Fluorine-free photothermal superhydrophobic composite coating for efficient anti-icing of wind turbine blades

Ice accretion severely compromises wind turbine efficiency. Herein, a fluorine-free photothermal superhydrophobic coating (FPSC) was fabricated via scalable spraying of MWCNTs-OH and TiN. The coating exhibited a water contact angle of 159.0 ± 2.5° and a low roll-off angle of 3.4 ± 0.3°, ensuring excellent water repellency and self-cleaning durability. Benefiting from the elevated nucleation energy barrier induced by its hierarchical micro/nanostructure, the FPSC significantly prolonged the droplet freezing process, achieving freezing times of 3907 ± 20 s, 1357 ± 15 s, 959 ± 13 s, and 731 ± 10 s at −5, −10, −15, and −20 °C, respectively. Furthermore, owing to strong solar absorption, the coating maintained stable performance over 40 photothermal cycles under 1 sun irradiation even after mud-contaminant removal, and melted frost and ice within 108 s and 255 s, respectively, under 1.5 sun irradiation. On a blade model, it achieved >99% initial anti-icing efficiency. Notably, a theoretical assessment accounting for environmental performance degradation indicates that the FPSC can recover approximately 487.3 h of annual operational downtime in Northeast China, corresponding to a recovery of 11.1% of annual energy production loss. Consequently, it is projected to contribute an additional 122.2 TWh generation gain by 2025. This scalable FPSC provides a robust, economically viable anti-icing solution.