Persistent electrochemical pillaring of graphene ensembles

The electrochemical activation of partially reduced graphite oxide (GOpr) with a layer spacing of 4.4 angstrom was monitored by in situ XRD. After anodic activation in 1 M TEABF(4) in acetonitrile (AN) the interlayer spacing of the graphene planes was increased from 4.4 angstrom to about 13 angstrom as indicated by a new (001) peak in the XRD pattern at about 2 theta = 3 degrees. During subsequent charge discharge cycles this peak is stable and demonstrates the existence of stable pillars between the graphene layers, resulting in slit-like pores of about 1 nm between the graphene layers. While the respective expansion of the activated GOpr moieties is in the order of 300%, dilatometry measurements of the electrode indicate an expansion of 40% only. After activation a stable capacitance of up to 220 F/g is achieved for the activated GOpr. (C) 2013 Elsevier B.V. All rights reserved.