Проблемы увеличения термоэлектрической эффективности поликристаллической керамики несоразмерных слоистых соединений на примере (Gd-=SUB=-x-=/SUB=-Dy-=SUB=-1-x-=/SUB=-S)-=SUB=-z-=/SUB=-NbS-=SUB=-2-=/SUB=-

Abstract

The lattice disorder of different architecture and dimensions influence on the thermoelectric properties (Seebeck coefficient S, resistivity , total thermal conductivity κtot, power factor S2/, figure of merit ZT) of the polycrystalline ternary sulfides MTS3 was studied. The high-temperature misfit layered compounds (MS)zNbS2 (MS is GdxDy1-xS solid solutions) were chosen as objects of the study. The variation of gadolinium concentration along the series x = 0.0, 0.1, 0.2, 0.5, 1.0 allowed one to alter the short-range and the long-range order of the crystal lattice and to study their effect on thermoelectric parameters of (GdxDy1-xS)zNbS2. At low concentration of x = 0.1 the crystallite size increases, cause the deformation stresses decrease and, thereby, leads to an abnormal changes of S, , κtot values and ZT decrease. An increase of the gadolinium concentration (x = 0.2–0.5) alters the electronic structure and the interatomic bonding character of the incommensurate subsystems (GdxDy1-xS) and NbS2. In this case, S and  values remains practically unaffected, while the thermal conductivity value decreases by 40% and ZT increases by 2 times. The nature of this phenomenon and the anisotropy of the thermoelectric properties were discussed.