Synergistic boost of output power density and efficiency in In-Li-codoped SnTe

We report enhanced thermoelectric performance of SnTe by further increasing its intrinsic high carrier concentration caused by Sn vacancies in contrast to the traditional method. Along with In₂Te₃ alloying, which results in an enhanced Seebeck coefficient, Li₂Te is added to further increase the carrier concentration in order to maintain high electrical conductivity. Finally, a relatively high PF of ∼28 μW cm^-1 K^-2 in the range between 300 and 873 K is obtained in an optimized SnTe-based compound. Furthermore, nanoprecipitates with extremely high density are constructed to scatter phonons strongly, resulting in an ultralow lattice thermal conductivity of ∼0.45 W m^-1 K^-1 at 873 K. Given that the Z value is temperature dependent, the (ZT) and (PF) values are adopted to accurately predict the performance of this material. Taking into account the Joule and Thomson heat, output power density of ∼5.53 W cm^-2 and leg efficiency of ∼9.6% are calculated for (SnTe)_2.94(In₂Te₃)_0.02-(Li₂Te)_0.045 with a leg length of 4 mm and cold- and hot-side temperatures of 300 and 870 K, respectively.