Effects of Li and Na intercalation on electronic, bonding and thermoelectric transport properties of MX2 (M = Ta; X = S or Se) dichalcogenides – Ab initio investigation

Abstract

Using the pseudo-potential method and semi-classical Boltzmann theory, electronic, chemical bonding and thermoelectric transport properties of sample and Li or Na intercalated Ta(S, Se)2 dichalcogenides have been reported. The chemical bonding is studied using the Quantum Theory of Atoms in Molecules (QTAIM). Then, the Seebeck coefficient, electrical resistivity, electrical conductivity, thermal conductivity and figure of merit have been calculated in the temperature range 100–700K. It was shown that the thermoelectric transport properties strongly depend on the Alkali metals doping and the two main structures 1T- or 2H- as well as the temperature. 2H-LiTaS2 have been selected as the best candidate for thermoelectrical applications with zT=1.1.