Kinetics of Polarization Mechanisms

Abstract

Polarization is a primary application process in electrochemical reactions. We have proposed a statistical thermodynamic theory for electrochemical reactions which is essential to investigate non-equilibrium, quasi-equilibrium, and equilibrium electrochemical reaction processes. We here apply the electrochemical reaction theory to understand the detailed non-equilibrium kinetics of polarization in electrochemical reactions. The unified approach demonstrates the current density as a function of electric potential, time, and space so that the theory leads to a new paradigm for polarization in electrochemical reactions. Three variable separation constants represent particle number constants and play the major roles in exploring the distinct polarization mechanisms. The kinetic theory accounts for the four control mechanisms of activation, concentration, resistance, and film polarization. Three limiting current densities and four activation potentials are adopted as input parameters. Theoretical calculations agree with existing experimental data in a wide range of electric potential including the four control regimes of polarization.