Polarization in Electrolytic Solutions. Part I. Theory

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Abstract
The theory of ``Conductance in Polarizable Media'' developed by one of the authors is modified in such a way as to be applicable to electrolytic solutions. This is achieved by the introduction of a new set of boundary conditions. In their original form they expressed the fact that the polarizing ions could not carry any current through the boundary. Now it is assumed that the discharge at the electrodes is a rate process of the first order, characterized by a rate constant ξ. In Sec. II the case of an applied ac voltage is treated. The expressions for the equivalent parallel conductance and capacitance of the polarization layer 1/Rp and Cp are derived by the same method, and to the same extent, as in the older theory. If ξ tends to zero, the previous results are obtained (``completely blocked electrode''). If ξ increases, the ``polarizationcapacitance'' and the ``excess resistance'' both decrease until they vanish for ξ=∞ (``open electrode''). The dependence on frequency remains similar for all finite values of ξ, and is represented in Figs. 1 and 2. Subsequently, in Sec. III, the older theory is improved by a determination of the thickness of the polarization layer. Reduced values of 1/Rp and Cp can be represented as universal functions of one reduced variable, which is proportional to the frequency. The two universal functions are tabulated to some extent in Table I. Finally the theory is extended to the case where several groups of ions of different mobilities are present in the electrolyte.