Solubility design leading to high figure of merit in low-cost Ce-CoSb3 skutterudites.

Tang, Yinglu; Hanus, Riley; Chen, Sinn-wen; Snyder, G Jeffrey · Nat Commun · 2015

basic_science · Level V

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Abstract

CoSb3-based filled skutterudite has emerged as one of the most viable candidates for thermoelectric applications in automotive industry. However, the scale-up commercialization of such materials is still a challenge due to the scarcity and cost of constituent elements. Here we study Ce, the most earth abundant and low-cost rare earth element as a single-filling element and demonstrate that, by solubility design using a phase diagram approach, the filling fraction limit (FFL) x in CexCo4Sb12 can be increased more than twice the amount reported previously (x=0.09). This ultra-high FFL (x=0.20) enables the optimization of carrier concentration such that no additional filling elements are needed to produce a state of the art n-type skutterudite material with a zT value of 1.3 at 850 K before nano-structuring. The earth abundance and low cost of Ce would potentially facilitate a widespread application of skutterudites.