Strong Anisotropic Thermal Conductivity In Polycrystalline Layers Of (Agxsn1-Xs)(1.2)(Tis2)(2) With Prospects Toward Improved Thermoelectric Performance

Anisotropic tuning is of crucial importance for designing and developing high-performance thermoelectric materials. Here, a prominent anisotropic thermoelectric characteristic of Ag-substituted misfit-layered (SnS)(1.2)(TiS2)(2) alloys is investigated in the perpendicular (in-plane) and parallel (out-of-plane) to the pressing direction. In the in-plane direction, the (AgxSn1-xS)(1.2)(TiS2)(2) alloys possess a highest power factor of 0.86 mW K-2 m(-1) at 520 K, while in the out-of-plane direction the lowest lattice thermal conductivity (0.37 W K-1 m(-1)) is achieved, which is driven by the natural intercalated structure where the out-of-plane phonon is strongly scattered without affecting the in-plane mobility. Moreover, along the in-plane orientation, the introduced point defects due to the substitution of Sn by Ag trigger a significant reduction of lattice thermal conductivity. In contrast, along the out-of-plane orientation, the decreased carrier concentration enables a large Seebeck coefficient and power factor, ultimately ensuring high thermoelectric performance. The present finding in the misfit-layered chalcogenide opens up a new route to manipulating thermoelectrics via anisotropy engineering.