Due to an oversight of the editorial office, a mistake was introduced in the references on page 3919, right column, at the start of the fourth paragraph. In the published paper the text segment on page 3919 reads: As mentioned, graphene can be grown on metal surfaces by surface segregation of carbon or by decomposition of hydrocarbons. However, this technique is only practical for graphene production if the as-grown graphene can be transferred from the metal substrates to other substrates, which looks straightforward but only was realized for multilayer and non-uniform films recently with Ni [160-162] and for uniform monolayer graphene, with Cu. [17] However, reference 160 does not relate to graphene segregation on metal surfaces. The authors first to report this technique were Qingkai Yu and co-workers as described in reference 246. Consequently, the start of the fourth paragraph on page 3919 should be corrected to read as follows: As mentioned, graphene can be grown on metal surfaces by surface segregation of carbon or by decomposition of hydrocarbons. However, this technique is only practical for graphene production if the as-grown graphene can be transferred from the metal substrates to other sub-strates, which looks straightforward but only was realized for multilayer and non-uniform films recently with Ni, [246,161,162] and for uniform monolayer graphene, with Cu. [17] The editorial office apologizes for any inconvenience caused. In addition, reference 160 was not published in 2009, so reference 160 should read: [160] J.

Supercapacitors, also called ultracapacitors or electrochemical capacitors, store electrical charge on high-surface-area conducting materials. Their widespread use is limited by their low energy storage density and relatively high effective series resistance. Using chemical activation of exfoliated graphite oxide, we synthesized a porous carbon with a Brunauer-Emmett-Teller surface area of up to 3100 square meters per gram, a high electrical conductivity, and a low oxygen and hydrogen content. This sp(2)-bonded carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form primarily 0.6- to 5-nanometer-width pores. Two-electrode supercapacitor cells constructed with this carbon yielded high values of gravimetric capacitance and energy density with organic and ionic liquid electrolytes. The processes used to make this carbon are readily scalable to industrial levels.

Reduced graphene oxide/Fe(2)O(3) composite was prepared using a facile two-step synthesis by homogeneous precipitation and subsequent reduction of the G-O with hydrazine under microwave irradiation to yield reduced graphene oxide (RG-O) platelets decorated with Fe(2)O(3) nanoparticles. As an anode material for Li-ion batteries, the RG-O/Fe(2)O(3) composite exhibited discharge and charge capacities of 1693 and 1227 mAh/g, respectively, normalized to the mass of Fe(2)O(3) in the composite (and ∼1355 and 982 mAh/g, respectively, based on the total mass of the composite), with good cycling performance and rate capability. Characterization shows that the Fe(2)O(3) nanoparticles are uniformly distributed on the surface of the RG-O platelets in the composite. The total specific capacity of RG-O/Fe(2)O(3) is higher than the sum of pure RG-O and nanoparticle Fe(2)O(3), indicating a positive synergistic effect of RG-O and Fe(2)O(3) on the improvement of electrochemical performance. The synthesis approach presents a promising route for a large-scale production of RG-O platelet/metal oxide nanoparticle composites as electrode materials for Li-ion batteries.

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We present a novel method to prepare highly conductive, free-standing, and flexible porous carbon thin films by chemical activation of reduced graphene oxide paper. These flexible carbon thin films possess a very high specific surface area of 2400 m(2) g(-1) with a high in-plane electrical conductivity of 5880 S m(-1). This is the highest specific surface area for a free-standing carbon film reported to date. A two-electrode supercapacitor using these carbon films as electrodes demonstrated an excellent high-frequency response, an extremely low equivalent series resistance on the order of 0.1 ohm, and a high-power delivery of about 500 kW kg(-1). While higher frequency and power values for graphene materials have been reported, these are the highest values achieved while simultaneously maintaining excellent specific capacitances and energy densities of 120 F g(-1) and 26 W h kg(-1), respectively. In addition, these free-standing thin films provide a route to simplify the electrode-manufacturing process by eliminating conducting additives and binders. The synthetic process is also compatible with existing industrial level KOH activation processes and roll-to-roll thin-film fabrication technologies.