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 [Formula: see text], Seebeck coefficient S, and the dimensionless figure of merit ZT of crystal Li₃Sb and Li₃Bi. The [Formula: see text] 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 [Formula: see text] eV, respectively. The low [Formula: see text] 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.