Electrical properties of new oxides (Ca0.85-xYxOH)1.16CoO2 synthesized by hydrothermal process

Layered cobalt oxides (Ca0.85-xYxOH)1.16CoO2 (x=0, 0.05, 0.1) were prepared by hydrothermal process and were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrical conductivity and Seebeck coefficient were measured from 323 to 573 K. The XRD and SEM analysis showed that all samples were single phase with plate-like morphology. The substitution of trivalent Y for divalent Ca had a remarkable effect on the enhancement of electrical properties. The maximum PF value, 9.17×10−5 W/(m·K2), was obtained for (Ca0.75Y0.1OH)1.16CoO2 at 573 K, indicating that they are promising thermoelectric materials for middle-temperature usage.