High Pressure Synthesis of p-Type Ce_yFe_4-xCo_xSb₁₂ Skutterudites

Co-substituted p-Type CeFe_4-xCo_xSb₁₂ skutterudites were successfully synthesized with a high pressure synthesis method. The structure, composition, and thermoelectric properties were investigated. The obtained Ce_yFe_4-xCo_xSb₁₂ samples show the skutterudite structure of I m 3 ¯ symmetry. The hole concentration decreases with elevating Co substitution level, leading to increased Seebeck coefficient and electrical resistivity. Meanwhile, the filling fraction of Ce decreases, which is unfavorable for reducing the lattice thermal conductivity. As a result, the thermoelectric performance of Ce_yFe_4-xCo_xSb₁₂ deteriorates with higher Co content. The maximal ZT of 0.91 was achieved at 763 K for the optimal Ce_0.92Fe₄Sb₁₂ sample.