Abstract
Thermoelectric (TE) materials enable direct conversion between heat and electricity, allowing efficient recovery of waste heat, which accounts for nearly 50% of global energy consumption. Therefore, TE materials hold great potential for applications in waste heat recovery and sustainable energy technologies. Owing to the composition of earth-abundant and low-toxicity elements, as well as the presence of relatively heavy elements and mixed-anion characteristics, SrZn(2)S(2)O is considered a promising, environmentally friendly TE material. In this study, the TE performance of SrZn(2)S(2)O was investigated based on density functional theory (DFT) and compared with that of the prototypical mixed-anion oxide BiCuSeO. The calculated results show that SrZn(2)S(2)O exhibits a higher optimal average p-type power factor than that of BiCuSeO at 900 K, reaching 1150 μW m(-1) K(-2) compared with 770 μW m(-1) K(-2) for BiCuSeO. In addition, nanostructuring strategies can reduce the lattice thermal conductivity of SrZn(2)S(2)O by 40% or more in all crystallographic directions. This leads to a maximum n-type ZT value of 0.65 along the b direction and a maximum p-type ZT value of 0.77 along the c direction for SrZn(2)S(2)O.