高性能BiCuSeO基热电材料的制备及其电热输运机制

Thermoelectric materials and its devices can directly convert the waste heat into usable electricity, which is an effective way to enhance the traditional energy utilization efficiency. It is very important to environmental protection and utilization of energy and resources. Oxides-based thermoelectric ceramics are thermally and chemically stable at high temperature in air, which are important for utilization of waste heat and reduce of environmental pollution. BiCuSeO possesses intrinsic low thermal conductivity with natural supperlattice structure, and the physical properties can be tuned by modification of (Cu2Se2)2- and (Bi2O2)2+ layers. This project will investigate the effects of nanostructures, band engineering and layers structure modification on the thermoelectric performance of BiCuSeO by experiment and theory calculation. Additionally, the theraml and electric transportation machanism will be proposed for higher thermoelectric performance, and realize ZT>1.5 in this BiCuSeO system.

基于热电材料的热电发电系统，可以直接将废热转化为电能，是一种有效提升传统能源利用效率的技术途径，对合理利用能源和资源，保护环境有着重要的意义。由于氧化物体系热电陶瓷物理化学稳定性好，可以在中高温区间使用，从而对于工业废热的利用和减少环境污染将有着重要的意义。BiCuSeO材料具有天然的层状超晶格结构，其本征热导率较低，可以分别对其(Cu2Se2)2-层和(Bi2O2)2+层进行调控来改善其性能。本项目将从实验和理论上深入研究纳米复合结构、能带工程以及层间结构修饰等对BiCuSeO材料热电性能的影响机制，进一步弄清其热、电传输机理，在该体系中实现热电材料性能的提升，获得ZT值>1.5的热电材料。

主要针对BiCuSeO、Bi2O2Se氧化物热电材料体系开展了深入研究，对材料的制备、能带结构和输运性能等进行了系统分析。通过掺杂、能带调控等手段将p型BiCuSeO的ZT值提高到了1.5； 通过载流子工程以及全尺度声子散射的协同作用实现了n型Bi2O2Se热电材料在500~823 K范围内0.3的平均ZT值。共发表SCI论文21篇，其中1篇发表在Energy Environ. Sci., 1篇发表在Nature Communications、5篇发表在J. Am. Ceram. Soc.上。其中发表在Energy Environ. Sci.上的论文还被选为当期封面文章。出版英文专著一部：Oxide Thermoelectric Materials: from Basic Principles to Applications。申请授权专利3项，在国际国内大会上做邀请报告10次。