Stretchable and Leakage‐Free Liquid Metal Networks for Thermal Management

Abstract Stretchable thermally conductive materials (TCMs) are highly desirable for efficient thermal management in wearable electronics. However, yielding stretchable TCMs that can simultaneously achieve superior thermal conductivity (TC) and high stretchability remains challenging owing to the contradiction between their thermal and mechanical behaviors. Herein, the design of a bi‐continuous structure that enables the creation of highly stretchable composites by incorporating liquid metal (LM) within a thermoplastic urethane (TPU) framework, is reported. The continuous TPU framework acts as a load‐bearing skeleton to ensure stretchability, while the LM forms 3D continuous thermal network, providing high‐speed channels for heat conduction. This innovative structure endows the resultant composite with a high out‐plane TC (4.16 W (m K) −1 ), outstanding stretchability (606%), and extremely stable TC, with a high retention of 92% at 100% strain and after 10 000 stretching‐releasing cycles. The stretchable composite also exhibits excellent leakage‐free behavior, without any LM leakage at a large strain of 400% and under a pressure of 500 kPa. These remarkable comprehensive properties make it a promising stretchable TCM for thermal management in wearable electronics.