The invention relates to a novel low-thermal-
conductivity argyrodite thermoelectric material and a preparation method thereof. A
chemical formula of the thermoelectric material is Ag9Ga1-XMx(Se1-YSy)6, wherein, M is one selected from Cr, Cd, Zn or Ge, 0< / =x< / =0.06, and 0< / =y< / =0.10; during preparation, a simple substance with the purity of more than 99.99% is used as a
raw material, and ingredients are weighed according to the stoichiometric ratio and placed in a sealed
quartz tube for vacuum packaging; a
muffle furnace is used for heating, so that the high-purity
raw material is subjected to a melt reaction at a high temperature and then to rapid quench cooling, to obtain a first
ingot; the first
ingot is vacuum packaged in the
quartz tube, and is subjected to high temperature annealing treatment and then to rapid quench cooling, to obtain a second
ingot; the second ingot is grinded into
powder which is placed in a
graphite mold, hot pressed
sintering is carried out throguh
induction heating and temperature rise in a vacuum
atmosphere, then
slow cooling is performed, and completing the preparation. Compared with the prior art, the thermoelectric material of the invention has the advantages of stable
mechanical property, very low
lattice thermal conductivity (0.2W / m K), and good application prospect.