A general view of the glass AFM cell for liquid used for the FE-AFM studies is shown in Figure . A detail of the glass AFM cell is depicted in Figures . In the bottom view (Figure ) it can be observed the o'ring that is in contact with the working electrode (WE), a plate of exfoliated HOPG whose exposed area (limited by the o'ring) is 0.5 cm 2 . The volume of the cell, once it is assembled is around 0.024 cm .