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Schlagwörter:
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Zusammenfassung:
The type I clathrates A8Ga16X30 (A=Sr, Ba, Eu; X=Si, Ge, Sn) and filled
skutterudites Ay(Fe1-xMx)4Sb12 (A=rare-earth, M=Co, Ni,) are
intermetallic compounds with good thermoelectric performance in the
temperature range 400-800K. Here we report on the first mixed
clathrate-skutterudite unicouple thermoelectric generator and address
important technical issues such as upscaling, contacting, and electrode
material selection. At 600K, the materials Eu8Ga16Ge30, Ba8Ga16Ge30, and
Mm0.7Fe3.5Ni0.5Sb12 synthesized for this purpose have figures of merit
ZT=0.32, 0.15, and 0.46, respectively. The clathrate and skutterudite
legs were brazed to a hot side nickel electrode. An average contact
resistivity of 16 mu cm2 was obtained with Pb-Ag (hot side) and In-Sn
(cold side) brazings combined with and intermediate Ni layer. For a
temperature difference T=250K (hot side temperature=573K), this
generator produced an open circuit voltage Uopen=54mV and an electrical
specific power P=178mWcm-2 as our best result with the couple
Mm0.7Fe3.5Ni0.5Sb12 and Eu8Ga16Ge30.
