Thermal analysis of electrochemical reactions: Part I. Kinetic method of determining Peltier heats

Abstract

The electrochemical Peltier effect is defined as a heat effect occurring at the electrode/electrolyte interface when a reversible electrode reaction proceeds at it. This effect is characterized quantitatively by the Peltier coefficient or Peltier heat, which is, unlike the heat of dissipation (Joule heat and heat due to the irreversibility of electrode processes and transfer processes), one of the fundamental characteristics of the electrode process. The quantities characterizing heat exchange at the interface are analysed using basic equations of irreversible thermodynamics - the entropy balance equation and the equation of entropy production rate in the electrode layer. Relationships have been derived which relate the overall heat effect to the Peltier heat and the kinetic parameters of the electrode process. A kinetic method for determining Peltier heats from data on the stationary heat effect at the interface has been developed. A linear dependence of the heat effect at the electrode/electrolyte interface on electrode polarization has been obtained experimentally and using basic data of other authors for various systems with aqueous electrolytes and salt melts. This made it possible to determine the Peltier coefficient values for the electrochemical systems considered.