Preparation and Thermoelectric Transport Properties of In-doping β-Zn_4Sb_3 Bulk Thermoelectric Materials

A series of In-doped β-Zn4Sb3-based materials with nominal compositions of Zn4Sb3-xInx(0-0.08,Δx=0.02) by substituting Sb with In were designed in the paper.The single-phase In-doped β-Zn4Sb3-based bulk materials with no cracks were prepared by the combination of vacuum melting,furnace cooling and spark plasma sintering techniques.The electrical and thermal transport properties of Zn4Sb3-xInx in the temperature range of 300-700 K indicate that the In substitution for Sb in Zn4Sb3 compound brought the remarkable enhancement in carrier concentration and electrical conductivity,the almost complete vanishing of instinct excitation under high temperature,and the significant reduction in the lattice thermal conductivity.The lattice thermal conductivity for x=0.04 and 0.08 samples is very low and only about 0.21 W/(m·K) at 700 K.All In-doped β-Zn4Sb3-based bulk materials had higher ZT values as compared to undoped β-Zn4Sb3 bulk material.A large ZT value of 1.13 has been achieved for Zn4Sb2.94In0.06 at 700 K that increased by 69%.