LiyCoO2 has a similar layered structure to NayCoO2, which is a typical p-type oxide thermoelectric material, and the average Co valence of 3 + y is controlled by the Li content y. We investigated the thermoelectric properties of LiCo1-xMxO2 samples (M = Cu, Mg, Ni, Zn) for the first time at high temperatures, in which Co3+ was substituted by the divalent M2+ ions, and the average Co valence of 3 + x can be controlled similarly to the Li content y in LiyCoO2. The substitution of the M2+ ions for the Co site was found to show thermoelectric properties similar to those of LiyCoO2 with the same average Co valence. The Mg-doped sample showed the highest thermoelectric performance at high temperatures in this study; the thermoelectric power factor P is 2.38 × 10-4 W m-1 K-2 at 1173 K and the dimensionless figure of merit ZT is 0.024 at 876 K. The thermoelectric potential of LiCo1-xMxO2 is discussed and compared with those of LiyCoO2 and NayCO2 systems.
ASJC Scopus subject areas
- Physics and Astronomy(all)