The thermoelectric potential of molten salt thermocells

The thermoelectric potential of a molten salt thermocell is not only dependent on the molten salt but also on the types of electrodes used for measurement. The thermo-electric potential of a thermocell with reversible electrodes constructed of the metal of the salt is determined by the entropy changes of the cation and is termed the 'cationic thermoelectric potential' by the author. Similarly, electrodes of the anionic component of the salt lead to an anionic thermoelectric potential. This paper is concerned with the thermoelectric potential of cationic thermocells containing pure salts, and binary mixtures of pure salts with a common anion or cation. Previous work has been reviewed and the theory of the thermoelectric potential and the entropies of transfer of ions in mixtures of salts has been extended. Experimental studies of cells containing argentous and cuprous halide mixtures between pure metal and alloy electrodes have generally confirmed this theory. The possibility of using the thermoelectric potential of a molten salt thermocell for electrical generation was examined experimentally by the construction of a 13 V trial generator. This form of direct generation was shown to be possible but the expected efficiency of no more than 10% rather limited the field of application.