Graphene/carbon nanotube composites not exhibiting synergic effect for supercapacitors: The resulting capacitance being average of capacitance of individual components

There were many claims of synergic effect of carbon nanotubes and graphene leading to enhanced capacitance of the resulting composite. Here we show that spacing of graphene sheets with carbon nanotubes does not yield to any synergic effect of dramatically improved capacitance but in contrary, the resulting capacitance is merely arithmetic average of weight specific capacitances of the individual components. (C) 2012 Elsevier B.V. All rights reserved.