Kirigami‐Based Stretchable, Deformable, Ultralight Thin‐Film Thermoelectric Generator for BodyNET Application

Abstract Thermoelectric generators (TEGs) as potential power supply have great prospects for wearable application. Nevertheless, difficulties in realizing deformability, ultralight weight, and high power density of TEGs at the same time has strongly frustrated their commercial applications to date. Herein, inspired by the art of kirigami, an innovative design to construct stretchable, deformable, ultralight 3D thin‐film TEG from a 2D structure by introducing rational kirigami cuts is proposed. Meanwhile, high‐performance inorganic thermoelectric films are compatibly introduced to the TEG without property degradation. In addition, the vertical heat flow is easily realized in the planar thin‐film TEG, which is beneficial for the establishment of large temperature differences. The fabricated ultralight kirigami‐based TEG (only 29 mg in weight), without an additional heat sink demonstrates the highest open voltage density of 6.712 V g⁻¹ with a maximum power density of 255.395 µW g⁻¹ at T_hot = 60 °C. Moreover, the TEG exhibits excellent compliance to extreme mechanical deformation and adaptability to variety surfaces. This work provides a new design concept for deformable TEGs with promising application in a broader set of BodyNET technology.