Carbon Nanotube‐Based Multi‐Functional “Yin”‐“Yang” Film: Dual Applications in Solar Water Evaporation and Blue Energy Harvesting

ABSTRACT The ocean abounds with a wide variety of energy sources and resources. To achieve more efficient exploitation of these, it is of great significance to design and prepare multifunctional composite materials capable of collecting and utilizing ocean energy and resources. Inspired by the complementary “Yin”‐“Yang” philosophy in traditional Chinese thought, this paper designed and fabricated a multi‐functional “Yin”‐“Yang” film (silk fiber‐carbon nanotube (SC) film), based on carbon nanotubes and silk. The film, which features a distinct gradient structure, is constructed through a simple vacuum filtration process. The “Yang” side enriches carbon nanotubes, demonstrating excellent photothermal conversion capability and negative triboelectric potential. While the “Yin” side is enriched with silk, exhibiting superhydrophilicity and mechanical support. Under one‐sun illumination, the SC‐based evaporator achieves an evaporation rate of 1.74 kg·m −2 ·h −1 with a photothermal conversion efficiency of 82.6%. And, the SC‐based triboelectric nanogenerator outputs an open‐circuit voltage of 59.4 V and a short‐circuit current of 8.57 µA at 4 Hz and 75 N, with a maximum power output of 271 µW and excellent cycling stability. Furthermore, it demonstrates the application of SC films in seawater desalination and wave energy harvesting, showcasing broad potential for island water supply, marine environmental monitoring, and blue energy development.