Carbon nanosheets are comprised of 1-7 graphene layers that are predominantly vertically oriented with respect to a substrate. The thickness and morphology of the nanosheets can vary depending on the growth precursor and the substrate temperature. They have an ultra-low in-plane resistivity. The capacitance of carbon nanosheets was measured by cyclic voltammetry in a standard electrochemical three-electrode cell, which contains a platinum counter electrode and a standard mercury/mercurous sulfate reference electrode in 6 M H2SO4 electrolyte. As a working electrode, the capacitance of carbon nanosheets per area was found to be 0.076 F cm(-2). A mathematical model was used to simulate the total possible capacitance of a virtual supercapacitor cell that contains carbon nanosheets as the electrode material and found to be 1.49 x 10(4)F. (C) 2009 Elsevier B.V. All rights reserved.