Multiple-Filling-Induced Full-Spectrum Phonon Scattering and Band Convergence Leading to High-Performance n-Type Skutterudites.
Multiple-Filling-Induced Full-Spectrum Phonon Scattering and Band Convergence Leading to High-Performance n-Type Skutterudites.
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DOI：
10.1021/acsami.1c06267
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发表时间：
2021-06
影响因子：
9.5
通讯作者：
Jialun Zhang;Lixia Zhang;W. Ren;Wenqin Gou;Juncheng Zhang;H. Geng
中科院分区：
文献类型：
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作者：
Jialun Zhang;Lixia Zhang;W. Ren;Wenqin Gou;Juncheng Zhang;H. Geng
将客体原子填充到方钴矿化合物的纳米空隙中，为低频声子提供了有效的散射，从而降低了晶格热导率。然而，在具有较高热电性能的n型方钴矿中同时实现全谱声子散射和能带工程仍然是困难的。在这里，我们揭示了五种类型的元素原子的组合在晶格纳米空隙带来了密集的位错，丰富的沉淀纳米粒子，和电子带收敛的n型方钴矿。由于费米能级附近态密度的增加，Seebeck系数增加，载流子迁移率几乎没有恶化，导致在823 K下功率因数增加11%。由于全谱声子散射，晶格热导率显著降低，接近玻璃极限。结果表明，在823 K时，ZT峰值约为1.7，在323 ~ 823 K时，ZT平均值约为1.2。高热电性能结合结构优化使模拟的方钴矿模块的最大能量转换效率达到15.0%。我们的发现开辟了一个新的维度掺杂原子，以实现同时优化的电和热性能的多元热电材料。
Filling guest atoms into the nanovoids of skutterudite compounds provides effective scattering for low-frequency phonons to reduce the lattice thermal conductivity. However, it is still difficult to simultaneously realize the full-spectrum phonon scattering and band engineering in the n-type skutterudites with higher thermoelectric performance. Here, we reveal that the combination of five types of element atoms in the lattice nanovoids brings about dense dislocations, abundant precipitated nanoparticles, and electronic band convergence in the n-type skutterudites. The Seebeck coefficient shows an increase with little deterioration on the carrier mobility due to the enhanced density of states near the Fermi level, leading to a 11% enhancement in the power factor at 823 K. The lattice thermal conductivity is significantly reduced to approach the glass limit due to the full-spectrum phonon scattering. As a result, a peak ZT value of about 1.7 at 823 K and an average ZT value of about 1.2 from 323 to 823 K are obtained. High thermoelectric performance combined with the structural optimization enables the simulated maximum energy conversion efficiency of the skutterudite module to reach up to 15.0%. Our finding opens a new dimension for doping atoms to achieve simultaneous optimization of electrical and thermal properties in polynary thermoelectric materials.