Detection of the temperature coefficients of thermal cells by the electrochemical Peltier heats

Abstract

The temperature coefficient is an important parameter for the thermo-electrochemical cells. It is divided into either the isothermal coefficient or thermal one. In view of the fact that there are some vague understandings to the temperature coefficients of a cell and its electrode, this paper used the Peltier heats on the interface between electrode and electrolyte to define the isothermal coefficient and thermal coefficient. The distinction between both of them is that the former is that the change in entropy of the standard hydrogen electrode with temperature is not taken into account, and the latter does. Logically, the isothermal coefficient is a special case of the thermal coefficient, and the latter seems to be a greater doctrinal point, with more practical significance. A type of isothermal single-fluid cell has been developed for more accurate measuring the temperature coefficient. This method can replace the early double-fluid cell in which the various polarizations caused by the temperature effect, liquid junction potential, etc., are hard to be avoided, resulting in the poor reproducibility. The definition and measuring method of the temperature coefficients in this paper are not only strict in theory but also makes operable. An experiment has been made on measure of the Peltier heats of the cupric sulfate/copper system at different concentrations, obtaining their thermal coefficients and isothermal coefficients more accurately.