A PHYSICAL INTERPRETATION OF SCHWAN LIMIT CURRENT OF LINEARITY

In this the second of a series of papers on the nonlinearity of the electrode-electrolyte interface impedance, the wealth of experimental observations which exists in the literature on AC impedance nonlinearity is physically interpreted. The interface impedance is well represented by the parallel combination of a constant phase angle impedance and a charge transfer resistance. The charge transfer resistance is the major source of the observed nonlinearities. As a result, the current limit of linearity, i(L), increases with frequency such that i(L) is proportional to omega(beta). The series resistance, R(s), of the interface impedance initially increases with applied signal amplitude, reaches a maximum and then decreases. The series reactance, X(s), decreases monotonically with signal amplitude.