Synergistic production of graphene microsheets by simultaneous anodic and cathodic electro-exfoliation of graphitic electrodes in aprotic ionic liquids

摘要

Electrochemically mediated exfoliation of graphite is a promising green and high throughput approach for production of graphene sheets (GNs). Previous research focused mostly on either anode or cathode exfoliation due to restrictions imposed by the investigated intercalating ions and insufficient consideration given to the design of the electrochemical cell. Consequently, in single graphite electrode studies, at the non-graphitic counter-electrode (e.g. Pt), unwanted electrode reactions such as gas evolution and electrolyte decomposition take place, leading to significant energy and chemical losses. Here, we report the simultaneous anodic and cathodic GN production in two types of electrochemical cells (undivided and divided) using aprotic electrolytes containing ionic liquids (ILs). We demonstrate a synergistic exfoliation effect when the iso-molded graphite anode and cathode are subjected to a constant cell potential, generating up to 3 times higher exfoliation yields compared to single-electrode studies on each side (similar to 6-fold improvement in total). Thorough characterization of the products collected from both electrode compartments confirmed the production of ultrathin GNs (<5 layers). The cathodic exfoliates were almost exclusively composed of GNs; whereas among the anodic products, in addition to the majority GNs, we detected traces of other morphologies such as nanoparticles, nanotubes, and larger rolled sheets. (C) 2014 Elsevier Ltd. All rights reserved.