A thermocell with molten carbonate electrolyte mixture with two identical gas (CO₂|O₂) electrodes may be a suitable alternative to the conventional semiconductor thermoelectric converters. Also, it shows the ability to harvest the waste heat at higher temperatures and utilize the available CO­­₂ off-gases from metal producing industries for the thermoelectric conversion. Using symmetrical gas electrodes, high Seebeck coefficients in the range of 1 mV/K were measured, whereas the most conventional semiconductor thermoelectric cell shows only 0.2 mV/K.

The inclusion of solid oxide in the electrolyte mixture was found to influence the transported entropy of the carbonate ions and expand the appropriate conditions for thermoelectric conversion. Similarly, the change in the cationic composition of the molten carbonate melt in the electrolyte mixture leads to alter the entropy of the ionic species. Thus, the effect of a compositional change in the electrolyte mixture is studied in detail, towards its contribution to the Seebeck coefficient of the molten carbonate thermocell.