# Reduced Lattice Thermal Conductivity in Thermoelectric α‑MgAgSb via Sb2Te3 Powder Atomic Layer Deposition

## TL;DR

This paper shows how coating α-MgAgSb with Sb2Te3 using a special deposition technique reduces heat transfer, improving its thermoelectric performance.

## Contribution

The study introduces powder ALD for coating α-MgAgSb with Sb2Te3 to reduce lattice thermal conductivity.

## Key findings

- A 10% decrease in lattice thermal conductivity was observed with 20 cycles of Sb2Te3 coating.
- The coating did not affect the primary phase purity of α-MgAgSb.
- Nonoxide powder ALD coatings are effective in suppressing lattice thermal transport.

## Abstract

α-MgAgSb is
an environmentally friendly alternative
to traditional
tellurium-based thermoelectric materials for near room temperature
applications. In this study, we enhance the thermoelectric properties
of α-MgAgSb by introducing a secondary Sb2Te3 phase using powder atomic layer deposition (powder ALD),
with the aim to modify phonon scattering mechanisms and reduce the
lattice thermal conductivity. Powder ALD is a thin-film deposition
technique that allows for the deposition of self-limiting monolayers
on high aspect ratio surfaces, enabling the conformal coating of nanopowder
regardless of particle morphology. Sb2Te3 was
selected as the coating material due to its oxygen-free synthesis
route and its potential for good interfacial compatibility with the
α-MgAgSb powders. Our results reveal a 10% decrease in lattice
thermal conductivity of bulk α-MgAgSb as the powder ALD coating
thickness increases from pristine to 20 cycles of Sb2Te3, without affecting the primary phase purity. Our findings
highlight the effectiveness of nonoxide powder ALD coatings in suppressing
lattice thermal transport, offering a promising pathway for interface-engineered,
low-toxicity thermoelectric materials.