Enhanced thermoelectric performance of lanthanum filled CoSb3 synthesized under high pressure

Abstract n -type lanthanum filled CoSb 3 skutterudites were successfully synthesized with high pressure synthesis. Structural, electrical, and thermoelectric properties were investigated. The synthesized La x Co 4 Sb 12 samples possess the skutterudite structure of Im 3 ¯ symmetry. The maximal filling fraction of La in high-pressure synthesized samples reaches 0.3, which is 30% higher than that of the ambient-pressure synthesized samples. Consequently, our samples show significantly enhanced thermoelectric properties. The power factor as high as 4600 μWm −1 K −2 is reached for the optimal La 0.29 Co 4 Sb 12 sample. Combined with the greatly suppressed thermal conductivity, the highest ZT of 1.06 is achieved at 863 K for La 0.29 Co 4 Sb 12 . Our results indicate the advantage of high pressure to increase the filling fraction, which benefits the thermoelectric performance enhancement of La-filled CoSb 3 skutterudites.