Abstract: A series of cobalt based oxide thermoelectric materials Ca₃Co₂O₆ and Ca_2.85M_0.15Co_2-yCu_yO₆ (M=A
g,Er; y=0,0.1,0.2) were prepared by solgel method and atmospheric sintering technology. The phase composition and morphology of the samples were studied by Xray diffraction (XRD) and scanning electron microscopy (SEM). The electrical conductivity and Seebeck coefficient of the samples were measured in the range of 300—1 000 K. The effects of different doping elements on the thermoelectric properties of the composite were investigated. The results show that all the materials prepared are single phase with compact structure, and the different codoping elements can enhance the thermoelectric p
roperties of the materials, when the doping amount of Ag⁺ and Cu^2+ is 015 and 02, respectively, the best thermoelectric properties can be obtained. The power factor of  Ca_2.85Ag_0.15Co_1.8Cu_0.2O₆ is 71 μW/(K2·m) at 965 K.

Key words: thermoelectric material,  , sol-gel,  , thermoelectric property, co-doping