Skutterudite unicouple characterization for energy harvesting applications

Abstract

Skutterudites are promising thermoelectric materials because of their high figure of merit, ZT, and good thermomechanical properties. This work reports the effective figure of merit, ZT[subscript eff], and the efficiency of skutterudite legs and a unicouple working under a large temperature difference. The p- and n-type legs are fabricated with electrodes sintered directly to the skutterudite during a hot pressing process. CoSi[subscript 2] is used as the electrode for the n-type skutterudite (Yb[subscript 0.35]Co[subscript 4]Sb[subscript 12]) and Co[subscript 2]Si for the p-type skutterudite (NdFe3.5Co0.5Sb12). A technique is developed to measure the ZTeff of individual legs and the efficiency of a unicouple. An ZT[subscript eff] of 0.74 is determined for the n-type legs operating between 52 and 595 °C, and an ZT[subscript eff] of 0.51 for the p-type legs operating between 77 and 600 °C. The efficiency of the p–n unicouple is determined to be 9.1% operating between ∼70 and 550 °C.