High-Performance N-type Mg3Sb2 towards Thermoelectric Application near Room Temperature

Se-doped Mg3.2Sb1.5Bi0.5-based thermoelectric materials are revisited in this study. An increased ZT value approximate to 1.4 at about 723 K is obtained in Mg3.2Sb1.5Bi0.49Se0.01 with optimized carrier concentration approximate to 1.9 x 10(19) cm(-3). Based on this composition, Co and Mn are incorporated for the manipulation of the carrier scattering mechanism, which are beneficial to the dramatically enhanced electrical conductivity and power factor around room temperature range. Combined with the lowered lattice thermal conductivity due to the introduction of effective phonon scattering centers in Se&Mn-codoped sample, a highest room temperature ZT value approximate to 0.63 and a peak ZT value approximate to 1.70 at 623 K are achieved for Mg3.15Mn0.05Sb1.5Bi0.49Se0.01, leading to a high average ZT approximate to 1.33 from 323 to 673 K. In particular, a remarkable average ZT approximate to 1.18 between the temperature of 323 and 523 K is achieved, suggesting the competitive substitution for the commercialized n-type Bi2Te3-based thermoelectric materials.