Fig. 3

Relationship between capacitance, hydration energy, charge transfer, and ion accessibility. a Specific capacitance of hierarchical carbon aerogel monoliths (HCAMs) measured in 1 and 0.05 M aqueous solutions at a scan rate of 0.5 mVs\({}^{-1}\). b Charge transfer (CT) per cation on graphene basal plane and in slit pore with a diameter of 6 Å. c Binding energies and kinetic barrier for ion adsorption and intercalation computed for the 6 Å diameter graphene slit pore and basal plane. d Computed binding energy of the cations as a function of pore size, the experimental pore size distribution is indicated by gray line. In all cases, the excess charge of the electrode is set to \({q}_{{\rm{grp}}}=-1e\), and negative binding energy indicates favorable adsorption