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 μV/K for Na0.99CoO2, −29.7 μV/K for Na0.52MnO2, −22.4 μV/K for Na0.51Mn0.5Fe0.5O2, and −6.8 μV/K for LiCoO2. In the thermocell with Na0.99CoO2, time-dependence of the electromotive force (ΔV) at a constant temperature difference (ΔT) was well reproduced by a mean-field approach of the chemical potential (ϕ)—Na+ concentration (x) relationship, indicating that the Na+ intercalation/deintercalation plays an intrinsic role in the electrochemical Seebeck effect.