Low lattice thermal conductivity and excellent thermoelectric behavior in Li3Sb and Li3Bi

Utilizing the first-principle calculations combined with Boltzmann transport equation and semiclassical analysis, we present a systematic investigation of the electron structure, lattice thermal conductivity , Seebeck coefficient S, and the dimensionless figure of merit ZT of crystal Li3Sb and Li3Bi. The of 2.2 and 2.09 W m−1 K−1 are obtained at room temperature in Li3Sb and Li3Bi systems with the band gap of eV, respectively. The low can induce excellent thermoelectric properties. Thus the effect of doping on the transport properties has been judiciously researched and the maximum ZT of 2.42, 1.54 is obtained at 900 K in the p-type doped Li3Sb and p-type doped Li3Bi with the stable structures. Up to date, experimental finding of the maximum ZT is 2.6 at 850 K in the Cu2Se sample with 1 mol indium, our results are very close to this value. This letter provides insight into the thermal transport properties of Li3Sb and Li3Bi, meanwhile, supports that crystalline Li3Sb and Li3Bi may be promising materials for thermoelectric devices and application.