High pressure synthesis of Te-doped CoSb3 with enhanced thermoelectric performance

Te-doped CoSb3 skutterudites were successfully synthesized with high pressure synthesis method followed by spark plasma sintering. The introducing of Te atoms into the lattice sites of CoSb3 resulted in n-type electrical conductivity, which increased with elevated Te doping level. An enhanced power factor, larger than 4,000 µWm−1K−2 for temperatures higher than 650 K, was observed for Co4Sb11.5Te0.5. This is a significant value for skutterudites substituted with a single element. Meanwhile, the thermal conductivity of Te-doped CoSb3 was greatly suppressed due to stronger electron–phonon scattering. The optimized Co4Sb11.5Te0.5 showed a ZT value of 1.15 at 883 K, which rivals the state-of-the-art single elemental filled skutterudites.