Authors: Ruoyan Li, Shuai Han, Chunyu Zhang, Suyao Liu, Wen Yin, Yuanguang Xia, Pengfei Liu, Zhen‐Hua Ge, Dongyao Zhao, Bingchao Yang, Lulu Huang, Zhi Zhang, Yongsheng Zhang, Yuan Yu, Bangzhi Ge, Chongjian Zhou
Published: 2025-03-12
Source: Full article
AbstractAgSbTe2‐based compounds, the most promising near‐room‐temperature thermoelectric material, so far fail to deliver n‐type performance neither theoretically nor experimentally. Its intrinsic electron‐killer defects with very low formation energy prevent conventional n‐type doping. Herein, the first n‐type AgSbTe2 by building a supercompliant lattice, which is extremely soft with an n‐type doping efficiency far beyond the Hume–Rothery rule settled phase boundary, is reported. The overdosed supercompliant lattice gives Young's modulus lower than the 2D van der Waals crystals, globally softening the phonons. This results in a minimal sound velocity of 1950 m·s−1, which lies far below all AgSbTe2‐based compounds previously reported. The substantially softened phonons lead to a low κ of 0.27 W·m−1·K−1 that approaches the theoretical minimum. Accordingly, the n‐type Ag0.8Na0.3Sb0.6Bi0.4Te2 demonstrates a ZT value of ≈0.45 at the near‐room‐temperature range, which is the highest n‐type performance ever reported. This work unlocks the door for AgSbTe2 as an exceptional n‐type thermoelectric material.