Ca2.7Bi0.3Co4O9/La0.9Bi0.1NiO3 thermoelectric devices with high output power density

Different versions of a thermoelectric unicouple composed of p-type Ca2.7Bi0.3Co4O9 (Co-349) and n-type La0.9Bi0.1NiO3 (Ni-113) bulks were constructed using Ag paste containing p- and n-type oxide powders, prepared from the same bulks, for connection of the p and n legs, respectively. Internal resistance (R-I) of the unicouple corrected using Ag paste containing 6 wt. % of the oxide powders is 26.2 mOmega at 1073 K in air and decreases with increasing temperature. Maximum output power (P-max), evaluated using the formula P-max=V-O(2)/4R(I), (V-O is open-circuit voltage), is 94 mW at 1073 K (DeltaT=500 K) and increases with temperature. This value corresponds to a volume power density of 0.66 W/cm(3). (C) 2004 American Institute of Physics.