Cu2X“声子液体”热电材料的反常电热输运与性能优化

项目名称： Cu2X“声子液体”热电材料的反常电热输运与性能优化

项目编号： No.51472262

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 史迅

作者单位： 中国科学院上海硅酸盐研究所

项目金额： 83万元

中文摘要： 以Cu2X（X=S，Se，Te）为代表的固态离子导体中的液态亚点阵具有横波阻尼效应，可降低热容和热导率，引出一类具有声子液体－电子晶体（PLEC）特征的新热电材料体系。Cu2X中两套亚晶格点阵结构为电子和声子的调控提供了独特平台，其热电优值zT达到1.5-1.7。然而，Cu2X声子液体材料中异常的声子和电子输运特征与机制尚不清楚，限制了该材料热电性能的进一步调控与优化。本项目以Cu2X为主要研究对象，结合理论计算、材料制备、输运性能测试，研究横波声子的基本特征，热传导的散射机制与低热导率的机理，以及电子输运的特性与方式，深刻理解晶体结构/微观结构/电子结构/声子振动特性与电热输运性能之间关系及其规律性，揭示声子液体－电子晶体输运特性的基本特征与微观机制，并基于以上理解针对性地开展元素替换、固溶、复合等性能优化研究，实现热电性能明显提升。

中文关键词： 热电材料；化合物半导体；声子液体；电输运；热导率

英文摘要： The liquid sublattice in Cu2X (X=S, Se, Te) solid ionic conductors could lower the specific heat and thermal conductivity, leading to a novel thermoelectric material under the concept of 'phonon-liquid electron-crystal' (PLEC). The two independent sublattices in Cu2X provide a unique platform to tune the electrons and phonons, resulting in the figure of merit zT up to 1.5-1.7. However, the mechanisms for the abnormal electron and phonon transports in Cu2X are still not clear, which limits the further optimization of the thermoelectric properties. In this project, we will continually study the Cu2X-based compounds, mainly focusing on the mechanism of electron/phonon transports by combining theory, materials synthesis, transport property measurement, and microstructure characterization. Our goal is to obtain in-depth understanding on the mechanisms of the collective electrical and thermal transport, reveal the relationship among TE transport properties, electronic structure, crystal structure, and phonon vibrations. We will also finish the study on the basic characters of transverse phonons, the mechanisms of phonon scattering and low thermal conductivity, and mechanism of electron transport. The scientific fundamentals of concept PLEC will be identified. Finally, the optimization of Cu2X materials will be performed through element substitution, doping, and solutions to greatly enhance the thermoelectric performance.

英文关键词： thermoelectric materials;semiconducting compounds;phonon liquid;electrical transport;thermal conductivity