3D Soft Architectures for Stretchable Thermoelectric Wearables with Electrical Self‐Healing and Damage Tolerance

• Published in: Advanced materials (Weinheim) 2024-12, Vol.36 (49), p.e2407073-n/a
• Main Authors: Han, Youngshang, Tetik, Halil, Malakooti, Mohammad H.
• Format: Article
• Language: English
• Subjects: 3D printing; Batteries; Damage tolerance; Elastomers; Energy conversion; Healing; Heat sinks; liquid metal; Liquid metals; Room temperature; Scavenging; self‐healing; Semiconductors; Stretchability; stretchable electronics; Structural integrity; Thermal insulation; Thermal management; thermoelectric; Thermoelectric cooling; Thermoelectric generators; Three dimensional composites; Three dimensional printing
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202407073

Flexible thermoelectric devices (TEDs) exhibit adaptability to curved surfaces, holding significant potential for small‐scale power generation and thermal management. However, they often compromise stretchability, energy conversion, or robustness, thus limiting their applications. Here, the implementation of 3D soft architectures, multifunctional composites, self‐healing liquid metal conductors, and rigid semiconductors is introduced to overcome these challenges. These TEDs are extremely stretchable, functioning at strain levels as high as 230%. Their unique design, verified through multiphysics simulations, results in a considerably high power density of 115.4 µW cm⁻2 at a low‐temperature gradient of 10 °C. This is achieved through 3D printing multifunctional elastomers and examining the effects of three distinct thermal insulation infill ratios (0%, 12%, and 100%) on thermoelectric energy conversion and structural integrity. The engineered structure is lighter and effectively maintains the temperature gradient across the thermoelectric semiconductors, thereby resulting in higher output voltage and improved heating and cooling performance. Furthermore, these thermoelectric generators show remarkable damage tolerance, remaining fully functional even after multiple punctures and 2000 stretching cycles at 50% strain. When integrated with a 3D‐printed heatsink, they can power wearable sensors, charge batteries, and illuminate LEDs by scavenging body heat at room temperature, demonstrating their application as self‐sustainable electronics. 3D‐printed soft multifunctional composites enhance thermoelectric energy conversion by 70%. These stretchable thermoelectric generators exhibit exceptional structural robustness and damage tolerance, with 230% stretchability and functionality maintained even after being damaged by sharp objects and strained for thousands of cycles. Their 3D architecture also enables sufficient energy harvesting from body heat to power LEDs and wearable sensors at room temperature.