▎ 摘　　要

We have synthesized graphene by reducing carbon dioxide in magnesium and calcium metal flames. The as-prepared graphene has been used as conductive additive to improve the electrical conduction of activated carbon-based supercapacitor electrodes. The graphene/activated carbon composite electrode showed an outstanding specific capacitance of 220 and 180 F g (1) at a current density of 0. 1 A g (1) in 6 M KOH electrolyte when using graphene obtained in magnesium and calcium flames, respectively. (C) 2013 Elsevier B.V. All rights reserved.