Lamellar Nanoconfined Phase‐Change Material for Smart Multimodal Thermal Management and Long‐Term High‐Performance Triboelectric Nanogenerator

Multifunctional phase‐change materials (PCMs) exhibit broad application prospects in intelligent thermal management and energy utilization. This study innovatively reported a PCM composite featuring unique lamellar nanoconfined structure. The composites have achieved comprehensive thermal management performance, including active thermal management functions such as photo/Joule‐thermal conversion, infrared dynamic thermal stealth, and rapid thermal conduction. The composite demonstrates high PCM encapsulation capacity of up to 90%, along with an impressive enthalpy of 200.7 J g −1 and substantial tensile strength as high as 39.79 MPa. When employed as the positive electrode of the triboelectric nanogenerator, the composite exhibits an electrical output of 233 V and high output power density of 248.65 mW m − 2 . Remarkably, the open‐circuit voltage retains 88.7% of its initial value after 100,000 cycles, demonstrating superior cycling durability that surpasses the majority current studies. Following two‐month environmental adaptation period, the composites exhibit ultrafast response (84 ms) and recovery (70 ms) capabilities. When utilized as a self‐powered smart sensing interface, they enable the precise identification of diverse handwritten letter trajectories. This work not only establishes a new paradigm for designing the next generation of high‐performance shape‐stabilized PCM but also pioneers their revolutionary applications in self‐driven sensing, adaptive infrared thermal camouflage, and multifunctional energy management.