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This content will become publicly available on May 31, 2019

Title: Performance of Functionally Graded Thermoelectric Materials and Devices: A Review

Direct energy conversion using thermoelectric generators (TEGs) is a research area of growing interest because of its potential for increasing energy efficiency. Bulk thermoelectric modules are used widely in industry as Peltier cooling devices. Currently, only bismuth telluride modules are commercially available for power generation. Significant efforts have been put into exploring promising materials and techniques to improve the figure of merit ( zT) at laboratory scale (5–20 g). A variety of techniques have been investigated to improve the output and useful temperature range for common industrial TEGs made from bulk polycrystalline materials including segmentation, geometric pinning, and property gradients. However, the improvement in zT at device level (500–1000 g and up) is exceptionally limited. In addition, the thermal degradation of TEGs occurs when cracks form due to thermal stresses that arise from transient heat sources, which consequently lead to a decreased lifetime. Functionally graded material (FGM) thermoelectrics in bulk and polycrystalline form have been developed to mitigate some of these issues by improving the temperature bandwidth, current output range, and lifetime. The present work provides a review of functionally graded TEGs, including their manufacturing, usage and current techniques for improving their performance. Furthermore, this article also provides a pathwaymore » to additional research and approaches for improving the efficiency and temperature range, as well as reducing the property degradation of bulk polycrystalline TEGs.« less
 [1] ; ORCiD logo [1] ;  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Colorado State Univ., Fort Collins, CO (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Electronic Materials
Additional Journal Information:
Journal Volume: 47; Journal Issue: 9; Journal ID: ISSN 0361-5235
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
Country of Publication:
United States
36 MATERIALS SCIENCE; Functionally Graded TEGs; thermal fatigue; polycrystalline TEGs; lifetime
OSTI Identifier: