Effect of starch addition on structural, electrical and thermal properties of delafossite CuAl0.9Fe0.1O2

In this study, starch was added to the delafossite CuAl0.9Fe0.1O2 with the purpose of creating porosity in the structure. Increasing porosity contributes to a decrease in thermal conductivity, which increases the figure of merit (ZT) for thermoelectric properties. The results show that the porosity of the material increased as starch content was raised from 0 to 3 wt%. The thermal conductivity of CuAl0.9Fe0.1O2 at room temperature decreased from 9.12 to 5.44 W/m.K as porosity increased from 12.0 to 43.4 vol%. The electrical conductivity decreased with increasing starch concentration, with the values ranging from 0.32 to 0.08 S/cm. Of all samples from 0 to 3 wt% starch, the sample with 1 wt% showed the highest ZT value. The increase of the ZT value resulted in a decrease in thermal conductivity due to sample porosity.