Discharge Behavior of Redox Thermogalvanic Cells

The discharge behavior of thermogalvanic cells based on a dissolved redox couple, namely ferro‐ferricyanide, was investigated as a function of redox couple concentration, temperature difference, electrode placement and configuration, and forced convection. The principal source of cell polarization was found to be the rate of mass transfer of electroactive species to the electrode surfaces. This concentration polarization is instrumental in limiting the power output of aqueous redox thermogalvanic cells to values <0.1 mW cm−2. A practical feature of such cells, however, is that a continuous power output can be maintained indefinitely provided that the half‐cell temperature difference remains constant.