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This study reports the direct preparation of graphene-based films using magnetron sputtering of graphite target. The nanomaterial was deposited at a low temperature of 620°C on silicon wafers and on metallic foils including aluminum. The films were used in fabrication of supercapacitors with a planar geometry. Electrochemical characterizations demonstrated that the films produced showed nearly ideal electrical capacitive behavior. The maximum capacitance obtained from cyclic voltammetry analysis was 325 F/g for a scan rate of 1 mV/s. The device is capable of delivering an energy density of 13.9 Wh/kg at a very high power density of 50 000 W/kg for ultrafast scan rate of 1000 mV/s. The graphene nanomaterial electrode retains the electrochemical stability over a large number of charge-discharge cycles. Key words: nanomaterials, graphenes, magnetron sputtering, supercapacitor. La presente etude decrit la fabrication directe de films a base de graphene a l'aide de la pulverisation magnetron d'unecible en graphite. Le nanomateriau a ete depose a basse temperature, soit 620°C, sur des plaquettes de silicium et sur des feuilles metalliques contenant de l'aluminium. Les films ont ete utilises dans la fabrication de supercondensateurs de forme geometrique plane. Les caracterisations electrochimiques ont montre que les films produits presentaient un comportement electrique capacitif presque parfait. La capacitance maximale obtenue par analyse voltammetrique cyclique etait de 325 F/g pour une vitesse de balayage de 1 mV/s. Le dispositif est capable de delivrer une densite d'energie de 13,9 Wh/kg a une puissance massique tres elevee de 50 000 W/kg et pour une tres grande vitesse de balayage de 1000 mV/s. L'electrode en nanomateriau de graphene reste electrochimiquement stable pendant un nombre important de cycles charge-decharge. [Traduit par la Redaction] Mots-cles: nanomateriaux, graphenes, pulverisation magnetron, supercondensateur., Introduction Nanostructured carbon materials, including nanotubes and graphene sheets, have attracted tremendous interest over the past few years because of their outstanding electrical and mechanical properties. (1-4) Graphene and few [...]

We report a two-step process for the growth/patterning of Ni honeycomb nanostructures on various substrates, such as carbon paper, carbon nanotubes (CNTs), silicon wafers, and copper grids, via the combination of a sputter-coating/patterning technique and a replacement reaction solution method. The morphology, crystallinity, and chemical composition of the honeycombs were analyzed by SEM, TEM, high-resolution TEM, and EDX. These honeycombs are composed of numerous nanocells, several tens of nanometers in diameter and with cell wall thickness of approximately 10 nm, randomly connecting to each other. The growth process of honeycomb nanostructures has been systematically studied. Interestingly, the diameter and wall thickness of the cells could be easily tuned by simply adjusting the experimental parameters, such as the concentrations and cations of metal salts. Additionally, this simple method has been successfully extended to synthesize Co nanostructures with well-controlled morphologies, which indicates the great potential of this strategy in the synthesis of other metal nanostructures on various desired substrates. These metal-substrate composites, especially with desired patterns, are expected to be ideal candidates for wide application in modern electronic and optoelectronic devices, sensors, fuel cells, and energy storage systems.