Ultracapacitors Based on Graphene/MWNT Composite Films

摘要

Ultracapacitors are promising candidate for alternative energy storage applications since they can store and deliver energy at relatively high rates. In this work, we integrated large area CVD graphene with multi-walled carbon nanotubes (MWNTs) to fabricate highly conductive, large surface-area composite thin films used as electrodes in ultracapacitors. Uniform, large area graphene layers were produced by CVD on copper foils and were chemically modified. Chemically shortened MWNTs, ranging in length of 200~500 nm, were deposited by dropping on graphene layers. Graphene/MWNT composite films with different thicknesses were obtained. The surface morphology was investigated by SEM. The results demonstrated relatively dense and homogeneous net nanostructure. The measurements of cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy (EIS) are conducted to determine its performance of graphene/MWNT film structures.