Cd substitution in Zintl phase Eu5In2Sb6 enhancing the thermoelectric performance

Rare earth-contained compound Eu5In2Sb6 which shows improved air stability and competitive thermoelectric properties in comparison to its alkaline earth analogues, has attracted much attention recently for thermoelectric applications. Polycrystalline samples Eu5In2-xCdxSb6 (x = 0, 0.01, 0.02, 0.06, 0.08, 0.1) were synthesized via a direct element combination reaction and subsequent hot-press sintering. With increasing Cd concentration, both the electrical resistivity and Seebeck coefficient decrease monotonously, and the conductive behaviors vary essentially from non-degenerate semiconductor to degenerate semiconductor. The maximum value of power factor (5.78 μW/cm*K2) can be obtained with x = 0.1. While the total thermal conductivity rise as a result of the contribution of electronic part, the thermoelectric figure of merit zT for Eu5In2-xCdxSb6 can be enhanced up to 0.5 at 709 K.