Research in carbon nanomaterials has seen tremendous growth in recent years; however, technological advances are limited by the lack of continuous and scalable synthesis methods. Here we present a scalable roll-to-roll process for synthesizing vertically-aligned multi-walled carbon nanotubes (VACNTs) on Al foil ribbons which are continuously drawn through a chemical vapor deposition (CVD) reactor operating at ambient pressure and a relatively low growth temperature (600 degrees C). Electrodes comprised of VACNT forests synthesized in this process are directly assembled into supercapacitor cells, which yield high power densities (1270 W/kg) and energy densities (11.5 Wh/kg). These devices exhibit excellent cycle stability with no loss in performance over more than a thousand cycles. (C) 2014 Elsevier Ltd. All rights reserved.