Copper ion liquid-like thermoelectrics
Copper ion liquid-like thermoelectrics
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DOI：
10.1038/nmat3273
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发表时间：
2012-05-01
期刊：
影响因子：
41.2
通讯作者：
Snyder, G. Jeffrey
中科院分区：
文献类型：
--
作者：
Liu, Huili;Shi, Xun;Snyder, G. Jeffrey
先进的热电技术提供了将工业废热转化为有用电能的潜力，以及一种固态冷却的零排放方法(1，2)。世界范围内寻找热电优值系数ZT值远高于1的材料的努力，往往集中在热导率较低的晶体半导体上。这里我们报道了Cu2-xSe，它在1000K时达到了1.5的zT，是所有块状材料中最高的值之一。而Cu2-xSe中的Se原子形成了刚性的面心立方晶格，为半导体电子(或者更准确地说是空穴)提供了结晶路径，而铜离子在Se亚晶格周围高度无序，具有类液体的迁移率。铜离子在Cu2-xSe中Se的结晶亚晶格周围的这种非同寻常的类似液体的行为导致了本质上非常低的晶格热导率，这使得这种原本简单的半导体具有很高的zT。这种不同寻常的性能组合导致了一种理想的热电材料。研究结果表明，通过探索在类液体离子包围下存在晶态亚晶格进行电子传导的体系，为高效热电材料的研究提供了新的策略和方向。
Advanced thermoelectric technology offers a potential for converting waste industrial heat into useful electricity, and an emission-free method for solid state cooling(1,2). Worldwide efforts to find materials with thermoelectric figure of merit, zT values significantly above unity, are frequently focused on crystalline semiconductors with low thermal conductivity(2). Here we report on Cu2-xSe, which reaches a zT of 1.5 at 1,000 K, among the highest values for any bulk materials. Whereas the Se atoms in Cu2-xSe form a rigid face-centred cubic lattice, providing a crystalline pathway for semiconducting electrons (or more precisely holes), the copper ions are highly disordered around the Se sublattice and are superionic with liquid-like mobility. This extraordinary 'liquid-like' behaviour of copper ions around a crystalline sublattice of Se in Cu2-xSe results in an intrinsically very low lattice thermal conductivity which enables high zT in this otherwise simple semiconductor. This unusual combination of properties leads to an ideal thermoelectric material. The results indicate a new strategy and direction for high-efficiency thermoelectric materials by exploring systems where there exists a crystalline sublattice for electronic conduction surrounded by liquid-like ions.