A secondary electrochemical cell includes a negative electrode including an output conductor, activated carbon having a BET surface area of at least 800 m2/g as a carbon-based storage material that enables storage of electrical charge in the electrode through formation of an electrical double layer (Helmholtz double layer), a positive electrode including an output conductor, and nickel hydroxide and/or nickel oxyhydroxide, a porous separator that separates the negative electrode and the positive electrode from one another, an aqueous alkaline electrolyte with which the electrodes and the separator are soaked, and a housing that encases the electrodes, the separator and the electrolyte.