The analysis of underpotential deposition (UPD)-based systems for the development of electrochemical supercapacitors is investigated employing the UPD of Tl on Ag in the presence of bromide ions, as an illustrative example. The specific capacitance is estimated with the help of multi-cycle voltammograms, galvanostatic charge/discharge experiments and impedance spectroscopy. The equivalent circuit for the system is constructed and the parameters are deduced from the simulation. The deduced magnitude of similar to 10(2) F g(-1) in conjunction with the satisfactory number of charge/discharge cycles obtained from galvanostatic experiments indicate the feasibility of these systems as supercapacitors.