Thermopower of non-superconducting and superconducing Nd1·85Ce0·15CuO4−y samples

The thermopower of single-phase samples of Nd_1·85Ce_0·15CuO_4−y was measured from 250 K down to 10 K. The as-prepared sample was not superconducting. It had a negative thermopower at 250 K, whose magnitude increased as temperature was decreased to 95 K. A further reduction in temperature caused a decrease in magnitude of thermopower. The sign of the thermopower changes to positive at 12 K. The superconducting sample also showed the same behaviour but the change of sign now occurred at 40 K. Below 40 K, the thermopower showed a positive peak and reduced to zero at the superconducting transition. These results were compared with previous studies.     

Thermoelectricity of BaTiO3+δ

Thermoelectricity of mixed ionic electronic conductor BaTiO₃₊ is thermodynamically analyzed, and measured across the mixed n/p regime of both undoped and 1.8 m/o A1-doped BaTiO₃ at elevated temperatures. There can be 4 different measurement conditions with respect to the nonstoichiometry () redistribution and types of atmosphere gases used to control the surrounding oxygen potential, which lead to differences in information content of the thermopower. Experimental thermopower isotherms are exhaustively analyzed to find that the ionic contribution is evident in the mixed n/p regime and that the heats of transport of electrons and holes are about the same as their migration enthalpies.     

Energy generation using thermopower waves: Experimental and analytical progress

Thermopower waves convert chemical energy into electrical power using nanostructured thermal conduits like carbon nanotubes (CNTs) by taking advantage of their high thermal conductivity to propagate the heat released by an exothermic reaction of a fuel layer coated around the conduit. Electron–phonon coupling in the CNTs then leads to an electrical output. Previous work using cyclotrimethylene‐trinitramine coated around multiwalled CNTs has shown electrical output as high as 7 kW kg^?1. This phenomenon has potential to aid the manufacture of nanoscale power sources capable of releasing large power pulses for specific applications. Researchers have studied the effects of other system properties, including the conduit thermal conductivity, the chemical properties of the fuel, and the coupling of the reactions to inorganic thermoelectric materials. An analytical solution for the governing heat and mass balance equations has also been derived. Here, we review the progress made in the field of thermopower waves. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3333–3341, 2013