A Wavy-Structured Highly Stretchable Thermoelectric Generator with Stable Energy Output and Self-Rescuing Capability

Abstract

Thermoelectric generators (TEGs) demonstrate great potential for flexible and wearable electronics due to the direct electrical energy harvested from waste heat. Good wearability requires high mechanical flexibility and preferable stretchability, while current TEGs are primarily developed with rigid or non-stretchable components, which do not conform well to human skin or accommodate human motions, thus hindering further applications. Herein, a wavy architecture was proposed to fabricate stretchable TEGs, wherein a stretchable and self-healable hydrogel was employed as a device substrate, and intrinsically flexible, high-performance thermoelectric (TE) films were attached to form wavy morphologies. The wavy-structured TEG could be stretched readily to 300%; in the meantime. It could sustain a stable energy output able to retain more than 90% TE performance, thus, outperforming most of the reported state-of-the-art TE materials and TEGs. It also demonstrated a desired device-level self-rescuing capability that originated from the effective self-healing of the hydrogel and the wavy structure of TE legs, thereby providing constant energy supply upon injuries or damages. This work offers a promising approach to the design of next-generation stretchable and wearable TEGs.