Statistical Thermodynamic Theory for Non-Equilibrium, Quasi-Equilibrium, and Equilibrium Electrochemical Reactions

Abstract

An electrochemical reaction as a branch of chemical reactions is one of the fundamental phenomena, but exact electrochemical reaction mechanisms have been unknown. We here propose a statistical thermodynamic theory for electrochemical reactions, which is vital to investigate electrochemical reactions for non-equilibrium, quasi-equilibrium, and equilibrium. The theory utilizes a postulate that electric potential, time, and space are independent and orthogonal variables in extended phase spaces. It is an internal Gibbs energy transport theory for electrochemical reactions leading to the unification of non-equilibrium and equilibrium reactions, a non-equilibrium generalization beyond quasi-equilibrium theories for migration and diffusion, and the integration of diffusion and convection mechanisms. It predicts that there are current density gaps and broken discrete symmetries at the activation potential, time, and displacement. It provides the Nernst equation, the rate equation, and the spatial cross section of electrochemical reactions. The electrochemical theory demonstrates relationships among electrochemical reactions, thermodynamics, and statistical physics.

Thermodynamic chemical energy transfer mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium chemical reactions

“…Internal energy transfer in a quasi-equilibrium (quasi-static) process is conventionally described only by extensive state variables, but internal energy in a non-equilibrium process can be stated by including intensive state variables. Here, the dependence of intensive state variables for internal energy transfer is discussed [30,31,33].…”

“…The statistical thermodynamic theory for electrochemical reactions [31,32] is generalized for a statistical thermodynamic theory for chemical reactions. Chemical reactions can be either spontaneous or non-spontaneous.…”

“…The connection between chemical and electrochemical reactions is considered here. The statistical thermodynamic theory to describe electrochemical reactions has been proposed [31,32]. A total system is in chemical non-equilibrium while it is in thermal and mechanical equilibrium.…”

“…We have furthermore proposed the statistical thermodynamic theory for electrochemical reactions [31,32] which is vital to examine both diffusive and internal convective electrochemical reactions. It is a transport theory for electrochemical reactions leading to the integration of diffusion and internal convection, a generalization beyond quasi-equilibrium theories for migration and diffusion, and the unification of internal equilibrium and equilibrium.…”

“…The theory is analogous to the statistical thermodynamic theory for electrochemical reactions [31,32]. It is able to probe internal convective chemical energy transfer in chemical reactions since it is a generalization beyond chemical energy transfer in quasiequilibrium.…”