Entropy, Enthalpy, and Free Energy of the Electrical Double Layer at an Ideal Polarized Electrode. Part I. Thermodynamic Theory

Abstract

There are several kinds of entropy, enthalpy, and free energy changes associated with the electrical double layer. Definitions of the thermodynamically significant quantities are given, together with equations for their evaluation. It is shown that the ideal polarized electrode may be regarded as one electrode in a galvanic cell and that the usual thermodynamic treatment of cells may be applied. The electrochemical process occurring in such a cell is identified, and a method of evaluating a new property, the transference number of the ions of the double layer, is given. The relationship between electrocapillary properties of metals and the thermodynamic properties of colloids is indicated. The thermodynamics of gas adsorption on solids is presented as an aid to the interpretation of the above.