A Novel Thermocell System Using Proton Solvation Entropy.

The entropy change associated with proton-coupled electron transfer (PCET) reactions significantly enhance the Seebeck coefficient (Se ) of thermocells. A redox pair of [Ru(Hx im)6 ]2+/3+ (Him=imidazole, x=0≈1) releases three protons in their one-electron redox reactions in thermocells, which gave a remarkably high Se of -3.7 mV K-1 as confirmed by temperature-dependent square wave voltammetry. The value of Se is proportional to the redox reaction entropy (ΔSrc ), which increased with the number of dissociating protons. This result demonstrates the utility of PCET reaction toward efficient thermoelectric conversion.