自掺杂 CoSb3 基方钴矿中的结构优化和多频声子散射促进热电,ACS Applied Materials & Interfaces

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自掺杂 CoSb3 基方钴矿中的结构优化和多频声子散射促进热电
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2023-01-20 , DOI: 10.1021/acsami.2c20292
Xuri Rao ₁ , Yan Zhong ₁ , Haoran Feng ₁ , Yadong Wang ₁ , Xiaobo Tan ₁ , Jianglong Zhu ₁ , Ran Ang _{1,

2}

Affiliation

利用热电装置将废热直接转化为电能是缓解全球能源危机的有效途径。然而，热电材料的低效率一直困扰着其广泛应用。CoSb ₃基方钴矿因其优异的热稳定性而受到器件集成的青睐，而原始CoSb ₃材料的发展受到超高导热性和较差的塞贝克系数的限制。在这项工作中，我们证明了在与过量 Sb 协调的 In-filled CoSb _{3中同时实现了结构改进和强声子相互作用。}额外的 Sb 补偿了 Sb _{4上的不足}环，提高塞贝克系数，并与 In 协同进一步提高载流子浓度。因此，结构优化和化学势调节最大化电性能。在热学上，残留的 InSb 纳米粒子和部分 In/Sb 合金化以及 In 在空隙中的振动共同缩短了多频声子弛豫时间，导致晶格热导率急剧下降。结果，在 In _1.4 Co ₄ Sb ₁₂ + 8%Sb 中分别获得了在 650 K 时约 1.27 的最大zT _max和在300 至 750 K 期间约 0.9的平均zT _{avg 。}_{我们的发现为选择 CoSb 3}提供了有价值的指导型方钴矿掺杂剂实现高性能热电材料。

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Structure Optimization and Multi-frequency Phonon Scattering Boosting Thermoelectrics in Self-Doped CoSb3-Based Skutterudites

The utilization of thermoelectric devices that directly convert waste heat to electricity is an effective approach to alleviate the global energy crisis. However, the low efficiency of thermoelectric materials has puzzled the widespread applications. The CoSb₃-based skutterudites are favored by device integration due to the excellent thermal stability, while the development of pristine CoSb₃ materials is limited by the ultra-high thermal conductivity and the poor Seebeck coefficient. In this work, we demonstrate that both structural improvement and strong phonon interaction are realized simultaneously in In-filled CoSb₃ coordinated with excessive Sb. The extra Sb compensates the deficiency on the Sb₄ ring, improving the Seebeck coefficient, and cooperates with In to further advance the carrier concentration. Therefore, the structure optimization and chemical potential regulation maximize the electrical properties. Thermally, the residual InSb nanoparticles and partial In/Sb-alloying, along with vibration of In in voids, jointly shorten the multi-frequency phonon relaxation time, leading to a dramatic decline in the lattice thermal conductivity. As a result, a maximum zT_max of ∼1.27 at 650 K and an average zT_avg of ∼0.9 from 300 to 750 K was obtained in In_1.4Co₄Sb₁₂ + 8%Sb, respectively. Our findings provide valuable guidance for the selection of CoSb₃-based skutterudite dopants to achieve high-performance thermoelectric materials.

更新日期：2023-01-20

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