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International audience; Ni nanorods prepared by electrochemical growth through an anodized aluminium oxide membrane were used as substrate for the electrodeposition of MnO2 either in potentiostatic mode or by a pulsed method. Electrochemical deposition parameters were chosen for an homogeneous deposit onto Ni nanorods. Resulting Ni supportedMnO2 electrodes were tested for electrochemical performances as nanostructured negative electrodes for supercapacitors. They exhibited initial capacitances up to 190 F/g and remarkable performances at high charge/discharge rates.

International audience; 3D-assembles of silica spheres were used as hard template to synthesize porous carbon materials with large mesopores to be included as current collectors in supercapacitors and developing large surface areas reaching up to 900m2.g-1. Birnessite-type MnO2 was deposited by a co-precipitation method in the porous network. Electrochemical performances of resulting MnO2/C nanocomposites were evaluated by cyclic voltammetry and showed an initial capacitance and a retained capacitance after 500 cycles for the nanocomposite at 6wt% MnO2 in C of about 660 and 490 F.g-1, respectively.

Mesoporous silicon carbide (SiC) was synthesized by a one-pot thermal reduction of SiO2/C composites by metallic Mg at the remarkably low temperature of 800 °C. Two distinct mesostructured silica were used as hard templates for composite preparation: a hexagonal 3D close-packed assembly of Stober silica spheres and an ordered mesoporous SBA15 silica. In the latter case, SiC has crystallized in its 2H–SiC hexagonal phase, which is rather unique at such a low temperature. Composites were obtained by impregnation/polymerisation/carbonisation of a molecular carbon precursor within the porous structure of the silica template. After thermal treatment at a moderate temperature in the presence of Mg and subsequent by-products rinsing off, both prepared SiC showed distinct mesoporous structures related to the initial SiO2 architectures. By comparison of the mesoporous characteristics, resulting SiC was found to retain the carbon structures of the pristine composites. The description of the synthetic mechanism of this topotactic reaction contrasts with the usual assumption stating the templating role of silica.