Seebeck effect in a battery-type thermocell

We demonstrated that battery-type thermocells, which consist of two paste-type electrodes with the same active material and electrolyte, show the Seebeck effect. The magnitudes of electrochemical Seebeck coefficient (S) of the thermocells with several layered oxides were evaluated: -12.7 mu V/K for Na0.99CoO2, -29.7 mu V/K for Na0.52MnO2, -22.4 mu V/K for Na0.51Mn0.5Fe0.5O2, and -6.8 mu V/K for LiCoO2. In the thermocell with Na0.99CoO2, time-dependence of the electromotive force (Delta V) at a constant temperature difference (Delta T) was well reproduced by a mean-field approach of the chemical potential (phi)-Na+ concentration (x) relationship, indicating that the Na+ intercalation/deintercalation plays an intrinsic role in the electrochemical Seebeck effect. (C) 2015 AIP Publishing LLC.