Ca3Co4-xCuxO9 polycrystalline thermoelectric ceramics with small amounts of Cu have been synthesized by the classical solid state method. X-ray diffraction data have shown that all the Cu has been incorporated into the Ca3Co4O9 structure and no Cu-containing secondary phases have been produced. Apparent density measurements have shown that all samples are very similar, with densities around 75 % of the theoretical one. Electrical resistivity decreases when Cu content increases until x = 0.03 while Seebeck coefficient remains practically constant for all samples. The improvement in resistivity leads to higher power factor values than the obtained for the undoped samples. © 2013 Springer Science+Business Media New York.

The authors wish to thank the Gobierno de Aragón (Research Groups T12 and T87) for financial support. The technical contributions of C. Estepa, and C. Gallego are also acknowledged. Sh. Rasekh acknowledges a JAE-PreDoc 2010 grant from CSIC.

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