TY - JOUR
T1 - Power generation from the Cu26Nb2Ge6S32-based single thermoelectric element with Au diffusion barrier
AU - Chetty, Raju
AU - Kikuchi, Yuta
AU - Bouyrie, Yohan
AU - Jood, Priyanka
AU - Yamamoto, Atsushi
AU - Suekuni, Koichiro
AU - Ohta, Michihiro
N1 - Funding Information:
This work was supported as part of the International Joint Research Program for Innovative Energy Technology funded by the Ministry of Economy, Trade and Industry (METI), Japan. The authors thank Ms Naoko Fujimoto and Mr Makoto Aihara of the AIST for helping in the preparation of the Cu26Nb2Ge6S32 thermoelectric element and the operation of the Mini PEM measurement system.
Publisher Copyright:
© 2019 The Royal Society of Chemistry.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019
Y1 - 2019
N2 - In this study, we have developed a diffusion barrier for thermoelectric colusite Cu26Nb2Ge6S32 and evaluated the conversion efficiency of the Cu26Nb2Ge6S32-based single thermoelectric element. This Cu26Nb2Ge6S32-based single element with metal diffusion barriers (Ti, Pt, Ni, and Au) was prepared through hot pressing. Microstructural investigations revealed microcrack formation at the interface between the Ti/Pt diffusion barriers and Cu26Nb2Ge6S32 due to the mismatch of the coefficient of thermal expansion between them. Although no cracks were observed at the interface between the Cu26Nb2Ge6S32 and Ni diffusion barriers, secondary phases of Ni-S, Ni-Ge, and Cu-S were formed around the interface. A good match in the coefficient of thermal expansion between Cu26Nb2Ge6S32 and Au resulted in a crack-free interface. Moreover, no secondary phases were found around the Cu26Nb2Ge6S32 and Au interface. Therefore, the Au diffusion barrier allows a reduced specific contact resistance of 4-5 × 10-10 Ω m2. In the conversion efficiency evaluation, the radiative heat transfer was compensated by using silica glass as a reference. The maximum thermoelectric conversion efficiency (ηmax) of ∼3.3% was estimated at the hot-side temperature (Th) of 570 K and the cold-side temperature (Tc) of 297 K for the Cu26Nb2Ge6S32-based single element with a Au diffusion barrier. Three-dimensional finite-element simulations for the Cu26Nb2Ge6S32-based single element predicted the ηmax of ∼4.5% at Th and Tc of 570 K and 297 K, respectively. Therefore, there is further scope for improvement in the performance of the Cu26Nb2Ge6S32-based element.
AB - In this study, we have developed a diffusion barrier for thermoelectric colusite Cu26Nb2Ge6S32 and evaluated the conversion efficiency of the Cu26Nb2Ge6S32-based single thermoelectric element. This Cu26Nb2Ge6S32-based single element with metal diffusion barriers (Ti, Pt, Ni, and Au) was prepared through hot pressing. Microstructural investigations revealed microcrack formation at the interface between the Ti/Pt diffusion barriers and Cu26Nb2Ge6S32 due to the mismatch of the coefficient of thermal expansion between them. Although no cracks were observed at the interface between the Cu26Nb2Ge6S32 and Ni diffusion barriers, secondary phases of Ni-S, Ni-Ge, and Cu-S were formed around the interface. A good match in the coefficient of thermal expansion between Cu26Nb2Ge6S32 and Au resulted in a crack-free interface. Moreover, no secondary phases were found around the Cu26Nb2Ge6S32 and Au interface. Therefore, the Au diffusion barrier allows a reduced specific contact resistance of 4-5 × 10-10 Ω m2. In the conversion efficiency evaluation, the radiative heat transfer was compensated by using silica glass as a reference. The maximum thermoelectric conversion efficiency (ηmax) of ∼3.3% was estimated at the hot-side temperature (Th) of 570 K and the cold-side temperature (Tc) of 297 K for the Cu26Nb2Ge6S32-based single element with a Au diffusion barrier. Three-dimensional finite-element simulations for the Cu26Nb2Ge6S32-based single element predicted the ηmax of ∼4.5% at Th and Tc of 570 K and 297 K, respectively. Therefore, there is further scope for improvement in the performance of the Cu26Nb2Ge6S32-based element.
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U2 - 10.1039/c9tc00868c
DO - 10.1039/c9tc00868c
M3 - Article
AN - SCOPUS:85064984996
VL - 7
SP - 5184
EP - 5192
JO - Journal of Materials Chemistry C
JF - Journal of Materials Chemistry C
SN - 2050-7526
IS - 17
ER -