The Seebeck coefficient of a thermocell consisting of [Fe(CN)(6)](4-/3-) undergoes salient change from -1.43 to +3.5 mVK(-1) by the addition of dodecyl tetramethylammonium bromide (DTAB) micelles. This originates from the unexpected binding affinity of [Fe(CN)(6)](3-) to DTAB micelles as compared to that of [Fe(CN)(6)](4-), which was confirmed by spectroscopic and electrochemical measurements. This result provides a novel strategy for improving the Seebeck coefficient of versatile redox species by taking advantage of the amphiphilic ion-paring.