Electrical double layer capacitor with enhanced working voltage

A method of conditioning a supercapacitor to its working voltage, wherein the supercapacitor comprising at least one pair of positively and negatively charged electrodes, including at least one polarisable micro/mesoporous carbon electrode, interleaved with porous ion-conductive separator and immersed in an electrolyte, wherein a destructive effect of heat of adsorption is suppressed by a multistep conditioning process, wherein before the conditioning of the supercapacitor, a supercapacitor cell is stored after filling with the electrolyte for penetration of micropores by electrolyte followed by step-by-step treatment of the supercapacitor with a conditioning voltage (Uc), which is increased gradually up to the working voltage (Uw) by voltage step (ΔUc) which is less than 0.3V, wherein during the conditioning step is performed the voltage cycling wherein the supercapacitor is charged to the conditioning voltage (Uc) and thereafter discharged to the voltage Uc-ΔU wherein the ΔU is between 0 and Uc.