Graphene-wrapped and cobalt oxide-intercalated hybrid for extremely durable super-capacitor with ultrahigh energy and power densities

We report an easy strategy to synthesize graphene-wrapped and cobalt oxide-intercalated (GWCI) hybrid nanostructures using microwave irradiation for an extremely durable supercapacitor with ultrahigh energy and power densities. The GWCI hybrid nanostructures that are mechanically protected and squeezed by graphene layers are beneficial for efficiently preventing the detachments of metal oxide nanoparticles from graphene surfaces due to volume expansion and contraction during charge and discharge cycling. This GWCI material shows a remarkable cycling stability over 10,000 cycles due to the intercalation of cobalt oxide (Co3O4) nanoparticles between graphene layers and external wrapping by graphene layers. The GWCI material exhibit nearly double specific capacitance as compared to partially microwave-exfoliated graphene oxide (MpEGO) material and also indicate extremely durable stability after 100 cycle, resulting from the excellent electrochemical performance of the GWCI material. (C) 2014 Elsevier Ltd. All rights reserved.