Electrochemical measurements further support the success of the functionalisation reaction and allow the amount of electrochemically accessible anthraquinone to be quantified. Cyclic voltammetry (CV) curves on two-electrode cells show clear differences in the charge storage behaviours of f-CMK-3 and u-CMK-3 (Figure ). In these measurements, a microporous carbon, YP80F, with excess charge storage capacity was used as the positively charged electrode. The CV curve of the u-CMK-3 cell (black line) displays typical electrochemical double-layer capacitive behaviour, identified by a square-like CV with the absence of obvious redox peaks. This so-called "double-layer capacity" seen in activated carbon materials arises from capacitor-like energy storage at the interface between the electronically charged carbon surface and oppositely charged ions in the electrolyte. In contrast, the CV curve of f-CMK-3 exhibits two charge storage mechanisms: (a) double-layer capacitance, evidenced by a rectangular contribution, and (b) Faradaic charge storage, evidenced by two redox couples centered at cell voltages of -1.5 V and -2.2 V which correspond to the two 1 e - reduction/oxidation processes of anthraquinone. A slight loss of double-layer capacity was seen at low cell voltages (e.g., -0.5 V) upon functionalization, likely owing to the reduction in surface area and pore blockage after anthraquinone functionalization on CMK-3, as seen by gas sorption. However, the overall charge-storage capacity increased by 25% from 39 to 52 mA h g -1 owing to the addition of the Faradaic contributions.