Thermodynamically metastable skutterudite crystalline-structured compounds

摘要

Thermodynamically metastable skutterudite crystalline- structured compounds are disclosed having preselected stoichiometric compositions and superior and optimizable thermoelectric properties. The compounds are formed at low nucleation temperatures and satisfy the formula:P P M.sub.1-x M'.sub.4-y Co.sub.y M".sub.12 PP wherein:PPM=any metal, metalloid, or mixture thereof, except for La, Ce, Pr, Nd, and Eu when x=0, and M'=Fe, Ru, or Os, and M"=Sb, P, or As;PPM'=Fe, Ru, Os, Rh, or mixture thereof; PPM"Sb, As, P, Bi, Ge.sub.0.5-w Se.sub.0. 5+w, wherein w=0 to 0.5 or mixture thereof;PPx=0 to 1; PP y=0 to 4; andPPwherein M' and/or M" are doped or undoped. These compounds generally have the crystalline structure of a skutterudite, wherein the crystalline structure is cubic with 34 atoms in the unit-cell in the space group Im3. The M".sub.12 atoms occupy unit- cell sites 24(g), the M'.sub.4-y atoms form a cubic sublattice occupying unit-cell sites 8(c), and the M.sub.1-x atoms are positioned in two remaining "holes" or interstitial sites in the unit- cell, namely sites 2(a). These thermodynamically metastable skutterudite crystalline- structured compounds possess relatively low thermal conductivity properties with relatively high electrical conductivity properties, making the compounds ideal for use in thermoelectric devices.