缺陷工程策略构建n型AMg2Sb2基Zintl相热电材料及其电声输运协同调控

Zintl相化合物具有玻璃般导热性和晶体般导电性的典型特征，在废热、太阳能、地热等清洁能源的可持续热电转换领域具有重要的应用前景。然而，由于大量固有点缺陷的存在，几乎所有本征Zintl相化合物均只能呈现p型导电，n型材料的开发面临瓶颈，电声结构和电声输运性能的协同调控遭遇困难，阻碍了热电转换技术的进一步发展。本项目采用缺陷工程策略，利用化学成分优化和合成优化双重手段，开展高性能n型AMg2Sb2（A=Ca、Sr和Ba）基Zintl相热电材料系统研究，阐明缺陷种类、浓度和分布等在本征p型导电转变为n型导电过程中的复杂演变机制，揭示本征缺陷和外源缺陷之间的复合效应对热电参数的交互作用规律，解决载流子输运特性转变、电声结构和电声输运性能协同调控关键科学问题，为在其他材料体系中通过合理的缺陷构建、设计和调控实现输运特性转变和高热电性能提供实验和理论支持。

Zintl phase compounds exhibit typical characteristics of glass-like thermal conductivity and crystal-like electrical conductivity, and have important application prospects in the field of sustainable thermoelectric conversion of clean energy such as waste heat, solar energy, and geothermal energy. However, the existence of a large number of inherent point defects in almost all intrinsic Zintl phase compounds leads to the persistent p-type conduction of these thermoelectric materials. A realization of n-type conduction in Zintl phase compounds is challenging. Optimization of the electron structure, phonon structure, electrical transport properties, and thermal transport properties simultaneously is facing bottlenecks. This project aims to construct the high-performance n-type AMg2Sb2 (A = Ca, Sr, and Ba)-based Zintl phase thermoelectric materials based on the defect engineering approach through rationally optimizing chemical composition and synthesis condition. The project focuses on the systematic study of the complex evolution mechanism of defect types, concentrations, and distributions during the conversion from intrinsic p-type to n-type conduction, and revealing the interaction of the combined effects between intrinsic and extrinsic defects on thermoelectric parameters. The proposed investigation is aimed at solving the key scientific problems of the conversion of carrier transport characteristics and the coordinated optimization of electron structure, phonon structure, electrical transport properties, and thermal transport properties. The study will provide experimental and theoretical supports in realizing p-n conduction characteristics and high thermoelectric performance in other material systems through reasonable defect construction, design, and regulation.