Enhanced Thermoelectric Performance of p‐Type Mg3Sb2 for Reliable and Low‐Cost all‐Mg3Sb2‐Based Thermoelectric Low‐Grade Heat Recovery. (7th December 2022)

• Record Type: Journal Article
• Authors: Liang, Zhongxin; Xu, Congcong; Song, Shaowei; Shi, Xin; Ren, Wuyang; Ren, Zhifeng
• Is Part Of: Advanced functional materials. Volume 33:Number 7(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-07
• Subjects: conversion efficiency -- low cost -- low‐grade heat recovery -- Mg 3Sb 2 -- thermoelectric unicouple; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202210016
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Bi2 Te3 ‐based devices have long dominated the commercial market for thermoelectric cooling applications, but their narrow operating temperature range and high cost have limited their possible applications for conversion of low‐grade heat into electric power. The recently developed n‐type Mg3 Sb2 ‐based compounds exhibit excellent transport properties across a wide temperature range, have low material costs, and are nontoxic, so it would be possible to substitute the conventional Bi2 Te3 module with a reliable and low‐cost all‐Mg3 Sb2 ‐based thermoelectric device if a good p‐type Mg3 Sb2 material can be obtained to match its n‐type counterpart. In this study, by comprehensively regulating the carrier concentration, carrier mobility, and lattice thermal conductivity, the thermoelectric performance of p‐type Mg3 Sb2 is significantly improved through Na and Yb doping in Mg1.8 Zn1.2 Sb2 . Moreover, p‐ and n‐type Mg3 Sb2 are similar in terms of their coefficients of thermal expansion and their good performance stability, thus allowing the construction of a reliable all‐Mg3 Sb2 ‐based unicouple. The decent conversion efficiency (≈5.5% at the hot‐side temperature of 573 K), good performance stability, and low cost of this unicouple effectively promote the practical application of Mg3 Sb2 ‐based thermoelectric generators for low‐grade heat recovery. Abstract : The thermoelectric performance of the p‐type Mg3 Sb2 ‐based compound is improved by fully optimizing its carrier concentration, mobility, and lattice thermal conductivity. As a result, a unicouple comprised of p‐type Mg1.594 Yb0.2 Na0.006 Zn1.2 Sb2 and n‐type Mg3.2 SbBi0.99 Te0.01 is successfully constructed, and exhibits high conversion efficiency, good stability, and low cost, showing its great potential for low‐grade heat recovery.