High thermoelectric cooling performance of n-type Mg ₃ Bi ₂ -based materials

TLDR

Thermoelectric materials exhibit a large Peltier effect, and Bi₂Te₃ alloys are the state‑of‑the‑art room‑temperature materials, but high cost due to expensive tellurium limits wider use. The study reports n‑type Mg₃Bi₂‑based materials achieving a peak figure of merit (ZT) of ~0.9 at 350 K, comparable to commercial Bi₂Te₃‑Se alloys but at lower cost. A cooling device using the Mg₃Bi₂ material and p‑type Bi₀.₅Sb₁.₅Te₃ achieved a temperature difference of ~91 K at a 350 K hot side, demonstrating the material’s promise for thermoelectric cooling.

Abstract

Thermoelectric materials have a large Peltier effect, making them attractive for solid-state cooling applications. Bismuth telluride (Bi2Te3)-based alloys have remained the state-of-the-art room-temperature materials for many decades. However, cost partially limited wider use of thermoelectric cooling devices because of the large amounts of expensive tellurium required. We report n-type magnesium bismuthide (Mg3Bi2)-based materials with a peak figure of merit (ZT) of ~0.9 at 350 kelvin, which is comparable to the commercial bismuth telluride selenide (Bi2Te3-x Se x ) but much cheaper. A cooling device made of our material and p-type bismuth antimony telluride (Bi0.5Sb1.5Te3) has produced a large temperature difference of ~91 kelvin at the hot-side temperature of 350 kelvin. n-type Mg3Bi2-based materials are promising for thermoelectric cooling applications.