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We demonstrate a simple, efficient, yet versatile method for the realization of core-shell assembly of graphene around various metal oxide (MO) nanostructures, including nanowires (NWs) and nanoparticles (NPs). The process is driven by (i) the ring-opening reaction between the epoxy groups and amine groups in graphene oxide (GO) platelets and amine-modified MO nanostructures, respectively, and (ii) electrostatic interaction between these two components. Nearly every single NW or NP is observed to be wrapped by graphene. To the best of our knowledge, this is the first report that substrate-supported MO NWs are fully coated with a graphene shell. As an example of the functional properties of these compound materials, the graphene@a-Fe 2 O 3 core-shell NPs are investigated as the lithium-ion battery (LIB) electrode, which show a high reversible capacity, improved cycling stability, and excellent rate capability with respect to the pristine a-Fe 2 O 3 . The superior performance of the composite electrode is presumably attributed to the effectiveness of the graphene shell in preventing the aggregation, buffering the volume change, maintaining the integrity of NPs, as well as improving the conductivity of the electrode.

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A new type of scrolled structure of Co(3)O(4)/reduced graphene oxide (r-GO) is facilely prepared through a two-step surfactant-assisted method. This assembly enables almost every single Co(3)O(4) scroll to connect with the r-GO platelets, thus leading to remarkable electrochemical performances in terms of high specific capacitance and good rate capability.

A simple, green and cost-effective approach has been reported to synthesize high-quality graphene oxide (GO) flakes via electrochemical exfoliation of pencil cores in aqueous electrolytes. The exfoliated GO flakes exhibit excellent electrocatalytic activity and toxicity tolerance for oxygen reduction reactions in alkaline solution. Our present results are promising for scaled-up preparation and further commercialization of graphene oxide in a low-cost and environmentally friendly way.