The Double Layer Capacitors developed by WIMA are storage capacitors with highest capacitance values in the Farad range. They are among others suited to serve as batteries, can deliver considerably higher currents for a short time, however, and are maintenance free.
The construction of a Double Layer Capacitor can be described as a plate capacitor where the most important topic is to obtain electrodes with an extremely large surface. For this purpose activated carbon is ideally suited, as it allows to obtain capacitance values of up to 100F/g of the active mass of the electrode.
The electrolyte, the conductive liquid between the electrodes, is a conducting salt dissolved in an aqueous or organic solvent which permits to apply voltages of 2 V (in special cases 3 V).
The actual double layer consists from ions which attach to the electrodes - negative ions to the positive electrode and positive ions to the negative electrode - as soon as a voltage is applied to the cell and thus create a dielectric of a few Angstrom only. According to the formula for the capacitor from the dielectric constant of the double layer (approx. 10) and the extremely thin dielectric you get an very high capacitance value. More Information from WIMA »
