Applications of non-equilibrium thermodynamics to the theory of overvoltage

Abstract

An unambiguous definition of the different overpotential terms is possible based on the theory of non-equilibrium thermodynamics. The overpotentials are a direct consequence of the thermodynamic irreversibility of the processes taking place in an electrochemical system, and the irreversible entropy production of a process occurring at a finite rate is a quantitative measure of this irreversibility. Therefore, the overpotential terms can be directly defined in terms of the entropy production rate of the process in question. ▪, with η i = ( T/I)(d S i/d t). Two examples are given: the separation of ohmic and diffusion overpotentials and the separation of the charge transfer and diffusion overpotentials.