Influence of electrode preparation on the electrochemical behaviour of carbon-based supercapacitors

This work investigates the influence of electrode preparation on the electrochemical behaviour of carbon-based supercapacitors. Studies were performed using the same activated carbon and polymer polyvynilidene fluoride (PVDF) in the same proportions (10 wt.% PVDF). Only the way in which these components were mixed was modified. The procedure for mixing the activated carbon and the polymer has a significant influence on the electrochemical behaviour of the electrode used in a supercapacitor, as this determines the surface area accessible to the electrolyte. The mixing procedure can be selected in order to ensure optimum performance of the electrode. The use of N-methyl-2-pyrrolidone (NMP) in the mixing procedure, the most common method reported in the literature, blocks a significant part of the porosity of the activated carbon, causing a decrease in capacitance. The addition of the polymer using one of the other methods studied reduces the accessible surface area to a lesser extent, although the use of ball milling causes a decrease in the size of the carbon particles which, in turn, increases the electrode resistance.