Hydrothermal synthesis, characterization, electronic structure, and thermoelectric properties of (Ca(0.85)OH)(1.16)CoO(2).
A layered cobalt oxide (Ca(0.85)OH)(1.16)CoO(2) was prepared at low temperature by hydrothermal process and characterized by powder x-ray diffraction, Fourier transform infrared, and scanning electron microscopy. The results showed that plate image powders could be obtained at 453 K for 12 h. The electronic calculation of the band structure and density of states revealed that (Ca(0.85)OH)(1.16)CoO(2) is a direct-gap semiconductor material and the conductive model is d-d transition of cobalt. The electrical conductivity, Seebeck coefficient, and thermal conductivity of (Ca(0.85)OH)(1.16)CoO(2) were measured from 290 to 573 K. It was found that the oxide behaves as p-type material in the temperature range measured and there is an M-I transition near 370 K. The ZT increases with the increase in temperature, and the maximum value of 0.02 is obtained at 573 K, indicating (Ca(0.85)OH)(1.16)CoO(2) is a promising thermoelectric oxide candidate at middle temperature usage.
Pei
J
J
Department of Applied Chemistry, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001, People's Republic of China.
Chen
G
G
Zhou
N
N