介观分级结构热电材料结构与性能机理研究

项目名称： 介观分级结构热电材料结构与性能机理研究

项目编号： No.U1532128

项目类型： 联合基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 徐伟

作者单位： 中国科学院高能物理研究所

项目金额： 58万元

中文摘要： 热电材料因固体制冷、废热转化等重要用途成为能源材料研究的热点之一。传统热电材料的性能遭遇瓶颈因素制约。研究表明，通过构筑纳米、介观到微米尺度分级结构，可调控电荷、声子载流子的输运，能显著提高材料的热电性能。然而，由于结构探测手段局限性，分级结构影响热电性能的物理机制仍属悬而未决的关键问题，常规的结构分析无法揭示不同尺度的输运机制。本项目拟以具有介观分级结构的新型高性能热电材料(如硫基化物、氧化物、金属互化物）为着眼点, 依托于上海光源等国内三大同步辐射装置，利用红外谱学及X射线谱学与衍射手段，结合密度泛函理论工具、分子动力学理论工具，从纳米到介观、微观尺度上，研究畴内畴间电子、声子传输、介观热电机制等关键科学问题, 旨在阐明分级结构-性能之间的关系，为新热电材料设计提供实验依据和理论指导。基于同步辐射的多尺度分级结构探测手段将能够拓展到同类功能材料的分级结构研究中，具有重要的学术价值。

中文关键词： 介观分级结构；热电材料；X射线；红外；同步辐射

英文摘要： Thermoelectrics arise as one of the hot topics in energy materials because of their promising applications in solid refrigeration and waste heat conversion. The performance of conventional thermoelectric materials was supressed due to bottleneck factors. It has been demonstrated that the thermoelectric properties can be improved significantly by artificially construct hierarchical structures extending from nano-, meso- to micro scales, which can tune the transport of charge, phonon carriers effectively. Nevertheless, the physical mechanism underpinning the influence of thermoelectricity imposed by hierarchical structures remains an unresolved but key issue, owing to the inherent limitations of various structural tools. The conventional tools cannot be relied to uncover the tranport mechanism at different scales. In this project, we mainly investigate the novel thermoelectrics with high thermoelectricity (e.g. chalcogenides, oxides, intermetallics). We attempt to address several fundamental issues on nano, meso and microscales, such as inter and intra domain phonon and charge transport, mesoscale thermoelectricity, through a synergy among infrared spectroscopy, X-ray absorption spectroscopy and X-ray diffraction available at the synchrotron facilities at Shanghai, Beijing, and Hefei , as well as Density Functional Theory and Molecular Dynamics. The main goal is to illustrate the relationship between hierarchical structures and thermoelectricity, offering experimental evidences and theoretical guides for designing new thermoelectrics. The multi-scale structural tool based on synchrotron can be extrapolated to investigate the hierarchical structures in other similar functional materials, bearing important academic significances.

英文关键词： meoscopic hierarchical structure;thermoelectrics;X-ray;infrared;synchrotron radiation