Improved figure of merit (z) at low temperatures for superior thermoelectric cooling in Mg₃(Bi,Sb)₂.

ABSTRACT: The low-temperature thermoelectric performance of Bi-rich n-type Mg₃(Bi,Sb)₂ was limited by the electron transport scattering at grain boundaries, while removing grain boundaries and bulk crystal growth of Mg-based Zintl phases are challenging due to the volatilities of elemental reactants and their severe corrosions to crucibles at elevated temperatures. Herein, for the first time, we reported a facile growth of coarse-grained Mg₃Bi_2-xSb_x crystals with an average grain size of ~800 μm, leading to a high carrier mobility of 210 cm² · V^-1 · s^-1 and a high z of 2.9 × 10^-3K^-1 at 300 K. A [Formula: see text]T of 68 K at T_h of 300 K, and a power generation efficiency of 5.8% below 450 K have been demonstrated for Mg₃Bi_1.5Sb_0.5- and Mg₃Bi_1.25Sb_0.75-based thermoelectric modules, respectively, which represent the cutting-edge advances in the near-room temperature thermoelectrics. In addition, the developed grain growth approach can be potentially extended to broad Zintl phases and other Mg-based alloys and compounds.

SUBMITTER: Chen N 

PROVIDER: S-EPMC10427716 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature