Filled Skutterudite Antimonides: A New Class of Thermoelectric Materials

TLDR

RM4X12 ternary semiconductors (R = lanthanum, cerium, praseodymium, neodymium, europium; M = iron, ruthenium, osmium; X = phosphorus, arsenic, antimony) offer a new approach to improved thermoelectric materials. The synthesized RM4X12 materials achieve a thermoelectric figure of merit ZT ≈ 1 at 800 K, comparable to the best known thermoelectrics, and calculations predict that optimization could raise ZT to 1.4, with CeFe4−xCoxSb12 and LaFe4−xCoxSb12 alloys already exhibiting high ZT values.

Abstract

A class of thermoelectric materials has been synthesized with a thermoelectric figure of merit ZT (where T is temperature and Z is a function of thermopower, electrical resistivity, and thermal conductivity) near 1 at 800 kelvin. Although these materials have not been optimized, this value is comparable to the best ZT values obtained for any previously studied thermoelectric material. Calculations indicate that the optimized material should have ZT values of 1.4. These ternary semiconductors have the general formula RM4X12 (where R is lanthanum, cerium, praseodymium, neodymium, or europium; M is iron, ruthenium, or osmium; and X is phosphorus, arsenic, or antimony) and represent a new approach to creating improved thermoelectric materials. Several alloys in the composition range CeFe4-xCoxSb12 or LaFe4-xCoxSb12 (0 < x < 4) have large values of ZT.