Improved thermoelectric performance through double substitution in shandite-type mixed-metal sulphides

Mangelis, P., Vaqueiro, P. ORCID: https://orcid.org/0000-0001-7545-6262 and Powell, A. V. (2020) Improved thermoelectric performance through double substitution in shandite-type mixed-metal sulphides. ACS Applied Energy Materials, 3 (3). pp. 2168-2174. ISSN 2574-0962 doi: 10.1021/acsaem.9b02272

Abstract/Summary

Substitution of tin by indium in shandite-type phases, A3Sn2S2 with mixed Co/Fe occupancy of the A-sites is used to tune the Fermi level within a region of the density of states in which there are sharp, narrow bands of predominantly metal d-character. Materials of general formula Co2.5+xFe0.5-xSn2-yInyS2 (x = 0, 0.167; 0.0  x  0.7) have been prepared by solid-state reaction and the products characterised by powder X-ray diffraction. Electrical transport property data reveal that the progressive depopulation of the upper conduction band as tin is replaced by indium, increases the electrical resistivity and the weakly temperature-dependent (T) becomes more semiconducting in character. Concomitant changes in the negative Seebeck coefficient, the temperature dependence of which becomes increasingly linear, suggests the more highly substituted materials are n-type degenerate semiconductors. The power factors of the substituted phases, while increased, exhibit a weak temperature dependence. The observed reductions in thermal conductivity are principally due to reductions in the charge-carrier contribution on hole doping. A maximum figure-of-merit of (ZT)max = 0.29 is obtained for the composition Co2.667Fe0.333Sn1.6In0.4S2 at 573 K: among the highest values for an n-type sulphide at this temperature.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/87580
Identification Number/DOI	10.1021/acsaem.9b02272
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) > Xray (CAF)
Publisher	American Chemical Society
Download/View statistics	View download statistics for this item