Demonstration of ultrahigh thermoelectric efficiency of ∼7.3% in Mg3Sb2/MgAgSb module for low-temperature energy harvesting

Zihang Liu, Naoki Sato, Weihong Gao, Kunio Yubuta, Naoyuki Kawamoto, Masanori Mitome, Keiji Kurashima, Yuka Owada, Kazuo Nagase, Chul Ho Lee, Jangho Yi, Koichi Tsuchiya, Takao Mori

Research output: Contribution to journalArticlepeer-review

209 Citations (Scopus)


Thermoelectric harvesting of low-temperature waste heat offers great opportunities for sustainable energy production. However, the investigations of related thermoelectric materials and modules remain sluggish. Here, we reported a great advance in the n-type Mg3Sb1.5Bi0.5 system by minor Cu additions. Some Cu atoms preferentially occupy interstitial sites within the Mg3Sb2 lattice and significantly modified phonon modes via filling in the phonon gap and increased anharmonic phonon scattering, thereby leading to the anomalously low thermal conductivity. Simultaneously, the detrimental behavior of thermally activated electrical conductivity was completely eliminated through grain-boundary complexion engineering. These two critical roles contributed to the remarkable improvement of zT. Based on this developed high-performance material coupled with p-type α-MgAgSb-based material, a fabricated thermoelectric module rivaling long-time champion Bi2Te3, demonstrated a record-high conversion efficiency ∼7.3% at the hot-side temperature of 593 K. These results pave the way for low-temperature thermoelectric harvesting.

Original languageEnglish
Pages (from-to)1196-1208
Number of pages13
Issue number5
Publication statusPublished - May 19 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Energy


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