Universitat de Barcelona, Spain
Title: Growth and electrochemical characterization of graphene nano walls and carbon nanotubes
Biography: Roger Amade
Electrochemical double layer capacitors (EDLC) or supercapacitors exhibit higher specific capacitance than conventional electrolytic capacitors due to their increased surface area and short distance between positive and negative charges at the electrode/electrolyte interface. Because of their high electric conductivity, chemical inertness, thermal and mechanical stability, carbon-based electrodes are the preferred material of choice in supercapacitor applications. In particular, carbon nanostructures such as carbon nanotubes (CNTs), with a high specific surface area may increase the capacitance upto about 100 F/g. Recently, graphene nanowalls (GNWs) are being the focus of research in different areas due to their outstanding properties. GNWs can be described as self-assembled, vertically-standing, few-layered graphene sheet nanostructures. The growth mechanism of these nanostructures is still not clear, but recent results indicate that they grow virtually on every substrate that withstand the synthesis temperature (around 600ºC) without the need of a catalyst. Thus, this new material has promising features that may improve performance of energy storage devices like supercapacitors or lithium ion batteries. Surface functionalization of these nanostructures by means of plasma treatments or deposition of metal oxides may further improve their pseudo capacitance and electrochemical performance. This study explores the growth of GNWs and their super capacitive properties grown under different conditions, and compares the results with those obtained for CNTs.