NSF/DOE Thermoelectrics Partnership:Collaborative Proposal: Integration of Advanced Materials, Interfaces, and Heat Transfer Augmentation Methods for Affordable and Durable Devices

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

1048726 Ju This proposal is concerned with recovering exhaust waste heat to improve the efficiency of vehicles. An interdisciplinary team of mechanical engineers, a material scientist, and a chemist is assembled to tackle this problem by synthesizing novel nanostructured silicides with improved thermoelectric figures of merit. Intellectual Merit: The proposed research on nanocomposites and related interfaces will help establish a scientific and engineering foundation for robust and flexible thermomechanical design of thermoelectric systems subjected to thermal cycling and vibration. The PIs will develop metal-matrix composites with tailorable coefficients of thermal exapansion (CTEs) using a filler material with an isotropic negative thermal expansion (NTE). NTE fillers, such as ZrW2O8 powders, can effectively offset the high CTE of the metal phase without significantly degrading the electrical and thermal conductivity. These nanocomposites may be used as electrodes or as interfacial layers for creating segmented thermoeletric elements. Thermomechanical models of TE modules will be developed to guide the design of the nanocomposites, including those with functionally graded compositions. Nanocomposites based on different metals, such as Ag, Al, and Ni, will be synthesized and their thermal and thermomechanical properties will be experimentally characterized. Methods to produce reliable electrical, thermal, and mechanical bonds with TE materials will also be developed. Broader Impact: The proposed research is designed to maximize the potential for large-scale implementation in vehicle exhaust heat recovery and other related engineering applications. The new material synthesis and bonding methods that will be developed is considered to facilitate economic fabrication of durable TE devices. Another component included in the plan is the training of students in interdisciplinary research whereby fundamental science is coupled to advanced engineering. The PI and graduate students will participate in outreach programs to bring science and engineering to pupils in grades K-12 through summer research programs hosted at UCLA.