Electrochemical energy storage in ordered porous carbon materials

Highly ordered porous carbon materials obtained by a replica technique have been used for supercapacitor application and electrochemical hydrogen storage. For the preparation of the well-tailored carbons, MCM-48, SBA-15 and MSU-1 molecular sieves served as templates, whereas a sucrose solution, propylene and pitch were the carbon source. A careful physico-chemical characterization (CO₂ and N₂ adsorption, X-ray diffraction, electron microscopy observations) allowed to estimate the total surface area, the pore size distribution, the micro/mesopore volume as well as the structure and the microtexture of the investigated carbons. The specific capacitance (F/g) and the hydrogen adsorption capacity in the carbon nanopores were correlated with the microtextural properties. Especially, a linear dependence has been found between the capacitance or the amount of electrochemically stored hydrogen and the ultramicropores (pores smaller than 0.7 nm) volume. It clearly indicates that in these carbons: (a) the major part of the electrical double layer is charged with non-solvated ions; (b) ultramicropores play a determinant role for hydrogen storage.