Figure 3: Ion- and velocity-dependent waving potential.

(a) Calculated adsorption energies of different ions on one side of monolayer graphene. Na⁺// is the value for a Na⁺ adsorbed on a bilayer graphene. (b) Induced peak voltages as functions of velocity of graphene inserting into LiCl, NaCl, KCl and HCl solutions with the same concentration of 0.6 M as well as into deionized water. (c) Peak voltages as functions of velocity of graphene insertion into a series of halide sodium solutions. (d) The magnitudes of positive- and negative-peak voltages as functions of moving velocity of graphene across the surface of 0.6 M NaCl solution.