Solvothermal Synthesis and Electrical Transport Properties of Te-doped CoSb_3 Skutterudites

Nanosized Te-doped skutterudites CoSb_(3-x)Te_x (x=0,0.05,0.1,0.2,0.4) were prepared by a solvothermal method using CoCl_2,SbCl_3 and pure telluride powder as precursors and NaBH_4 as reduc- tant.It is found that trace of other impurity phases such as CoTe_2 are coexisted for x≥0.2.The size of synthesized CoSb_(3-x)Te_x powders is about 40nm,and the grains are grown up to an average size of about 300nm after hot-pressing.Transport properties measurements indicate that the Te-doped CoSb_(3-x)Te_x have n-type conduction.As the Te fraction increases,the values of electrical conductivity increase,while the absolute Seebeck coefficient values decrease.A maximum power factor of 2.3×10~(-3)W·m~(-1).K~(-2) is obtained at 773K for CoSb_(2.8)We_(0.2).