High performance p-type segmented leg of misfit-layered cobaltite and half-Heusler alloy

•p-type segmented leg of oxide and half-Heusler was for the first time demonstrated.•The maximum conversion efficiency reached a value of about 5%.•The results are among the highest reported values so far for oxide-based legs.•Oxide-based segmented leg is very promising for generating electricity. In this study, a segmented p-type leg of doped misfit-layered cobaltite Ca2.8Lu0.15Ag0.05Co4O9+δ and half-Heusler Ti0.3Zr0.35Hf0.35CoSb0.8Sn0.2 alloy was fabricated and characterized. The thermoelectric properties of single components, segmented leg, and the electrical contact resistance of the joint part were measured as a function of temperature. The output power generation characteristics of segmented legs were characterized in air under various temperature gradients, ΔT, with the hot side temperature up to 1153K. At ΔT≈756K, the maximum conversion efficiency reached a value of ∼5%, which is about 65% of that expected from the materials without parasitic losses. The long-term stability investigation for two weeks at the hot and cold side temperatures of 1153/397K shows that the segmented leg has good durability as a result of stable and low electrical resistance contacts.