Volume effect of organic solvent on electrochemical Seebeck coefficient of [Fe(CN)6]4−/[Fe(CN)6]3− in water

A thermocell with use of the electrochemical Seebeck coefficient ( E and T are the redox potential and temperature, respectively). is a promising energy-harvesting device. α is the key parameter that governs the thermal efficiency (η) of the thermocell. Here, we systematically investigated the variation (Δα) in α of a redox couple of [Fe(CN)6]4−/[Fe(CN)6]3− in water, by adding 9% organic solvent in molar ratio. We found that Δα for 11 organic solvents well scale to the molar volume (V). The empirical volume effect is understood in terms of the replacement of water molecules with organic molecules depending on V.