EAGER: Spark Plasma Sintering of Bulk Nanostructured Thermoelectric Materials

Oklahoma State University, Stillwater OK

Investigators

Abstract

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.