Thermoelectric anisotropy and texture of intercalated TiS2

This study addresses the effect of anisotropy on the electrical and thermal properties of CuxTiS2 compounds. We show that the anisotropy of the electrical resistivity (ρcross-plane/ρin-plane > 1) tends to be reduced as the covalent character along c is increased with the Cu content. For all x values (x ≤ 0.1), the absolute value of S is always found to be higher in-plane than in the cross-plane direction due to band structure anisotropy, leading to higher in-plane power factor values. Interestingly, the κin-plane/κcross-plane thermal conductivity ratio, with values similar to the only data reported for TiS2 crystals, are always higher than ρcross-plane/ρin-plane. This anisotropy relation leads to equivalent zT values for the in-plane and cross-plane directions, reaching 0.35–0.5 at 800 K.