Four square centimeter carbon-carbon supercapacitor cells were assembled with Al current collectors in organic electrolyte. Different treatments of the Al current collectors were made in order to increase the supercapacitor performances. A sol-gel deposit of a conducting carbonaceous material led to the best results. On the basis of electrochemical impedance spectroscopy measurements, the differences observed with the previous treatments were assumed to be linked to the modification of the Al/active material interface. The cell using sol-gel treated current collector presented an activated carbon specific capacitance of 100 F/g and a series resistance of 0.8 Omega cm(2) in acetonitrile 1 M NEt4BF4, that are characteristics compatible with high power applications. (C) 2003 Elsevier Ltd. All rights reserved.