SEMINAR
The State Key Lab of
High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics, Chinese Academy of Sciences
中 国 科 学 院 上 海 硅 酸 盐 研 究 所 高 性 能 陶 瓷 和 超 微 结 构 国 家 重 点 实 验 室
Designing high-performance thermoelectric Mg3Sb2 and its analogues by combining theory and experiment
张家伟
Department of Chemistry, Aarhus University, Denmark
时间：2019 年 5 月28日（星期二）上午10:00
地点：嘉定园区F楼5（1）会议室
欢迎广大科研人员和研究生参与讨论！
联系人：史 迅
报告摘要：
Thermoelectric materials enable the interconversion between heat and electricity with no moving parts, showing potential applications in waste heat harvesting and solid state refrigeration. Systematically optimizing the thermoelectric performance of a material remains a great challenge due to the transport parameters being correlated with each other. Focusing on Mg3Sb2 and and related CaAl2Si2-type materials, for p-type transport we propose a simple yet successful strategy to discover and design high-performance layered thermoelectric materials through minimizing the crystal field splitting energy of orbitals to realize high orbital degeneracy. The approach naturally leads to design maps for optimizing the thermoelectric power factor through forming solid solutions and biaxial strain. For n-type transport, we present the successful discovery of high-performance low-cost n-type Mg3Sb2-based thermoelectric materials with multi-valley conduction bands combining theoretical prediction and experimental validation. The considerably enhanced power factor, which is the main origin of high thermoelectric performance, is attributed to a unique near-edge conduction band with six anisotropic conducting carrier pockets. Moreover, we conduct the quantitative chemical bonding analysis and reveal the breakdown of the Zintl concept in Mg3Sb2 with a nearly isotropic three-dimensional chemical bonding network. This unique chemical bonding feature can be used to understand the nearly isotropic structural and thermal properties. Our results here thus provide an insightful guidance for the design and discovery of novel high-performance thermoelectric materials.
报告人简介:
张家伟博士，目前就职于丹麦奥胡斯大学化学系，博士后。20011年南京工业大学材料专业本科毕业，2014年在上海硅酸盐研究所材料物理与化学专业硕士毕业，2018年获得丹麦奥胡斯大学无机材料化学方向博士学位，2018至今在丹麦奥胡斯大学从事博士后研究。至今，已在 Nature Materials，Nature Communications, Advanced Materials, Advanced Energy Materials, Chemisty of Materials等国际期刊上发表文章20余篇。通过理论计算和实验表征，主要研究工作是探索层状热电材料的结构、化学键的定量分析、以及电热输运性能的微观调控。
