High efficiency GeTe-based materials and modules for thermoelectric power generation

Abstract

GeTe-Based materials have great potential to be used in thermoelectric generators for waste heat recovery due to their excellent thermoelectric performance, but their module research is greatly lagging behind material research. In this work, we successfully fabricate a GeTe-based thermoelectric module and report a high energy conversion efficiency of 7.8% under a temperature gradient of 500 K. An Sb-, Bi-, and Se-doped GeTe-based material, with a chemical composition of Ge_0.92Sb_0.04Bi_0.04Te_0.95Se_0.05 and a peak ZT of 2.0 at 700 K, is used to make the p-type legs in the module. By using a high-throughput strategy, Mo is screened from 12 pure metals as an effective diffusion barrier material between the GeTe-based material and the electrode. Based on the optimal geometry predicted by three-dimensional numerical analysis, one eight-couple Ge_0.92Sb_0.04Bi_0.04Te_0.95Se_0.05/Yb_0.3Co₄Sb₁₂ TE module is fabricated and evaluated, which shows a comparable energy conversion efficiency with those of skutterudite- and half-Heusler-based modules in a similar temperature range. This study opens the door for the development of GeTe-based modules.