This separation of two layers of polarized ions through the double-layer stores electrical charges in the same way as in a conventional capacitor. The double-layer charge forms a static electric field in the molecular IHP layer of the solvent molecules that corresponds to the strength of the applied voltage. Double-layer capacitance is the important characteristic of the which appears at the interface between a and a (for example, between a conductive and an adjacent liquid ). • Development of the double layer and pseudocapacitance model see • Development of the electrochemical components see • • Béguin, Francois; (18 November 2009). Carbons for Electrochemical Energy Storage and Conversion Systems. Taylor & Francis. pp. 329–375. laid the theoretical foundations for understanding the double layer phenomenon. The formation of double layers is exploited in every to store electrical energy. Every capacitor has two electrodes, mechanically separated.