Enhancing Recoverable Bendability of Ag2Te-Based Thermoelectrics by Elastic Strain Manipulation

Abstract

Inherent rigidity of high-performing inorganic thermoelectric materials constrains their potential applications as flexible power sources for the wearable electronics. Deformation within the elastic region ensures the reservation of a material's initial functionalities, motivating the current work to focus on the elasticity enhancement of Ag₂Te thermoelectric. Ag₂S-alloying results in an observable reduction in the modulus of Ag₂Te_1-xS_x alloys (x ≤ 0.3), which thereby enables not only a great increase in the elastic strain but also a significant plasticization of the alloys, allowing the plastic deformability by the rolling at a temperature of ≈120 °C. Such a plastic deformation-induced improvement in yield strength leads to a further improvement of the elastic strain up to 1.8%, corresponding to ≈200% enhancements as compared to pristine Ag₂Te (≈0.6%). Eventually, the multi-pass hot-rolled Ag₂Te_0.9S_0.1 film achieves a full recoverability in transport properties even after elastic bending within a tiny radius of ≈3 mm for 100 000 times and a power density as high as ≈25 W m⁻² in six-leg device. This work robustly demonstrates a universal strategy to advance the recoverable bendability of inorganic thermoelectric materials for flexible applications.