribution of non-diffusion-limited pseudocapacitance to the capacity is prominent at high rates. VO2/EOGF based supercapacitor also exhibits fast response, with a characteristic frequency of 15 Hz when the phase angle reaches −45°, or a relaxation time constant of 66.7 ms. These results suggest the promising potential of EOGF as a scaffold in supporting active nanomaterials for electrochemical energy storage and other applications.