-Yi-Hsien Lu, et al. present a new methodology that enables studies of the molecular structure of graphenesolution interfaces with nanoscale spatial resolution, based on nano-FT-IR, where the IR field is plasmonically enhanced near the tip apex of an AFM; the method makes it possible to determine changes in ion concentration in the diffuse layer as a function of bias , i.e., to obtain the ECS / VCS function X=F(L).