# Computational Investigation of the Thermoelectric Performance of Environmentally Friendly and Earth-Abundant SrZn2S2O

## TL;DR

This paper explores SrZn2S2O as a promising, eco-friendly thermoelectric material that could help recover waste heat and improve energy efficiency.

## Contribution

The study introduces SrZn2S2O as a new environmentally friendly thermoelectric candidate with superior performance compared to existing materials.

## Key findings

- SrZn2S2O has a higher p-type power factor than BiCuSeO at 900 K.
- Nanostructuring reduces SrZn2S2O's thermal conductivity by over 40%.
- SrZn2S2O achieves maximum n-type and p-type ZT values of 0.65 and 0.77, respectively.

## 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, SrZn2S2O is considered a promising, environmentally friendly TE material.
In this study, the TE performance of SrZn2S2O was investigated based on density functional theory (DFT) and compared
with that of the prototypical mixed-anion oxide BiCuSeO. The calculated
results show that SrZn2S2O 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 SrZn2S2O 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 SrZn2S2O.