Concentration dependence of resistance components in solutions containing dissolved Fe 2+ /Fe 3 .

Electrolyte solutions containing Fe 2+ /Fe 3+ are suitable for liquid thermoelectric conversion devices (LTEs), because they are inexpensive materials and exhibit a high electrochemical Seebeck coefficient α . Here, we investigated the concentration ( c ) dependence of resistance components, i.e. , solvent ( R s ), charge-transfer ( R ct ), and diffusion ( R dif ) resistances, of dissolved-Fe 2+ /Fe 3+ -containing aqueous, methanol (MeOH), acetone, and propylene carbonate (PC) solutions. We found that the c dependence of R s and R dif are well reproduced by empirical formulas, and , where η ( c ) is viscosity at c . We further found that the magnitudes of C s and C dif are nearly independent of solvent, suggesting that η is one of the significant solution parameters that determine R s and R dif .