Full-Heusler alloys with earth-abundant elements exhibit high mechanical strength and favorable electrical transport behavior, but their high intrinsic lattice thermal conductivity limits potential thermoelectric application. Here, the thermoelectric transport properties of Fe-based Full-Heusler Fe₂MAl (M = V, Nb, Ta) alloys are comprehensively investigated utilizing density functional theory. The results suggest that Fe₂NbAl exhibits exceptionally low lattice thermal conductivity due to low phonon velocities and weakly bound Nb atoms. In Fe₂NbAl, the underbonding of the Nb atoms leads large Grüneisen parameters and high anharmonic scattering rates of low-frequency acoustic phonon. Meanwhile, the high band degeneracy and large electrical conductivity lead to a maximum p-type power factor of 255.6 μW·K⁻²·cm⁻¹ at 900 K. The combination of low lattice thermal conductivity and favorable electrical transport properties leads a maximum p-type dimensionless figure of merit of 1.7. Our work indicates Fe₂NbAl, as a low-cost, environmentally friendly, is a potential high-performance p-type thermoelectric material.

含有地球丰富元素的全霍斯勒合金表现出高机械强度和良好的电传输行为，但其高固有晶格导热率限制了潜在的热电应用。在这里，利用密度泛函理论全面研究了铁基Full-Heusler Fe ₂ MAl (M = V, Nb, Ta)合金的热电输运性能。结果表明，由于低声子速度和弱结合的 Nb 原子，Fe ₂ NbAl 表现出极低的晶格热导率。在Fe ₂ NbAl中，Nb原子的欠键合导致了大的Grüneisen参数和低频声子的高非谐波散射率。同时，高能带简并性和大电导率导致在900 K时最大p型功率因数为255.6 μW·K ^-2 ·cm ^{-1 。}低晶格热导率和良好的电传输性能的结合导致最大p型功率因数-型无量纲品质因数为 1.7。我们的工作表明Fe ₂ NbAl作为一种低成本、环境友好的材料，是一种潜在的高性能p型热电材料。