Improved double layer energy storage device

Improved electrical double layer energy devices containing at least one carbon electrode are prepared by the process of adding a voltage regulating agent, such as bromide, to the electrolyte prior to making the carbon electrodes. An electrical double layer energy storage cell comprises: a) a positive electrode and a negative electrode wherein at least one electrode is comprised of carbon which is substantially free of adsorbed gases, in admixture with an electrolyte and a voltage regulating agent;b) a porous ionically conductive separator between the electrodes; andc) a first and a second ion-insulating connector impervious to the electrolyte wherein the first connector is electronically contacted to the positive electrode and the second connector is electronically contacted to the negative electrode.