A Comparison of Exfoliation Methods on Microstructure and Electrochemical Performance of Graphene Nanosheets for Supercapacitors

Graphene nanosheets (GNS) were exfoliated by thermal expansion and microwave irradiation, respectively. The influence of exfoliation methods on GNS's surface structure and electrochemical property were analyzed. The porosity structure of GNS was measured by N-2 adsorption. The N-2 adsorption results proved that both the specific surface area and pore volume of the GNS exfoliated by thermal expansion are larger than those by microwave irradiation. And the surface morphology was observed by scanning electron microscopy and transmission electron microscopy. The electrochemical performance of the graphene nanosheets were Comparatively tested by cyclic voltammetry and galvanostatic discharge-charge tests. The GNS via thermal expansion exhibited better electrochemical property with the specific capacity of 188 F/g at the current density of 0.1 A/g.