Abstract
Electric double-layer supercapacitors (SCs) 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 SCs due to its high conductivity and large surface area. In this paper, we consider SC electrodes made from a stack of graphene sheets with randomly inserted spacer molecules. We show that the large volumetric capacitances C100F/cm3 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.
Original language | English (US) |
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Article number | 235133 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 84 |
Issue number | 23 |
DOIs | |
State | Published - Dec 21 2011 |