EAGER: Spark Plasma Sintering of Bulk Nanostructured Thermoelectric Materials

热电材料可以直接将余热中的热能转化为电能。探索性研究的早期概念拨款（EAGER）为开发大块形状的高性能纳米结构热电材料提供资金。一种新的火花等离子烧结（SPS）工艺将热电成分的机械合金纳米结构粉末烧结成块状。SPS过程将包括同时应用单轴压力和脉冲直流电到放置在石墨模具中的纳米结构粉末。本提案的研究将集中在以碲化铋和碲化铅为基础的热电材料组成的体纳米结构上。研究计划的重点是研究纳米结构热电粉末在SPS过程中的基本致密化机制，以及在纳米尺度（50 nm）范围内热电性能与晶粒/特征尺寸的关系。该项目的成功完成将极大地推动体热电材料纳米结构的发展，提高这些材料的性能。所提出的研究将为晶粒尺寸对热电性能的影响提供有价值的信息，这对于优化这些材料的性能具有重要意义。由于能量转换需要大量的材料，使用SPS制造体积形状的纳米结构热电材料的可能性有望加速这些材料在现实世界热电器件中的利用。拟议的EAGER计划将为研究生和本科生提供研究经验和培训，并为他们未来在能源材料这一重要领域的职业生涯做好准备。建议的研究结果也将纳入现代材料研究生课程，以实现更广泛的影响。

Thermoelectric materials can directly convert thermal energy available in waste heat into electrical energy. This EArly Concept Grant for Exploratory Research (EAGER) provides funding for the development of bulk shapes of high performance nanostructured thermoelectric materials. A novel spark plasma sintering (SPS) process will be used to sinter mechanically alloyed nanostructured powder of thermoelectric compositions into bulk shapes. The SPS process will involve simultaneous application of uniaxial pressure and pulsed direct current to nanostructured powder placed in the graphite dies. The investigations of this proposal will be focused on bulk nanostructuring of bismuth telluride- and lead telluride-based compositions of thermoelectric materials. Major emphasis of the research plan will be on investigating the fundamental densification mechanisms of nanostructured thermoelectric powder during SPS and the dependence of thermoelectric performance on grain/feature size in nano-scale range ( 50 nm). Successful completion of this project will significantly advance the state-of-the-art in nanostructuring of bulk thermoelectric materials for improving the performance of these materials. The proposed investigations will provide valuable information about the influence of grain size on the thermoelectric performance which is important for optimizing the performance these materials. Since large amounts of materials are needed for energy conversion, the possibilities of fabricating bulk shapes of the nanostructured thermoelectric materials using SPS is expected to accelerate utilization of these materials in real-world thermoelectric devices. The proposed EAGER plan will provide research experiences and training to graduate and undergraduate students, and prepare them for future career in this important field of energy materials. The results of the proposed research will also be incorporated in the graduate course on Modern Materials to achieve the broader impact.