降低热导率是实现绿色环保型Mg2Si基热电材料性能突破的关键。本项目组在前期研究中发现，Mg2Si基材料的Si侧高含量Sb置换可导致材料宏观贫镁，并使材料具有接近于理论下限的低声子热导率。围绕这种贫镁Mg2Si基材料的特殊晶体结构及其对电声输运影响，本项目拟通过多种手段互洽的微结构表征分析和系统的电声输运机制研究，阐明宏观贫镁的微观晶体结构特征、晶体缺陷表现形式和形成演变规律，揭示由于Mg缺失所形成的晶体结构和晶体缺陷对材料能带结构、载流子和声子输运特性的影响规律，并在此基础上探索实现Mg2Si基热电材料性能突破的新方向和可行途径。

The non-toxic, naturally abundant constituent elements and the favorable electronic properties make Mg2Si based thermoelectric materials excellent candidates for large scale applications. To improve their thermoelectric properties the thermal conductivity must be reduced. It was found in our recent work that alloying Sb in the Si-site could make the Mg2Si based materials magnesium deficient and result in a very low phonon thermal conductivity near the theoretical limit. Focusing on the crystal structures and electron/phonon transports, the present proposal suggests to investigate the magnesium deficient Mg2Si based thermoelectric materials with various microstructure analysis and transport measurement, to clarify the crystal structures, lattice defects and their formation, development in the magnesium deficient Mg2Si based thermoelectric materials, to reveal the effects of the magnesium deficient microstructures on the band structure, carrier- and phonon-transports, and to explore the potential direction and feasible route for high performance advanced Mg2Si based thermoelectric materials.