Elastic Thermoelectric Generators Illustrated in Constantan

ABSTRACT Functionalities of materials tightly relate to the atomic and electronic structures, the coupling between which through lattice and charge gives birth to thermoelectricity, enabling a direct heat‐electricity conversion. Booming wearable electronics nowadays urgently demand thermoelectric film generators as self‐powered units using body and environment heats, of which highly recoverable deformability and power are the core challenges. This indicates the great importance of elasticity since a plastic deformation otherwise actuates lattice slips to unsecure both thermoelectricity and recoverability. It is illustrated in this work texturization and dislocations for enhancing elasticity in cold‐rolled constantan foils, a metal thermoelectric enabling one of the highest power outputs near room temperature for deformable wearables. The device can work in a purely elastic region, to secure orders of magnitude improvement in recoverable bendability with an extraordinary specific power density, at a bending radius down to 5 mm fitting the curvature of an adult's little finger. This work delivers a strategy for bringing robust deformability to thermoelectricity for powering wearable electronics.