An All-Weather Fabric Evaporator with Photonic-Electric-Thermal Conversion for Scalable and Efficient Solar Desalination

The development of efficient and sustainable solar-driven water evaporation systems is crucial for mitigating global water scarcity. However, the intermittent nature of solar radiation presents a major challenge for achieving continuous steam generation under all conditions. Most current fabrication methods for solar evaporators lack scalability, flexibility, and environmental compatibility. Herein, we present a scalable-fabricated solar evaporator with a gradient-heating design, constructed from PET/CNT/PDA/CNC@CuS composites for continuous steam generation. This device synergistically utilizes solar illumination and electrical heating, enabled by the strong broadband light absorption and excellent electrical conductivity imparted by a two-step spray-coating of carbon nanotubes (CNT) and CuS-decorated cellulose nanocrystals (CNC@CuS). Cellulose nanocrystals (CNC) are used to uniformly load commercial CuS powder onto CNT/PDA-coated PET fabric via electrostatic and hydrogen-bond interactions. Synergistic effect combining 1-sun illumination and 5 V input elevates the evaporation rate to 5.49 kg m–2 h–1, with temperature surpassing individual modes by 6.8 °C (light-only) and 4.2 °C (electricity-only). The evaporator demonstrates remarkable salt tolerance, maintaining 5.3 kg m–2 h–1 in 3.5 wt % NaCl (1-sun and 5 V) and 2.3 kg m–2 h–1 (only 5 V), with no performance decline over 7 days. Furthermore, the CNC@CuS coatings also impart intrinsic antibacterial and UV-shielding properties. This study provides a promising approach for environmentally friendly, efficient, and all-weather seawater desalination.