The aim of this work is to characterize the performance of asymmetric activated carbon and manganese dioxide based supercapacitor in a potassium sulphate aqueous electrolyte. A calorimetric device was designed specifically for thermal (heat and power dissipated over time) and electrical measurements (current and voltage over time, durations of charges and discharges, capacitance) on small size C-MnO2 supercapacitors as a function of several parameters: current density, potential range of cycling and ambient temperature. Measurements showed dissipated heat induced by transport and transfer of electric charges in the electrolyte and the electrodes. The heat involved in the adsorption of ions from the electrolyte on the carbon surface and the intercalation of K + ions in MnO2 was quantified. Electrical capacity and energy efficiency of the cell were also studied. Electrochemical and calorimetric measurements have shown the consequences of electrolyte decomposition beyond 1.5 V. A model was developed for electrothermal simulation of C-MnO2 supercapacitors. This model was established from measurements obtained on a small size cell. The simulations, performed on devices of 500 F and 1,700 F and taking into account the thermo-electrochemical coupling, showed temperature heterogeneities affecting the electrochemical behavior.
