Abstract
Thermoelectric skutterudite materials have been widely investigated for their potential application in mid-temperature waste heat recovery that has not been efficiently utilized A large amount of research has focused on developing materials with a high thermoelectric figure of merit (zT). However, the translation of material properties to device performance has limited success. Here, we demonstrate single-filling n-type Yb0.25Fe0.25Co3.75Sb12 and multi-filling La0.7Ti0.1Ga0.1Fe2.7Co1.3Sb12 skutterudites with a maximum zT of ~1.3 at 740 K and ~0.97 at 760 K. The peak zT of skutterudites usually occurs above 800 K, but, as shown here, the shift in peak zT to lower temperatures is beneficial for enhancing conversion efficiency at a lower hot-side temperature. In this work, we have demonstrated that the Fe-substitution significantly reduces the thermal conductivity of n-type skutterudite, closer to p-type skutterudite thermal conductivity, resulting in a module that is more compatible to operate at elevated temperatures. A uni-couple skutterudite module was fabricated using a molybdenum electrode and Ga–Sn liquid metal as the thermal interface material. A conversion efficiency of 7.27% at a low temperature gradient of 366 K was achieved, which is among the highest efficiencies reported in the literature at this temperature gradient. These results highlight that peak zT shift and optimized module design can improve conversion efficiency of thermoelectric modules at a low temperature gradient.
Highlights
Solid-state thermoelectric (TE) power generation technology is commonly used for converting waste thermal energy into electricity by utilizing the Seebeck effect
The obtained from Rietveld refinement are 9.0511 Å and 9.1173 Å for n-type skutterudites (n-SKD) and p-type skutterudites (p-SKD), respectively, lattice parameters obtained from Rietveld refinement are 9.0511 Å and 9.1173 Å for n-SKD and pwhichSKD, matches prior results available in the literature [15,16,20,27,44]
A single-filling n-type Yb0.25Fe0.25Co3.75Sb12 with Fe-substitution on Co-site and multi-filling p-type La0.7Ti0.1Ga0.1Fe2.7Co1.3Sb12 were synthesized via a melting–quenching–annealing
Summary
Solid-state thermoelectric (TE) power generation technology is commonly used for converting waste thermal energy into electricity by utilizing the Seebeck effect. It provides a promising solution for energy harvesting from automobile exhausts, solar heat, waste heat from fuel cells, and industrial waste heat [1,2,3]. The conversion efficiency (η), given by Equation (1), is used to evaluate the TE performance, η=. Energies 2019, 12, 4292; doi:10.3390/en12224292 √ Th − Tc 1 + zTave − 1 ·√ Th. 1 + zTave + Tc /Th (1). ZTave is the average TE figure-of-merit determined by using the temperature range and materials zT, which is given by Equation (2), zT = α2 σ
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
