Recyclable Dry-Processed PTFE Composite Films for Passive Radiative Cooling With Interfacial Energy Harvesting

Passive radiative cooling (PRC) enables electricity-free sub-ambient cooling by emitting thermal radiation through atmospheric transparency windows. However, most high-performance PRC materials still rely on solution-based processing, which consumes solvents, releases volatile organic compounds (VOCs), and weakens their sustainability. Herein, we report a reprocessable dry-processing strategy that uses in situ polytetrafluoroethylene (PTFE) fibrillation to construct an entangled fibril-micro/nanoparticle entangled network. The resulting hierarchical photonic architecture with high solar reflectance (93.3%) and mid-infrared emissivity (91.1%), achieving an average sub-ambient cooling of 5.5-10.6°C at relative humidities of 28.7%-50.4%. In addition, the film exhibits excellent thermal stability (decomposition temperature > 500°C) and environmental durability (540 h of accelerated UV aging). To address the low utilization of PRC films in rainy conditions, the dielectric property of the film is easily exploited to construct solid-liquid triboelectric nanogenerator (TENG), with a peak power density of 89.85 W m^-2, for raindrop energy harvesting. Furthermore, the film maintains stable optical, cooling, and triboelectric performance after repeated recycling. This low-carbon recyclable strategy provides a scalable approach for all-weather energy management and sustainable green technologies.