Year: 2025
Type: article
Abstract: Waste heat from industrial processes, vehicle exhaust, and electronic devices accounts for roughly two-thirds of all primary energy consumed worldwide, yet converting even a fraction of it into electricity remains an unsolved engineering problem. Thermoelectric materials based on bismuth telluride (Bi₂Te₃) offer a solid-state route to this conversion, but their figure of merit (ZT) has hovered near unity for decades. This research investigated the effect of nanostructuring on the thermoelectric performance of Bi₂Te₃ and two ternary variants—Bi₂Te₂.₇Se₀.₃ and Bi₁.₈Sb₀.₂Te₃—prepared by mechanical alloying followed by spark plasma sintering. Nanostructured pellets exhibited grain sizes of 28–45 nm confirmed by X-ray diffraction and transmission electron microscopy. Compared with their bulk counterparts, nanostructured samples showed 34–49% lower lattice thermal conductivity while retaining 82–89% of the electrical conductivity, resulting in ZT enhancements of 52–71%. The highest ZT of 1.56 was achieved for nanostructured Bi₁.₈Sb₀.₂Te₃ at 350 K. Seebeck coefficients increased by 12–16% in nanostructured specimens, attributed to energy filtering at grain boundaries. These results confirm that grain-size reduction below 50 nm is an effective strategy for pushing bismuth telluride performance beyond the conventional ceiling.
Authors: Daisuke Shimizu, Asami Shimizu
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W7154245615