Modulating Solid‐Solution Solubility to Enhance Thermoelectric Performance and Maintain Structural Stability in Phase‐Transition Silver Chalcogenides

Abstract Silver chalcogenides exhibit exceptional transport properties but face structural instability at high temperatures, limiting their practical applications. Using Ag ₂ Te as a model, it is confirm that silver whisker growth above the phase transition renders Ag ₂ Te unsuitable for thermoelectric applications. Here, the whisker growth mechanism is investigated and propose an inhibition strategy, overcoming a major obstacle in using silver chalcogenides. The presence of highly mobile Ag and lattice strain cause by phase transition are two factors leading to the formation of silver whiskers. Adding a trace amount of Ga inhibits silver whisker growth by forming an immobile Ag‐Ga solid‐solution phase and optimizing thermoelectric performance simultaneously. Consequently, a single leg of Ga‐Ag ₂ Te achieves a conversion efficiency of 2.3% with a ΔT of 300 K and remains whisker‐free after high‐temperature testing. A thermally robust, high‐performance thermoelectric single leg based on liquid‐like silver chalcogenides is successfully developed.