High thermoelectric power factor in Ni-Fe alloy for active cooling applications

Metallic thermoelectric materials are promising candidates for active cooling applications, where high thermal conductivity and a high thermoelectric power factor are essential to maximize effective thermal conductivity. While metals inherently possess high thermal and electrical conductivities, they typically exhibit low Seebeck coefficients. In this work, we create a database of the Seebeck coefficient of binary metallic alloys and apply machine learning techniques to identify alloys with large Seebeck coefficients. Specifically, we identify Ni-Fe as a promising candidate for active cooling around room temperature. We then fabricate Ni-Fe ingots and demonstrate thermoelectric power factor values as high as 120 μW cm^-1 K^-2 at 200 K for these stable alloys, which are composed of cost-effective and abundant elements. Furthermore, we demonstrate that the effective thermal conductivity of these alloys, under small temperature differences, can exceed that of pure copper within the 250-400 K temperature range.