Electric double layer supercapacitors are promising devices for high-power energy storage based on the reversible absorption of ions into porous, conducting electrodes. Graphene is a particularly good candidate for the electrode material in supercapacitors due to its high conductivity and large surface area. In this paper we consider supercapacitor electrodes made from a stack of graphene sheets with randomly-inserted "spacer" molecules. We show that the large volumetric capacitances C > 100 F/cm^3 observed experimentally can be understood as a result of collective intercalation of ions into the graphene stack and the accompanying nonlinear screening by graphene electrons that renormalizes the charge of the ion clusters.
@article{arxiv.1109.0978,
title = {A model of large volumetric capacitance in graphene supercapacitors based on ion clustering},
author = {Brian Skinner and M. M. Fogler and B. I. Shklovskii},
journal= {arXiv preprint arXiv:1109.0978},
year = {2015}
}
Comments
13 pages, 5 figures; additional discussion and supporting calculations added