High thermoelectric properties realized in earth abundant Bi2S3 bulk materials via Se and Cl co-doping in solution synthesis process

Abstract

• Se and Cl co-doped nanostructured Bi 2 S 3 powders were successfully synthesized via hydrothermal. • A high σ value of 483 S cm −1 is obtained at 300 K for the Bi 2 S 2.4 Se 0.4 Cl 0.20 sample. • A high PFave. of 411 μW m −1 K −2 is achieved for the Bi 2 S 2.4 Se 0.4 Cl 0.20 . • The highest ZT value of 0.66 is achieved at 673 K for the Bi 2 S 2.4 Se 0.4 Cl 0.20 sample. Bi 2 S 3 -based alloys are considered promising thermoelectric materials due to their large Seebeck coefficient and low lattice thermal conductivity. However, low electrical conductivity usually leads to poor electrical transport properties, which seriously restricts their further application in thermoelectric refrigeration and/or power generation. In this work, Bi 2 S 3 with high electrical transport properties is synthesized hydrothermally via Se and Cl co-doping. The maximum electrical conductivity value of 483 S cm −1 was obtained for the Bi 2 S 2.4 Se 0.4 Cl 0.20 sample at room temperature. The significant improvement of electrical conductivity gives rise to a high average power factor of 411 μW m −1 K −2 during the measuring temperature range and a peak value of 456 μW m −1 K −2 at 673 K. Benefiting from the largely improved electrical transport properties, a superior ZT value of approximately 0.66 and ZT ave . of 0.36 were obtained for Bi 2 S 2.4 Se 0.4 Cl 0.20 , and the theoretically calculated conversion efficiency reached 5.7%. The results indicate that Bi 2 S 3 is a promising candidate for thermoelectric applications at medium temperatures. A high ZT value in Bi2S3 system of ∼0.66 was achieved at 673 K for Bi2S3 with Se and Cl co-doped through a facile hydrothermal followed by spark plasma sintering.