High-Performance Thermoelectric Energy Conversion: A Tale of Atomic Ordering in AgSbTe₂

Abstract

The highly enhanced thermoelectric figure of merit, zT ≈ 2.6 at 573 K, obtained recently in Cd-doped polycrystalline AgSbTe2 by Roychowdhury et al. (Science2021371722) brings it to the forefront of thermoelectric and energy materials research. Ag/Sb cationic ordering in polycrystalline AgSbTe2 was a challenging issue for a long time: their ordered arrangement in the cationic sublattice in polycrystalline samples remained elusive despite multiple theoretical predictions and experimental studies. Recently, selective cation doping has been used to enhance the Ag/Sb ordering, and cation ordered nanoscale (2–4 nm) domains were observed in polycrystalline AgSbTe2, which reduce lattice thermal conductivity. The enhanced cation ordering also delocalizes disorder-induced localized electronic states, and consequently the electronic transport enhances. In this Focus Review, we provide the details of the rational design of a high-performance thermoelectric material using the recently developed atomic order–disorder optimization strategy with AgSbTe2 as an example. Atomic disorder is ubiquitous in most thermoelectric materials, and the atomic order–disorder optimization strategy applies to a large variety of thermoelectric materials.

Advances and Challenges of AgSbSe2‐based Thermoelectric Materials

“…The order‐disorder regulation offers great enhancement of thermoelectric performance of AgSbTe 2 , resulting in an astonishing high ZT of ∼2.6 at 573 K [33,82] . Considering the similarity between AgSbSe 2 and AgSbTe 2 , we suppose this strategy is applicable to AgSbSe 2 system as well.…”

Durable, stretchable and washable inorganic-based woven thermoelectric textiles for power generation and solid-state cooling

“…Bi 2 Te 3 -based TE materials), with a rigid and brittle nature, have been reconsidered to develop flexible TETs with high TE power generation and solid-state cooling. [12][13][14][15][16] For flexible TETs, it is of vital importance and more convenient to suppress rigidity by re-designing ISC based TETs in terms of the device configuration rather than by time-and-cost consuming material engineering. [17][18][19] Recently, two main strategies have been developed to realize flexibility.…”

Recent advances in designing thermoelectric materials

“…One of the most potential efforts in this direction is exploring the thermoelectric performance of AgSbTe 2 . 316,331,332 AgSbTe 2 is a well-known thermoelectric material with a rock-salt structure; however, the nature of the occupancy of Ag or Sb in cationic sites is relatively ambiguous. Additionally, pristine AgSbTe 2 exhibits two distinct disorders, such as the impurity phases of Ag 2 Te and Sb 2 Te 3 , and Ag or Sb cationic disorders.…”