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High-Entropy Perovskites: An Emergent Class of Oxide Thermoelectrics with Ultralow Thermal Conductivity
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2020-11-05 , DOI: 10.1021/acssuschemeng.0c03849
Ritwik Banerjee 1 , Sabitabrata Chatterjee 1, 2 , Mani Ranjan 1 , Tathagata Bhattacharya 1 , Soham Mukherjee 1, 2 , Subhra Sourav Jana 1 , Akansha Dwivedi 2 , Tanmoy Maiti 1
Affiliation  

Although SrTiO3-based perovskites showed a lot of promise as n-type thermoelectric (TE) materials, they demonstrated a low figure of merit value primarily because of their high lattice thermal conductivity (kl). Researchers found it difficult to reduce kl, as a popular route like nanostructuring did not work well with these perovskites possessing low phonon mean free paths. Here, we put forward a novel strategy of designing high-entropy perovskite (HEP) oxides having five transition metals in the B site to induce more anharmonicity causing enhanced multiphonon scattering in order to decrease kl. Using detailed thermodynamic calculations, we designed and synthesized a highly dense Sr(Ti0.2Fe0.2Mo0.2Nb0.2Cr0.2)O3 HEP ceramic. An ultralow thermal conductivity of 0.7 W/mK at 1100 K was achieved in this n-type rare-earth-free HEP oxide TE material. The concept of designing HEPs to achieve ultralow thermal conductivity potentially opens up a new avenue for enhancing TE performance of environmentally benign bulk oxides for high-temperature TE power generation.

中文翻译:

高熵钙钛矿:具有超低导热率的新兴氧化物热电类

尽管基于SrTiO 3的钙钛矿显示出作为n型热电(TE)材料的广阔前景,但它们由于具有较高的晶格导热率(k l)而显示出较低的品质因数。研究人员发现很难降低k l,因为像纳米结构这样的流行途径对于这些具有低声子平均自由程的钙钛矿并不适用。在这里,我们提出了一种新颖的策略,设计一种在B位具有5种过渡金属的高熵钙钛矿(HEP)氧化物,以诱导更多的非谐性,从而引起增强的多声子散射,从而降低k l。使用详细的热力学计算,我们设计并合成了高密度的Sr(Ti0.2 Fe 0.2 Mo 0.2 Nb 0.2 Cr 0.2)O 3 HEP陶瓷。在这种n型无稀土HEP氧化物TE材料中,在1100 K下实现了0.7 W / mK的超低导热率。设计HEP以实现超低导热率的概念可能为增强用于高温TE发电的环境无害的本体氧化物的TE性能开辟了一条新途径。
更新日期:2020-11-23
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