Abstract
Thermoelectric(TE) oxide materials have been attracted attention, since it was reported that NaCo2O4 had high TE properties. Because layered α-titanate NaCo0.5Ti0.5O2 has the same crystal structure as NaCo2O4, which is edge-shared CoO6, TiO6-octahedral structure, it is expected to become a new TE material have high properties. In this study, we investigate a possibility of NaCo0.5Ti0.5O2 for a new TE material and effect of metal-ion substitution for A, B-site. Single phase α-NaFeO2-type titanate of the products formed at 1000°C in air. The values of TE power and electric resistivity decreased with increasing temperature, showing a semiconductor behavior. TE properties were improved by the substitution of Nb for Ti-site.
