α-MgAgSb, as a promising near-room-temperature thermoelectric (TE) material, has suffered from incompetent carrier mobility induced by the scattering of vacancies and grain boundaries. Synthesis of stoichiometric α-MgAgSb with large crystal grains has been challenging. Here, owing to an improved ball-milling process, the phase purity of α-MgAgSb powder precursor was effectively increased during mechanochemical synthesis. After subsequent spark plasma sintering (SPS) and post annealing at 583 K, near-stoichiometric α-MgAgSb exhibiting a mosaic structure was obtained, registering a significantly enhanced μ of 93.3 cm2V−1s−1 and zTavg of 1.4 in 300–573 K. A 7-pair TE module based on α-MgAgSb/Mg3BiSb was fabricated, which demonstrated a record-high efficiency of 12% at Th ≤ 583 K and a cooling ΔTmax of 61 K at 300 K. This work lays the foundation for broad applications of Mg-based TEs.

中文翻译：

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高性能 MgAgSb/Mg3（Sb，Bi）2 基热电器件，在 T ≤ 583K 时 η = 12%


α-MgAgSb 作为一种很有前途的近室温热电 （TE） 材料，由于空位和晶界的散射而引起了载流子迁移率低下的问题。具有大晶粒的化学计量 α-MgAgSb 的合成一直具有挑战性。在这里，由于改进了球磨工艺，α-MgAgSb 粉末前驱体在机械化学合成过程中有效地提高了相纯度。随后的放电等离子体烧结 （SPS） 和 583 K 后退火后，获得了表现出马赛克结构的近化学计量 α-MgAgSb，在 300-573 K 中记录了 93.3 cm2V-1s-1 的显着增强μ和 1.4 的 zTavg。制备了基于 α-MgAgSb/Mg3BiSb 的 7 对 TE 模块，在 Th ≤ 583 K 时表现出创纪录的 12% 效率和 61 K 的冷却 ΔTmax，在 300 K 下。这项工作为基于 Mg 的 TE 的广泛应用奠定了基础。