Electrode kinetic aspects of electrochemical energy conversion

The basic similarities and dissimilarities among the three electrochemical devices-electrochemical substance producer, electrochemical electricity producer and electrochemical electricity storer — are presented. Expressions are derived for the terminal cell potential, differential resistance, efficiency and power of an electrochemical electricity producer as a function, of the current drawn from it. These expressions have been used in numerical calculations to examine the effect of the various factors (e.g., exchange currents, limiting currents, ohmic internal resistance) on the performance of the electrochemical energy converter. Analytical expressions for the maximum power, the terminal cell potential and the current, when the power is a maximum, are derived for two special cases.

The importance of electrocatalysis from the point of view of improving the performance of electrochemical electricity producers is stressed. Recent work on the kinetics of the important oxygen electrode reaction and on the mechanism of electroorganic oxidation is discussed. Some models of electrode design for increasing the apparent current density (and thereby reduce efficiency and power losses) are dealt with theoretically.